anchor.diff:        : super._subclass(configuration);
   
     String computeCompilerPath() {
  -    var prefix = 'sdk/bin';
  +    var prefix =
  +        // TODO(38701): Cleanup after merging the forked SDK into mainline.
  +        _configuration.nnbdMode == NnbdMode.legacy ? 'sdk/bin' : 'sdk_nnbd/bin';
       var suffix = shellScriptExtension;
   
       if (_isHostChecked) {
  
positive.code:       CommandArtifact artifact) {
      var sdk = _useSdk
          ? Uri.directory(_configuration.buildDirectory).resolve('dart-sdk/')
          : Uri.directory(Repository.dir.toNativePath()).resolve('sdk/');
      var preambleDir = sdk.resolve('lib/_internal/js_runtime/lib/preambles/');
      return runtimeConfiguration.dart2jsPreambles(preambleDir)
        ..add(artifact.filename);
  
negative.code:   String computeCompilerPath() {
      var dir = _useSdk
          ? "${_configuration.buildDirectory}/dart-sdk"
          // TODO(38701): Cleanup after merging the forked SDK into mainline.
          : _configuration.nnbdMode == NnbdMode.legacy ? "sdk" : "sdk_nnbd";
      return "$dir/bin/dartdevc$shellScriptExtension";
    }
  