private static @NotNull NlsInfo fromVariableReference(UExpression receiver) {
    if (receiver instanceof UReferenceExpression && TypeUtils.isJavaLangString(receiver.getExpressionType())) {
      PsiElement target = ((UReferenceExpression)receiver).resolve();
      if (target instanceof PsiVariable) {
        return factory().fromModifierListOwner((PsiVariable)target);
      }
    }
    return NlsUnspecified.UNKNOWN;
  }
private static @NotNull NlsInfo fromVariableReference(UExpression receiver)