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

lib/compiler/implementation/universe/universe.dart

Index: lib/compiler/implementation/universe/universe.dart
===================================================================
--- lib/compiler/implementation/universe/universe.dart	(revision 14125)
+++ lib/compiler/implementation/universe/universe.dart	(working copy)
@@ -523,7 +523,23 @@
     }
 
     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);
     }