protected void registerExternalAnnotations(@NotNull Object key, @NotNull PsiFile annotationsFile) {
    myExternalAnnotationsCache.compute(key, (k, v) -> {
      if (v == null || v == NULL_LIST) {
        return new SmartList<>(annotationsFile);
      }

      v.add(annotationsFile);
      return v;
    });
  }
protected void registerExternalAnnotations(@NotNull Object key, @NotNull PsiFile annotationsFile)