[FIX] component: make arrow-function capture backwards compatible

When fixing the absence of capture for arrow functions passed as props,
we unintentionally introduced a breaking change: bare function calls in
the arrow functions used to be called  with the rendering context as
their this value and this was no longer the case.

This commit fixes that by intentionally not capturing the value of
functions that are called withing the arrow function.

src/qweb/compilation_context.ts

@@ -162,7 +162,7 @@ export class CompilationContext {
     const tokens = compileExprToArray(expr, this.variables);
     const done = new Set();
     return tokens
-      .map((tok) => {
+      .map((tok, i) => {
         // "this" in captured expressions should be the current component
         if (tok.value === "this") {
           if (!done.has("this")) {
@@ -174,7 +174,14 @@ export class CompilationContext {
         // Variables that should be looked up in the scope. isLocal is for arrow
         // function arguments that should stay untouched (eg "ev => ev" should
         // not become "const ev_1 = scope['ev']; ev_1 => ev_1")
-        if (tok.varName && !tok.isLocal) {
+        if (
+          tok.varName &&
+          !tok.isLocal &&
+          // HACK: for backwards compatibility, we don't capture bare methods
+          // this allows them to be called with the rendering context/scope
+          // as their this value.
+          (!tokens[i + 1] || tokens[i + 1].type !== "LEFT_PAREN")
+        ) {
           if (!done.has(tok.varName)) {
             done.add(tok.varName);
             this.addLine(`const ${tok.varName}_${argId} = ${tok.value};`);