Issue #19134 has been updated by shugo (Shugo Maeda).
Eregon (Benoit Daloze) wrote in #note-5:
IMHO if `...` is used then `*`, `**` and `&`
should all be forbidden (a SyntaxError at parse time).
Because that way is the best for optimizing delegation.
And also taking apart `*` and `**` is arguably not really delegation anymore.
`&` is allowed in 3.1, so it's a breaking change to prohibit it.
----------------------------------------
Feature #19134: ** is not allowed in def foo(...)
https://bugs.ruby-lang.org/issues/19134#change-100493
* Author: shugo (Shugo Maeda)
* Status: Closed
* Priority: Normal
* Assignee: matz (Yukihiro Matsumoto)
----------------------------------------
`*` and `&` are allowed in the body of a method with `...` argument forwarding, but
`**` is not allowed.
```
def foo(...)
bar(*) # OK
baz(&) # OK
quux(**) # NG
end
```
Is it intended behavior?
It seems that parse.y has code like `#ifdef RUBY3_KEYWORDS`, and if RUBY3_KEYWORDS, `**`
will also be supported.
--
https://bugs.ruby-lang.org/