anchor.diff:  
       if (!enableMacros) {
         if (augmentToken != null) {
  -        var feature = ExperimentalFeatures.macros;
  -        handleRecoverableError(
  -            templateExperimentNotEnabled.withArguments(
  -              feature.enableString,
  -              _versionAsString(ExperimentStatus.currentVersion),
  -            ),
  -            augmentToken,
  -            augmentToken);
  +        _reportFeatureNotEnabled(
  +          feature: ExperimentalFeatures.macros,
  +          startToken: augmentToken,
  +        );
           // Pretend that 'augment' didn't occur while this feature is incomplete.
           augmentToken = null;
         }
  
positive.code:       Token token = tmpArguments != null
            ? tmpArguments.argumentList.beginToken
            : tmpConstructor!.beginToken;
        var feature = ExperimentalFeatures.enhanced_enums;
        handleRecoverableError(
          templateExperimentNotEnabled.withArguments(
            feature.enableString,
            _versionAsString(feature.releaseVersion!),
          ),
          token,
          token,
        );
      }
  
  
negative.code:     debugEvent("FormalParameter");
  
      if (superKeyword != null && !enableSuperParameters) {
        _reportFeatureNotEnabled(
          feature: ExperimentalFeatures.super_parameters,
          startToken: superKeyword,
        );
      }
  
  