Lazy implementation of final variables.

lib/compiler/implementation/elements/elements.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.
 
 #library('elements');
 
 #import('dart:uri');
 
 #import('../tree/tree.dart');
 #import('../scanner/scannerlib.dart');
@@ skipping 151 matching lines @@
 
   // TODO(johnniwinther): This breaks for libraries (for which enclosing
   // elements are null) and is invalid for top level variable declarations for
   // which the enclosing element is a VariableDeclarations and not a compilation
   // unit.
   bool isTopLevel() {
     return enclosingElement !== null && enclosingElement.isCompilationUnit();
   }
 
   bool isAssignable() {
-    if (modifiers != null && modifiers.isFinal()) return false;
+    if (modifiers != null && modifiers.isFinalOrConst()) return false;
     if (isFunction() || isGenerativeConstructor()) return false;
     return true;
   }
 
   Token position() => null;
 
   Token findMyName(Token token) {
     for (Token t = token; t.kind !== EOF_TOKEN; t = t.next) {
       if (t.value == name) return t;
     }
@@ skipping 1296 matching lines @@
   Node parseNode(compiler) => cachedNode;
 
   String toString() => "${enclosingElement.toString()}.${name.slowToString()}";
 
   TypeVariableElement cloneTo(Element enclosing, DiagnosticListener listener) {
     TypeVariableElement result =
         new TypeVariableElement(name, enclosing, node, type, bound);
     return result;
   }
 }