Avoid creating invalid TypeMask.nonNullExact

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

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of ssa;
 
 class SsaCodeGeneratorTask extends CompilerTask {
 
   final JavaScriptBackend backend;
   final SourceInformationStrategy sourceInformationFactory;
@@ skipping 1738 matching lines @@
     } else {
       Selector selector = node.selector;
 
       if (!backend.maybeRegisterAliasedSuperMember(superMethod, selector)) {
         js.Name methodName;
         if (selector.isGetter) {
           // If the selector we need to register a typed getter to the
           // [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(
               new UniverseSelector(selector, receiverType));
           registry.registerGetterForSuperMethod(node.element);
           methodName = backend.namer.invocationName(selector);
         } else {
           assert(invariant(node, compiler.hasIncrementalSupport));
           methodName = backend.namer.instanceMethodName(superMethod);
         }
@@ skipping 1107 matching lines @@
     }
     registry.registerStaticUse(helper);
     return backend.emitter.staticFunctionAccess(helper);
   }
 
   @override
   void visitRef(HRef node) {
     visit(node.value);
   }
 }