diff --git a/src/qweb/compiler.ts b/src/qweb/compiler.ts
index 8860b653..411d0742 100644
--- a/src/qweb/compiler.ts
+++ b/src/qweb/compiler.ts
@@ -274,7 +274,7 @@ export class QWebCompiler {
     // define blocks and utility functions
     this.addLine(`let { text, createBlock, list, multi, html, toggler, component } = bdom;`);
     this.addLine(
-      `let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;`
+      `let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;`
     );
     if (this.shouldDefineAssign) {
       this.addLine(`let assign = Object.assign;`);
@@ -308,6 +308,7 @@ export class QWebCompiler {
     }
     if (this.shouldProtectScope) {
       this.addLine(`  ctx = Object.create(ctx);`);
+      this.addLine(`  ctx[isBoundary] = 1`);
     }
     if (this.target.hasCache) {
       this.addLine(`  let cache = ctx.cache || {};`);
@@ -815,9 +816,9 @@ export class QWebCompiler {
 
   compileTCall(ast: ASTTCall, ctx: Context) {
     let { block, forceNewBlock } = ctx;
-    // this.hasTCall = true;
     if (ast.body) {
       this.addLine(`ctx = Object.create(ctx);`);
+      this.addLine(`ctx[isBoundary] = 1;`);
       const nextId = BlockDescription.nextBlockId;
       const subCtx: Context = createContext(ctx, { preventRoot: true });
       this.compileAST({ type: ASTType.Multi, content: ast.body }, subCtx);
@@ -883,7 +884,7 @@ export class QWebCompiler {
       } else {
         value = expr;
       }
-      this.addLine(`ctx[\`${ast.name}\`] = ${value};`);
+      this.addLine(`setContextValue(ctx, "${ast.name}", ${value});`);
     }
   }
 
diff --git a/src/qweb/inline_expressions.ts b/src/qweb/inline_expressions.ts
index 2474c414..24a533d8 100644
--- a/src/qweb/inline_expressions.ts
+++ b/src/qweb/inline_expressions.ts
@@ -25,9 +25,10 @@
 // Misc types, constants and helpers
 //------------------------------------------------------------------------------
 
-const RESERVED_WORDS = "true,false,NaN,null,undefined,debugger,console,window,in,instanceof,new,function,return,this,eval,void,Math,RegExp,Array,Object,Date".split(
-  ","
-);
+const RESERVED_WORDS =
+  "true,false,NaN,null,undefined,debugger,console,window,in,instanceof,new,function,return,this,eval,void,Math,RegExp,Array,Object,Date".split(
+    ","
+  );
 
 const WORD_REPLACEMENT: { [key: string]: string } = Object.assign(Object.create(null), {
   and: "&&",
diff --git a/src/qweb/template_helpers.ts b/src/qweb/template_helpers.ts
index 8c178974..2978969b 100644
--- a/src/qweb/template_helpers.ts
+++ b/src/qweb/template_helpers.ts
@@ -65,16 +65,34 @@ function prepareList(collection: any): [any[], any[], number, any[]] {
   const n = values.length;
   return [keys, values, n, new Array(n)];
 }
+
+const isBoundary = Symbol("isBoundary");
+
+function setContextValue(ctx: { [key: string]: any }, key: string, value: any): void {
+  const ctx0 = ctx;
+  while (!ctx.hasOwnProperty(key) && !ctx.hasOwnProperty(isBoundary)) {
+    const newCtx = ctx.__proto__;
+    if (!newCtx) {
+      ctx = ctx0;
+      break;
+    }
+    ctx = newCtx;
+  }
+  ctx[key] = value;
+}
+
 export const UTILS = {
   // elem,
   // setText,
   withDefault,
   zero: Symbol("zero"),
+  isBoundary,
   callSlot,
   capture,
   // toClassObj,
   withKey,
   prepareList,
+  setContextValue,
   shallowEqual,
 };
 
diff --git a/tests/components/__snapshots__/app.test.ts.snap b/tests/components/__snapshots__/app.test.ts.snap
index 03f8245d..e837bd88 100644
--- a/tests/components/__snapshots__/app.test.ts.snap
+++ b/tests/components/__snapshots__/app.test.ts.snap
@@ -4,7 +4,7 @@ exports[`app destroy remove the widget from the DOM 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div/>\`);
   
diff --git a/tests/components/__snapshots__/basics.test.ts.snap b/tests/components/__snapshots__/basics.test.ts.snap
index 327a35e6..4744b613 100644
--- a/tests/components/__snapshots__/basics.test.ts.snap
+++ b/tests/components/__snapshots__/basics.test.ts.snap
@@ -4,7 +4,7 @@ exports[`basics Multi root component 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block2 = createBlock(\`<span>1</span>\`);
   let block4 = createBlock(\`<span>2</span>\`);
@@ -22,7 +22,7 @@ exports[`basics a class component inside a class component, no external dom 1`]
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div>simple vnode</div>\`);
   
@@ -36,7 +36,7 @@ exports[`basics a class component inside a class component, no external dom 2`]
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`Child\`, {}, key + \`__1\`, node, ctx);
@@ -48,7 +48,7 @@ exports[`basics a component cannot be mounted in a detached node 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div/>\`);
   
@@ -62,7 +62,7 @@ exports[`basics a component inside a component 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div>simple vnode</div>\`);
   
@@ -76,7 +76,7 @@ exports[`basics a component inside a component 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
   
@@ -91,7 +91,7 @@ exports[`basics can be clicked on and updated 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/><button block-handler-1=\\"click\\">Inc</button></div>\`);
   
@@ -108,7 +108,7 @@ exports[`basics can handle empty props 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -123,7 +123,7 @@ exports[`basics can handle empty props 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -138,7 +138,7 @@ exports[`basics can mount a component with just some text 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return text(\`just text\`);
@@ -150,7 +150,7 @@ exports[`basics can mount a component with no text 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return text(\`\`);
@@ -162,7 +162,7 @@ exports[`basics can mount a simple component 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>simple vnode</span>\`);
   
@@ -176,7 +176,7 @@ exports[`basics can mount a simple component with multiple roots 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block2 = createBlock(\`<span/>\`);
   let block3 = createBlock(\`<div/>\`);
@@ -193,7 +193,7 @@ exports[`basics can mount a simple component with props 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -208,7 +208,7 @@ exports[`basics cannot mount on a documentFragment 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div>content</div>\`);
   
@@ -222,7 +222,7 @@ exports[`basics child can be updated 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return text(ctx['props'].value);
@@ -234,7 +234,7 @@ exports[`basics child can be updated 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`Child\`, {value: ctx['state'].counter}, key + \`__1\`, node, ctx);
@@ -246,7 +246,7 @@ exports[`basics class component with dynamic text 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>My value: <block-text-0/></span>\`);
   
@@ -261,7 +261,7 @@ exports[`basics class parent, class child component with props 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
@@ -276,7 +276,7 @@ exports[`basics class parent, class child component with props 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`Child\`, {value: 42}, key + \`__1\`, node, ctx);
@@ -288,7 +288,7 @@ exports[`basics component with dynamic content can be updated 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -303,7 +303,7 @@ exports[`basics do not remove previously rendered dom if not necessary 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div/>\`);
   
@@ -317,7 +317,7 @@ exports[`basics do not remove previously rendered dom if not necessary, variatio
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><h1>h1</h1><span><block-text-0/></span></div>\`);
   
@@ -370,7 +370,7 @@ exports[`basics has no el after creation 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>simple</span>\`);
   
@@ -384,7 +384,7 @@ exports[`basics higher order components parent and child 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div>a</div>\`);
   
@@ -398,7 +398,7 @@ exports[`basics higher order components parent and child 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>b</span>\`);
   
@@ -412,7 +412,7 @@ exports[`basics higher order components parent and child 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     let b2,b3;
@@ -430,7 +430,7 @@ exports[`basics higher order components parent and child 4`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`Child\`, {child: ctx['state'].child}, key + \`__1\`, node, ctx);
@@ -442,7 +442,7 @@ exports[`basics list of two sub components inside other nodes 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>asdf</span>\`);
   
@@ -456,7 +456,7 @@ exports[`basics list of two sub components inside other nodes 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block3 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
@@ -481,7 +481,7 @@ exports[`basics parent, child and grandchild 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div>hey</div>\`);
   
@@ -495,7 +495,7 @@ exports[`basics parent, child and grandchild 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`GrandChild\`, {}, key + \`__1\`, node, ctx);
@@ -507,7 +507,7 @@ exports[`basics parent, child and grandchild 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`Child\`, {}, key + \`__1\`, node, ctx);
@@ -519,7 +519,7 @@ exports[`basics props is set on root component 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>simple vnode</span>\`);
   
@@ -533,7 +533,7 @@ exports[`basics reconciliation alg is not confused in some specific situation 1`
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>child</span>\`);
   
@@ -547,7 +547,7 @@ exports[`basics reconciliation alg is not confused in some specific situation 2`
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
   
@@ -563,7 +563,7 @@ exports[`basics rerendering a widget with a sub widget 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/><button block-handler-1=\\"click\\">Inc</button></div>\`);
   
@@ -580,7 +580,7 @@ exports[`basics rerendering a widget with a sub widget 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`Counter\`, {}, key + \`__1\`, node, ctx);
@@ -592,7 +592,7 @@ exports[`basics same t-keys in two different places 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -607,7 +607,7 @@ exports[`basics same t-keys in two different places 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><div><block-child-0/></div><div><block-child-1/></div></div>\`);
   
@@ -623,7 +623,7 @@ exports[`basics simple component with a dynamic text 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
@@ -638,7 +638,7 @@ exports[`basics simple component, useState 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
@@ -653,7 +653,7 @@ exports[`basics some simple sanity checks (el/status) 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>simple vnode</span>\`);
   
@@ -667,7 +667,7 @@ exports[`basics sub components between t-ifs 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>child</span>\`);
   
@@ -681,7 +681,7 @@ exports[`basics sub components between t-ifs 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/><span><block-child-2/></span><block-child-3/></div>\`);
   let block2 = createBlock(\`<h1>hey</h1>\`);
@@ -708,7 +708,7 @@ exports[`basics t-elif works with t-component 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>hey</span>\`);
   
@@ -722,7 +722,7 @@ exports[`basics t-elif works with t-component 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
   let block2 = createBlock(\`<div>somediv</div>\`);
@@ -743,7 +743,7 @@ exports[`basics t-else with empty string works with t-component 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>hey</span>\`);
   
@@ -757,7 +757,7 @@ exports[`basics t-else with empty string works with t-component 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
   let block2 = createBlock(\`<div>somediv</div>\`);
@@ -778,7 +778,7 @@ exports[`basics t-else works with t-component 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>hey</span>\`);
   
@@ -792,7 +792,7 @@ exports[`basics t-else works with t-component 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
   let block2 = createBlock(\`<div>somediv</div>\`);
@@ -813,7 +813,7 @@ exports[`basics t-if works with t-component 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>hey</span>\`);
   
@@ -827,7 +827,7 @@ exports[`basics t-if works with t-component 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -845,7 +845,7 @@ exports[`basics t-key on a component with t-if, and a sibling component 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>child</span>\`);
   
@@ -859,7 +859,7 @@ exports[`basics t-key on a component with t-if, and a sibling component 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
   
@@ -878,7 +878,7 @@ exports[`basics text after a conditional component 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<p>simple vnode</p>\`);
   
@@ -892,7 +892,7 @@ exports[`basics text after a conditional component 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><span><block-text-0/></span></div>\`);
   
@@ -911,7 +911,7 @@ exports[`basics three level of components with collapsing root nodes 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div>2</div>\`);
   
@@ -925,7 +925,7 @@ exports[`basics three level of components with collapsing root nodes 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`GrandChild\`, {}, key + \`__1\`, node, ctx);
@@ -937,7 +937,7 @@ exports[`basics three level of components with collapsing root nodes 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`Child\`, {}, key + \`__1\`, node, ctx);
@@ -949,7 +949,7 @@ exports[`basics throws if mounting on target=null 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>simple vnode</span>\`);
   
@@ -963,7 +963,7 @@ exports[`basics two child components 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div>simple vnode</div>\`);
   
@@ -977,7 +977,7 @@ exports[`basics two child components 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     let b2 = component(\`Child\`, {}, key + \`__1\`, node, ctx);
@@ -991,7 +991,7 @@ exports[`basics updating a component with t-foreach as root 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
@@ -1010,7 +1010,7 @@ exports[`basics widget after a t-foreach 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div/>\`);
   
@@ -1024,7 +1024,7 @@ exports[`basics widget after a t-foreach 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
   
@@ -1049,7 +1049,7 @@ exports[`basics zero or one child components 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div>simple vnode</div>\`);
   
@@ -1063,7 +1063,7 @@ exports[`basics zero or one child components 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     let b2;
diff --git a/tests/components/__snapshots__/concurrency.test.ts.snap b/tests/components/__snapshots__/concurrency.test.ts.snap
index f2fabfde..dc991183 100644
--- a/tests/components/__snapshots__/concurrency.test.ts.snap
+++ b/tests/components/__snapshots__/concurrency.test.ts.snap
@@ -4,7 +4,7 @@ exports[`async rendering destroying a widget before start is over 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div/>\`);
   
@@ -18,7 +18,7 @@ exports[`calling render in destroy 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, inTCall, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
@@ -57,7 +57,7 @@ exports[`change state and call manually render: no unnecessary rendering 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
@@ -72,7 +72,7 @@ exports[`changing state before first render does not trigger a render (with pare
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
@@ -87,7 +87,7 @@ exports[`changing state before first render does not trigger a render (with pare
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -105,7 +105,7 @@ exports[`changing state before first render does not trigger a render 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
@@ -120,7 +120,7 @@ exports[`concurrent renderings scenario 1 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/><block-text-1/></span>\`);
   
@@ -136,7 +136,7 @@ exports[`concurrent renderings scenario 1 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<p><block-child-0/></p>\`);
   
@@ -151,7 +151,7 @@ exports[`concurrent renderings scenario 1 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -166,7 +166,7 @@ exports[`concurrent renderings scenario 2 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/><block-text-1/></span>\`);
   
@@ -182,7 +182,7 @@ exports[`concurrent renderings scenario 2 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<p><block-child-0/></p>\`);
   
@@ -197,7 +197,7 @@ exports[`concurrent renderings scenario 2 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/><block-child-0/></div>\`);
   
@@ -213,7 +213,7 @@ exports[`concurrent renderings scenario 2bis 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/><block-text-1/></span>\`);
   
@@ -229,7 +229,7 @@ exports[`concurrent renderings scenario 2bis 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<p><block-child-0/></p>\`);
   
@@ -244,7 +244,7 @@ exports[`concurrent renderings scenario 2bis 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -259,7 +259,7 @@ exports[`concurrent renderings scenario 3 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<i><block-text-0/><block-text-1/></i>\`);
   
@@ -275,7 +275,7 @@ exports[`concurrent renderings scenario 3 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
   
@@ -290,7 +290,7 @@ exports[`concurrent renderings scenario 3 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<p><block-child-0/></p>\`);
   
@@ -305,7 +305,7 @@ exports[`concurrent renderings scenario 3 4`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -320,7 +320,7 @@ exports[`concurrent renderings scenario 4 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<i><block-text-0/><block-text-1/></i>\`);
   
@@ -336,7 +336,7 @@ exports[`concurrent renderings scenario 4 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
   
@@ -351,7 +351,7 @@ exports[`concurrent renderings scenario 4 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<p><block-child-0/></p>\`);
   
@@ -366,7 +366,7 @@ exports[`concurrent renderings scenario 4 4`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -381,7 +381,7 @@ exports[`concurrent renderings scenario 5 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<p><block-text-0/></p>\`);
   
@@ -396,7 +396,7 @@ exports[`concurrent renderings scenario 5 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -411,7 +411,7 @@ exports[`concurrent renderings scenario 6 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<p><block-text-0/></p>\`);
   
@@ -426,7 +426,7 @@ exports[`concurrent renderings scenario 6 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -441,7 +441,7 @@ exports[`concurrent renderings scenario 7 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<p><block-text-0/><block-text-1/></p>\`);
   
@@ -457,7 +457,7 @@ exports[`concurrent renderings scenario 7 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -472,7 +472,7 @@ exports[`concurrent renderings scenario 8 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<p><block-text-0/><block-text-1/></p>\`);
   
@@ -488,7 +488,7 @@ exports[`concurrent renderings scenario 8 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -503,7 +503,7 @@ exports[`concurrent renderings scenario 9 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/><block-text-1/></span>\`);
   
@@ -519,7 +519,7 @@ exports[`concurrent renderings scenario 9 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<p><block-child-0/></p>\`);
   
@@ -534,7 +534,7 @@ exports[`concurrent renderings scenario 9 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<b><block-text-0/></b>\`);
   
@@ -549,7 +549,7 @@ exports[`concurrent renderings scenario 9 4`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/><block-child-0/><block-child-1/></div>\`);
   
@@ -566,7 +566,7 @@ exports[`concurrent renderings scenario 10 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -581,7 +581,7 @@ exports[`concurrent renderings scenario 10 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<p><block-child-0/></p>\`);
   
@@ -599,7 +599,7 @@ exports[`concurrent renderings scenario 10 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -614,7 +614,7 @@ exports[`concurrent renderings scenario 11 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/>|<block-text-1/></span>\`);
   
@@ -630,7 +630,7 @@ exports[`concurrent renderings scenario 11 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -645,7 +645,7 @@ exports[`concurrent renderings scenario 12 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -660,7 +660,7 @@ exports[`concurrent renderings scenario 12 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -675,7 +675,7 @@ exports[`concurrent renderings scenario 13 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -690,7 +690,7 @@ exports[`concurrent renderings scenario 13 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
   
@@ -709,7 +709,7 @@ exports[`concurrent renderings scenario 14 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<p><span><block-text-0/></span><span><block-text-1/></span><span><block-text-2/></span></p>\`);
   
@@ -726,7 +726,7 @@ exports[`concurrent renderings scenario 14 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<p><block-child-0/></p>\`);
   
@@ -741,7 +741,7 @@ exports[`concurrent renderings scenario 14 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<p><block-child-0/></p>\`);
   
@@ -756,7 +756,7 @@ exports[`concurrent renderings scenario 15 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<p><span><block-text-0/></span><span><block-text-1/></span><span><block-text-2/></span></p>\`);
   
@@ -773,7 +773,7 @@ exports[`concurrent renderings scenario 15 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<p><block-child-0/></p>\`);
   
@@ -788,7 +788,7 @@ exports[`concurrent renderings scenario 15 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<p><block-child-0/></p>\`);
   
@@ -803,7 +803,7 @@ exports[`concurrent renderings scenario 16 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<ul>DDD</ul>\`);
   
@@ -817,7 +817,7 @@ exports[`concurrent renderings scenario 16 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<p><span><block-text-0/></span><span><block-text-1/></span><span><block-text-2/></span><block-child-0/></p>\`);
   
@@ -838,7 +838,7 @@ exports[`concurrent renderings scenario 16 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<p><block-child-0/></p>\`);
   
@@ -853,7 +853,7 @@ exports[`concurrent renderings scenario 16 4`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<p><block-child-0/></p>\`);
   
@@ -868,7 +868,7 @@ exports[`creating two async components, scenario 1 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -883,7 +883,7 @@ exports[`creating two async components, scenario 1 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>b</span>\`);
   
@@ -897,7 +897,7 @@ exports[`creating two async components, scenario 1 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     let b2,b3;
@@ -916,7 +916,7 @@ exports[`creating two async components, scenario 2 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>a<block-text-0/></span>\`);
   
@@ -931,7 +931,7 @@ exports[`creating two async components, scenario 2 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>b<block-text-0/></span>\`);
   
@@ -946,7 +946,7 @@ exports[`creating two async components, scenario 2 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
   
@@ -965,7 +965,7 @@ exports[`creating two async components, scenario 3 (patching in the same frame)
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>a<block-text-0/></span>\`);
   
@@ -980,7 +980,7 @@ exports[`creating two async components, scenario 3 (patching in the same frame)
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>b<block-text-0/></span>\`);
   
@@ -995,7 +995,7 @@ exports[`creating two async components, scenario 3 (patching in the same frame)
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
   
@@ -1014,7 +1014,7 @@ exports[`destroying/recreating a subwidget with different props (if start is not
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>child:<block-text-0/></span>\`);
   
@@ -1029,7 +1029,7 @@ exports[`destroying/recreating a subwidget with different props (if start is not
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -1047,7 +1047,7 @@ exports[`properly behave when destroyed/unmounted while rendering  1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div/>\`);
   
@@ -1061,7 +1061,7 @@ exports[`properly behave when destroyed/unmounted while rendering  2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -1076,7 +1076,7 @@ exports[`properly behave when destroyed/unmounted while rendering  3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -1094,7 +1094,7 @@ exports[`render method wait until rendering is done 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
@@ -1109,7 +1109,7 @@ exports[`rendering component again in next microtick 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div>Child</div>\`);
   
@@ -1123,7 +1123,7 @@ exports[`rendering component again in next microtick 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><button block-handler-0=\\"click\\">Click</button><block-child-0/></div>\`);
   
@@ -1142,7 +1142,7 @@ exports[`two renderings initiated between willPatch and patched 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<abc><block-text-0/></abc>\`);
   
@@ -1157,7 +1157,7 @@ exports[`two renderings initiated between willPatch and patched 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -1175,7 +1175,7 @@ exports[`update a sub-component twice in the same frame 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -1190,7 +1190,7 @@ exports[`update a sub-component twice in the same frame 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -1205,7 +1205,7 @@ exports[`update a sub-component twice in the same frame, 2 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -1220,7 +1220,7 @@ exports[`update a sub-component twice in the same frame, 2 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
diff --git a/tests/components/__snapshots__/error_handling.test.ts.snap b/tests/components/__snapshots__/error_handling.test.ts.snap
index f39ed6f7..d27afa38 100644
--- a/tests/components/__snapshots__/error_handling.test.ts.snap
+++ b/tests/components/__snapshots__/error_handling.test.ts.snap
@@ -4,7 +4,7 @@ exports[`basics no component catching error lead to full app destruction 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div>hey<block-text-0/></div>\`);
   
@@ -19,7 +19,7 @@ exports[`basics no component catching error lead to full app destruction 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
diff --git a/tests/components/__snapshots__/event_handling.test.ts.snap b/tests/components/__snapshots__/event_handling.test.ts.snap
index f4fdcc0d..c23d9860 100644
--- a/tests/components/__snapshots__/event_handling.test.ts.snap
+++ b/tests/components/__snapshots__/event_handling.test.ts.snap
@@ -4,7 +4,7 @@ exports[`event handling can set handler on sub component 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div>simple vnode</div>\`);
   
@@ -18,7 +18,7 @@ exports[`event handling can set handler on sub component 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   return function template(ctx, node, key = \\"\\") {
@@ -34,7 +34,7 @@ exports[`event handling handler receive the event as argument 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div>simple vnode</div>\`);
   
@@ -48,7 +48,7 @@ exports[`event handling handler receive the event as argument 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   return function template(ctx, node, key = \\"\\") {
@@ -64,7 +64,7 @@ exports[`event handling support for callable expression in event handler 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/><input type=\\"text\\" block-handler-1=\\"input\\"/></div>\`);
   
diff --git a/tests/components/__snapshots__/higher_order_component.test.ts.snap b/tests/components/__snapshots__/higher_order_component.test.ts.snap
index 64ad0d18..ee4c3a7f 100644
--- a/tests/components/__snapshots__/higher_order_component.test.ts.snap
+++ b/tests/components/__snapshots__/higher_order_component.test.ts.snap
@@ -4,7 +4,7 @@ exports[`basics basic use 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>child<block-text-0/></span>\`);
   
@@ -19,7 +19,7 @@ exports[`basics basic use 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`Child\`, {p: 1}, key + \`__1\`, node, ctx);
@@ -31,7 +31,7 @@ exports[`basics can select a sub widget  1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>CHILD 1</span>\`);
   
@@ -45,7 +45,7 @@ exports[`basics can select a sub widget  2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div>CHILD 2</div>\`);
   
@@ -59,7 +59,7 @@ exports[`basics can select a sub widget  3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     let b2,b3;
@@ -78,7 +78,7 @@ exports[`basics can select a sub widget, part 2 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>CHILD 1</span>\`);
   
@@ -92,7 +92,7 @@ exports[`basics can select a sub widget, part 2 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div>CHILD 2</div>\`);
   
@@ -106,7 +106,7 @@ exports[`basics can select a sub widget, part 2 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     let b2,b3;
@@ -125,7 +125,7 @@ exports[`basics sub widget is interactive 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><button block-handler-0=\\"click\\">click</button>child<block-text-1/></span>\`);
   
@@ -141,7 +141,7 @@ exports[`basics sub widget is interactive 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`Child\`, {p: 1}, key + \`__1\`, node, ctx);
@@ -153,7 +153,7 @@ exports[`basics top level sub widget with a parent 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>Hello</span>\`);
   
@@ -167,7 +167,7 @@ exports[`basics top level sub widget with a parent 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`ComponentC\`, {}, key + \`__1\`, node, ctx);
@@ -179,7 +179,7 @@ exports[`basics top level sub widget with a parent 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
diff --git a/tests/components/__snapshots__/lifecycle.test.ts.snap b/tests/components/__snapshots__/lifecycle.test.ts.snap
index 18adf0c3..ec6b0f90 100644
--- a/tests/components/__snapshots__/lifecycle.test.ts.snap
+++ b/tests/components/__snapshots__/lifecycle.test.ts.snap
@@ -4,7 +4,7 @@ exports[`lifecycle hooks basic checks for a component 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>test</span>\`);
   
@@ -18,7 +18,7 @@ exports[`lifecycle hooks components are unmounted and destroyed if no longer in
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div/>\`);
   
@@ -32,7 +32,7 @@ exports[`lifecycle hooks components are unmounted and destroyed if no longer in
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     let b2;
@@ -48,7 +48,7 @@ exports[`lifecycle hooks components are unmounted and destroyed if no longer in
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -63,7 +63,7 @@ exports[`lifecycle hooks components are unmounted and destroyed if no longer in
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block2 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -82,7 +82,7 @@ exports[`lifecycle hooks hooks are called in proper order in widget creation/des
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div/>\`);
   
@@ -96,7 +96,7 @@ exports[`lifecycle hooks hooks are called in proper order in widget creation/des
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -111,7 +111,7 @@ exports[`lifecycle hooks lifecycle semantics 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div/>\`);
   
@@ -125,7 +125,7 @@ exports[`lifecycle hooks lifecycle semantics 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -140,7 +140,7 @@ exports[`lifecycle hooks lifecycle semantics, part 2 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div/>\`);
   
@@ -154,7 +154,7 @@ exports[`lifecycle hooks lifecycle semantics, part 2 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`GrandChild\`, {}, key + \`__1\`, node, ctx);
@@ -166,7 +166,7 @@ exports[`lifecycle hooks lifecycle semantics, part 2 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     let b2;
@@ -182,7 +182,7 @@ exports[`lifecycle hooks lifecycle semantics, part 3 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div/>\`);
   
@@ -196,7 +196,7 @@ exports[`lifecycle hooks lifecycle semantics, part 3 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`GrandChild\`, {}, key + \`__1\`, node, ctx);
@@ -208,7 +208,7 @@ exports[`lifecycle hooks lifecycle semantics, part 3 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     let b2;
@@ -224,7 +224,7 @@ exports[`lifecycle hooks lifecycle semantics, part 4 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div/>\`);
   
@@ -238,7 +238,7 @@ exports[`lifecycle hooks lifecycle semantics, part 4 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`GrandChild\`, {}, key + \`__1\`, node, ctx);
@@ -250,7 +250,7 @@ exports[`lifecycle hooks lifecycle semantics, part 4 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     let b2;
@@ -266,7 +266,7 @@ exports[`lifecycle hooks lifecycle semantics, part 5 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div/>\`);
   
@@ -280,7 +280,7 @@ exports[`lifecycle hooks lifecycle semantics, part 5 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     let b2;
@@ -296,7 +296,7 @@ exports[`lifecycle hooks lifecycle semantics, part 6 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div/>\`);
   
@@ -310,7 +310,7 @@ exports[`lifecycle hooks lifecycle semantics, part 6 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`Child\`, {value: ctx['state'].value}, key + \`__1\`, node, ctx);
@@ -322,7 +322,7 @@ exports[`lifecycle hooks mounted hook is called if mounted in DOM 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div/>\`);
   
@@ -336,7 +336,7 @@ exports[`lifecycle hooks mounted hook is called on subcomponents, in proper orde
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div/>\`);
   
@@ -350,7 +350,7 @@ exports[`lifecycle hooks mounted hook is called on subcomponents, in proper orde
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -365,7 +365,7 @@ exports[`lifecycle hooks mounted hook is called on subsubcomponents, in proper o
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div/>\`);
   
@@ -379,7 +379,7 @@ exports[`lifecycle hooks mounted hook is called on subsubcomponents, in proper o
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -394,7 +394,7 @@ exports[`lifecycle hooks mounted hook is called on subsubcomponents, in proper o
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -412,7 +412,7 @@ exports[`lifecycle hooks onRender 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<button block-handler-0=\\"click\\"><block-text-1/></button>\`);
   
@@ -428,7 +428,7 @@ exports[`lifecycle hooks onRender 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`Child\`, {}, key + \`__1\`, node, ctx);
@@ -440,7 +440,7 @@ exports[`lifecycle hooks patched hook is called after updateProps 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div/>\`);
   
@@ -454,7 +454,7 @@ exports[`lifecycle hooks patched hook is called after updateProps 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -469,7 +469,7 @@ exports[`lifecycle hooks patched hook is called after updating State 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div/>\`);
   
@@ -483,7 +483,7 @@ exports[`lifecycle hooks sub widget (inside sub node): hooks are correctly calle
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div/>\`);
   
@@ -497,7 +497,7 @@ exports[`lifecycle hooks sub widget (inside sub node): hooks are correctly calle
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     let b2;
@@ -513,7 +513,7 @@ exports[`lifecycle hooks willPatch, patched hook are called on subsubcomponents,
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
@@ -528,7 +528,7 @@ exports[`lifecycle hooks willPatch, patched hook are called on subsubcomponents,
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -543,7 +543,7 @@ exports[`lifecycle hooks willPatch, patched hook are called on subsubcomponents,
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -558,7 +558,7 @@ exports[`lifecycle hooks willStart hook is called on sub component 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div/>\`);
   
@@ -572,7 +572,7 @@ exports[`lifecycle hooks willStart hook is called on sub component 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`Child\`, {}, key + \`__1\`, node, ctx);
@@ -584,7 +584,7 @@ exports[`lifecycle hooks willStart is called 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>simple vnode</span>\`);
   
@@ -598,7 +598,7 @@ exports[`lifecycle hooks willStart is called with component as this 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>simple vnode</span>\`);
   
@@ -612,7 +612,7 @@ exports[`lifecycle hooks willStart, mounted on subwidget rendered after main is
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div/>\`);
   
@@ -626,7 +626,7 @@ exports[`lifecycle hooks willStart, mounted on subwidget rendered after main is
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
   let block3 = createBlock(\`<div/>\`);
@@ -647,7 +647,7 @@ exports[`lifecycle hooks willUpdateProps hook is called 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -662,7 +662,7 @@ exports[`lifecycle hooks willUpdateProps hook is called 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`Child\`, {n: ctx['state'].n}, key + \`__1\`, node, ctx);
diff --git a/tests/components/__snapshots__/props.test.ts.snap b/tests/components/__snapshots__/props.test.ts.snap
index ea2de893..380cf7ee 100644
--- a/tests/components/__snapshots__/props.test.ts.snap
+++ b/tests/components/__snapshots__/props.test.ts.snap
@@ -4,7 +4,7 @@ exports[`basics accept ES6-like syntax for props (with getters) 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -19,7 +19,7 @@ exports[`basics accept ES6-like syntax for props (with getters) 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -34,7 +34,7 @@ exports[`basics explicit object prop 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -49,7 +49,7 @@ exports[`basics explicit object prop 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -64,7 +64,7 @@ exports[`basics t-set with a body expression can be passed in props, and then t-
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/><block-child-0/></span>\`);
   
@@ -80,13 +80,14 @@ exports[`basics t-set with a body expression can be passed in props, and then t-
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block2 = createBlock(\`<p>43</p>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
     let b2 = block2();
     ctx[\`abc\`] = b2;
     let b3 = component(\`Child\`, {val: ctx['abc']}, key + \`__1\`, node, ctx);
@@ -99,7 +100,7 @@ exports[`basics t-set with a body expression can be used as textual prop 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -114,13 +115,14 @@ exports[`basics t-set with a body expression can be used as textual prop 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
-    ctx[\`abc\`] = \`42\`;
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"abc\\", \`42\`);
     let b2 = component(\`Child\`, {val: ctx['abc']}, key + \`__1\`, node, ctx);
     return block1([], [b2]);
   }
@@ -131,7 +133,7 @@ exports[`basics t-set works  1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -146,13 +148,14 @@ exports[`basics t-set works  2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
-    ctx[\`val\`] = 42;
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"val\\", 42);
     let b2 = component(\`Child\`, {val: ctx['val']}, key + \`__1\`, node, ctx);
     return block1([], [b2]);
   }
diff --git a/tests/components/__snapshots__/refs.test.ts.snap b/tests/components/__snapshots__/refs.test.ts.snap
index fd0d90e4..8b1e0e7d 100644
--- a/tests/components/__snapshots__/refs.test.ts.snap
+++ b/tests/components/__snapshots__/refs.test.ts.snap
@@ -4,7 +4,7 @@ exports[`refs refs are properly bound in slots 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
   
@@ -19,7 +19,7 @@ exports[`refs refs are properly bound in slots 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><span class=\\"counter\\"><block-text-0/></span><block-child-0/></div>\`);
diff --git a/tests/components/__snapshots__/slots.test.ts.snap b/tests/components/__snapshots__/slots.test.ts.snap
index 6992085b..1268f9fa 100644
--- a/tests/components/__snapshots__/slots.test.ts.snap
+++ b/tests/components/__snapshots__/slots.test.ts.snap
@@ -4,7 +4,7 @@ exports[`slots can define and call slots 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><div><block-child-0/></div><div><block-child-1/></div></div>\`);
   
@@ -20,7 +20,7 @@ exports[`slots can define and call slots 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -47,7 +47,7 @@ exports[`slots content is the default slot (variation) 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return callSlot(ctx, node, key, 'default');
@@ -59,7 +59,7 @@ exports[`slots content is the default slot (variation) 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<span>sts rocks</span>\`);
@@ -78,7 +78,7 @@ exports[`slots content is the default slot 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -93,7 +93,7 @@ exports[`slots content is the default slot 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -114,7 +114,7 @@ exports[`slots dafault slots can define a default content 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
   
@@ -133,7 +133,7 @@ exports[`slots dafault slots can define a default content 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -148,7 +148,7 @@ exports[`slots default content is not rendered if named slot is provided 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
   
@@ -167,7 +167,7 @@ exports[`slots default content is not rendered if named slot is provided 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -188,7 +188,7 @@ exports[`slots default content is not rendered if slot is provided 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
   
@@ -207,7 +207,7 @@ exports[`slots default content is not rendered if slot is provided 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -227,7 +227,7 @@ exports[`slots default slot next to named slot, with default content 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div class=\\"Dialog\\"><div class=\\"content\\"><block-child-0/></div><div class=\\"footer\\"><block-child-1/></div></div>\`);
   
@@ -251,7 +251,7 @@ exports[`slots default slot next to named slot, with default content 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -272,7 +272,7 @@ exports[`slots default slot work with text nodes (variation) 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return callSlot(ctx, node, key, 'default');
@@ -284,7 +284,7 @@ exports[`slots default slot work with text nodes (variation) 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   const slot2 = ctx => (node, key) => {
@@ -301,7 +301,7 @@ exports[`slots default slot work with text nodes 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -316,7 +316,7 @@ exports[`slots default slot work with text nodes 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -336,7 +336,7 @@ exports[`slots dynamic t-slot call 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<button block-handler-0=\\"click\\"><block-child-0/></button>\`);
   
@@ -353,7 +353,7 @@ exports[`slots dynamic t-slot call 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -383,7 +383,7 @@ exports[`slots dynamic t-slot call with default 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<button block-handler-0=\\"click\\"><block-child-0/></button>\`);
   
@@ -403,7 +403,7 @@ exports[`slots dynamic t-slot call with default 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -433,7 +433,7 @@ exports[`slots fun: two calls to the same slot 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     let b2 = callSlot(ctx, node, key, 'default');
@@ -447,7 +447,7 @@ exports[`slots fun: two calls to the same slot 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   const slot2 = ctx => (node, key) => {
@@ -464,7 +464,7 @@ exports[`slots missing slots are ignored 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/><span>some content</span><block-child-1/></span>\`);
   
@@ -480,7 +480,7 @@ exports[`slots missing slots are ignored 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -495,7 +495,7 @@ exports[`slots multiple roots are allowed in a default slot 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -510,7 +510,7 @@ exports[`slots multiple roots are allowed in a default slot 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -534,7 +534,7 @@ exports[`slots multiple roots are allowed in a named slot 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -549,7 +549,7 @@ exports[`slots multiple roots are allowed in a named slot 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -574,7 +574,7 @@ exports[`slots multiple slots containing components 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -589,7 +589,7 @@ exports[`slots multiple slots containing components 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
   
@@ -605,7 +605,7 @@ exports[`slots multiple slots containing components 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   const slot3 = ctx => (node, key) => {
@@ -627,7 +627,7 @@ exports[`slots named slot inside slot 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
   
@@ -643,7 +643,7 @@ exports[`slots named slot inside slot 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -677,7 +677,7 @@ exports[`slots named slot inside slot, part 3 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
   
@@ -693,7 +693,7 @@ exports[`slots named slot inside slot, part 3 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -727,7 +727,7 @@ exports[`slots named slots can define a default content 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
   
@@ -746,7 +746,7 @@ exports[`slots named slots can define a default content 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -761,7 +761,7 @@ exports[`slots named slots inside slot, again 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<child><block-child-0/><block-child-1/><block-child-2/></child>\`);
   
@@ -786,7 +786,7 @@ exports[`slots named slots inside slot, again 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -820,7 +820,7 @@ exports[`slots nested slots in same template 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span id=\\"c1\\"><div><block-child-0/></div></span>\`);
   
@@ -835,7 +835,7 @@ exports[`slots nested slots in same template 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span id=\\"c2\\"><block-child-0/></span>\`);
   
@@ -850,7 +850,7 @@ exports[`slots nested slots in same template 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>Child 3</span>\`);
   
@@ -864,7 +864,7 @@ exports[`slots nested slots in same template 4`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<span id=\\"parent\\"><block-child-0/></span>\`);
@@ -888,7 +888,7 @@ exports[`slots nested slots: evaluation context and parented relationship 1`] =
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -903,7 +903,7 @@ exports[`slots nested slots: evaluation context and parented relationship 2`] =
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -918,7 +918,7 @@ exports[`slots nested slots: evaluation context and parented relationship 3`] =
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   const slot2 = ctx => (node, key) => {
@@ -935,7 +935,7 @@ exports[`slots nested slots: evaluation context and parented relationship 4`] =
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   const slot2 = ctx => (node, key) => {
@@ -952,7 +952,7 @@ exports[`slots no named slot content => just no children 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
   
@@ -967,7 +967,7 @@ exports[`slots no named slot content => just no children 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`Dialog\`, {}, key + \`__1\`, node, ctx);
@@ -979,7 +979,7 @@ exports[`slots simple default slot 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
   
@@ -994,7 +994,7 @@ exports[`slots simple default slot 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   const slot2 = ctx => (node, key) => {
@@ -1011,7 +1011,7 @@ exports[`slots simple default slot, variation 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return callSlot(ctx, node, key, 'default');
@@ -1023,7 +1023,7 @@ exports[`slots simple default slot, variation 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   const slot2 = ctx => (node, key) => {
@@ -1040,7 +1040,7 @@ exports[`slots slot and (inline) t-call 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<p>sokka</p>\`);
   
@@ -1054,7 +1054,7 @@ exports[`slots slot and (inline) t-call 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
   
@@ -1069,7 +1069,7 @@ exports[`slots slot and (inline) t-call 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   const callTemplate_5 = getTemplate(\`__template__9\`);
   
@@ -1091,7 +1091,7 @@ exports[`slots slot and (inline) t-esc 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
   
@@ -1106,7 +1106,7 @@ exports[`slots slot and (inline) t-esc 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -1126,7 +1126,7 @@ exports[`slots slot and t-call 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<p>sokka</p>\`);
   
@@ -1140,7 +1140,7 @@ exports[`slots slot and t-call 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
   
@@ -1155,7 +1155,7 @@ exports[`slots slot and t-call 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   const callTemplate_5 = getTemplate(\`__template__9\`);
   
@@ -1177,7 +1177,7 @@ exports[`slots slot and t-esc 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
   
@@ -1192,7 +1192,7 @@ exports[`slots slot and t-esc 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -1212,7 +1212,7 @@ exports[`slots slot are properly rendered if inner props are changed 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div> SC:<block-text-0/></div>\`);
   
@@ -1227,7 +1227,7 @@ exports[`slots slot are properly rendered if inner props are changed 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -1242,7 +1242,7 @@ exports[`slots slot are properly rendered if inner props are changed 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><button block-handler-0=\\"click\\">Inc[<block-text-1/>]</button><block-child-0/></div>\`);
@@ -1264,7 +1264,7 @@ exports[`slots slot content is bound to caller 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
   
@@ -1279,7 +1279,7 @@ exports[`slots slot content is bound to caller 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<button block-handler-0=\\"click\\">some text</button>\`);
@@ -1299,7 +1299,7 @@ exports[`slots slot preserves properly parented relationship 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return callSlot(ctx, node, key, 'default');
@@ -1311,7 +1311,7 @@ exports[`slots slot preserves properly parented relationship 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return text(\`Grand Child\`);
@@ -1323,7 +1323,7 @@ exports[`slots slot preserves properly parented relationship 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -1343,7 +1343,7 @@ exports[`slots slot preserves properly parented relationship, even through t-cal
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return callSlot(ctx, node, key, 'default');
@@ -1355,7 +1355,7 @@ exports[`slots slot preserves properly parented relationship, even through t-cal
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return text(\`Grand Child\`);
@@ -1367,7 +1367,7 @@ exports[`slots slot preserves properly parented relationship, even through t-cal
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`GrandChild\`, {}, key + \`__1\`, node, ctx);
@@ -1379,7 +1379,7 @@ exports[`slots slot preserves properly parented relationship, even through t-cal
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   const callTemplate_5 = getTemplate(\`sub\`);
   
@@ -1401,7 +1401,7 @@ exports[`slots slots and wrapper components 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<a href=\\"abc\\"><block-child-0/></a>\`);
   
@@ -1416,7 +1416,7 @@ exports[`slots slots and wrapper components 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   const slot2 = ctx => (node, key) => {
@@ -1433,7 +1433,7 @@ exports[`slots slots are rendered with proper context 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
   
@@ -1448,7 +1448,7 @@ exports[`slots slots are rendered with proper context 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><span class=\\"counter\\"><block-text-0/></span><block-child-0/></div>\`);
@@ -1472,7 +1472,7 @@ exports[`slots slots are rendered with proper context, part 2 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<a block-attribute-0=\\"href\\"><block-child-0/></a>\`);
   
@@ -1488,7 +1488,7 @@ exports[`slots slots are rendered with proper context, part 2 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><u><block-child-0/></u></div>\`);
@@ -1520,7 +1520,7 @@ exports[`slots slots are rendered with proper context, part 3 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<a block-attribute-0=\\"href\\"><block-child-0/></a>\`);
   
@@ -1536,7 +1536,7 @@ exports[`slots slots are rendered with proper context, part 3 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><u><block-child-0/></u></div>\`);
@@ -1548,12 +1548,13 @@ exports[`slots slots are rendered with proper context, part 3 2`] = `
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
     ctx = Object.create(ctx);
     const [k_block2, v_block2, l_block2, c_block2] = prepareList(ctx['state'].users);
     for (let i1 = 0; i1 < l_block2; i1++) {
       ctx[\`user\`] = v_block2[i1];
       let key1 = ctx['user'].id;
-      ctx[\`userdescr\`] = 'User '+ctx['user'].name;
+      setContextValue(ctx, \\"userdescr\\", 'User '+ctx['user'].name);
       const ctx2 = capture(ctx);
       let b5 = assign(component(\`Link\`, {to: '/user/'+ctx['user'].id}, key + \`__1__\${key1}\`, node, ctx), {slots: {'default': slot3(ctx2)}});
       c_block2[i1] = withKey(block3([], [b5]), key1);
@@ -1568,7 +1569,7 @@ exports[`slots slots are rendered with proper context, part 4 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<a block-attribute-0=\\"href\\"><block-child-0/></a>\`);
   
@@ -1584,7 +1585,7 @@ exports[`slots slots are rendered with proper context, part 4 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -1595,7 +1596,8 @@ exports[`slots slots are rendered with proper context, part 4 2`] = `
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
-    ctx[\`userdescr\`] = 'User '+ctx['state'].user.name;
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"userdescr\\", 'User '+ctx['state'].user.name);
     const ctx2 = capture(ctx);
     let b3 = assign(component(\`Link\`, {to: '/user/'+ctx['state'].user.id}, key + \`__1\`, node, ctx), {slots: {'default': slot3(ctx2)}});
     return block1([], [b3]);
@@ -1607,7 +1609,7 @@ exports[`slots slots in slots, with vars 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
   
@@ -1622,7 +1624,7 @@ exports[`slots slots in slots, with vars 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -1642,7 +1644,7 @@ exports[`slots slots in slots, with vars 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -1655,7 +1657,8 @@ exports[`slots slots in slots, with vars 3`] = `
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
-    ctx[\`test\`] = ctx['state'].name;
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"test\\", ctx['state'].name);
     const ctx2 = capture(ctx);
     let b3 = assign(component(\`A\`, {}, key + \`__1\`, node, ctx), {slots: {'default': slot3(ctx2)}});
     return block1([], [b3]);
@@ -1667,7 +1670,7 @@ exports[`slots slots in t-foreach and re-rendering 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/><block-child-0/></span>\`);
   
@@ -1683,7 +1686,7 @@ exports[`slots slots in t-foreach and re-rendering 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -1712,7 +1715,7 @@ exports[`slots slots in t-foreach in t-foreach 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -1727,7 +1730,7 @@ exports[`slots slots in t-foreach in t-foreach 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -1771,7 +1774,7 @@ exports[`slots slots in t-foreach with t-set and re-rendering 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/><block-child-0/></span>\`);
   
@@ -1787,7 +1790,7 @@ exports[`slots slots in t-foreach with t-set and re-rendering 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -1798,13 +1801,14 @@ exports[`slots slots in t-foreach with t-set and re-rendering 2`] = `
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
     ctx = Object.create(ctx);
     const [k_block2, v_block2, l_block2, c_block2] = prepareList(Array(2));
     for (let i1 = 0; i1 < l_block2; i1++) {
       ctx[\`n\`] = v_block2[i1];
       ctx[\`n_index\`] = i1;
       let key1 = ctx['n_index'];
-      ctx[\`dummy\`] = ctx['n_index'];
+      setContextValue(ctx, \\"dummy\\", ctx['n_index']);
       const ctx2 = capture(ctx);
       c_block2[i1] = withKey(assign(component(\`Child\`, {}, key + \`__1__\${key1}\`, node, ctx), {slots: {'default': slot3(ctx2)}}), key1);
     }
@@ -1818,7 +1822,7 @@ exports[`slots t-debug on a t-set-slot (defining a slot) 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
   
@@ -1833,7 +1837,7 @@ exports[`slots t-debug on a t-set-slot (defining a slot) 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -1855,7 +1859,7 @@ exports[`slots t-set t-value in a slot 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
   
@@ -1870,18 +1874,19 @@ exports[`slots t-set t-value in a slot 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
   const slot3 = ctx => (node, key) => {
-    ctx[\`rainbow\`] = 'dash';
+    setContextValue(ctx, \\"rainbow\\", 'dash');
     return text(ctx['rainbow']);
   }
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
     const ctx2 = capture(ctx);
     let b3 = assign(component(\`Dialog\`, {}, key + \`__1\`, node, ctx), {slots: {'default': slot3(ctx2)}});
     return block1([], [b3]);
@@ -1893,7 +1898,7 @@ exports[`slots t-slot in recursive templates 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<wrapper><block-child-0/></wrapper>\`);
   
@@ -1908,7 +1913,7 @@ exports[`slots t-slot in recursive templates 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   const callTemplate_5 = getTemplate(\`_test_recursive_template\`);
   
@@ -1928,8 +1933,9 @@ exports[`slots t-slot in recursive templates 2`] = `
         b5 = text(ctx['item'].name);
       } else {
         ctx = Object.create(ctx);
-        ctx[\`name\`] = ctx['item'].name;
-        ctx[\`items\`] = ctx['item'].children;
+        ctx[isBoundary] = 1;
+        setContextValue(ctx, \\"name\\", ctx['item'].name);
+        setContextValue(ctx, \\"items\\", ctx['item'].children);
         b6 = callTemplate_5(ctx, node, key + \`__4__\${key1}\`);
         ctx = ctx.__proto__;
       }
@@ -1942,6 +1948,7 @@ exports[`slots t-slot in recursive templates 2`] = `
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
     const ctx2 = capture(ctx);
     return assign(component(\`Wrapper\`, {}, key + \`__1\`, node, ctx), {slots: {'default': slot3(ctx2)}});
   }
@@ -1952,7 +1959,7 @@ exports[`slots t-slot nested within another slot 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>Child 3</span>\`);
   
@@ -1966,7 +1973,7 @@ exports[`slots t-slot nested within another slot 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span id=\\"modal\\"><block-child-0/></span>\`);
   
@@ -1981,7 +1988,7 @@ exports[`slots t-slot nested within another slot 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span id=\\"portal\\"><block-child-0/></span>\`);
   
@@ -1996,7 +2003,7 @@ exports[`slots t-slot nested within another slot 4`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<span id=\\"c2\\"><block-child-0/></span>\`);
@@ -2020,7 +2027,7 @@ exports[`slots t-slot nested within another slot 5`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<span id=\\"c1\\"><block-child-0/></span>\`);
@@ -2040,7 +2047,7 @@ exports[`slots t-slot scope context 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return callSlot(ctx, node, key, 'default');
@@ -2052,7 +2059,7 @@ exports[`slots t-slot scope context 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div block-handler-0=\\"click\\"><block-child-0/></div>\`);
@@ -2073,7 +2080,7 @@ exports[`slots t-slot scope context 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<button>The Button</button>\`);
@@ -2092,7 +2099,7 @@ exports[`slots t-slot within dynamic t-call 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div class=\\"child\\"/>\`);
   
@@ -2106,7 +2113,7 @@ exports[`slots t-slot within dynamic t-call 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div class=\\"slotted\\"><block-child-0/></div>\`);
   
@@ -2121,7 +2128,7 @@ exports[`slots t-slot within dynamic t-call 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div class=\\"slot\\"><block-child-0/></div>\`);
   
@@ -2136,7 +2143,7 @@ exports[`slots t-slot within dynamic t-call 4`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -2158,7 +2165,7 @@ exports[`slots template can just return a slot 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -2173,7 +2180,7 @@ exports[`slots template can just return a slot 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return callSlot(ctx, node, key, 'default');
@@ -2185,7 +2192,7 @@ exports[`slots template can just return a slot 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
diff --git a/tests/components/__snapshots__/style_class.test.ts.snap b/tests/components/__snapshots__/style_class.test.ts.snap
index 878bb5c6..3d0e8b00 100644
--- a/tests/components/__snapshots__/style_class.test.ts.snap
+++ b/tests/components/__snapshots__/style_class.test.ts.snap
@@ -4,7 +4,7 @@ exports[`style and class handling can set class on multi root component 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block2 = createBlock(\`<div>a</div>\`);
   let block3 = createBlock(\`<span block-attribute-0=\\"class\\">b</span>\`);
@@ -22,7 +22,7 @@ exports[`style and class handling can set class on multi root component 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`Child\`, {class: 'fromparent'}, key + \`__1\`, node, ctx);
@@ -34,7 +34,7 @@ exports[`style and class handling can set class on sub component, as prop 1`] =
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\">child</div>\`);
   
@@ -49,7 +49,7 @@ exports[`style and class handling can set class on sub component, as prop 2`] =
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`Child\`, {class: 'some-class'}, key + \`__1\`, node, ctx);
@@ -61,7 +61,7 @@ exports[`style and class handling can set class on sub sub component 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\">childchild</div>\`);
   
@@ -76,7 +76,7 @@ exports[`style and class handling can set class on sub sub component 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`ChildChild\`, {class: (ctx['props'].class||'')+' fromchild'}, key + \`__1\`, node, ctx);
@@ -88,7 +88,7 @@ exports[`style and class handling can set class on sub sub component 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`Child\`, {class: 'fromparent'}, key + \`__1\`, node, ctx);
@@ -100,7 +100,7 @@ exports[`style and class handling can set more than one class on sub component 1
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\">child</div>\`);
   
@@ -115,7 +115,7 @@ exports[`style and class handling can set more than one class on sub component 2
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`Child\`, {class: 'a  b'}, key + \`__1\`, node, ctx);
@@ -127,7 +127,7 @@ exports[`style and class handling can set style and class inside component 1`] =
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div style=\\"font-weight:bold;\\" class=\\"some-class\\">world</div>\`);
   
@@ -156,7 +156,7 @@ exports[`style and class handling class on sub component, which is switched to a
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\">a</div>\`);
   
@@ -171,7 +171,7 @@ exports[`style and class handling class on sub component, which is switched to a
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span block-attribute-0=\\"class\\">b</span>\`);
   
@@ -186,7 +186,7 @@ exports[`style and class handling class on sub component, which is switched to a
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     let b2,b3;
@@ -204,7 +204,7 @@ exports[`style and class handling class on sub component, which is switched to a
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`Child\`, {class: 'someclass',child: ctx['state'].child}, key + \`__1\`, node, ctx);
@@ -216,7 +216,7 @@ exports[`style and class handling class with extra whitespaces (variation) 1`] =
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\"/>\`);
   
@@ -231,7 +231,7 @@ exports[`style and class handling class with extra whitespaces (variation) 2`] =
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<p><block-child-0/></p>\`);
   
@@ -246,7 +246,7 @@ exports[`style and class handling class with extra whitespaces 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\"/>\`);
   
@@ -261,7 +261,7 @@ exports[`style and class handling class with extra whitespaces 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`Child\`, {class: 'a  b c   d'}, key + \`__1\`, node, ctx);
@@ -273,7 +273,7 @@ exports[`style and class handling component class and parent class combine toget
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div class=\\"child\\" block-attribute-0=\\"class\\">child</div>\`);
   
@@ -288,7 +288,7 @@ exports[`style and class handling component class and parent class combine toget
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`Child\`, {class: 'from parent'}, key + \`__1\`, node, ctx);
@@ -327,7 +327,7 @@ exports[`style and class handling empty class attribute is not added on widget r
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span block-attribute-0=\\"class\\"/>\`);
   
@@ -342,7 +342,7 @@ exports[`style and class handling empty class attribute is not added on widget r
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -357,7 +357,7 @@ exports[`style and class handling error in subcomponent with class 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\"><block-text-1/></div>\`);
   
@@ -373,7 +373,7 @@ exports[`style and class handling error in subcomponent with class 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`Child\`, {class: 'a'}, key + \`__1\`, node, ctx);
@@ -385,7 +385,7 @@ exports[`style and class handling no class is set is child ignores it 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div>child</div>\`);
   
@@ -399,7 +399,7 @@ exports[`style and class handling no class is set is child ignores it 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`Child\`, {class: 'hey'}, key + \`__1\`, node, ctx);
@@ -411,7 +411,7 @@ exports[`style and class handling no class is set is parent does not give it as
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\">child</div>\`);
   
@@ -426,7 +426,7 @@ exports[`style and class handling no class is set is parent does not give it as
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`Child\`, {}, key + \`__1\`, node, ctx);
@@ -438,7 +438,7 @@ exports[`style and class handling style is properly added on widget root el 1`]
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"style\\"/>\`);
   
@@ -453,7 +453,7 @@ exports[`style and class handling style is properly added on widget root el 2`]
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`Child\`, {style: 'font-weight: bold;'}, key + \`__1\`, node, ctx);
@@ -465,7 +465,7 @@ exports[`style and class handling t-att-class is properly added/removed on widge
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span class=\\"c\\" block-attribute-0=\\"class\\"/>\`);
   
@@ -480,7 +480,7 @@ exports[`style and class handling t-att-class is properly added/removed on widge
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
diff --git a/tests/components/__snapshots__/t_call.test.ts.snap b/tests/components/__snapshots__/t_call.test.ts.snap
index 9c256d31..24377cc7 100644
--- a/tests/components/__snapshots__/t_call.test.ts.snap
+++ b/tests/components/__snapshots__/t_call.test.ts.snap
@@ -4,10 +4,11 @@ exports[`t-call dynamic t-call 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1;
     let b1 = text(\` owl \`);
     ctx[zero] = b1;
     const template2 = (ctx['current'].template);
@@ -20,7 +21,7 @@ exports[`t-call dynamic t-call 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div>foo</div>\`);
   
@@ -34,7 +35,7 @@ exports[`t-call dynamic t-call 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return text(\`bar\`);
@@ -46,7 +47,7 @@ exports[`t-call handlers are properly bound through a t-call 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<p block-handler-0=\\"click\\">lucas</p>\`);
   
@@ -61,7 +62,7 @@ exports[`t-call handlers are properly bound through a t-call 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`__template__9\`);
   
   let block1 = createBlock(\`<div><block-child-0/><block-text-0/></div>\`);
@@ -78,7 +79,7 @@ exports[`t-call handlers with arguments are properly bound through a t-call 1`]
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<p block-handler-0=\\"click\\">lucas</p>\`);
   
@@ -94,7 +95,7 @@ exports[`t-call handlers with arguments are properly bound through a t-call 2`]
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`__template__9\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -110,7 +111,7 @@ exports[`t-call parent is set within t-call 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`Child\`, {}, key + \`__1\`, node, ctx);
@@ -122,7 +123,7 @@ exports[`t-call parent is set within t-call 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>lucas</span>\`);
   
@@ -136,7 +137,7 @@ exports[`t-call parent is set within t-call 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`__template__9\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -152,7 +153,7 @@ exports[`t-call parent is set within t-call with no parentNode 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`Child\`, {}, key + \`__1\`, node, ctx);
@@ -164,7 +165,7 @@ exports[`t-call parent is set within t-call with no parentNode 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>lucas</span>\`);
   
@@ -178,7 +179,7 @@ exports[`t-call parent is set within t-call with no parentNode 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`__template__9\`);
   
   return function template(ctx, node, key = \\"\\") {
@@ -191,7 +192,7 @@ exports[`t-call sub components in two t-calls 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -206,7 +207,7 @@ exports[`t-call sub components in two t-calls 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`sub\`);
   const callTemplate_4 = getTemplate(\`sub\`);
   
@@ -229,7 +230,7 @@ exports[`t-call sub components in two t-calls 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`Child\`, {val: ctx['state'].val}, key + \`__1\`, node, ctx);
@@ -241,7 +242,7 @@ exports[`t-call t-call in t-foreach and children component 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return component(\`Child\`, {val: ctx['val']}, key + \`__1\`, node, ctx);
@@ -253,7 +254,7 @@ exports[`t-call t-call in t-foreach and children component 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -268,7 +269,7 @@ exports[`t-call t-call in t-foreach and children component 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`__template__9\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
diff --git a/tests/components/__snapshots__/t_call_block.test.ts.snap b/tests/components/__snapshots__/t_call_block.test.ts.snap
index e5d91448..cda7abd5 100644
--- a/tests/components/__snapshots__/t_call_block.test.ts.snap
+++ b/tests/components/__snapshots__/t_call_block.test.ts.snap
@@ -4,7 +4,7 @@ exports[`t-call-block simple t-call-block with static text 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
diff --git a/tests/components/__snapshots__/t_component.test.ts.snap b/tests/components/__snapshots__/t_component.test.ts.snap
index bd999847..ec4b3078 100644
--- a/tests/components/__snapshots__/t_component.test.ts.snap
+++ b/tests/components/__snapshots__/t_component.test.ts.snap
@@ -4,7 +4,7 @@ exports[`t-component can switch between dynamic components without the need for
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>child a</span>\`);
   
@@ -18,7 +18,7 @@ exports[`t-component can switch between dynamic components without the need for
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>child b</span>\`);
   
@@ -32,7 +32,7 @@ exports[`t-component can switch between dynamic components without the need for
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -48,7 +48,7 @@ exports[`t-component can use dynamic components (the class) if given (with diffe
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>child a</span>\`);
   
@@ -62,7 +62,7 @@ exports[`t-component can use dynamic components (the class) if given (with diffe
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div>child b</div>\`);
   
@@ -76,7 +76,7 @@ exports[`t-component can use dynamic components (the class) if given (with diffe
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     let Comp2 = ctx['myComponent'];
@@ -89,7 +89,7 @@ exports[`t-component can use dynamic components (the class) if given 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>child a</span>\`);
   
@@ -103,7 +103,7 @@ exports[`t-component can use dynamic components (the class) if given 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>child b</span>\`);
   
@@ -117,7 +117,7 @@ exports[`t-component can use dynamic components (the class) if given 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     let Comp2 = ctx['myComponent'];
@@ -130,7 +130,7 @@ exports[`t-component modifying a sub widget 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/><button block-handler-1=\\"click\\">Inc</button></div>\`);
   
@@ -147,7 +147,7 @@ exports[`t-component modifying a sub widget 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -163,7 +163,7 @@ exports[`t-component switching dynamic component 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div>child a</div>\`);
   
@@ -177,7 +177,7 @@ exports[`t-component switching dynamic component 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return text(\`child b\`);
@@ -189,7 +189,7 @@ exports[`t-component switching dynamic component 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     let Comp2 = ctx['Child'];
@@ -202,7 +202,7 @@ exports[`t-component t-component not on a <t> node 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>1</span>\`);
   
@@ -216,7 +216,7 @@ exports[`t-component t-component works in simple case 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div>child</div>\`);
   
@@ -230,7 +230,7 @@ exports[`t-component t-component works in simple case 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     let Comp2 = ctx['Child'];
diff --git a/tests/components/__snapshots__/t_foreach.test.ts.snap b/tests/components/__snapshots__/t_foreach.test.ts.snap
index af6c42cb..68e2f3ae 100644
--- a/tests/components/__snapshots__/t_foreach.test.ts.snap
+++ b/tests/components/__snapshots__/t_foreach.test.ts.snap
@@ -4,7 +4,7 @@ exports[`list of components components in a node in a t-foreach  1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
@@ -19,7 +19,7 @@ exports[`list of components components in a node in a t-foreach  2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><ul><block-child-0/></ul></div>\`);
   let block3 = createBlock(\`<li><block-child-0/></li>\`);
@@ -43,7 +43,7 @@ exports[`list of components list of sub components inside other nodes 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>asdf</span>\`);
   
@@ -57,7 +57,7 @@ exports[`list of components list of sub components inside other nodes 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block3 = createBlock(\`<div><block-child-0/></div>\`);
@@ -81,7 +81,7 @@ exports[`list of components reconciliation alg works for t-foreach in t-foreach
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
@@ -96,7 +96,7 @@ exports[`list of components reconciliation alg works for t-foreach in t-foreach
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -128,7 +128,7 @@ exports[`list of components reconciliation alg works for t-foreach in t-foreach,
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
@@ -143,7 +143,7 @@ exports[`list of components reconciliation alg works for t-foreach in t-foreach,
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block3 = createBlock(\`<p><block-child-0/></p>\`);
@@ -177,7 +177,7 @@ exports[`list of components simple list 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -192,7 +192,7 @@ exports[`list of components simple list 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
@@ -211,7 +211,7 @@ exports[`list of components sub components rendered in a loop 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<p><block-text-0/></p>\`);
   
@@ -226,7 +226,7 @@ exports[`list of components sub components rendered in a loop 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -248,7 +248,7 @@ exports[`list of components sub components with some state rendered in a loop 1`
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<p><block-text-0/></p>\`);
   
@@ -263,7 +263,7 @@ exports[`list of components sub components with some state rendered in a loop 2`
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -285,7 +285,7 @@ exports[`list of components t-foreach with t-component, and update 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/><block-text-1/></span>\`);
   
@@ -301,7 +301,7 @@ exports[`list of components t-foreach with t-component, and update 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
diff --git a/tests/components/__snapshots__/t_on.test.ts.snap b/tests/components/__snapshots__/t_on.test.ts.snap
index 1b50a452..03977e39 100644
--- a/tests/components/__snapshots__/t_on.test.ts.snap
+++ b/tests/components/__snapshots__/t_on.test.ts.snap
@@ -4,14 +4,15 @@ exports[`t-on t-on expression captured in t-foreach 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block3 = createBlock(\`<div><button block-handler-0=\\"click\\">expr</button></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
-    ctx[\`iter\`] = 0;
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"iter\\", 0);
     ctx = Object.create(ctx);
     const [k_block2, v_block2, l_block2, c_block2] = prepareList(ctx['arr']);
     for (let i1 = 0; i1 < l_block2; i1++) {
@@ -20,7 +21,7 @@ exports[`t-on t-on expression captured in t-foreach 1`] = `
       const v1 = ctx['otherState'];
       const v2 = ctx['iter'];
       let d1 = (e) => {const res = (() => { return v1.vals.push(v2+'_'+v2) })(); if (typeof res === 'function') { res(e) }};
-      ctx[\`iter\`] = ctx['iter']+1;
+      setContextValue(ctx, \\"iter\\", ctx['iter']+1);
       c_block2[i1] = withKey(block3([d1]), key1);
     }
     let b2 = list(c_block2);
@@ -33,7 +34,7 @@ exports[`t-on t-on expression in t-foreach 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block3 = createBlock(\`<div><block-text-0/>: <block-text-1/><button block-handler-2=\\"click\\">Expr</button></div>\`);
@@ -62,21 +63,22 @@ exports[`t-on t-on expression in t-foreach with t-set 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block3 = createBlock(\`<div><block-text-0/>: <block-text-1/><button block-handler-2=\\"click\\">Expr</button></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
-    ctx[\`bossa\`] = 'nova';
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"bossa\\", 'nova');
     ctx = Object.create(ctx);
     const [k_block2, v_block2, l_block2, c_block2] = prepareList(ctx['state'].values);
     for (let i1 = 0; i1 < l_block2; i1++) {
       ctx[\`val\`] = v_block2[i1];
       ctx[\`val_index\`] = i1;
       let key1 = ctx['val'];
-      ctx[\`bossa\`] = ctx['bossa']+'_'+ctx['val_index'];
+      setContextValue(ctx, \\"bossa\\", ctx['bossa']+'_'+ctx['val_index']);
       let d1 = ctx['val_index'];
       let d2 = ctx['val']+'';
       const v1 = ctx['otherState'];
@@ -95,7 +97,7 @@ exports[`t-on t-on method call in t-foreach 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block3 = createBlock(\`<div><block-text-0/>: <block-text-1/><button block-handler-2=\\"click\\">meth call</button></div>\`);
@@ -123,7 +125,7 @@ exports[`t-on t-on on destroyed components 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-handler-0=\\"click\\"/>\`);
   
@@ -138,7 +140,7 @@ exports[`t-on t-on on destroyed components 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
diff --git a/tests/components/__snapshots__/t_set.test.ts.snap b/tests/components/__snapshots__/t_set.test.ts.snap
new file mode 100644
index 00000000..b4ca3c16
--- /dev/null
+++ b/tests/components/__snapshots__/t_set.test.ts.snap
@@ -0,0 +1,174 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`t-set slot setted value (with t-set) not accessible with t-esc 1`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component } = bdom;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
+  
+  let block1 = createBlock(\`<div><block-text-0/><block-text-1/></div>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
+    let d1 = ctx['iter'];
+    setContextValue(ctx, \\"iter\\", 'called');
+    let d2 = ctx['iter'];
+    return block1([d1, d2]);
+  }
+}"
+`;
+
+exports[`t-set slot setted value (with t-set) not accessible with t-esc 2`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component } = bdom;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
+  let assign = Object.assign;
+  
+  let block1 = createBlock(\`<div><p><block-text-0/></p><block-child-0/><p><block-text-1/></p></div>\`);
+  
+  const slot3 = ctx => (node, key) => {
+    setContextValue(ctx, \\"iter\\", 'inCall');
+  }
+  
+  return function template(ctx, node, key = \\"\\") {
+    ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"iter\\", 'source');
+    let d1 = ctx['iter'];
+    const ctx2 = capture(ctx);
+    let b2 = assign(component(\`Childcomp\`, {}, key + \`__1\`, node, ctx), {slots: {'default': slot3(ctx2)}});
+    let d2 = ctx['iter'];
+    return block1([d1, d2], [b2]);
+  }
+}"
+`;
+
+exports[`t-set t-set can't alter component even if key in component 1`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component } = bdom;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
+  
+  let block1 = createBlock(\`<div><p><block-text-0/></p><p><block-text-1/></p></div>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
+    let d1 = ctx['iter'];
+    setContextValue(ctx, \\"iter\\", 5);
+    let d2 = ctx['iter'];
+    return block1([d1, d2]);
+  }
+}"
+`;
+
+exports[`t-set t-set can't alter component if key not in component 1`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component } = bdom;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
+  
+  let block1 = createBlock(\`<div><p><block-text-0/></p><p><block-text-1/></p></div>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
+    let d1 = ctx['iter'];
+    setContextValue(ctx, \\"iter\\", 5);
+    let d2 = ctx['iter'];
+    return block1([d1, d2]);
+  }
+}"
+`;
+
+exports[`t-set t-set in t-if 1`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component } = bdom;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
+  
+  let block1 = createBlock(\`<div><block-child-0/><block-child-0/><block-child-0/><p><block-text-0/></p></div>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"flag\\", ctx['state'].flag);
+    if (ctx['flag']==='if') {
+      setContextValue(ctx, \\"iter\\", 2);
+    } else if (ctx['flag']==='elif') {
+      setContextValue(ctx, \\"iter\\", 3);
+    } else {
+      setContextValue(ctx, \\"iter\\", 4);
+    }
+    let d1 = ctx['iter'];
+    return block1([d1]);
+  }
+}"
+`;
+
+exports[`t-set t-set not altered by child comp 1`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component } = bdom;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
+  
+  let block1 = createBlock(\`<div><block-text-0/><block-text-1/></div>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
+    let d1 = ctx['iter'];
+    setContextValue(ctx, \\"iter\\", 'called');
+    let d2 = ctx['iter'];
+    return block1([d1, d2]);
+  }
+}"
+`;
+
+exports[`t-set t-set not altered by child comp 2`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component } = bdom;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
+  
+  let block1 = createBlock(\`<div><p><block-text-0/></p><block-child-0/><p><block-text-1/></p></div>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"iter\\", 'source');
+    let d1 = ctx['iter'];
+    let b2 = component(\`Childcomp\`, {}, key + \`__1\`, node, ctx);
+    let d2 = ctx['iter'];
+    return block1([d1, d2], [b2]);
+  }
+}"
+`;
+
+exports[`t-set t-set outside modified in t-if 1`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component } = bdom;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
+  
+  let block1 = createBlock(\`<div><block-child-0/><block-child-0/><block-child-0/><p><block-text-0/></p></div>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"iter\\", 0);
+    setContextValue(ctx, \\"flag\\", ctx['state'].flag);
+    if (ctx['flag']==='if') {
+      setContextValue(ctx, \\"iter\\", 2);
+    } else if (ctx['flag']==='elif') {
+      setContextValue(ctx, \\"iter\\", 3);
+    } else {
+      setContextValue(ctx, \\"iter\\", 4);
+    }
+    let d1 = ctx['iter'];
+    return block1([d1]);
+  }
+}"
+`;
diff --git a/tests/components/error_handling.test.ts b/tests/components/error_handling.test.ts
index 67ef11ef..963f5676 100644
--- a/tests/components/error_handling.test.ts
+++ b/tests/components/error_handling.test.ts
@@ -43,7 +43,8 @@ describe("basics", () => {
     expect(fixture.innerHTML).toBe("");
     expect(status(parent)).toBe("destroyed");
     expect(error).toBeDefined();
-    const regexp = /Cannot read properties of undefined \(reading 'this'\)|Cannot read property 'this' of undefined/g;
+    const regexp =
+      /Cannot read properties of undefined \(reading 'this'\)|Cannot read property 'this' of undefined/g;
     expect(error.message).toMatch(regexp);
   });
 
@@ -112,7 +113,8 @@ describe.skip("errors and promises", () => {
       error = e;
     }
     expect(error).toBeDefined();
-    const regexp = /Cannot read properties of undefined \(reading 'crash'\)|Cannot read property 'crash' of undefined/g;
+    const regexp =
+      /Cannot read properties of undefined \(reading 'crash'\)|Cannot read property 'crash' of undefined/g;
     expect(error.message).toMatch(regexp);
 
     expect(console.error).toBeCalledTimes(0);
@@ -225,7 +227,8 @@ describe.skip("errors and promises", () => {
       error = e;
     }
     expect(error).toBeDefined();
-    const regexp = /Cannot read properties of undefined \(reading 'crash'\)|Cannot read property 'crash' of undefined/g;
+    const regexp =
+      /Cannot read properties of undefined \(reading 'crash'\)|Cannot read property 'crash' of undefined/g;
     expect(error.message).toMatch(regexp);
 
     expect(console.error).toBeCalledTimes(0);
@@ -251,7 +254,8 @@ describe.skip("errors and promises", () => {
       error = e;
     }
     expect(error).toBeDefined();
-    const regexp = /Cannot read properties of undefined \(reading 'crash'\)|Cannot read property 'crash' of undefined/g;
+    const regexp =
+      /Cannot read properties of undefined \(reading 'crash'\)|Cannot read property 'crash' of undefined/g;
     expect(error.message).toMatch(regexp);
 
     expect(console.error).toBeCalledTimes(0);
@@ -274,7 +278,8 @@ describe.skip("errors and promises", () => {
       error = e;
     }
     expect(error).toBeDefined();
-    const regexp = /Cannot read properties of undefined \(reading 'y'\)|Cannot read property 'y' of undefined/g;
+    const regexp =
+      /Cannot read properties of undefined \(reading 'y'\)|Cannot read property 'y' of undefined/g;
     expect(error.message).toMatch(regexp);
   });
 
diff --git a/tests/components/style_class.test.ts b/tests/components/style_class.test.ts
index e44a1262..2f75798f 100644
--- a/tests/components/style_class.test.ts
+++ b/tests/components/style_class.test.ts
@@ -341,7 +341,8 @@ describe("style and class handling", () => {
       error = e;
     }
     expect(error).toBeDefined();
-    const regexp = /Cannot read properties of undefined \(reading 'crash'\)|Cannot read property 'crash' of undefined/g;
+    const regexp =
+      /Cannot read properties of undefined \(reading 'crash'\)|Cannot read property 'crash' of undefined/g;
     expect(error.message).toMatch(regexp);
     expect(fixture.innerHTML).toBe("");
   });
diff --git a/tests/components/t_set.test.ts b/tests/components/t_set.test.ts
new file mode 100644
index 00000000..000866a2
--- /dev/null
+++ b/tests/components/t_set.test.ts
@@ -0,0 +1,155 @@
+import { Component, mount, xml } from "../../src";
+import { makeTestFixture, snapshotEverything } from "../helpers";
+
+snapshotEverything();
+
+let fixture: HTMLElement;
+
+beforeEach(() => {
+  fixture = makeTestFixture();
+});
+
+// -----------------------------------------------------------------------------
+// t-set
+// -----------------------------------------------------------------------------
+
+describe("t-set", () => {
+  test("t-set outside modified in t-if", async () => {
+    class Comp extends Component {
+      static template = xml`
+        <div>
+          <t t-set="iter" t-value="0"/>
+          <t t-set="flag" t-value="state.flag" />
+          <t t-if="flag === 'if'">
+            <t t-set="iter" t-value="2"/>
+          </t>
+          <t t-elif="flag === 'elif'">
+            <t t-set="iter" t-value="3"/>
+          </t>
+          <t t-else="">
+            <t t-set="iter" t-value="4"/>
+          </t>
+          <p><t t-esc="iter"/></p>
+        </div>`;
+      state = { flag: "if" };
+    }
+    const comp = await mount(Comp, fixture);
+
+    expect(fixture.innerHTML).toBe("<div><p>2</p></div>");
+    comp.state.flag = "elif";
+    await comp.render();
+    expect(fixture.innerHTML).toBe("<div><p>3</p></div>");
+    comp.state.flag = "false";
+    await comp.render();
+    expect(fixture.innerHTML).toBe("<div><p>4</p></div>");
+  });
+
+  test("t-set in t-if", async () => {
+    // Weird that code block within 'if' leaks outside of it
+    // Python does the same
+    class Comp extends Component {
+      static template = xml`
+        <div>
+          <t t-set="flag" t-value="state.flag" />
+          <t t-if="flag === 'if'">
+            <t t-set="iter" t-value="2"/>
+          </t>
+          <t t-elif="flag === 'elif'">
+            <t t-set="iter" t-value="3"/>
+          </t>
+          <t t-else="">
+            <t t-set="iter" t-value="4"/>
+          </t>
+          <p><t t-esc="iter"/></p>
+        </div>`;
+      state = { flag: "if" };
+    }
+    const comp = await mount(Comp, fixture);
+
+    expect(fixture.innerHTML).toBe("<div><p>2</p></div>");
+    comp.state.flag = "elif";
+    await comp.render();
+    expect(fixture.innerHTML).toBe("<div><p>3</p></div>");
+    comp.state.flag = "false";
+    await comp.render();
+    expect(fixture.innerHTML).toBe("<div><p>4</p></div>");
+  });
+
+  test("t-set can't alter component even if key in component", async () => {
+    class Comp extends Component {
+      static template = xml`
+        <div>
+          <p><t t-esc="iter"/></p>
+          <t t-set="iter" t-value="5"/>
+          <p><t t-esc="iter"/></p>
+        </div>`;
+      iter = 1;
+    }
+    const comp = await mount(Comp, fixture);
+
+    expect(fixture.innerHTML).toBe("<div><p>1</p><p>5</p></div>");
+    expect(comp.iter).toBe(1);
+  });
+
+  test("t-set can't alter component if key not in component", async () => {
+    class Comp extends Component {
+      static template = xml`
+        <div>
+          <p><t t-esc="iter"/></p>
+          <t t-set="iter" t-value="5"/>
+          <p><t t-esc="iter"/></p>
+        </div>`;
+    }
+    const comp = await mount(Comp, fixture);
+
+    expect(fixture.innerHTML).toBe("<div><p></p><p>5</p></div>");
+    expect((comp as any).iter).toBeUndefined();
+  });
+
+  test("slot setted value (with t-set) not accessible with t-esc", async () => {
+    class Childcomp extends Component {
+      static template = xml`<div><t t-esc="iter"/><t t-set="iter" t-value="'called'"/><t t-esc="iter"/></div>`;
+    }
+    class Comp extends Component {
+      static components = { Childcomp };
+      static template = xml`
+        <div>
+          <t t-set="iter" t-value="'source'"/>
+          <p><t t-esc="iter"/></p>
+          <Childcomp>
+            <t t-set="iter" t-value="'inCall'"/>
+          </Childcomp>
+          <p><t t-esc="iter"/></p>
+        </div>`;
+    }
+    await mount(Comp, fixture);
+
+    expect(fixture.innerHTML).toBe("<div><p>source</p><div>called</div><p>source</p></div>");
+  });
+
+  test("t-set not altered by child comp", async () => {
+    let child;
+    class Childcomp extends Component {
+      static template = xml`<div><t t-esc="iter"/><t t-set="iter" t-value="'called'"/><t t-esc="iter"/></div>`;
+      iter = "child";
+      setup() {
+        super.setup();
+        child = this;
+      }
+    }
+    class Comp extends Component {
+      static components = { Childcomp };
+      static template = xml`
+        <div>
+          <t t-set="iter" t-value="'source'"/>
+          <p><t t-esc="iter"/></p>
+          <Childcomp/>
+          <p><t t-esc="iter"/></p>
+        </div>`;
+    }
+    await mount(Comp, fixture);
+
+    expect(fixture.innerHTML).toBe("<div><p>source</p><div>childcalled</div><p>source</p></div>");
+    expect((child as any).iter).toBe("child");
+  });
+});
diff --git a/tests/misc/__snapshots__/memo.test.ts.snap b/tests/misc/__snapshots__/memo.test.ts.snap
index f21e3032..2ec3190f 100644
--- a/tests/misc/__snapshots__/memo.test.ts.snap
+++ b/tests/misc/__snapshots__/memo.test.ts.snap
@@ -4,7 +4,7 @@ exports[`Memo if no prop change, prevent renderings from above  1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return text(ctx['props'].value);
@@ -16,7 +16,7 @@ exports[`Memo if no prop change, prevent renderings from above  2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   const slot2 = ctx => (node, key) => {
@@ -40,7 +40,7 @@ exports[`Memo if no props, prevent renderings from above  1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return text(ctx['props'].value);
@@ -52,7 +52,7 @@ exports[`Memo if no props, prevent renderings from above  2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   const slot3 = ctx => (node, key) => {
@@ -71,7 +71,7 @@ exports[`Memo if no props, prevent renderings from above (work with simple html)
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   const slot2 = ctx => (node, key) => {
diff --git a/tests/misc/__snapshots__/portal.test.ts.snap b/tests/misc/__snapshots__/portal.test.ts.snap
index b45539fe..5a4c9a16 100644
--- a/tests/misc/__snapshots__/portal.test.ts.snap
+++ b/tests/misc/__snapshots__/portal.test.ts.snap
@@ -4,7 +4,7 @@ exports[`Portal Portal composed with t-slot 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div>child2</div>\`);
   
@@ -18,7 +18,7 @@ exports[`Portal Portal composed with t-slot 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   const slot2 = ctx => (node, key) => {
@@ -35,7 +35,7 @@ exports[`Portal Portal composed with t-slot 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -56,7 +56,7 @@ exports[`Portal basic use of portal 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><span>1</span><block-child-0/></div>\`);
@@ -77,7 +77,7 @@ exports[`Portal conditional use of Portal (with sub Component) 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<p><block-text-0/></p>\`);
   
@@ -92,7 +92,7 @@ exports[`Portal conditional use of Portal (with sub Component) 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block2 = createBlock(\`<span>1</span>\`);
@@ -116,7 +116,7 @@ exports[`Portal conditional use of Portal 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block2 = createBlock(\`<span>1</span>\`);
@@ -141,7 +141,7 @@ exports[`Portal lifecycle hooks of portal sub component are properly called 1`]
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -156,7 +156,7 @@ exports[`Portal lifecycle hooks of portal sub component are properly called 2`]
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -179,7 +179,7 @@ exports[`Portal portal could have dynamically no content 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -205,7 +205,7 @@ exports[`Portal portal with child and props 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -220,7 +220,7 @@ exports[`Portal portal with child and props 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -240,7 +240,7 @@ exports[`Portal portal with dynamic body 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -269,7 +269,7 @@ exports[`Portal portal with many children 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -293,7 +293,7 @@ exports[`Portal portal with no content 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -317,7 +317,7 @@ exports[`Portal portal with only text as content 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -358,7 +358,7 @@ exports[`Portal portal's parent's env is not polluted 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<button>child</button>\`);
   
@@ -372,7 +372,7 @@ exports[`Portal portal's parent's env is not polluted 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -392,7 +392,7 @@ exports[`Portal with target in template (after portal) 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><span>1</span><block-child-0/><div id=\\"local-target\\"/></div>\`);
@@ -413,7 +413,7 @@ exports[`Portal with target in template (before portal) 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><div id=\\"local-target\\"/><span>1</span><block-child-0/></div>\`);
@@ -434,7 +434,7 @@ exports[`Portal: UI/UX focus is kept across re-renders 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<input id=\\"target-me\\" block-attribute-0=\\"placeholder\\"/>\`);
   
@@ -449,7 +449,7 @@ exports[`Portal: UI/UX focus is kept across re-renders 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
diff --git a/tests/qweb/__snapshots__/attributes.test.ts.snap b/tests/qweb/__snapshots__/attributes.test.ts.snap
index 3fbf6bdb..7886548e 100644
--- a/tests/qweb/__snapshots__/attributes.test.ts.snap
+++ b/tests/qweb/__snapshots__/attributes.test.ts.snap
@@ -4,7 +4,7 @@ exports[`attributes changing a class with t-att-class (preexisting class 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div class=\\"hoy\\" block-attribute-0=\\"class\\"/>\`);
   
@@ -19,7 +19,7 @@ exports[`attributes changing a class with t-att-class 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\"/>\`);
   
@@ -34,7 +34,7 @@ exports[`attributes changing an attribute with t-att- 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"value\\"/>\`);
   
@@ -49,7 +49,7 @@ exports[`attributes class and t-att-class should combine together 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\" class=\\"hello\\"/>\`);
   
@@ -64,7 +64,7 @@ exports[`attributes class and t-attf-class with ternary operation 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div class=\\"hello\\" block-attribute-0=\\"class\\"/>\`);
   
@@ -79,7 +79,7 @@ exports[`attributes dynamic attribute evaluating to 0 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"foo\\"/>\`);
   
@@ -94,7 +94,7 @@ exports[`attributes dynamic attribute falsy variable  1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"foo\\"/>\`);
   
@@ -109,7 +109,7 @@ exports[`attributes dynamic attribute with a dash 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"data-action-id\\"/>\`);
   
@@ -124,7 +124,7 @@ exports[`attributes dynamic attributes 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"foo\\"/>\`);
   
@@ -139,7 +139,7 @@ exports[`attributes dynamic class attribute 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\"/>\`);
   
@@ -154,7 +154,7 @@ exports[`attributes dynamic class attribute evaluating to 0 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\"/>\`);
   
@@ -169,7 +169,7 @@ exports[`attributes dynamic empty class attribute 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\"/>\`);
   
@@ -184,7 +184,7 @@ exports[`attributes dynamic formatted attributes with a dash 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"aria-label\\"/>\`);
   
@@ -199,7 +199,7 @@ exports[`attributes fixed variable 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"foo\\"/>\`);
   
@@ -214,7 +214,7 @@ exports[`attributes format expression 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"foo\\"/>\`);
   
@@ -229,7 +229,7 @@ exports[`attributes format literal 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"foo\\"/>\`);
   
@@ -244,7 +244,7 @@ exports[`attributes format multiple 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"foo\\"/>\`);
   
@@ -259,7 +259,7 @@ exports[`attributes format value 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"foo\\"/>\`);
   
@@ -274,13 +274,14 @@ exports[`attributes from object variables set previously 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><span block-attribute-0=\\"class\\"/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
-    ctx[\`o\`] = {a:'b'};
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"o\\", {a:'b'});
     let d1 = ctx['o'].a;
     return block1([d1]);
   }
@@ -291,13 +292,14 @@ exports[`attributes from variables set previously (no external node) 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span block-attribute-0=\\"class\\"/>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
-    ctx[\`abc\`] = 'def';
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"abc\\", 'def');
     let d1 = ctx['abc'];
     return block1([d1]);
   }
@@ -308,13 +310,14 @@ exports[`attributes from variables set previously 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><span block-attribute-0=\\"class\\"/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
-    ctx[\`abc\`] = 'def';
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"abc\\", 'def');
     let d1 = ctx['abc'];
     return block1([d1]);
   }
@@ -325,7 +328,7 @@ exports[`attributes object 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attributes=\\"0\\"/>\`);
   
@@ -340,7 +343,7 @@ exports[`attributes static attributes 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div foo=\\"a\\" bar=\\"b\\" baz=\\"c\\"/>\`);
   
@@ -354,7 +357,7 @@ exports[`attributes static attributes on void elements 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<img src=\\"/test.skip.jpg\\" alt=\\"Test\\"/>\`);
   
@@ -368,7 +371,7 @@ exports[`attributes static attributes with dashes 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div aria-label=\\"Close\\"/>\`);
   
@@ -382,7 +385,7 @@ exports[`attributes t-att-class and class should combine together 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div class=\\"hello\\" block-attribute-0=\\"class\\"/>\`);
   
@@ -397,7 +400,7 @@ exports[`attributes t-att-class with multiple classes 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\"/>\`);
   
@@ -412,7 +415,7 @@ exports[`attributes t-att-class with multiple classes 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\"/>\`);
   
@@ -427,7 +430,7 @@ exports[`attributes t-att-class with multiple classes, some of which are duplica
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\"/>\`);
   
@@ -442,7 +445,7 @@ exports[`attributes t-att-class with object 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div class=\\"static\\" block-attribute-0=\\"class\\"/>\`);
   
@@ -457,7 +460,7 @@ exports[`attributes t-attf-class 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\"/>\`);
   
@@ -472,7 +475,7 @@ exports[`attributes t-attf-class should combine with class 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div class=\\"hello\\" block-attribute-0=\\"class\\"/>\`);
   
@@ -487,7 +490,7 @@ exports[`attributes t-attf-class with multiple classes 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\"/>\`);
   
@@ -502,7 +505,7 @@ exports[`attributes t-attf-class with multiple classes separated by multiple spa
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\"/>\`);
   
@@ -517,7 +520,7 @@ exports[`attributes tuple literal 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attributes=\\"0\\"/>\`);
   
@@ -532,7 +535,7 @@ exports[`attributes tuple variable 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attributes=\\"0\\"/>\`);
   
@@ -547,7 +550,7 @@ exports[`attributes two classes 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div class=\\"a b\\"/>\`);
   
@@ -561,7 +564,7 @@ exports[`attributes two dynamic attributes 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"foo\\" block-attribute-1=\\"bar\\"/>\`);
   
@@ -577,7 +580,7 @@ exports[`attributes updating classes (with obj notation) 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div class=\\"hoy\\" block-attribute-0=\\"class\\"/>\`);
   
@@ -592,7 +595,7 @@ exports[`attributes various escapes 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div foo=\\"&lt;foo\\" block-attribute-0=\\"bar\\" block-attribute-1=\\"baz\\" block-attributes=\\"2\\"/>\`);
   
@@ -609,7 +612,7 @@ exports[`attributes various escapes 2 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div> &lt; </div>\`);
   
@@ -623,7 +626,7 @@ exports[`special cases for some specific html attributes/properties input of typ
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<input type=\\"checkbox\\" block-attribute-0=\\"indeterminate\\"/>\`);
   
@@ -638,7 +641,7 @@ exports[`special cases for some specific html attributes/properties input type=
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<input type=\\"checkbox\\" block-attribute-0=\\"checked\\"/>\`);
   
@@ -653,7 +656,7 @@ exports[`special cases for some specific html attributes/properties input with t
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<input block-attribute-0=\\"value\\"/>\`);
   
@@ -668,7 +671,7 @@ exports[`special cases for some specific html attributes/properties various bool
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><input type=\\"checkbox\\" checked=\\"checked\\"/><input checked=\\"checked\\"/><div checked=\\"checked\\"/><div selected=\\"selected\\"/><option selected=\\"selected\\" other=\\"1\\"/><input readonly=\\"readonly\\"/><button disabled=\\"disabled\\"/></div>\`);
   
diff --git a/tests/qweb/__snapshots__/comments.test.ts.snap b/tests/qweb/__snapshots__/comments.test.ts.snap
index 3e42785c..5c7f2e05 100644
--- a/tests/qweb/__snapshots__/comments.test.ts.snap
+++ b/tests/qweb/__snapshots__/comments.test.ts.snap
@@ -4,7 +4,7 @@ exports[`comments only a comment 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<!-- comment-->\`);
   
@@ -18,7 +18,7 @@ exports[`comments properly handle comments 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div>hello <!-- comment-->owl</div>\`);
   
@@ -32,7 +32,7 @@ exports[`comments properly handle comments between t-if/t-else 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
   let block2 = createBlock(\`<span>true</span>\`);
diff --git a/tests/qweb/__snapshots__/event_handling.test.ts.snap b/tests/qweb/__snapshots__/event_handling.test.ts.snap
index 23ff0ff1..e5e5307f 100644
--- a/tests/qweb/__snapshots__/event_handling.test.ts.snap
+++ b/tests/qweb/__snapshots__/event_handling.test.ts.snap
@@ -4,7 +4,7 @@ exports[`t-on can bind event handler 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<button block-handler-0=\\"click\\">Click</button>\`);
   
@@ -19,7 +19,7 @@ exports[`t-on can bind handlers with arguments 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<button block-handler-0=\\"click\\">Click</button>\`);
   
@@ -35,7 +35,7 @@ exports[`t-on can bind handlers with empty  object 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<button block-handler-0=\\"click\\">Click</button>\`);
   
@@ -51,7 +51,7 @@ exports[`t-on can bind handlers with empty object (with non empty inner string)
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<button block-handler-0=\\"click\\">Click</button>\`);
   
@@ -67,7 +67,7 @@ exports[`t-on can bind handlers with empty object (with non empty inner string)
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<ul><block-child-0/></ul>\`);
   let block3 = createBlock(\`<li><a block-handler-0=\\"click\\">link</a></li>\`);
@@ -93,7 +93,7 @@ exports[`t-on can bind handlers with object arguments 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<button block-handler-0=\\"click\\">Click</button>\`);
   
@@ -109,7 +109,7 @@ exports[`t-on can bind two event handlers 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<button block-handler-0=\\"click\\" block-handler-1=\\"dblclick\\">Click</button>\`);
   
@@ -125,7 +125,7 @@ exports[`t-on handler is bound to proper owner 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<button block-handler-0=\\"click\\">Click</button>\`);
   
@@ -140,7 +140,7 @@ exports[`t-on handler is bound to proper owner, part 2 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block2 = createBlock(\`<button block-handler-0=\\"click\\">Click</button>\`);
   
@@ -162,7 +162,7 @@ exports[`t-on handler is bound to proper owner, part 3 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<button block-handler-0=\\"click\\">Click</button>\`);
   
@@ -177,7 +177,7 @@ exports[`t-on handler is bound to proper owner, part 3 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`sub\`);
   
   return function template(ctx, node, key = \\"\\") {
@@ -190,7 +190,7 @@ exports[`t-on handler is bound to proper owner, part 4 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<button block-handler-0=\\"click\\">Click</button>\`);
   
@@ -205,7 +205,7 @@ exports[`t-on handler is bound to proper owner, part 4 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`sub\`);
   
   return function template(ctx, node, key = \\"\\") {
@@ -229,7 +229,7 @@ exports[`t-on receive event in first argument 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<button block-handler-0=\\"click\\">Click</button>\`);
   
@@ -244,7 +244,7 @@ exports[`t-on t-on with inline statement (function call) 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<button block-handler-0=\\"click\\">Click</button>\`);
   
@@ -260,7 +260,7 @@ exports[`t-on t-on with inline statement 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<button block-handler-0=\\"click\\">Click</button>\`);
   
@@ -276,7 +276,7 @@ exports[`t-on t-on with inline statement, part 2 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<button block-handler-0=\\"click\\">Toggle</button>\`);
   
@@ -292,7 +292,7 @@ exports[`t-on t-on with inline statement, part 3 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<button block-handler-0=\\"click\\">Toggle</button>\`);
   
@@ -309,7 +309,7 @@ exports[`t-on t-on with t-call 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<p block-handler-0=\\"click\\">lucas</p>\`);
   
@@ -324,7 +324,7 @@ exports[`t-on t-on with t-call 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -340,7 +340,7 @@ exports[`t-on t-on, with arguments and t-call 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<p block-handler-0=\\"click\\">lucas</p>\`);
   
@@ -356,7 +356,7 @@ exports[`t-on t-on, with arguments and t-call 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
diff --git a/tests/qweb/__snapshots__/misc.test.ts.snap b/tests/qweb/__snapshots__/misc.test.ts.snap
index a011278c..d2a88b0f 100644
--- a/tests/qweb/__snapshots__/misc.test.ts.snap
+++ b/tests/qweb/__snapshots__/misc.test.ts.snap
@@ -4,7 +4,7 @@ exports[`misc complex template 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div block-attribute-0=\\"class\\"><div block-attribute-1=\\"class\\"><div class=\\"batch_header\\"><a block-attribute-2=\\"href\\" block-attribute-3=\\"class\\" title=\\"View Batch\\"><block-text-4/><block-child-0/><i class=\\"arrow fa fa-window-maximize\\"/></a></div><block-child-1/><div class=\\"batch_slots\\"><block-child-2/><block-child-3/></div><div class=\\"batch_commits\\"><block-child-4/></div></div></div>\`);
   let block2 = createBlock(\`<i class=\\"fa fa-exclamation-triangle\\"/>\`);
@@ -82,7 +82,7 @@ exports[`misc global 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<año block-attribute-0=\\"falló\\"><block-child-0/></año>\`);
   
@@ -98,7 +98,7 @@ exports[`misc global 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -113,7 +113,7 @@ exports[`misc global 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -129,7 +129,7 @@ exports[`misc global 4`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`_callee-uses-foo\`);
   const callTemplate_4 = getTemplate(\`_callee-uses-foo\`);
   const callTemplate_6 = getTemplate(\`_callee-uses-foo\`);
@@ -141,6 +141,7 @@ exports[`misc global 4`] = `
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
     ctx = Object.create(ctx);
     const [k_block2, v_block2, l_block2, c_block2] = prepareList([4,5,6]);
     for (let i1 = 0; i1 < l_block2; i1++) {
@@ -153,12 +154,14 @@ exports[`misc global 4`] = `
       let d1 = ctx['value'];
       let b4 = block4([d1]);
       ctx = Object.create(ctx);
+      ctx[isBoundary] = 1;
       ctx = Object.create(ctx);
-      ctx[\`foo\`] = 'aaa';
+      ctx[isBoundary] = 1;
+      setContextValue(ctx, \\"foo\\", 'aaa');
       let b6 = callTemplate_2(ctx, node, key + \`__1__\${key1}\`);
       ctx = ctx.__proto__;
       let b7 = callTemplate_4(ctx, node, key + \`__3__\${key1}\`);
-      ctx[\`foo\`] = 'bbb';
+      setContextValue(ctx, \\"foo\\", 'bbb');
       let b8 = callTemplate_6(ctx, node, key + \`__5__\${key1}\`);
       let b5 = multi([b6, b7, b8]);
       ctx[zero] = b5;
@@ -178,7 +181,7 @@ exports[`misc other complex template 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_3 = getTemplate(\`LOAD_INFOS_TEMPLATE\`);
   
   let block1 = createBlock(\`<div><header><nav class=\\"navbar navbar-expand-md navbar-light bg-light\\"><a block-attribute-0=\\"href\\"><b style=\\"color:#777;\\"><block-text-1/></b></a><button type=\\"button\\" class=\\"navbar-toggler\\" data-toggle=\\"collapse\\" data-target=\\"#top_menu_collapse\\"><span class=\\"navbar-toggler-icon\\"/></button><div class=\\"collapse navbar-collapse\\" id=\\"top_menu_collapse\\" aria-expanded=\\"false\\"><ul class=\\"nav navbar-nav ml-auto text-right\\" id=\\"top_menu\\"><block-child-0/><li class=\\"nav-item divider\\"/><block-child-1/></ul><div><div class=\\"input-group input-group-sm\\"><div class=\\"input-group-prepend input-group-sm\\"><button class=\\"btn btn-default fa fa-cog\\" title=\\"Settings\\" block-handler-2=\\"click\\"/><button class=\\"btn btn-default\\" block-handler-3=\\"click\\"> More </button><block-child-2/></div><input class=\\"form-control\\" type=\\"text\\" placeholder=\\"Search\\" aria-label=\\"Search\\" name=\\"search\\" block-attribute-4=\\"value\\" block-handler-5=\\"keyup\\" block-handler-6=\\"change\\" block-ref=\\"7\\"/><div class=\\"input-group-append\\"><button class=\\"btn btn-default fa fa-eraser\\" block-handler-8=\\"click\\"/></div></div></div></div></nav></header><div class=\\"container-fluid\\" block-ref=\\"9\\"><div class=\\"row\\"><!--div class=\\"form-group col-md-6\\">
diff --git a/tests/qweb/__snapshots__/simple_templates.test.ts.snap b/tests/qweb/__snapshots__/simple_templates.test.ts.snap
index 85046bd2..42677945 100644
--- a/tests/qweb/__snapshots__/simple_templates.test.ts.snap
+++ b/tests/qweb/__snapshots__/simple_templates.test.ts.snap
@@ -4,7 +4,7 @@ exports[`simple templates, mostly static can render a table row 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<tr><td>cell</td></tr>\`);
   
@@ -18,7 +18,7 @@ exports[`simple templates, mostly static div with a class attribute 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div class=\\"abc\\">foo</div>\`);
   
@@ -32,7 +32,7 @@ exports[`simple templates, mostly static div with a class attribute with a quote
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div class=\\"a'bc\\">word</div>\`);
   
@@ -46,7 +46,7 @@ exports[`simple templates, mostly static div with a span child node 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><span>word</span></div>\`);
   
@@ -60,7 +60,7 @@ exports[`simple templates, mostly static div with an arbitrary attribute with a
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div abc=\\"a'bc\\">word</div>\`);
   
@@ -74,7 +74,7 @@ exports[`simple templates, mostly static div with an empty class attribute 1`] =
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div>word</div>\`);
   
@@ -88,7 +88,7 @@ exports[`simple templates, mostly static div with content 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div>foo</div>\`);
   
@@ -102,7 +102,7 @@ exports[`simple templates, mostly static dom node with t-esc 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
@@ -117,7 +117,7 @@ exports[`simple templates, mostly static dom node with t-esc 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
@@ -132,7 +132,7 @@ exports[`simple templates, mostly static dynamic text value 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return text(ctx['text']);
@@ -144,7 +144,7 @@ exports[`simple templates, mostly static empty div 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div/>\`);
   
@@ -158,7 +158,7 @@ exports[`simple templates, mostly static empty string 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return text(\`\`);
@@ -170,7 +170,7 @@ exports[`simple templates, mostly static empty string in a template set 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return text(\`\`);
@@ -182,7 +182,7 @@ exports[`simple templates, mostly static multiple root nodes 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block2 = createBlock(\`<div>foo</div>\`);
   let block3 = createBlock(\`<span>hey</span>\`);
@@ -199,7 +199,7 @@ exports[`simple templates, mostly static simple string 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return text(\`hello vdom\`);
@@ -211,7 +211,7 @@ exports[`simple templates, mostly static simple string in t tag 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return text(\`hello vdom\`);
@@ -223,7 +223,7 @@ exports[`simple templates, mostly static static text and dynamic text (no t tag)
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     let b2 = text(\`hello \`);
@@ -237,7 +237,7 @@ exports[`simple templates, mostly static static text and dynamic text 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     let b2 = text(\`hello \`);
@@ -251,7 +251,7 @@ exports[`simple templates, mostly static t-esc in dom node 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
@@ -266,7 +266,7 @@ exports[`simple templates, mostly static t-esc in dom node, variations 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div>hello <block-text-0/></div>\`);
   
@@ -281,7 +281,7 @@ exports[`simple templates, mostly static t-esc in dom node, variations 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div>hello <block-text-0/> world</div>\`);
   
@@ -296,7 +296,7 @@ exports[`simple templates, mostly static two t-escs next to each other 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     let b2 = text(ctx['text1']);
@@ -310,7 +310,7 @@ exports[`simple templates, mostly static two t-escs next to each other 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     let b2 = text(ctx['text1']);
@@ -324,7 +324,7 @@ exports[`simple templates, mostly static two t-escs next to each other, in a div
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/><block-text-1/></div>\`);
   
diff --git a/tests/qweb/__snapshots__/t_call.test.ts.snap b/tests/qweb/__snapshots__/t_call.test.ts.snap
index 86d9782a..427bc495 100644
--- a/tests/qweb/__snapshots__/t_call.test.ts.snap
+++ b/tests/qweb/__snapshots__/t_call.test.ts.snap
@@ -4,7 +4,7 @@ exports[`t-call (template calling) basic caller 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>ok</span>\`);
   
@@ -18,7 +18,7 @@ exports[`t-call (template calling) basic caller 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`_basic-callee\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -34,7 +34,7 @@ exports[`t-call (template calling) basic caller, no parent node 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>ok</span>\`);
   
@@ -48,7 +48,7 @@ exports[`t-call (template calling) basic caller, no parent node 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`_basic-callee\`);
   
   return function template(ctx, node, key = \\"\\") {
@@ -61,7 +61,7 @@ exports[`t-call (template calling) call with several sub nodes on same line 1`]
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -76,7 +76,7 @@ exports[`t-call (template calling) call with several sub nodes on same line 2`]
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -85,6 +85,7 @@ exports[`t-call (template calling) call with several sub nodes on same line 2`]
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1;
     let b3 = block3();
     let b4 = text(\` \`);
     let b5 = block5();
@@ -100,7 +101,7 @@ exports[`t-call (template calling) cascading t-call t-raw='0' 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><span>cascade 2</span><block-child-0/></div>\`);
   
@@ -115,7 +116,7 @@ exports[`t-call (template calling) cascading t-call t-raw='0' 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`finalTemplate\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -123,6 +124,7 @@ exports[`t-call (template calling) cascading t-call t-raw='0' 2`] = `
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1;
     let b3 = block3();
     let b4 = html(ctx[zero]);
     let b2 = multi([b3, b4]);
@@ -137,7 +139,7 @@ exports[`t-call (template calling) cascading t-call t-raw='0' 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`subSubTemplate\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -145,6 +147,7 @@ exports[`t-call (template calling) cascading t-call t-raw='0' 3`] = `
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1;
     let b3 = block3();
     let b4 = html(ctx[zero]);
     let b2 = multi([b3, b4]);
@@ -159,7 +162,7 @@ exports[`t-call (template calling) cascading t-call t-raw='0' 4`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`subTemplate\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -168,6 +171,7 @@ exports[`t-call (template calling) cascading t-call t-raw='0' 4`] = `
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1;
     let b3 = block3();
     let b4 = text(\` \`);
     let b5 = block5();
@@ -183,7 +187,7 @@ exports[`t-call (template calling) cascading t-call t-raw='0', without external
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block2 = createBlock(\`<span>cascade 2</span>\`);
   
@@ -199,13 +203,14 @@ exports[`t-call (template calling) cascading t-call t-raw='0', without external
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`finalTemplate\`);
   
   let block2 = createBlock(\`<span>cascade 1</span>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1;
     let b2 = block2();
     let b3 = html(ctx[zero]);
     let b1 = multi([b2, b3]);
@@ -219,13 +224,14 @@ exports[`t-call (template calling) cascading t-call t-raw='0', without external
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`subSubTemplate\`);
   
   let block2 = createBlock(\`<span>cascade 0</span>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1;
     let b2 = block2();
     let b3 = html(ctx[zero]);
     let b1 = multi([b2, b3]);
@@ -239,7 +245,7 @@ exports[`t-call (template calling) cascading t-call t-raw='0', without external
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`subTemplate\`);
   
   let block2 = createBlock(\`<span>hey</span>\`);
@@ -247,6 +253,7 @@ exports[`t-call (template calling) cascading t-call t-raw='0', without external
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1;
     let b2 = block2();
     let b3 = text(\` \`);
     let b4 = block4();
@@ -261,7 +268,7 @@ exports[`t-call (template calling) dynamic t-call 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<foo><block-text-0/></foo>\`);
   
@@ -276,7 +283,7 @@ exports[`t-call (template calling) dynamic t-call 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<bar><block-text-0/></bar>\`);
   
@@ -291,7 +298,7 @@ exports[`t-call (template calling) dynamic t-call 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -307,7 +314,7 @@ exports[`t-call (template calling) inherit context 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return text(ctx['foo']);
@@ -319,14 +326,15 @@ exports[`t-call (template calling) inherit context 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
-    ctx[\`foo\`] = 1;
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"foo\\", 1);
     let b2 = callTemplate_2(ctx, node, key + \`__1\`);
     return block1([], [b2]);
   }
@@ -337,7 +345,7 @@ exports[`t-call (template calling) recursive template, part 1 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`recursive\`);
   
   let block1 = createBlock(\`<div><span>hey</span><block-child-0/></div>\`);
@@ -356,15 +364,17 @@ exports[`t-call (template calling) recursive template, part 2 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`nodeTemplate\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
     ctx = Object.create(ctx);
-    ctx[\`node\`] = ctx['root'];
+    ctx[isBoundary] = 1;
+    setContextValue(ctx, \\"node\\", ctx['root']);
     let b2 = callTemplate_2(ctx, node, key + \`__1\`);
     return block1([], [b2]);
   }
@@ -375,13 +385,14 @@ exports[`t-call (template calling) recursive template, part 2 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`nodeTemplate\`);
   
   let block1 = createBlock(\`<div><p><block-text-0/></p><block-child-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
     let d1 = ctx['node'].val;
     ctx = Object.create(ctx);
     const [k_block2, v_block2, l_block2, c_block2] = prepareList(ctx['node'].children||[]);
@@ -393,7 +404,8 @@ exports[`t-call (template calling) recursive template, part 2 2`] = `
       ctx[\`subtree_value\`] = k_block2[i1];
       let key1 = ctx['subtree_index'];
       ctx = Object.create(ctx);
-      ctx[\`node\`] = ctx['subtree'];
+      ctx[isBoundary] = 1;
+      setContextValue(ctx, \\"node\\", ctx['subtree']);
       c_block2[i1] = withKey(callTemplate_2(ctx, node, key + \`__1__\${key1}\`), key1);
       ctx = ctx.__proto__;
     }
@@ -407,15 +419,17 @@ exports[`t-call (template calling) recursive template, part 3 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`nodeTemplate\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
     ctx = Object.create(ctx);
-    ctx[\`node\`] = ctx['root'];
+    ctx[isBoundary] = 1;
+    setContextValue(ctx, \\"node\\", ctx['root']);
     let b2 = callTemplate_2(ctx, node, key + \`__1\`);
     return block1([], [b2]);
   }
@@ -426,13 +440,14 @@ exports[`t-call (template calling) recursive template, part 3 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`nodeTemplate\`);
   
   let block1 = createBlock(\`<div><p><block-text-0/></p><block-child-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
     let d1 = ctx['node'].val;
     ctx = Object.create(ctx);
     const [k_block2, v_block2, l_block2, c_block2] = prepareList(ctx['node'].children||[]);
@@ -444,7 +459,8 @@ exports[`t-call (template calling) recursive template, part 3 2`] = `
       ctx[\`subtree_value\`] = k_block2[i1];
       let key1 = ctx['subtree_index'];
       ctx = Object.create(ctx);
-      ctx[\`node\`] = ctx['subtree'];
+      ctx[isBoundary] = 1;
+      setContextValue(ctx, \\"node\\", ctx['subtree']);
       c_block2[i1] = withKey(callTemplate_2(ctx, node, key + \`__1__\${key1}\`), key1);
       ctx = ctx.__proto__;
     }
@@ -458,16 +474,18 @@ exports[`t-call (template calling) recursive template, part 4: with t-set recurs
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`nodeTemplate\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
     ctx = Object.create(ctx);
-    ctx[\`recursive_idx\`] = 1;
-    ctx[\`node\`] = ctx['root'];
+    ctx[isBoundary] = 1;
+    setContextValue(ctx, \\"recursive_idx\\", 1);
+    setContextValue(ctx, \\"node\\", ctx['root']);
     let b2 = callTemplate_2(ctx, node, key + \`__1\`);
     return block1([], [b2]);
   }
@@ -478,14 +496,15 @@ exports[`t-call (template calling) recursive template, part 4: with t-set recurs
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`nodeTemplate\`);
   
   let block1 = createBlock(\`<div><p><block-text-0/> <block-text-1/></p><block-child-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
-    ctx[\`recursive_idx\`] = ctx['recursive_idx']+1;
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"recursive_idx\\", ctx['recursive_idx']+1);
     let d1 = ctx['node'].val;
     let d2 = ctx['recursive_idx'];
     ctx = Object.create(ctx);
@@ -498,7 +517,8 @@ exports[`t-call (template calling) recursive template, part 4: with t-set recurs
       ctx[\`subtree_value\`] = k_block2[i1];
       let key1 = ctx['subtree_index'];
       ctx = Object.create(ctx);
-      ctx[\`node\`] = ctx['subtree'];
+      ctx[isBoundary] = 1;
+      setContextValue(ctx, \\"node\\", ctx['subtree']);
       c_block2[i1] = withKey(callTemplate_2(ctx, node, key + \`__1__\${key1}\`), key1);
       ctx = ctx.__proto__;
     }
@@ -512,7 +532,7 @@ exports[`t-call (template calling) scoped parameters 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return text(\`ok\`);
@@ -524,15 +544,17 @@ exports[`t-call (template calling) scoped parameters 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/><block-text-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
     ctx = Object.create(ctx);
-    ctx[\`foo\`] = 42;
+    ctx[isBoundary] = 1;
+    setContextValue(ctx, \\"foo\\", 42);
     let b2 = callTemplate_2(ctx, node, key + \`__1\`);
     ctx = ctx.__proto__;
     let d1 = ctx['foo'];
@@ -545,7 +567,7 @@ exports[`t-call (template calling) scoped parameters, part 2 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return text(ctx['foo']);
@@ -557,16 +579,18 @@ exports[`t-call (template calling) scoped parameters, part 2 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/><block-text-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
-    ctx[\`foo\`] = 11;
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"foo\\", 11);
     ctx = Object.create(ctx);
-    ctx[\`foo\`] = 42;
+    ctx[isBoundary] = 1;
+    setContextValue(ctx, \\"foo\\", 42);
     let b2 = callTemplate_2(ctx, node, key + \`__1\`);
     ctx = ctx.__proto__;
     let d1 = ctx['foo'];
@@ -579,7 +603,7 @@ exports[`t-call (template calling) t-call allowed on a non t node 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -595,7 +619,7 @@ exports[`t-call (template calling) t-call allowed on a non t node 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>ok</span>\`);
   
@@ -609,7 +633,7 @@ exports[`t-call (template calling) t-call with body content as root of a templat
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<foo><block-child-0/></foo>\`);
   
@@ -624,13 +648,14 @@ exports[`t-call (template calling) t-call with body content as root of a templat
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`antony\`);
   
   let block1 = createBlock(\`<p>antony</p>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1;
     let b1 = block1();
     ctx[zero] = b1;
     return callTemplate_2(ctx, node, key + \`__1\`);
@@ -642,7 +667,7 @@ exports[`t-call (template calling) t-call with t-if 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -661,7 +686,7 @@ exports[`t-call (template calling) t-call with t-if 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span>ok</span>\`);
   
@@ -675,15 +700,17 @@ exports[`t-call (template calling) t-call with t-set inside and body text conten
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
     ctx = Object.create(ctx);
-    ctx[\`val\`] = \`yip yip\`;
+    ctx[isBoundary] = 1;
+    setContextValue(ctx, \\"val\\", \`yip yip\`);
     let b2 = callTemplate_2(ctx, node, key + \`__1\`);
     return block1([], [b2]);
   }
@@ -694,7 +721,7 @@ exports[`t-call (template calling) t-call with t-set inside and body text conten
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<p><block-text-0/></p>\`);
   
@@ -709,13 +736,14 @@ exports[`t-call (template calling) t-call with t-set inside and outside 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
     ctx = Object.create(ctx);
     const [k_block2, v_block2, l_block2, c_block2] = prepareList(ctx['list']);
     for (let i1 = 0; i1 < l_block2; i1++) {
@@ -725,9 +753,10 @@ exports[`t-call (template calling) t-call with t-set inside and outside 1`] = `
       ctx[\`v_index\`] = i1;
       ctx[\`v_value\`] = k_block2[i1];
       let key1 = ctx['v_index'];
-      ctx[\`val\`] = ctx['v'].val;
+      setContextValue(ctx, \\"val\\", ctx['v'].val);
       ctx = Object.create(ctx);
-      ctx[\`val3\`] = ctx['val']*3;
+      ctx[isBoundary] = 1;
+      setContextValue(ctx, \\"val3\\", ctx['val']*3);
       c_block2[i1] = withKey(callTemplate_2(ctx, node, key + \`__1__\${key1}\`), key1);
       ctx = ctx.__proto__;
     }
@@ -741,7 +770,7 @@ exports[`t-call (template calling) t-call with t-set inside and outside 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -756,13 +785,14 @@ exports[`t-call (template calling) t-call with t-set inside and outside. 2 1`] =
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
     ctx = Object.create(ctx);
     const [k_block2, v_block2, l_block2, c_block2] = prepareList(ctx['list']);
     for (let i1 = 0; i1 < l_block2; i1++) {
@@ -772,9 +802,10 @@ exports[`t-call (template calling) t-call with t-set inside and outside. 2 1`] =
       ctx[\`v_index\`] = i1;
       ctx[\`v_value\`] = k_block2[i1];
       let key1 = ctx['v_index'];
-      ctx[\`val\`] = ctx['v'].val;
+      setContextValue(ctx, \\"val\\", ctx['v'].val);
       ctx = Object.create(ctx);
-      ctx[\`val3\`] = ctx['val']*3;
+      ctx[isBoundary] = 1;
+      setContextValue(ctx, \\"val3\\", ctx['val']*3);
       c_block2[i1] = withKey(callTemplate_2(ctx, node, key + \`__1__\${key1}\`), key1);
       ctx = ctx.__proto__;
     }
@@ -788,7 +819,7 @@ exports[`t-call (template calling) t-call with t-set inside and outside. 2 2`] =
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block2 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -805,14 +836,15 @@ exports[`t-call (template calling) t-call with t-set inside and outside. 2 3`] =
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`main\`);
   
   let block1 = createBlock(\`<p><block-child-0/></p>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
-    ctx[\`w\`] = 'fromwrapper';
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"w\\", 'fromwrapper');
     let b2 = callTemplate_2(ctx, node, key + \`__1\`);
     return block1([], [b2]);
   }
@@ -823,7 +855,7 @@ exports[`t-call (template calling) t-call, conditional and t-set in t-call body
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div>callee1</div>\`);
   
@@ -837,7 +869,7 @@ exports[`t-call (template calling) t-call, conditional and t-set in t-call body
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div>callee2 <block-text-0/></div>\`);
   
@@ -852,7 +884,7 @@ exports[`t-call (template calling) t-call, conditional and t-set in t-call body
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`callee1\`);
   const callTemplate_4 = getTemplate(\`callee2\`);
   
@@ -860,13 +892,15 @@ exports[`t-call (template calling) t-call, conditional and t-set in t-call body
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
     let b2,b3;
-    ctx[\`v1\`] = 'elif';
+    setContextValue(ctx, \\"v1\\", 'elif');
     if (ctx['v1']==='if') {
       b2 = callTemplate_2(ctx, node, key + \`__1\`);
     } else if (ctx['v1']==='elif') {
       ctx = Object.create(ctx);
-      ctx[\`v\`] = 'success';
+      ctx[isBoundary] = 1;
+      setContextValue(ctx, \\"v\\", 'success');
       b3 = callTemplate_4(ctx, node, key + \`__3\`);
       ctx = ctx.__proto__;
     }
@@ -879,14 +913,15 @@ exports[`t-call (template calling) t-esc inside t-call, with t-set outside 1`] =
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
-    ctx[\`v\`] = \`Hi\`;
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"v\\", \`Hi\`);
     let b2 = callTemplate_2(ctx, node, key + \`__1\`);
     return block1([], [b2]);
   }
@@ -897,7 +932,7 @@ exports[`t-call (template calling) t-esc inside t-call, with t-set outside 2`] =
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -912,7 +947,7 @@ exports[`t-call (template calling) with unused body 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div>ok</div>\`);
   
@@ -926,11 +961,12 @@ exports[`t-call (template calling) with unused body 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`sub\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1;
     let b1 = text(\`WHEEE\`);
     ctx[zero] = b1;
     return callTemplate_2(ctx, node, key + \`__1\`);
@@ -942,7 +978,7 @@ exports[`t-call (template calling) with unused setbody 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div>ok</div>\`);
   
@@ -956,13 +992,15 @@ exports[`t-call (template calling) with unused setbody 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`sub\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
     ctx = Object.create(ctx);
-    ctx[\`qux\`] = 3;
+    ctx[isBoundary] = 1;
+    setContextValue(ctx, \\"qux\\", 3);
     return callTemplate_2(ctx, node, key + \`__1\`);
   }
 }"
@@ -972,7 +1010,7 @@ exports[`t-call (template calling) with used body 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<h1><block-text-0/></h1>\`);
   
@@ -987,11 +1025,12 @@ exports[`t-call (template calling) with used body 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`sub\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1;
     let b1 = text(\`ok\`);
     ctx[zero] = b1;
     return callTemplate_2(ctx, node, key + \`__1\`);
@@ -1003,7 +1042,7 @@ exports[`t-call (template calling) with used setbody 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return text(ctx['foo']);
@@ -1015,15 +1054,17 @@ exports[`t-call (template calling) with used setbody 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
     ctx = Object.create(ctx);
-    ctx[\`foo\`] = 'ok';
+    ctx[isBoundary] = 1;
+    setContextValue(ctx, \\"foo\\", 'ok');
     let b2 = callTemplate_2(ctx, node, key + \`__1\`);
     return block1([], [b2]);
   }
diff --git a/tests/qweb/__snapshots__/t_debug_log.test.ts.snap b/tests/qweb/__snapshots__/t_debug_log.test.ts.snap
index 38a44e29..a8287e96 100644
--- a/tests/qweb/__snapshots__/t_debug_log.test.ts.snap
+++ b/tests/qweb/__snapshots__/t_debug_log.test.ts.snap
@@ -4,7 +4,7 @@ exports[`debugging t-debug 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block2 = createBlock(\`<span>hey</span>\`);
@@ -25,13 +25,14 @@ exports[`debugging t-log 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div/>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
-    ctx[\`foo\`] = 42;
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"foo\\", 42);
     console.log(ctx['foo']+3);
     return block1();
   }
diff --git a/tests/qweb/__snapshots__/t_esc.test.ts.snap b/tests/qweb/__snapshots__/t_esc.test.ts.snap
index b00e302b..1e6bae99 100644
--- a/tests/qweb/__snapshots__/t_esc.test.ts.snap
+++ b/tests/qweb/__snapshots__/t_esc.test.ts.snap
@@ -4,7 +4,7 @@ exports[`t-esc div with falsy values 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><p><block-text-0/></p><p><block-text-1/></p><p><block-text-2/></p><p><block-text-3/></p><p><block-text-4/></p></div>\`);
   
@@ -23,7 +23,7 @@ exports[`t-esc escaping 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -38,7 +38,7 @@ exports[`t-esc escaping on a node 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -53,7 +53,7 @@ exports[`t-esc escaping on a node with a body 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -68,7 +68,7 @@ exports[`t-esc escaping on a node with a body, as a default 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -83,7 +83,7 @@ exports[`t-esc falsy values in text nodes 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     let b2 = text(ctx['v1']);
@@ -104,7 +104,7 @@ exports[`t-esc literal 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -119,13 +119,14 @@ exports[`t-esc t-esc is escaped 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   let block2 = createBlock(\`<p>escaped</p>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
     let b2 = block2();
     ctx[\`var\`] = b2;
     let d1 = ctx['var'];
@@ -138,7 +139,7 @@ exports[`t-esc t-esc work with spread operator 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -153,7 +154,7 @@ exports[`t-esc t-esc=0 is escaped 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -168,7 +169,7 @@ exports[`t-esc t-esc=0 is escaped 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -176,6 +177,7 @@ exports[`t-esc t-esc=0 is escaped 2`] = `
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1;
     let b2 = block2();
     ctx[zero] = b2;
     let b3 = callTemplate_2(ctx, node, key + \`__1\`);
@@ -188,7 +190,7 @@ exports[`t-esc variable 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-text-0/></span>\`);
   
diff --git a/tests/qweb/__snapshots__/t_foreach.test.ts.snap b/tests/qweb/__snapshots__/t_foreach.test.ts.snap
index eeabc2e6..e279a38c 100644
--- a/tests/qweb/__snapshots__/t_foreach.test.ts.snap
+++ b/tests/qweb/__snapshots__/t_foreach.test.ts.snap
@@ -4,7 +4,7 @@ exports[`t-foreach does not pollute the rendering context 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -26,7 +26,7 @@ exports[`t-foreach iterate on items (on a element node) 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block3 = createBlock(\`<span><block-text-0/></span>\`);
@@ -50,7 +50,7 @@ exports[`t-foreach iterate on items 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -81,7 +81,7 @@ exports[`t-foreach iterate, dict param 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -112,7 +112,7 @@ exports[`t-foreach iterate, position 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -148,7 +148,7 @@ exports[`t-foreach simple iteration (in a node) 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -170,7 +170,7 @@ exports[`t-foreach simple iteration 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
@@ -189,7 +189,7 @@ exports[`t-foreach simple iteration with two nodes inside 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block3 = createBlock(\`<span>a<block-text-0/></span>\`);
   let block4 = createBlock(\`<span>b<block-text-0/></span>\`);
@@ -215,7 +215,7 @@ exports[`t-foreach t-call with body in t-foreach in t-foreach 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     let b2 = text(\` [\`);
@@ -234,7 +234,7 @@ exports[`t-foreach t-call with body in t-foreach in t-foreach 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/><span>[<block-text-0/>][<block-text-1/>][<block-text-2/>]</span></div>\`);
@@ -242,6 +242,7 @@ exports[`t-foreach t-call with body in t-foreach in t-foreach 2`] = `
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
     ctx = Object.create(ctx);
     const [k_block2, v_block2, l_block2, c_block2] = prepareList(ctx['numbers']);
     for (let i1 = 0; i1 < l_block2; i1++) {
@@ -261,7 +262,8 @@ exports[`t-foreach t-call with body in t-foreach in t-foreach 2`] = `
         ctx[\`b_value\`] = k_block4[i2];
         let key2 = ctx['b'];
         ctx = Object.create(ctx);
-        ctx[\`c\`] = 'x'+'_'+ctx['a']+'_'+ctx['b'];
+        ctx[isBoundary] = 1;
+        setContextValue(ctx, \\"c\\", 'x'+'_'+ctx['a']+'_'+ctx['b']);
         c_block4[i2] = withKey(callTemplate_2(ctx, node, key + \`__1__\${key1}__\${key2}\`), key2);
         ctx = ctx.__proto__;
       }
@@ -285,11 +287,12 @@ exports[`t-foreach t-call without body in t-foreach in t-foreach 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
-    ctx[\`c\`] = 'x'+'_'+ctx['a']+'_'+ctx['b'];
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"c\\", 'x'+'_'+ctx['a']+'_'+ctx['b']);
     let b2 = text(\` [\`);
     let b3 = text(ctx['a']);
     let b4 = text(\`] [\`);
@@ -306,7 +309,7 @@ exports[`t-foreach t-call without body in t-foreach in t-foreach 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/><span>[<block-text-0/>][<block-text-1/>][<block-text-2/>]</span></div>\`);
@@ -353,7 +356,7 @@ exports[`t-foreach t-foreach in t-foreach 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -387,7 +390,7 @@ exports[`t-foreach t-foreach with t-if inside (no external node) 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block3 = createBlock(\`<span><block-text-0/></span>\`);
   
@@ -413,7 +416,7 @@ exports[`t-foreach t-foreach with t-if inside 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block4 = createBlock(\`<span><block-text-0/></span>\`);
@@ -441,7 +444,7 @@ exports[`t-foreach throws error if invalid loop expression 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block3 = createBlock(\`<span/>\`);
@@ -465,7 +468,7 @@ exports[`t-foreach warn if no key in some case 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block3 = createBlock(\`<span><block-text-0/></span>\`);
@@ -489,7 +492,7 @@ exports[`t-foreach with t-memo 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   let assign = Object.assign;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
diff --git a/tests/qweb/__snapshots__/t_if.test.ts.snap b/tests/qweb/__snapshots__/t_if.test.ts.snap
index c56b3ef9..4e475542 100644
--- a/tests/qweb/__snapshots__/t_if.test.ts.snap
+++ b/tests/qweb/__snapshots__/t_if.test.ts.snap
@@ -4,7 +4,7 @@ exports[`t-if a t-if next to a div 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block2 = createBlock(\`<div>foo</div>\`);
   
@@ -23,7 +23,7 @@ exports[`t-if a t-if with two inner nodes 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block3 = createBlock(\`<span>yip</span>\`);
   let block4 = createBlock(\`<div>yip</div>\`);
@@ -44,7 +44,7 @@ exports[`t-if boolean value condition elif (no outside node) 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     let b2,b3,b4,b5;
@@ -66,7 +66,7 @@ exports[`t-if boolean value condition elif 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/><block-child-2/><block-child-3/></div>\`);
   
@@ -90,7 +90,7 @@ exports[`t-if boolean value condition else 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><span>begin</span><block-child-0/><block-child-1/><span>end</span></div>\`);
   
@@ -110,7 +110,7 @@ exports[`t-if boolean value condition false else 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><span>begin</span><block-child-0/><block-child-1/><span>end</span></div>\`);
   
@@ -130,7 +130,7 @@ exports[`t-if boolean value condition missing 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
   
@@ -148,7 +148,7 @@ exports[`t-if can use some boolean operators in expressions 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/><block-child-2/><block-child-3/><block-child-4/><block-child-5/><block-child-6/><block-child-7/></div>\`);
   
@@ -187,7 +187,7 @@ exports[`t-if div containing a t-if with two inner nodes 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block3 = createBlock(\`<span>yip</span>\`);
@@ -209,7 +209,7 @@ exports[`t-if dynamic content after t-if with two children nodes 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><block-text-0/></div>\`);
   let block3 = createBlock(\`<p>1</p>\`);
@@ -232,7 +232,7 @@ exports[`t-if just a t-if 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     let b2;
@@ -248,7 +248,7 @@ exports[`t-if simple t-if/t-else 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     let b2,b3;
@@ -266,7 +266,7 @@ exports[`t-if simple t-if/t-else in a div 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
   
@@ -286,7 +286,7 @@ exports[`t-if t-esc with t-elif 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
   
@@ -306,7 +306,7 @@ exports[`t-if t-esc with t-if 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -324,7 +324,7 @@ exports[`t-if t-if and t-else with two nodes 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block4 = createBlock(\`<span>a</span>\`);
   let block5 = createBlock(\`<span>b</span>\`);
@@ -347,7 +347,7 @@ exports[`t-if t-if in a div 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -365,7 +365,7 @@ exports[`t-if t-if in a t-if 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block2 = createBlock(\`<span>1<block-child-0/></span>\`);
@@ -388,7 +388,7 @@ exports[`t-if t-if/t-else with more content 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     let b2,b3;
@@ -408,14 +408,15 @@ exports[`t-if t-set, then t-if 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
     let b2;
-    ctx[\`title\`] = 'test';
+    setContextValue(ctx, \\"title\\", 'test');
     if (ctx['title']) {
       b2 = text(ctx['title']);
     }
@@ -428,16 +429,17 @@ exports[`t-if t-set, then t-if, part 2 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block2 = createBlock(\`<span>COUCOU</span>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
     let b2;
-    ctx[\`y\`] = true;
-    ctx[\`x\`] = ctx['y'];
+    setContextValue(ctx, \\"y\\", true);
+    setContextValue(ctx, \\"x\\", ctx['y']);
     if (ctx['x']) {
       b2 = block2();
     }
@@ -450,7 +452,7 @@ exports[`t-if t-set, then t-if, part 3 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
   let block2 = createBlock(\`<span>AAA</span>\`);
@@ -458,9 +460,10 @@ exports[`t-if t-set, then t-if, part 3 1`] = `
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
     let b2,b3;
-    ctx[\`y\`] = false;
-    ctx[\`x\`] = ctx['y'];
+    setContextValue(ctx, \\"y\\", false);
+    setContextValue(ctx, \\"x\\", ctx['y']);
     if (ctx['x']) {
       b2 = block2();
     } else if (!ctx['x']) {
@@ -475,7 +478,7 @@ exports[`t-if two consecutive t-if 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     let b2,b3;
@@ -494,7 +497,7 @@ exports[`t-if two consecutive t-if in a div 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
   
@@ -515,7 +518,7 @@ exports[`t-if two t-ifs next to each other 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-1/></div>\`);
   let block2 = createBlock(\`<span><block-text-0/></span>\`);
diff --git a/tests/qweb/__snapshots__/t_raw.test.ts.snap b/tests/qweb/__snapshots__/t_raw.test.ts.snap
index 1d288e5f..e77cc5c0 100644
--- a/tests/qweb/__snapshots__/t_raw.test.ts.snap
+++ b/tests/qweb/__snapshots__/t_raw.test.ts.snap
@@ -4,7 +4,7 @@ exports[`t-raw literal 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
   
@@ -19,7 +19,7 @@ exports[`t-raw literal, no outside html element 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return html('ok');
@@ -31,7 +31,7 @@ exports[`t-raw multiple calls to t-raw 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><div>Greeter</div><block-child-1/></div>\`);
   
@@ -47,7 +47,7 @@ exports[`t-raw multiple calls to t-raw 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -55,6 +55,7 @@ exports[`t-raw multiple calls to t-raw 2`] = `
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1;
     let b2 = block2();
     ctx[zero] = b2;
     let b3 = callTemplate_2(ctx, node, key + \`__1\`);
@@ -67,7 +68,7 @@ exports[`t-raw not escaping 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
@@ -82,7 +83,7 @@ exports[`t-raw t-raw and another sibling node 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><span>hello</span><block-child-0/></span>\`);
   
@@ -97,7 +98,7 @@ exports[`t-raw t-raw on a node with a body, as a default 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
   
@@ -113,7 +114,7 @@ exports[`t-raw t-raw on a node with a dom node in body, as a default 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
   let block3 = createBlock(\`<div>nope</div>\`);
@@ -130,7 +131,7 @@ exports[`t-raw t-raw with a <t/> in body 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return html(ctx['var']);
@@ -142,7 +143,7 @@ exports[`t-raw t-raw with comment 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
   
@@ -157,7 +158,7 @@ exports[`t-raw t-raw with just a t-set t-value in body 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     return html(ctx['var']);
@@ -169,7 +170,7 @@ exports[`t-raw variable 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<span><block-child-0/></span>\`);
   
diff --git a/tests/qweb/__snapshots__/t_ref.test.ts.snap b/tests/qweb/__snapshots__/t_ref.test.ts.snap
index 8ad70a95..1329f983 100644
--- a/tests/qweb/__snapshots__/t_ref.test.ts.snap
+++ b/tests/qweb/__snapshots__/t_ref.test.ts.snap
@@ -4,7 +4,7 @@ exports[`t-ref can get a dynamic ref on a node 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><span block-ref=\\"0\\"/></div>\`);
   
@@ -21,7 +21,7 @@ exports[`t-ref can get a ref on a node 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><span block-ref=\\"0\\"/></div>\`);
   
@@ -37,7 +37,7 @@ exports[`t-ref ref in a t-call 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   const callTemplate_2 = getTemplate(\`sub\`);
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
@@ -53,7 +53,7 @@ exports[`t-ref ref in a t-call 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div>1<span block-ref=\\"0\\"/>2</div>\`);
   
@@ -69,7 +69,7 @@ exports[`t-ref ref in a t-if 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block2 = createBlock(\`<span block-ref=\\"0\\"/>\`);
@@ -90,7 +90,7 @@ exports[`t-ref refs in a loop 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block3 = createBlock(\`<div block-ref=\\"0\\"><block-text-1/></div>\`);
@@ -117,7 +117,7 @@ exports[`t-ref two refs, one in a t-if 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><p block-ref=\\"0\\"/></div>\`);
   let block2 = createBlock(\`<span block-ref=\\"0\\"/>\`);
diff --git a/tests/qweb/__snapshots__/t_set.test.ts.snap b/tests/qweb/__snapshots__/t_set.test.ts.snap
index 630fa956..62b989b0 100644
--- a/tests/qweb/__snapshots__/t_set.test.ts.snap
+++ b/tests/qweb/__snapshots__/t_set.test.ts.snap
@@ -4,13 +4,14 @@ exports[`t-set evaluate value expression 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
-    ctx[\`value\`] = 1+2;
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"value\\", 1+2);
     let d1 = ctx['value'];
     return block1([d1]);
   }
@@ -21,13 +22,14 @@ exports[`t-set evaluate value expression, part 2 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
-    ctx[\`value\`] = ctx['somevariable']+2;
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"value\\", ctx['somevariable']+2);
     let d1 = ctx['value'];
     return block1([d1]);
   }
@@ -38,11 +40,12 @@ exports[`t-set set from attribute literal (no outside div) 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
-    ctx[\`value\`] = 'ok';
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"value\\", 'ok');
     return text(ctx['value']);
   }
 }"
@@ -52,13 +55,14 @@ exports[`t-set set from attribute literal 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
-    ctx[\`value\`] = 'ok';
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"value\\", 'ok');
     let d1 = ctx['value'];
     return block1([d1]);
   }
@@ -69,13 +73,14 @@ exports[`t-set set from attribute lookup 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
-    ctx[\`stuff\`] = ctx['value'];
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"stuff\\", ctx['value']);
     let d1 = ctx['stuff'];
     return block1([d1]);
   }
@@ -86,11 +91,12 @@ exports[`t-set set from body literal 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
-    ctx[\`value\`] = \`ok\`;
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"value\\", \`ok\`);
     return text(ctx['value']);
   }
 }"
@@ -100,12 +106,13 @@ exports[`t-set set from body lookup 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
     let b2 = text(ctx['value']);
     ctx[\`stuff\`] = b2;
     let d1 = ctx['stuff'];
@@ -118,13 +125,14 @@ exports[`t-set set from empty body 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
-    ctx[\`stuff\`] = null;
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"stuff\\", null);
     let d1 = ctx['stuff'];
     return block1([d1]);
   }
@@ -135,14 +143,15 @@ exports[`t-set t-set and t-if 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
     let b2;
-    ctx[\`v\`] = ctx['value'];
+    setContextValue(ctx, \\"v\\", ctx['value']);
     if (ctx['v']==='ok') {
       b2 = text(\`grimbergen\`);
     }
@@ -155,35 +164,139 @@ exports[`t-set t-set body is evaluated immediately 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block2 = createBlock(\`<span><block-text-0/></span>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
-    ctx[\`v1\`] = 'before';
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"v1\\", 'before');
     let d1 = ctx['v1'];
     let b2 = block2([d1]);
     ctx[\`v2\`] = b2;
-    ctx[\`v1\`] = 'after';
+    setContextValue(ctx, \\"v1\\", 'after');
     let b3 = html(ctx['v2']);
     return block1([], [b3]);
   }
 }"
 `;
 
+exports[`t-set t-set can't alter from within callee 1`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component } = bdom;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
+  
+  let block1 = createBlock(\`<div><block-text-0/><block-text-1/></div>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
+    let d1 = ctx['iter'];
+    setContextValue(ctx, \\"iter\\", 'called');
+    let d2 = ctx['iter'];
+    return block1([d1, d2]);
+  }
+}"
+`;
+
+exports[`t-set t-set can't alter from within callee 2`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component } = bdom;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
+  const callTemplate_2 = getTemplate(\`sub\`);
+  
+  let block1 = createBlock(\`<div><p><block-text-0/></p><block-child-0/><p><block-text-1/></p></div>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"iter\\", 'source');
+    let d1 = ctx['iter'];
+    let b2 = callTemplate_2(ctx, node, key + \`__1\`);
+    let d2 = ctx['iter'];
+    return block1([d1, d2], [b2]);
+  }
+}"
+`;
+
+exports[`t-set t-set can't alter in t-call body 1`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component } = bdom;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
+  
+  let block1 = createBlock(\`<div><block-text-0/><block-text-1/></div>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
+    let d1 = ctx['iter'];
+    setContextValue(ctx, \\"iter\\", 'called');
+    let d2 = ctx['iter'];
+    return block1([d1, d2]);
+  }
+}"
+`;
+
+exports[`t-set t-set can't alter in t-call body 2`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component } = bdom;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
+  const callTemplate_2 = getTemplate(\`sub\`);
+  
+  let block1 = createBlock(\`<div><p><block-text-0/></p><block-child-0/><p><block-text-1/></p></div>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"iter\\", 'source');
+    let d1 = ctx['iter'];
+    ctx = Object.create(ctx);
+    ctx[isBoundary] = 1;
+    setContextValue(ctx, \\"iter\\", 'inCall');
+    let b2 = callTemplate_2(ctx, node, key + \`__1\`);
+    ctx = ctx.__proto__;
+    let d2 = ctx['iter'];
+    return block1([d1, d2], [b2]);
+  }
+}"
+`;
+
+exports[`t-set t-set does not modify render context existing key values 1`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component } = bdom;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
+  
+  let block1 = createBlock(\`<div><block-text-0/></div>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"value\\", 35);
+    let d1 = ctx['value'];
+    return block1([d1]);
+  }
+}"
+`;
+
 exports[`t-set t-set evaluates an expression only once 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/><block-text-1/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
-    ctx[\`v\`] = ctx['value']+' artois';
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"v\\", ctx['value']+' artois');
     let d1 = ctx['v'];
     let d2 = ctx['v'];
     return block1([d1, d2]);
@@ -191,18 +304,109 @@ exports[`t-set t-set evaluates an expression only once 1`] = `
 }"
 `;
 
+exports[`t-set t-set outside modified in t-foreach 1`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component } = bdom;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
+  
+  let block1 = createBlock(\`<div><block-child-0/><p>EndLoop: <block-text-0/></p></div>\`);
+  let block3 = createBlock(\`<p>InLoop: <block-text-0/></p>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"iter\\", 0);
+    ctx = Object.create(ctx);
+    const [k_block2, v_block2, l_block2, c_block2] = prepareList(['a','b']);
+    for (let i1 = 0; i1 < l_block2; i1++) {
+      ctx[\`val\`] = v_block2[i1];
+      let key1 = ctx['val'];
+      let d1 = ctx['iter'];
+      c_block2[i1] = withKey(block3([d1]), key1);
+      setContextValue(ctx, \\"iter\\", ctx['iter']+1);
+    }
+    ctx = ctx.__proto__;
+    let b2 = list(c_block2);
+    let d2 = ctx['iter'];
+    return block1([d2], [b2]);
+  }
+}"
+`;
+
+exports[`t-set t-set outside modified in t-foreach increment-after operator 1`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component } = bdom;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
+  
+  let block1 = createBlock(\`<div><block-child-0/><p>EndLoop: <block-text-0/></p></div>\`);
+  let block3 = createBlock(\`<p>InLoop: <block-text-0/></p>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"iter\\", 0);
+    ctx = Object.create(ctx);
+    const [k_block2, v_block2, l_block2, c_block2] = prepareList(['a','b']);
+    for (let i1 = 0; i1 < l_block2; i1++) {
+      ctx[\`val\`] = v_block2[i1];
+      let key1 = ctx['val'];
+      let d1 = ctx['iter'];
+      c_block2[i1] = withKey(block3([d1]), key1);
+      setContextValue(ctx, \\"iter\\", ctx['iter']++);
+    }
+    ctx = ctx.__proto__;
+    let b2 = list(c_block2);
+    let d2 = ctx['iter'];
+    return block1([d2], [b2]);
+  }
+}"
+`;
+
+exports[`t-set t-set outside modified in t-foreach increment-before operator 1`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component } = bdom;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
+  
+  let block1 = createBlock(\`<div><block-child-0/><p>EndLoop: <block-text-0/></p></div>\`);
+  let block3 = createBlock(\`<p>InLoop: <block-text-0/></p>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"iter\\", 0);
+    ctx = Object.create(ctx);
+    const [k_block2, v_block2, l_block2, c_block2] = prepareList(['a','b']);
+    for (let i1 = 0; i1 < l_block2; i1++) {
+      ctx[\`val\`] = v_block2[i1];
+      let key1 = ctx['val'];
+      let d1 = ctx['iter'];
+      c_block2[i1] = withKey(block3([d1]), key1);
+      setContextValue(ctx, \\"iter\\", ++ctx['iter']);
+    }
+    ctx = ctx.__proto__;
+    let b2 = list(c_block2);
+    let d2 = ctx['iter'];
+    return block1([d2], [b2]);
+  }
+}"
+`;
+
 exports[`t-set t-set should reuse variable if possible 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block3 = createBlock(\`<div><span>v<block-text-0/></span></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
-    ctx[\`v\`] = 1;
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"v\\", 1);
     ctx = Object.create(ctx);
     const [k_block2, v_block2, l_block2, c_block2] = prepareList(ctx['list']);
     for (let i1 = 0; i1 < l_block2; i1++) {
@@ -210,7 +414,7 @@ exports[`t-set t-set should reuse variable if possible 1`] = `
       ctx[\`elem_index\`] = i1;
       let key1 = ctx['elem_index'];
       let d1 = ctx['v'];
-      ctx[\`v\`] = ctx['elem'];
+      setContextValue(ctx, \\"v\\", ctx['elem']);
       c_block2[i1] = withKey(block3([d1]), key1);
     }
     let b2 = list(c_block2);
@@ -223,12 +427,13 @@ exports[`t-set t-set with content and sub t-esc 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
     let b3 = text(ctx['beep']);
     let b4 = text(\` boop\`);
     let b2 = multi([b3, b4]);
@@ -243,20 +448,21 @@ exports[`t-set t-set with t-value (falsy) and body 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block2 = createBlock(\`<span><block-text-0/></span>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
-    ctx[\`v3\`] = false;
-    ctx[\`v1\`] = 'before';
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"v3\\", false);
+    setContextValue(ctx, \\"v1\\", 'before');
     let d1 = ctx['v1'];
     let b2 = block2([d1]);
     ctx[\`v2\`] = withDefault(ctx['v3'], b2);
-    ctx[\`v1\`] = 'after';
-    ctx[\`v3\`] = true;
+    setContextValue(ctx, \\"v1\\", 'after');
+    setContextValue(ctx, \\"v3\\", true);
     let b3 = html(ctx['v2']);
     return block1([], [b3]);
   }
@@ -267,20 +473,21 @@ exports[`t-set t-set with t-value (truthy) and body 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/></div>\`);
   let block2 = createBlock(\`<span><block-text-0/></span>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
-    ctx[\`v3\`] = 'Truthy';
-    ctx[\`v1\`] = 'before';
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"v3\\", 'Truthy');
+    setContextValue(ctx, \\"v1\\", 'before');
     let d1 = ctx['v1'];
     let b2 = block2([d1]);
     ctx[\`v2\`] = withDefault(ctx['v3'], b2);
-    ctx[\`v1\`] = 'after';
-    ctx[\`v3\`] = false;
+    setContextValue(ctx, \\"v1\\", 'after');
+    setContextValue(ctx, \\"v3\\", false);
     let b3 = html(ctx['v2']);
     return block1([], [b3]);
   }
@@ -291,16 +498,17 @@ exports[`t-set t-set, t-if, and mix of expression/body lookup, 1 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-0/><block-text-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
     if (ctx['flag']) {
-      ctx[\`ourvar\`] = \`1\`;
+      setContextValue(ctx, \\"ourvar\\", \`1\`);
     } else {
-      ctx[\`ourvar\`] = 0;
+      setContextValue(ctx, \\"ourvar\\", 0);
     }
     let d1 = ctx['ourvar'];
     return block1([d1]);
@@ -312,16 +520,17 @@ exports[`t-set t-set, t-if, and mix of expression/body lookup, 2 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-child-0/><block-child-0/><block-text-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
     if (ctx['flag']) {
-      ctx[\`ourvar\`] = 1;
+      setContextValue(ctx, \\"ourvar\\", 1);
     } else {
-      ctx[\`ourvar\`] = \`0\`;
+      setContextValue(ctx, \\"ourvar\\", \`0\`);
     }
     let d1 = ctx['ourvar'];
     return block1([d1]);
@@ -333,15 +542,16 @@ exports[`t-set t-set, t-if, and mix of expression/body lookup, 3 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
     let b2;
     if (ctx['flag']) {
-      ctx[\`ourvar\`] = 1;
+      setContextValue(ctx, \\"ourvar\\", 1);
     } else {
-      ctx[\`ourvar\`] = \`0\`;
+      setContextValue(ctx, \\"ourvar\\", \`0\`);
     }
     b2 = text(ctx['ourvar']);
     return multi([b2]);
@@ -353,13 +563,14 @@ exports[`t-set value priority (with non text body 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   let block2 = createBlock(\`<span>2</span>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
+    ctx[isBoundary] = 1
     let b2 = block2();
     ctx[\`value\`] = withDefault(1, b2);
     let d1 = ctx['value'];
@@ -372,13 +583,14 @@ exports[`t-set value priority 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><block-text-0/></div>\`);
   
   return function template(ctx, node, key = \\"\\") {
     ctx = Object.create(ctx);
-    ctx[\`value\`] = withDefault(1, \`2\`);
+    ctx[isBoundary] = 1
+    setContextValue(ctx, \\"value\\", withDefault(1, \`2\`));
     let d1 = ctx['value'];
     return block1([d1]);
   }
diff --git a/tests/qweb/__snapshots__/translation.test.ts.snap b/tests/qweb/__snapshots__/translation.test.ts.snap
index e6372da1..c8fa705c 100644
--- a/tests/qweb/__snapshots__/translation.test.ts.snap
+++ b/tests/qweb/__snapshots__/translation.test.ts.snap
@@ -1,10 +1,24 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`translation support can set translatable attributes 1`] = `
+"function anonymous(bdom, helpers
+) {
+  let { text, createBlock, list, multi, html, toggler, component } = bdom;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
+  
+  let block1 = createBlock(\`<div tomato=\\"word\\" potato=\\"mot\\" title=\\"word\\">text</div>\`);
+  
+  return function template(ctx, node, key = \\"\\") {
+    return block1();
+  }
+}"
+`;
+
 exports[`translation support can translate node content 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div>mot</div>\`);
   
@@ -18,7 +32,7 @@ exports[`translation support does not translate node content if disabled 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><span>mot</span><span>word</span></div>\`);
   
@@ -32,7 +46,7 @@ exports[`translation support some attributes are translated 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><p label=\\"mot\\">mot</p><p title=\\"mot\\">mot</p><p placeholder=\\"mot\\">mot</p><p alt=\\"mot\\">mot</p><p something=\\"word\\">mot</p></div>\`);
   
@@ -46,7 +60,7 @@ exports[`translation support translation is done on the trimmed text, with extra
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div> mot </div>\`);
   
@@ -55,17 +69,3 @@ exports[`translation support translation is done on the trimmed text, with extra
   }
 }"
 `;
-
-exports[`translation support can set translatable attributes 1`] = `
-"function anonymous(bdom, helpers
-) {
-  let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
-  
-  let block1 = createBlock(\`<div tomato=\\"word\\" potato=\\"mot\\" title=\\"word\\">text</div>\`);
-  
-  return function template(ctx, node, key = \\"\\") {
-    return block1();
-  }
-}"
-`;
diff --git a/tests/qweb/__snapshots__/white_space.test.ts.snap b/tests/qweb/__snapshots__/white_space.test.ts.snap
index ec2276d4..152ee492 100644
--- a/tests/qweb/__snapshots__/white_space.test.ts.snap
+++ b/tests/qweb/__snapshots__/white_space.test.ts.snap
@@ -4,7 +4,7 @@ exports[`white space handling consecutives whitespaces are condensed into a sing
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div> abc </div>\`);
   
@@ -18,7 +18,7 @@ exports[`white space handling nothing is done in pre tags 1`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<pre>   </pre>\`);
   
@@ -32,7 +32,7 @@ exports[`white space handling nothing is done in pre tags 2`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<pre>
           some text
@@ -48,7 +48,7 @@ exports[`white space handling nothing is done in pre tags 3`] = `
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<pre>
           
@@ -64,7 +64,7 @@ exports[`white space handling white space only text nodes are condensed into a s
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div> </div>\`);
   
@@ -78,7 +78,7 @@ exports[`white space handling whitespace only text nodes with newlines are remov
 "function anonymous(bdom, helpers
 ) {
   let { text, createBlock, list, multi, html, toggler, component } = bdom;
-  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, shallowEqual } = helpers;
+  let { withDefault, getTemplate, prepareList, withKey, zero, call, callSlot, capture, isBoundary, shallowEqual, setContextValue } = helpers;
   
   let block1 = createBlock(\`<div><span>abc</span></div>\`);
   
diff --git a/tests/qweb/t_set.test.ts b/tests/qweb/t_set.test.ts
index 2cb8a966..840b1f84 100644
--- a/tests/qweb/t_set.test.ts
+++ b/tests/qweb/t_set.test.ts
@@ -1,4 +1,4 @@
-import { renderToString, snapshotEverything } from "../helpers";
+import { renderToString, snapshotEverything, TestContext } from "../helpers";
 
 snapshotEverything();
 
@@ -12,6 +12,13 @@ describe("t-set", () => {
     expect(renderToString(template)).toBe("<div>ok</div>");
   });
 
+  test("t-set does not modify render context existing key values", () => {
+    const template = `<div><t t-set="value" t-value="35"/><t t-esc="value"/></div>`;
+    const ctx = { value: 17 };
+    expect(renderToString(template, ctx)).toBe("<div>35</div>");
+    expect(ctx.value).toBe(17);
+  });
+
   test("set from attribute literal (no outside div)", () => {
     const template = `<t><t t-set="value" t-value="'ok'"/><t t-esc="value"/></t>`;
     expect(renderToString(template)).toBe("ok");
@@ -179,4 +186,92 @@ describe("t-set", () => {
 
     expect(renderToString(template)).toBe("<div>Truthy</div>");
   });
+
+  test("t-set outside modified in t-foreach", async () => {
+    const template = `
+      <div>
+        <t t-set="iter" t-value="0"/>
+        <t t-foreach="['a','b']" t-as="val" t-key="val">
+          <p>InLoop: <t t-esc="iter"/></p>
+          <t t-set="iter" t-value="iter + 1"/>
+        </t>
+        <p>EndLoop: <t t-esc="iter"/></p>
+      </div>
+    `;
+    expect(renderToString(template)).toBe(
+      "<div><p>InLoop: 0</p><p>InLoop: 1</p><p>EndLoop: 2</p></div>"
+    );
+  });
+
+  test("t-set outside modified in t-foreach increment-after operator", async () => {
+    const template = `
+      <div>
+        <t t-set="iter" t-value="0"/>
+        <t t-foreach="['a','b']" t-as="val" t-key="val">
+          <p>InLoop: <t t-esc="iter"/></p>
+          <t t-set="iter" t-value="iter++"/>
+        </t>
+        <p>EndLoop: <t t-esc="iter"/></p>
+      </div>
+    `;
+    expect(renderToString(template)).toBe(
+      "<div><p>InLoop: 0</p><p>InLoop: 0</p><p>EndLoop: 0</p></div>"
+    );
+  });
+
+  test("t-set outside modified in t-foreach increment-before operator", async () => {
+    const template = `
+      <div>
+        <t t-set="iter" t-value="0"/>
+        <t t-foreach="['a','b']" t-as="val" t-key="val">
+          <p>InLoop: <t t-esc="iter"/></p>
+          <t t-set="iter" t-value="++iter"/>
+        </t>
+        <p>EndLoop: <t t-esc="iter"/></p>
+      </div>
+    `;
+    expect(renderToString(template)).toBe(
+      "<div><p>InLoop: 0</p><p>InLoop: 1</p><p>EndLoop: 0</p></div>"
+    );
+  });
+
+  test("t-set can't alter from within callee", async () => {
+    const context = new TestContext();
+    const sub = `<div><t t-esc="iter"/><t t-set="iter" t-value="'called'"/><t t-esc="iter"/></div>`;
+    const main = `
+      <div>
+        <t t-set="iter" t-value="'source'"/>
+        <p><t t-esc="iter"/></p>
+        <t t-call="sub"/>
+        <p><t t-esc="iter"/></p>
+      </div>
+    `;
+    context.addTemplate("sub", sub);
+    context.addTemplate("main", main);
+
+    expect(context.renderToString("main")).toBe(
+      "<div><p>source</p><div>sourcecalled</div><p>source</p></div>"
+    );
+  });
+
+  test("t-set can't alter in t-call body", async () => {
+    const context = new TestContext();
+    const sub = `<div><t t-esc="iter"/><t t-set="iter" t-value="'called'"/><t t-esc="iter"/></div>`;
+    const main = `
+      <div>
+        <t t-set="iter" t-value="'source'"/>
+        <p><t t-esc="iter"/></p>
+        <t t-call="sub">
+          <t t-set="iter" t-value="'inCall'"/>
+        </t>
+        <p><t t-esc="iter"/></p>
+      </div>
+    `;
+    context.addTemplate("sub", sub);
+    context.addTemplate("main", main);
+
+    expect(context.renderToString("main")).toBe(
+      "<div><p>source</p><div>inCallcalled</div><p>source</p></div>"
+    );
+  });
 });