protected Collection<PsiElement> findElementsToHighlight(M caller, PsiElement callee) {
    Query<PsiReference> references = ReferencesSearch.search(callee, new LocalSearchScope(caller), false);
    return ContainerUtil.mapNotNull(references, psiReference -> psiReference.getElement());
  }
protected Collection<PsiElement> findElementsToHighlight(M caller, PsiElement callee)