Bug #20033: `/#{''}(?<lvar>)/ =~ s` looks like a dynamic regexp match but assigns to local variable

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: ruby 3.3.0dev (2023-11-30T16:23:25Z master d048bae96b) [x86_64-linux]
• Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN

[tompng (tomoya ishida)]

I expect all of these code not to assign to lvar because all regexp looks like embedded dynamic regexp.

/#{''}(?<lvar>)/ =~ '' # assings to lvar

/#{"#{''}"}(?<lvar>)/ =~ '' # does not assign to lvar

/#{<<A}(?<lvar>)/ =~ '' # assigns to lvar
  string
A

/#{<<A}(?<lvar>)/ =~ '' # does not assign to lvar
  #{'string'}
A

I think /#{'a'}/ can be a DREGX because for string, "#{'a'}#{'b'}" is DSTR (DSTR@1:0-1:14 "ab" nil nil).

[Eregon (Benoit Daloze)]

+1, it should only be static regexp literals which assign variables (= without #{}), that's much simpler for everyone to understand.
The current situation feels like mixing parsing and compilation/optimization in the parser.

[nobu (Nobuyoshi Nakada)]

https://github.com/ruby/ruby/pull/9097

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Closed

Applied in changeset git|a607d62d8c5786087916413c369dbde0c62db573.

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[Bug #20033] Dynamic regexp should not assign captures