Properly emit variable declarations.

lib/compiler/implementation/dart_backend/emitter.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.
 
 /**
  * Dart backend helper for converting program IR back to source code.
  */
 class Emitter {
 
   final Compiler compiler;
   final StringBuffer sb;
   final ConflictingRenamer renamer;
+  final Set<VariableListElement> processedVariableLists;
 
   Emitter(Compiler compiler) :
       this.compiler = compiler,
       sb = new StringBuffer(),
-      renamer = new ConflictingRenamer(compiler);
+      renamer = new ConflictingRenamer(compiler),
+      processedVariableLists = new Set<VariableListElement>();
 
   /**
    * Outputs given class element with selected inner elements.
    */
   void outputClass(ClassElement classElement, Set<Element> innerElements) {
     Unparser unparser = new Unparser(renamer);
     renamer.setContext(classElement.getCompilationUnit());
     ClassNode classNode = classElement.parseNode(compiler);
     // classElement.beginToken is 'class', 'interface', or 'abstract'.
     sb.add(classElement.beginToken.slowToString());
@@ skipping 31 matching lines @@
 
   void outputElement(Element element) {
     Unparser unparser = new Unparser(renamer);
     renamer.setContext(element);
     // TODO(smok): Figure out why AbstractFieldElement appears here,
     // we have used getters/setters resolved instead of it.
     if (element is SynthesizedConstructorElement
         || element is AbstractFieldElement) return;
     if (element.isField()) {
       assert(element is VariableElement);
-      sb.add(unparser.unparse(element.variables.parseNode(compiler)));
+      // Different VariableElement's may refer to the same VariableListElement.
+      // Output this list only once.
+      final variableList = element.variables;
+      if (!processedVariableLists.contains(variableList)) {

[Roman, 2012/07/31 18:45:03]

Hmm, I just thought about it in another way - we output the whole list of
defined variables, even the ones we don't need, right?
Maybe a TODO to fix it? (you may assign it to me if you want) Although the fix
will probably require some duplication of unparser code

[Anton Muhin, 2012/07/31 18:55:37]

Good point, todo added.

On 2012/07/31 18:45:03, Roman wrote:

+        processedVariableLists.add(variableList);
+        sb.add(unparser.unparse(variableList.parseNode(compiler)));
+      }
     } else {
       sb.add(unparser.unparse(element.parseNode(compiler)));
     }
   }
 
   String toString() {
     final result = new StringBuffer();
     final libraries = compiler.libraries;
     for (final uri in libraries.getKeys()) {
       // Same library element may be a value for different uris as of now
       // e.g., core libraryElement is a value for both keys 'dart:core'
       // and full file name.  Only care about uris with dart scheme.
       if (!uri.startsWith('dart:')) continue;
       final lib = libraries[uri];
       if (renamer.imports.containsKey(lib)) {
         result.add('#import("$uri", prefix: "${renamer.imports[lib]}");');
       }
     }
     result.add(sb);
     return result.toString();
   }
 }