Use index in J/KTypeVariable and fix remaining inequivalence

pkg/compiler/lib/src/js_backend/backend.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 js_backend.backend;
 
 import '../common.dart';
 import '../common/backend_api.dart'
     show ForeignResolver, NativeRegistry, ImpactTransformer;
 import '../common/codegen.dart' show CodegenWorkItem;
@@ skipping 668 matching lines @@
   /// One category of elements that do not apply is runtime helpers that the
   /// backend calls, but the optimizations don't see those calls.
   bool canFunctionParametersBeUsedForGlobalOptimizations(
       FunctionElement element, ClosedWorld closedWorld) {
     if (element.isLocal) return true;
     MethodElement method = element;
     return !closedWorld.backendUsage.isFunctionUsedByBackend(method) &&
         !mirrorsData.invokedReflectively(method);
   }
 
-  bool operatorEqHandlesNullArgument(FunctionEntity operatorEqfunction) {
-    return specialOperatorEqClasses.contains(operatorEqfunction.enclosingClass);
-  }
-
   void validateInterceptorImplementsAllObjectMethods(
       ClassEntity interceptorClass) {
     if (interceptorClass == null) return;
     ClassEntity objectClass = frontendStrategy.commonElements.objectClass;
     frontendStrategy.elementEnvironment.forEachClassMember(objectClass,
         (_, MemberEntity member) {
       if (member.isConstructor) return;
       MemberEntity interceptorMember = frontendStrategy.elementEnvironment
           .lookupClassMember(interceptorClass, member.name);
       // Interceptors must override all Object methods due to calling convention
@@ skipping 345 matching lines @@
   void onLibrariesLoaded(
       CommonElements commonElements, LoadedLibraries loadedLibraries) {
     if (loadedLibraries.containsLibrary(Uris.dart_core)) {
       assert(loadedLibraries.containsLibrary(Uris.dart_core));
       assert(loadedLibraries.containsLibrary(Uris.dart__interceptors));
       assert(loadedLibraries.containsLibrary(Uris.dart__js_helper));
 
       // These methods are overwritten with generated versions.
       inlineCache.markAsNonInlinable(commonElements.getInterceptorMethod,
           insideLoop: true);
-
-      specialOperatorEqClasses
-        ..add(commonElements.objectClass)
-        ..add(commonElements.jsInterceptorClass)
-        ..add(commonElements.jsNullClass);
     }
   }
 
   /// Called when the compiler starts running the codegen enqueuer. The
   /// [WorldImpact] of enabled backend features is returned.
   WorldImpact onCodegenStart(ClosedWorld closedWorld,
       CodegenWorldBuilder codegenWorldBuilder, Sorter sorter) {
     functionCompiler.onCodegenStart();
     _oneShotInterceptorData = new OneShotInterceptorData(
         closedWorld.interceptorData, closedWorld.commonElements);
@@ skipping 327 matching lines @@
 
   bool canUseAliasedSuperMember(MemberEntity member, Selector selector) {
     return !selector.isGetter;
   }
 
   /// Returns `true` if [member] is called from a subclass via `super`.
   bool isAliasedSuperMember(MemberEntity member) {
     return _aliasedSuperMembers.contains(member);
   }
 }