fixes #217, Object members on extension types

lib/src/codegen/js_codegen.dart

 // Copyright (c) 2015, 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 dev_compiler.src.codegen.js_codegen;
 
 import 'dart:collection' show HashSet, HashMap, SplayTreeSet;
 
 import 'package:analyzer/analyzer.dart' hide ConstantEvaluator;
 import 'package:analyzer/src/generated/ast.dart' hide ConstantEvaluator;
@@ skipping 76 matching lines @@
   final _exportsVar = new JS.TemporaryId('exports');
   final _namedArgTemp = new JS.TemporaryId('opts');
 
   ConstFieldVisitor _constField;
 
   ModuleItemLoadOrder _loader;
 
   /// _interceptors.JSArray<E>, used for List literals.
   ClassElement _jsArray;
 
+  Map<String, DartType> _objectMembers;
+
   JSCodegenVisitor(AbstractCompiler compiler, this.libraryInfo,
       this._extensionTypes, this._fieldsNeedingStorage)
       : compiler = compiler,
         options = compiler.options,
         rules = compiler.rules,
         root = compiler.entryPointUri {
     _loader = new ModuleItemLoadOrder(_emitModuleItem);
 
     var context = compiler.context;
     var src = context.sourceFactory.forUri('dart:_interceptors');
     var interceptors = context.computeLibraryElement(src);
     _jsArray = interceptors.getType('JSArray');
+
+    _objectMembers = getObjectMemberMap(types);
   }
 
   LibraryElement get currentLibrary => libraryInfo.library;
   TypeProvider get types => rules.provider;
 
   JS.Program emitLibrary(LibraryUnit library) {
     String jsDefaultValue = null;
 
     // Modify the AST to make coercions explicit.
     new CoercionReifier(library, compiler).reify();
@@ skipping 452 matching lines @@
 
     if (_extensionTypes.contains(classElem)) {
       var dartxNames = [];
       for (var m in methods) {
         if (!m.isAbstract && !m.isStatic && m.element.isPublic) {
           dartxNames.add(_elementMemberName(m.element, allowExtensions: false));
         }
       }
       if (dartxNames.isNotEmpty) {
         body.add(js.statement('dart.defineExtensionNames(#)',
-        [new JS.ArrayInitializer(dartxNames, multiline: true)]));
+            [new JS.ArrayInitializer(dartxNames, multiline: true)]));
       }
     }
 
     body.add(new JS.ClassDeclaration(cls));
 
     // TODO(jmesserly): we should really just extend native Array.
     if (jsPeerName != null && classElem.typeParameters.isNotEmpty) {
       body.add(js.statement('dart.setBaseClass(#, dart.global.#);', [
         classElem.name,
         _propertyName(jsPeerName)
@@ skipping 2078 matching lines @@
 
     if (name == '[]') {
       name = 'get';
     } else if (name == '[]=') {
       name = 'set';
     } else if (name == '-' && unary) {
       name = 'unary-';
     }
 
     // Dart "extension" methods. Used for JS Array, Boolean, Number, String.
-    if (allowExtensions && _extensionTypes.contains(type.element)) {
+    if (allowExtensions &&
+        _extensionTypes.contains(type.element) &&
+        !_objectMembers.containsKey(name)) {
       return js.call('dartx.#', _propertyName(name));
     }
 
     return _propertyName(name);
   }
 
   bool _externalOrNative(node) =>
       node.externalKeyword != null || _functionBody(node) is NativeFunctionBody;
 
   FunctionBody _functionBody(node) =>
@@ skipping 89 matching lines @@
 
 /// A special kind of element created by the compiler, signifying a temporary
 /// variable. These objects use instance equality, and should be shared
 /// everywhere in the tree where they are treated as the same variable.
 class TemporaryVariableElement extends LocalVariableElementImpl {
   TemporaryVariableElement.forNode(Identifier name) : super.forNode(name);
 
   int get hashCode => identityHashCode(this);
   bool operator ==(Object other) => identical(this, other);
 }