anchor.diff:  const String experimentalFlagOptions = '--enable-experiment=';
   
   class TestOptions {
  -  final Map<ExperimentalFlag, bool> experimentalFlags;
  +  final Map<ExperimentalFlag, bool> _experimentalFlags;
     final bool forceLateLowering;
     final bool forceNnbdChecks;
     final bool forceNoExplicitGetterCalls;
     final bool nnbdAgnosticMode;
     final String target;
   
  -  TestOptions(this.experimentalFlags,
  +  TestOptions(this._experimentalFlags,
         {this.forceLateLowering: false,
         this.forceNnbdChecks: false,
         this.forceNoExplicitGetterCalls: false,
  
positive.code: 
    Future<Result<int>> run(ComponentResult result, FastaContext context) async {
      TestOptions testOptions = context.computeTestOptions(result.description);
      switch (testOptions.target) {
        case "vm":
          if (context.platformUri == null) {
  
negative.code: 
    Map<ExperimentalFlag, bool> computeExperimentalFlags(
        Map<ExperimentalFlag, bool> forcedExperimentalFlags) {
      Map<ExperimentalFlag, bool> flags = new Map.from(defaultExperimentalFlags);
      flags.addAll(_experimentalFlags);
      flags.addAll(forcedExperimentalFlags);
      return flags;
    }
  