@Nullable
  private static PsiElement findTargetMember(@Nullable PsiElement element) {
    if (element == null) return null;
    final ChangeSignatureHandler fileHandler = getChangeSignatureHandler(element);
    if (fileHandler != null) {
      final PsiElement targetMember = fileHandler.findTargetMember(element);
      if (targetMember != null) return targetMember;
    }
    PsiReference reference = element.getReference();
    if (reference == null && element instanceof PsiNameIdentifierOwner) {
      return element;
    }
    if (reference != null) {
      return reference.resolve();
    }
    return null;
  }
@Nullable
  private static PsiElement findTargetMember(@Nullable PsiElement element)