Support overriding fields with fields.

dart/lib/compiler/implementation/namer.dart

 // Copyright (c) 2011, 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.
 
 /**
  * Assigns JavaScript identifiers to Dart variables, class-names and members.
  */
 class Namer {
   final Compiler compiler;
 
@@ skipping 62 matching lines @@
     // TODO(floitsch): mangle, while preserving uniqueness.
     StringBuffer buffer = new StringBuffer();
     List<SourceString> names = selector.getOrderedNamedArguments();
     for (SourceString argumentName in names) {
       buffer.add(@'$');
       argumentName.printOn(buffer);
     }
     return '${privateName(lib, name)}\$${selector.argumentCount}$buffer';
   }
 
-  String instanceFieldName(LibraryElement lib, SourceString name) {
-    String proposedName = privateName(lib, name);
+  String instanceFieldName(ClassElement cls, SourceString name) {
+    String proposedName = privateName(cls.getLibrary(), name);
+    if (cls.lookupSuperMember(name) !== null) {
+      String libName = getName(cls.getLibrary());
+      String clsName = getName(cls);
+      proposedName = '$libName\$$clsName\$$proposedName';
+    }
     return safeName(proposedName);
   }
 
   String setterName(LibraryElement lib, SourceString name) {
     // We dynamically create setters from the field-name. The setter name must
     // therefore be derived from the instance field-name.
-    return 'set\$${instanceFieldName(lib, name)}';
+    String safeName = safeName(privateName(lib, name));
+    return 'set\$$safeName';
   }
 
   String getterName(LibraryElement lib, SourceString name) {
     // We dynamically create getters from the field-name. The getter name must
     // therefore be derived from the instance field-name.
-    return 'get\$${instanceFieldName(lib, name)}';
+    String safeName = safeName(privateName(lib, name));
+    return 'get\$$safeName';
   }
 
   String getFreshGlobalName(String proposedName) {
     int usedCount = usedGlobals[proposedName];
     if (usedCount === null) {
       // No element with this name has been used before.
       usedGlobals[proposedName] = 1;
       return proposedName;
     } else {
       // Not the first time we see this name. Append a number to make it unique.
@@ skipping 65 matching lines @@
       } else if (element.kind == ElementKind.FUNCTION) {
         FunctionElement functionElement = element;
         return instanceMethodName(element.getLibrary(),
                                   element.name,
                                   functionElement.parameterCount(compiler));
       } else if (element.kind == ElementKind.GETTER) {
         return getterName(element.getLibrary(), element.name);
       } else if (element.kind == ElementKind.SETTER) {
         return setterName(element.getLibrary(), element.name);
       } else {
-        return instanceFieldName(element.getLibrary(), element.name);
+        return instanceFieldName(element.getEnclosingClass(), element.name);
       }
     } else {
       // Dealing with a top-level or static element.
       String cached = globals[element];
       if (cached !== null) return cached;
 
       String guess = _computeGuess(element);
       switch (element.kind) {
         case ElementKind.VARIABLE:
         case ElementKind.PARAMETER:
@@ skipping 40 matching lines @@
   }
 
   String safeName(String name) {
     if (jsReserved.contains(name) || name.startsWith('\$')) {
       name = "\$$name";
       assert(!jsReserved.contains(name));
     }
     return name;
   }
 }