Fix for issue #6259: also look for subclasses when checking if a typed selector applies to an eleme…

lib/compiler/implementation/universe/universe.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.
 
 library universe;
 
 import '../closure.dart';
 import '../elements/elements.dart';
 import '../dart2jslib.dart';
 import '../runtime_types.dart';
@@ skipping 505 matching lines @@
     // class A {
     //   get foo => () => 42;
     //   bar() => foo(); // The call to 'foo' is a typed selector.
     // }
     ClassElement other = element.getEnclosingClass();
     if (identical(other.superclass, compiler.closureClass)) {
       return appliesUntyped(element, compiler);
     }
 
     ClassElement self = receiverType.element;
-    if (other.implementsInterface(self) || other.isSubclassOf(self)) {
+
+    // Checks if a subclass of [superClass] implements [self]. If one
+    // is found, [element] is a candidate.
+    bool hasOneSubclassThatImplements(ClassElement superClass) {

[ahe, 2012/10/29 06:18:29]

Have you measured the compile-time impact of this?

+      // [TypedSelector] are only used when compiling.
+      assert(compiler.phase == Compiler.PHASE_COMPILING);
+      Set<ClassElement> subclasses = compiler.world.subtypes[superClass];
+      if (subclasses == null) return false;
+      for (ClassElement cls in subclasses) {
+        if (cls.implementsInterface(self)) return true;
+      }
+      return false;
+    }
+
+    if (other.implementsInterface(self)
+        || other.isSubclassOf(self)
+        || hasOneSubclassThatImplements(other)) {
       return appliesUntyped(element, compiler);
     }
 
     if (!self.isInterface() && self.isSubclassOf(other)) {
       // Resolve an invocation of [element.name] on [self]. If it
       // is found, this selector is a candidate.
       return hasElementIn(self, element) && appliesUntyped(element, compiler);
     }
 
     return false;
   }
 }