anchor.diff:  
   /// Allocate an object specified by [type] using the initial value specified by [value].
   BinaryData alloc(type, [value]) {
  +  _ensure();
     BinaryType bt = _getBinaryType(type);
     return bt.alloc(value);
   }
  
positive.code: 
  /// Invoke the system calls specified by [name] with the arguments specified by [args].
  dynamic invoke(String name, [List<dynamic> args = const [], List<BinaryType> vartypes]) {
    return LibC.invoke(name, args, vartypes);
  }
  
negative.code: 
  /// Read a string from [input].
  String readNativeString(input) {
    _ensure();
    if (input is String) {
      return input;
    }
  