Fix a pretty bad bug of a class inheriting a patched class. The fix is

sdk/lib/_internal/compiler/implementation/universe/full_function_set.dart

 // Copyright (c) 2013, 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 universe;
 
 class FullFunctionSet extends FunctionSet {
   FullFunctionSet(Compiler compiler) : super(compiler);
 
   FunctionSetNode newNode(SourceString name)
@@ skipping 41 matching lines @@
       classes.add(enclosing);
     }
     return classes;
   }
 
   static bool isExactClass(List<ClassElement> classes, Compiler compiler) {
     if (classes == null || classes.length != 1) return false;
     ClassElement single = classes[0];
     // Return true if the single class in our list does not have a
     // single instantiated subclass.
-    Set<ClassElement> subtypes = compiler.world.subtypes[single];
+    Set<ClassElement> subtypes = compiler.world.subtypesOf(single);
     return subtypes == null
         || subtypes.every((ClassElement each) => !each.isSubclassOf(single));
   }
 }
 
 class FullFunctionSetQuery extends FunctionSetQuery {
   final List<ClassElement> classes;
   final bool isExact;
   FullFunctionSetQuery(List<Element> functions, this.classes, this.isExact)
       : super(functions);
 }