anchor.diff:      } else {
         final appPath = _makePathAbsolute(argResults['app']);
         String viewerPath;
  -      BuildConfig config = _getCurrentHostConfig();
  +      BuildConfiguration config = _getCurrentHostConfig();
         if (config.type == BuildType.prebuilt) {
           Artifact artifact = ArtifactStore.getArtifact(type: ArtifactType.viewer, targetPlatform: TargetPlatform.linux);
           viewerPath = _makePathAbsolute(await ArtifactStore.getPath(artifact));
  
positive.code: 
      return await runCommandAndStreamOutput(await _getShellConfig());
    }
  }
  
negative.code:     return _makePathAbsolute(path.join(argResults['mojo-path'], 'out', mojoBuildType, 'mojo_shell'));
    }
  
    BuildConfiguration _getCurrentHostConfig() {
      BuildConfiguration result;
      TargetPlatform target = getCurrentHostPlatformAsTarget();
      for (BuildConfiguration config in buildConfigurations) {
  