Fix this capturing in closures.

frog/leg/ssa/builder.dart

Index: frog/leg/ssa/builder.dart
diff --git a/frog/leg/ssa/builder.dart b/frog/leg/ssa/builder.dart
index 1d2a16ed5112c41ab394030e28592ae26301e0f0..e2900ef3fbc59dc3788b41696d4de47502d5393c 100644
--- a/frog/leg/ssa/builder.dart
+++ b/frog/leg/ssa/builder.dart
@@ -261,6 +261,18 @@ class LocalsHandler {
       // treat as if it was a local.
       directLocals[element] = parameter;
     });
+    if (closureData.thisElement !== null) {
+      // Note that closures, once they are mapped to classes, might have
+      // instance-members that do *not* have any thisElement.

[ngeoffray, 2012/02/29 12:22:17]

Please explain why.

[floitsch, 2012/02/29 12:35:28]

Done.

+      assert(function.isInstanceMember() || function.isGenerativeConstructor());
+      // We have to introduce 'this' before we enter the scope, since it might
+      // need to be copied into a box (if it is captured). This is similar
+      // to all other parameters that are introduced.
+      HInstruction thisInstruction = new HThis();
+      builder.add(thisInstruction);
+      // directLocals[closureData.thisElement] = thisInstruction;

[ngeoffray, 2012/02/29 12:22:17]

Why is this commented out?

[floitsch, 2012/02/29 12:35:28]

this one is the correct one...

+      updateLocal(closureData.thisElement, thisInstruction);

[ngeoffray, 2012/02/29 12:22:17]

Why do you call updateLocal, and not use directLocals, like for parameters line
262.

[floitsch, 2012/02/29 12:35:28]

debug code...

+    }
 
     enterScope(node);
 
@@ -275,11 +287,6 @@ class LocalsHandler {
       HInstruction thisInstruction = new HThis();
       builder.add(thisInstruction);
       updateLocal(closureData.closureElement, thisInstruction);
-    } else if (function.isInstanceMember() ||
-               function.isGenerativeConstructor()) {
-      HInstruction thisInstruction = new HThis();
-      builder.add(thisInstruction);
-      updateLocal(closureData.thisElement, thisInstruction);
     }
   }