@Nullable
  private static PsiFunctionalExpression findPsiByAST(PsiFile file, int offset) {
    PsiFunctionalExpression expression =
      PsiTreeUtil.findElementOfClassAtOffset(file, offset, PsiFunctionalExpression.class, false);
    if (expression == null || expression.getTextRange().getStartOffset() != offset) {
      return null;
    }
    return expression;
  }
@Nullable
  private static PsiFunctionalExpression findPsiByAST(PsiFile file, int offset)