@Nullable
    private VirtualFile findClosestRoot(@NotNull VirtualFile vFile) {
      VirtualFile sourceRoot = myProjectFileIndex.getSourceRootForFile(vFile);
      if (sourceRoot != null) return sourceRoot;
      VirtualFile contentRoot = myProjectFileIndex.getContentRootForFile(vFile);
      if (contentRoot != null) return contentRoot;
      VirtualFile libraryRoot = myProjectFileIndex.getClassRootForFile(vFile);
      if (libraryRoot != null) return libraryRoot;
      return null;
    }
@Nullable
    private VirtualFile findClosestRoot(@NotNull VirtualFile vFile)