@Override
  public MultiMap<PsiElement, String> findConflicts(ChangeInfo info, Ref<UsageInfo[]> refUsages) {
    if (info instanceof JavaChangeInfo) {
      return new GrChangeSignatureConflictSearcher((JavaChangeInfo)info).findConflicts(refUsages);
    }
    else {
      return new MultiMap<>();
    }
  }
@Override
  public MultiMap<PsiElement, String> findConflicts(ChangeInfo info, Ref<UsageInfo[]> refUsages)