Avoid creating invalid TypeMask.nonNullExact

pkg/compiler/lib/src/ssa/codegen.dart

Index: pkg/compiler/lib/src/ssa/codegen.dart
diff --git a/pkg/compiler/lib/src/ssa/codegen.dart b/pkg/compiler/lib/src/ssa/codegen.dart
index 22bd55d35cae352b1a967aa989d96eb589fce3e2..82fb689437c03ed938b0d40544c851be197a2cd2 100644
--- a/pkg/compiler/lib/src/ssa/codegen.dart
+++ b/pkg/compiler/lib/src/ssa/codegen.dart
@@ -1756,7 +1756,7 @@ class SsaCodeGenerator implements HVisitor, HBlockInformationVisitor {
           // [world]. The emitter needs to know if it needs to emit a
           // bound closure for a method.
           TypeMask receiverType =
-              new TypeMask.nonNullExact(superClass, compiler.world);
+              new TypeMask.nonNullExact(node.caller.superclass, compiler.world);

[Johnni Winther, 2015/10/13 10:14:55]

superMethod is mixed in [superClass] might not be live. We use the super of the
access instead.

[floitsch, 2015/10/13 12:15:42]

add comment.

[Johnni Winther, 2015/10/13 13:06:37]

Done.

           // TODO(floitsch): we know the target. We shouldn't register a
           // dynamic getter.
           registry.registerDynamicGetter(