@Nullable
  private static GrLiteral getRegexAtTheBeginning(PsiElement expr) {
    PsiElement firstChild = expr;
    while (firstChild != null) {
      if (firstChild instanceof GrLiteral && GrStringUtil.isRegex((GrLiteral)firstChild)) return (GrLiteral)firstChild;
      firstChild = firstChild.getFirstChild();
    }
    return null;
  }
@Nullable
  private static GrLiteral getRegexAtTheBeginning(PsiElement expr)