Better mirrors support for mixins and private fields

pkg/dev_compiler/lib/src/compiler/code_generator.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.
 
 import 'dart:collection' show HashMap, HashSet;
 import 'dart:math' show min, max;
 
 import 'package:analyzer/analyzer.dart' hide ConstantEvaluator;
 import 'package:analyzer/dart/ast/ast.dart';
@@ skipping 106 matching lines @@
   /// The dart:_interceptors JSArray element.
   final ClassElement _jsArray;
 
   final ClassElement boolClass;
   final ClassElement intClass;
   final ClassElement interceptorClass;
   final ClassElement nullClass;
   final ClassElement numClass;
   final ClassElement objectClass;
   final ClassElement stringClass;
+  final ClassElement symbolClass;
 
   ConstFieldVisitor _constants;
 
   /// The current function body being compiled.
   FunctionBody _currentFunction;
 
   /// Helper class for emitting elements in the proper order to allow
   /// JS to load the module.
   ElementLoader _loader;
 
@@ skipping 20 matching lines @@
         _jsArray = _getLibrary(c, 'dart:_interceptors').getType('JSArray'),
         interceptorClass =
             _getLibrary(c, 'dart:_interceptors').getType('Interceptor'),
         dartCoreLibrary = _getLibrary(c, 'dart:core'),
         boolClass = _getLibrary(c, 'dart:core').getType('bool'),
         intClass = _getLibrary(c, 'dart:core').getType('int'),
         numClass = _getLibrary(c, 'dart:core').getType('num'),
         nullClass = _getLibrary(c, 'dart:core').getType('Null'),
         objectClass = _getLibrary(c, 'dart:core').getType('Object'),
         stringClass = _getLibrary(c, 'dart:core').getType('String'),
+        symbolClass = _getLibrary(c, 'dart:_internal').getType('Symbol'),
         dartJSLibrary = _getLibrary(c, 'dart:js');
 
   LibraryElement get currentLibrary => _loader.currentElement.library;
 
   /// The main entry point to JavaScript code generation.
   ///
   /// Takes the metadata for the build unit, as well as resolved trees and
   /// errors, and computes the output module code and optionally the source map.
   JSModuleFile compile(BuildUnit unit, List<CompilationUnit> compilationUnits,
       List<String> errors) {
@@ skipping 5008 matching lines @@
 
   @override
   visitDoubleLiteral(DoubleLiteral node) => js.number(node.value);
 
   @override
   visitNullLiteral(NullLiteral node) => new JS.LiteralNull();
 
   @override
   visitSymbolLiteral(SymbolLiteral node) {
     JS.Expression emitSymbol() {
-      // TODO(vsm): When we canonicalize, we need to treat private symbols
-      // correctly.
+      // TODO(vsm): Handle qualified symbols correctly.
+      var last = node.components.last.toString();
       var name = js.string(node.components.join('.'), "'");
-      return js
-          .call('#.new(#)', [_emitConstructorAccess(types.symbolType), name]);
+      if (last.startsWith('_')) {
+        var nativeSymbol = _emitPrivateNameSymbol(currentLibrary, last);
+        return js.call('new #.es6(#, #)',
+            [_emitConstructorAccess(symbolClass.type), name, nativeSymbol]);
+      } else {
+        return js
+            .call('#.new(#)', [_emitConstructorAccess(types.symbolType), name]);
+      }
     }
 
     return _emitConst(emitSymbol);
   }
 
   @override
   visitListLiteral(ListLiteral node) {
     var isConst = node.constKeyword != null;
     JS.Expression emitList() {
       JS.Expression list = new JS.ArrayInitializer(
@@ skipping 507 matching lines @@
   var targetIdentifier = target as SimpleIdentifier;
 
   if (targetIdentifier.staticElement is! PrefixElement) return false;
   var prefix = targetIdentifier.staticElement as PrefixElement;
 
   // The library the prefix is referring to must come from a deferred import.
   var containingLibrary = (target.root as CompilationUnit).element.library;
   var imports = containingLibrary.getImportsWithPrefix(prefix);
   return imports.length == 1 && imports[0].isDeferred;
 }