Start using the new union/intersection code for HType.INDEXABLE_PRIMITIVE.

sdk/lib/_internal/compiler/implementation/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.
 
 part of js_backend;
 
 typedef void Recompile(Element element);
 
 class ReturnInfo {
   HType returnType;
@@ skipping 624 matching lines @@
       new Map<Element, jsAst.Expression>();
 
   ClassElement jsStringClass;
   ClassElement jsArrayClass;
   ClassElement jsNumberClass;
   ClassElement jsIntClass;
   ClassElement jsDoubleClass;
   ClassElement jsFunctionClass;
   ClassElement jsNullClass;
   ClassElement jsBoolClass;
+  ClassElement jsIndexableClass;
   Element jsArrayLength;
   Element jsStringLength;
   Element jsArrayRemoveLast;
   Element jsArrayAdd;
   Element jsStringSplit;
   Element jsStringConcat;
   Element jsStringToString;
   Element getInterceptorMethod;
   Element interceptedNames;
   Element fixedLengthListConstructor;
@@ skipping 157 matching lines @@
       // The int class must be before the double class, because the
       // emitter relies on this list for the order of type checks.
       jsIntClass = compiler.findInterceptor(const SourceString('JSInt')),
       jsDoubleClass = compiler.findInterceptor(const SourceString('JSDouble')),
       jsNumberClass = compiler.findInterceptor(const SourceString('JSNumber')),
       jsNullClass = compiler.findInterceptor(const SourceString('JSNull')),
       jsFunctionClass =
           compiler.findInterceptor(const SourceString('JSFunction')),
       jsBoolClass = compiler.findInterceptor(const SourceString('JSBool'))];
 
+    jsIndexableClass =
+        compiler.findInterceptor(const SourceString('JSIndexable'));
+
     jsArrayClass.ensureResolved(compiler);
     jsArrayLength = compiler.lookupElementIn(
         jsArrayClass, const SourceString('length'));
     jsArrayRemoveLast = compiler.lookupElementIn(
         jsArrayClass, const SourceString('removeLast'));
     jsArrayAdd = compiler.lookupElementIn(
         jsArrayClass, const SourceString('add'));
 
     jsStringClass.ensureResolved(compiler);
     jsStringLength = compiler.lookupElementIn(
@@ skipping 675 matching lines @@
     assert(invariant(element, element.isDeclaration));
     generatedCode.remove(element);
     generatedBailoutCode.remove(element);
     compiler.enqueuer.codegen.addToWorkList(element);
   }
 
   bool isNullImplementation(ClassElement cls) {
     return cls == jsNullClass;
   }
 }