[FIX] slots: propagate vars to correct function

closes #529

src/qweb/base_directives.ts

@@ -237,7 +237,7 @@ QWeb.addDirective({
         varCode = `{${content}}`;
       }
       ctx.addLine(
-        `this.recursiveFns['${subTemplateName}'].call(this, context, Object.assign({}, extra, {parentNode: c${ctx.parentNode}, fiber: {vars: ${varCode}, scope}}));`
+        `this.recursiveFns['${subTemplateName}'].call(this, context, Object.assign({}, extra, {parentNode: c${ctx.parentNode}, vars: ${varCode}, fiber: {scope}}));`
       );
       return true;
     }

src/qweb/extensions.ts

@@ -210,8 +210,11 @@ QWeb.addDirective({
       ctx.addLine(`let ${parentNode}= []`);
       ctx.addLine(`result = {}`);
     }
+    // if we are in a slot of a component, we need to get the vars from the
+    // parent fiber instead.
+    const vars = ctx.allowMultipleRoots ? "extra.fiber.parent.vars" : "extra.fiber.vars";
     ctx.addLine(
-      `slot${slotKey}.call(this, context.__owl__.parent, Object.assign({}, extra, {parentNode: ${parentNode}, vars: extra.vars, parent: extra.parent || owner}));`
+      `slot${slotKey}.call(this, context.__owl__.parent, Object.assign({}, extra, {parentNode: ${parentNode}, parent: extra.parent || owner, vars: ${vars}}));`
     );
     if (!ctx.parentNode) {
       ctx.addLine(`utils.defineProxy(result, ${parentNode}[0]);`);

src/qweb/qweb.ts

@@ -371,12 +371,12 @@ export class QWeb extends EventBus {
       for (let v in parentContext.variables) {
         let variable = <any>parentContext.variables[v];
         if (variable.id) {
-          ctx.addLine(`let ${variable.id} = extra.fiber.vars.${variable.id}`);
+          ctx.addLine(`let ${variable.id} = extra.vars.${variable.id};`);
         }
       }
     }
     if (parentContext) {
-      ctx.addLine("    Object.assign(context, extra.fiber.scope);");
+      ctx.addLine("Object.assign(context, extra.fiber.scope);");
     }
     this._compileNode(elem, ctx);