anchor.diff:    /// value for the output interpreter.
     ///
     /// Not marked final since tests modify value.
  -  dynamic runtime;
  +  TRuntime runtime;
   
     /// Same as runtime but evaluates function before using value.
     final Function runtimeCallback;
  
positive.code:   return _COMPILE_METADATA_FROM_JSON[data["class"]](data);
  }
  
  class CompileIdentifierMetadata implements CompileMetadataWithIdentifier {
    String name;
    String prefix;
    String moduleUrl;
  
negative.code: }
  
  class CompileFactoryMetadata
      implements
          CompileIdentifierMetadata<Function>,
          CompileMetadataWithIdentifier {
    Function runtime;
    Function runtimeCallback;
    String name;
  