Don't hide interceptors in mirrors.

sdk/lib/_internal/compiler/implementation/ssa/builder.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;
 
 /**
  * A special element for the extra parameter taken by intercepted
  * methods. We need to implement [TypedElement.type] because our
  * optimizers may look at its declared type.
@@ skipping 3190 matching lines @@
       List<HInstruction> inputs = <HInstruction>[expression, runtimeType];
       pushInvokeStatic(null, helper, inputs, backend.boolType);
       HInstruction call = pop();
       return new HIs.variable(type, expression, call, backend.boolType);
     } else if (RuntimeTypes.hasTypeArguments(type)) {
       ClassElement element = type.element;
       Element helper = backend.getCheckSubtype();
       HInstruction representations =
           buildTypeArgumentRepresentations(type);
       add(representations);
-      String operator =
-          backend.namer.operatorIs(backend.getImplementationClass(element));
+      String operator = backend.namer.operatorIs(element);
       HInstruction isFieldName = addConstantString(operator);
       HInstruction asFieldName = compiler.world.hasAnySubtype(element)
           ? addConstantString(backend.namer.substitutionName(element))
           : graph.addConstantNull(compiler);
       List<HInstruction> inputs = <HInstruction>[expression,
                                                  isFieldName,
                                                  representations,
                                                  asFieldName];
       pushInvokeStatic(node, helper, inputs, backend.boolType);
       HInstruction call = pop();
@@ skipping 3093 matching lines @@
     DartType unaliased = type.unalias(builder.compiler);
     if (unaliased is TypedefType) throw 'unable to unalias $type';
     unaliased.accept(this, builder);
   }
 
   void visitDynamicType(DynamicType type, SsaBuilder builder) {
     ClassElement cls = builder.compiler.findHelper('DynamicRuntimeType');
     builder.push(new HDynamicType(type, new TypeMask.exact(cls)));
   }
 }