@Nullable
  @Override
  public Result acceptChar(char c, int prefixLength, @NotNull Lookup lookup) {
    if (!lookup.isCompletion()) return null;
    PsiFile file = lookup.getPsiFile();
    if (file == null) return null;
    TextCompletionProvider provider = TextCompletionUtil.getProvider(file);
    if (provider != null) return provider.acceptChar(c);
    return null;
  }
@Nullable
  @Override
  public Result acceptChar(char c, int prefixLength, @NotNull Lookup lookup)