Issue #20033 has been updated by 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.
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Bug #20033: `/#{''}(?<lvar>)/ =~ s` looks like a dynamic regexp match but
assigns to local variable
https://bugs.ruby-lang.org/issues/20033#change-105498
* Author: tompng (tomoya ishida)
* Status: Open
* Priority: Normal
* 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
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I expect all of these code not to assign to lvar because all regexp looks like embedded
dynamic regexp.
~~~ruby
/#{''}(?<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)`.
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