private static boolean isInSourceFiles(@Nullable VirtualFile file, @NotNull Project project) {
    if (file != null && !(file instanceof LightVirtualFile)) {
      final FileIndexFacade index = FileIndexFacade.getInstance(project);
      if (index.isInSource(file) || index.isInLibraryClasses(file)) {
        return true;
      }
    }
    return false;
  }
private static boolean isInSourceFiles(@Nullable VirtualFile file, @NotNull Project project)