# Ruby -c and ripper inconsistency: /(?\<n\>a(b|\\g\<n\>))/

**URL:** <https://www.ruby-forum.com/t/ruby-c-and-ripper-inconsistency-n-a-b-g-n/233278>\
**Category:** Development\
**Created:** [November 30, 2014, 2:18pm UTC](https://www.ruby-forum.com/t/ruby-c-and-ripper-inconsistency-n-a-b-g-n/233278 "2014-11-30T14:18:40Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![addis\_a](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c4cdca/32.png) [@addis\_a](https://www.ruby-forum.com/u/addis_a)\
**Post date:** [November 30, 2014, 2:18pm UTC](https://www.ruby-forum.com/t/ruby-c-and-ripper-inconsistency-n-a-b-g-n/233278/1 "2014-11-30T14:18:40Z")

</div>

Issue #10543 has been updated by Tomoyuki C…

Backport changed from 2.0.0: UNKNOWN, 2.1: UNKNOWN to 2.0.0: DONTNEED,  
2.1: DONTNEED

it seems introduced at r48504.

* * *

Bug #10543: ruby -c and ripper inconsistency: /(?a(b|\g))/

> **[Bug #10543: ruby -c and ripper inconsistency: /(?a(b|\\g))/ - Ruby master -...](https://bugs.ruby-lang.org/issues/10543#change-50208)**
>
> Redmine

- Author: Akira T.
- Status: Closed
- Priority: Normal
- Assignee:
- Category:
- Target version:
- ruby -v: ruby 2.2.0dev (2014-11-26 trunk 48577) [x86\_64-linux]
- Backport: 2.0.0: DONTNEED, 2.1: DONTNEED

* * *

以下のように、/(?a(b|\g))/ というだけのソースは  
ruby -c では問題無しとなりますが、  
Ripper.sexp では構文木でなく nil が返ってきてしまいます。

```auto
% cat z.rb
/(?<n>a(b|\g<n>))/
% ./ruby -c z.rb
Syntax OK
% ./ruby -rripper -e 'p Ripper.sexp(STDIN.read)' < z.rb
nil
% ./ruby -v
ruby 2.2.0dev (2014-11-26 trunk 48577) [x86_64-linux]

```