Treat assignment to final as an error

frog/tree.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.
 /**
  * The base type for all nodes in a dart abstract syntax tree.
  */
 class Node {
   /** The source code this [Node] represents. */
   SourceSpan span;
 
@@ skipping 27 matching lines @@
 /** The base type for expressions. */
 class Expression extends Node {
   Expression(SourceSpan span): super(span) {}
 }
 
 class TypeReference extends Node {
   Type type;
   TypeReference(SourceSpan span, [this.type=null]): super(span) {}
 
   visit(TreeVisitor visitor) => visitor.visitTypeReference(this);
+
+  bool get isFinal() => false;

[jimhug, 2011/11/17 15:36:15]

You mean you're going to get the type system right with this change?  What a
difference having type checks makes. <smile>

 }
 
 // TODO(jimhug): Clean-up and factor out of core.
 /** Simple class to provide a textual dump of trees for debugging. */
 class TreeOutput {
   int depth;
   StringBuffer buf;
 
   var printer;
 
@@ skipping 64 matching lines @@
         if (node != null) {
           node.visit(printer);
         } else {
           writeln('null');
         }
       }
       depth -= 1;
     }
   }
 }