@Override
    public boolean isAvailableImpl(@NotNull Project project, Editor editor, PsiFile file) {
      if (!myReference.isValid()) {
        return false;
      }
      final PsiFile psiFile = myReference.getContainingFile();
      assert psiFile != null;
      //noinspection ConstantValue -- rechecking of isValid is intended
      return myReference.isValid() && psiFile.isValid();
    }
@Override
    public boolean isAvailableImpl(@NotNull Project project, Editor editor, PsiFile file)