[ruby-dev:52012] [Ruby master Feature#19134] ** is not allowed in def foo(...)

4 Dec 2022

      Issue #19134 has been updated by shugo (Shugo Maeda).

Status changed from Closed to Open

I think it's most conservative to probhibit `*` and `**`:

```
def foo(...)
  bar(&) # OK
  baz(*) # error
  quux(**) # error
end
```

And a error should occur in the following code instead of dropping keyword arguments:

```
def foo(*, **, &)
  bar(...)
end

def bar(*args, **kw, &block)
  p [args, kw, block&.call]
end

foo(1, 2, x: 3, y: 4) { 5 }
```

What do you think, Matz?

----------------------------------------
Feature #19134: ** is not allowed in def foo(...)
https://bugs.ruby-lang.org/issues/19134#change-100495

* Author: shugo (Shugo Maeda)
* Status: Open
* 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/