anchor.diff:    }
   
     void forgetElement(Element element) {
  -    _initialVariableValues.remove(element);
  +    initialVariableValues.remove(element);
       if (element is ScopeContainerElement) {
  -      element.forEachLocalMember(_initialVariableValues.remove);
  +      element.forEachLocalMember(initialVariableValues.remove);
       }
       if (element is FunctionElement && element.hasFunctionSignature) {
         element.functionSignature.forEachParameter(this.forgetElement);
  
positive.code:   @override
    @deprecated
    ConstantValue getConstantValueForVariable(VariableElement element) {
      return getConstantValue(_initialVariableValues[element.declaration]);
    }
  
    ConstantExpression compileConstant(VariableElement element) {
  
negative.code:   /// report an error if [element] does not typecheck.
    ConstantExpression internalCompileVariable(
        VariableElement element, bool isConst, bool checkType) {
      if (initialVariableValues.containsKey(element.declaration)) {
        ConstantExpression result = initialVariableValues[element.declaration];
        return result;
      }
      if (element.hasConstant) {
  