anchor.diff:      // TODO(asgerf): If we use these annotations for testing, the necessary
       //   bindings should arguably be part of the API for the Builder.
       visualizer.variableNodes.forEach((int variable, GraphNode node) {
  -      for (Annotation annotation in node.annotationForContext.values) {
  +      for (Annotation annotation in node.annotations) {
           if (annotation.node is VariableDeclaration && annotation.info == null) {
             variables[annotation.node] = variable;
           }
  
positive.code:   }
  
    void addAnnotation(Member member, TreeNode astNode, String info) {
      annotationForContext[member] = new Annotation(astNode, info);
    }
  }
  
  
negative.code:   final int variable;
    final List<Edge> inputs = <Edge>[];
    final List<Edge> outputs = <Edge>[];
    final List<Annotation> annotations = <Annotation>[];
  
    /// The annotation to show when visualized in the context of a given member.
    final Map<Member, Annotation> annotationForContext = <Member, Annotation>{};
  