anchor.diff:    UnlinkedTypeRef serializeTypeText(String text,
         {String otherDeclarations: '', bool allowErrors: false}) {
       return serializeVariableText('$otherDeclarations\n$text v;',
  -        allowErrors: allowErrors).type;
  +            allowErrors: allowErrors)
  +        .type;
     }
   
     /**
  
positive.code: 
    test_executable_operator_index_set() {
      UnlinkedExecutable executable = serializeClassText(
          'class C { void operator[]=(int i, bool v) => null; }').executables[0];
      expect(executable.kind, UnlinkedExecutableKind.functionOrMethod);
      expect(executable.name, '[]=');
      expect(executable.hasImplicitReturnType, false);
  
negative.code:     expect(executable.isStatic, isTrue);
    }
  
    test_executable_type_param_f_bound_function() {
      UnlinkedExecutable ex =
          serializeExecutableText('void f<T, U extends List<T>>() {}');
      UnlinkedTypeRef typeArgument = ex.typeParameters[1].bound.typeArguments[0];
      checkParamTypeRef(typeArgument, 2);
    }
  
    test_executable_type_param_f_bound_method() {
      UnlinkedExecutable ex =
          serializeMethodText('void f<T, U extends List<T>>() {}');
      UnlinkedTypeRef typeArgument = ex.typeParameters[1].bound.typeArguments[0];
      checkParamTypeRef(typeArgument, 2);
    }
  
    test_executable_type_param_f_bound_self_ref_function() {
      UnlinkedExecutable ex =
          serializeExecutableText('void f<T, U extends List<U>>() {}');
      UnlinkedTypeRef typeArgument = ex.typeParameters[1].bound.typeArguments[0];
      checkParamTypeRef(typeArgument, 1);
    }
  
    test_executable_type_param_f_bound_self_ref_method() {
      UnlinkedExecutable ex =
          serializeMethodText('void f<T, U extends List<U>>() {}');
      UnlinkedTypeRef typeArgument = ex.typeParameters[1].bound.typeArguments[0];
      checkParamTypeRef(typeArgument, 1);
    }
  
    test_executable_type_param_in_parameter_function() {
      UnlinkedExecutable ex = serializeExecutableText('void f<T>(T t) {}');
      checkParamTypeRef(ex.parameters[0].type, 1);
    }
  
    test_executable_type_param_in_parameter_method() {
      UnlinkedExecutable ex = serializeMethodText('void f<T>(T t) {}');
      checkParamTypeRef(ex.parameters[0].type, 1);
    }
  
    test_executable_type_param_in_return_type_function() {
      UnlinkedExecutable ex = serializeExecutableText('T f<T>() => null;');
      checkParamTypeRef(ex.returnType, 1);
    }
  
    test_executable_type_param_in_return_type_method() {
      UnlinkedExecutable ex = serializeMethodText('T f<T>() => null;');
      checkParamTypeRef(ex.returnType, 1);
    }
  