anchor.diff:      });
     }
   
  -  visitInstanceCreation(InstanceCreation node) {
  +  @override
  +  Constant visitInstanceCreation(InstanceCreation node) {
       return withNewInstanceBuilder(node.classNode, node.typeArguments, () {
         for (AssertStatement statement in node.asserts) {
           checkAssert(statement);
  
positive.code:   final bool desugarSets;
    final Field unmodifiableSetMap;
  
    final isInstantiated = new IsInstantiatedVisitor().isInstantiated;
  
    final Map<Constant, Constant> canonicalizationCache;
    final Map<Node, Object> nodeCache;
  
negative.code: 
    // Handle use-sites of constants (and "inline" constant expressions):
  
    @override
    Expression visitSymbolLiteral(SymbolLiteral node) {
      return makeConstantExpression(constantEvaluator.evaluate(node), node);
    }
  
    @override
    Expression visitStaticGet(StaticGet node) {
      final Member target = node.target;
      if (target is Field && target.isConst) {
        // Make sure the initializer is evaluated first.
  