From: "jeremyevans0 (Jeremy Evans)" <noreply@...>
Date: 2022-03-13T16:57:42+00:00
Subject: [ruby-core:107884] [Ruby master Bug#18629] block args array splatting assigns to higher scope _ var

Issue #18629 has been updated by jeremyevans0 (Jeremy Evans).


I'm guessing this isn't a bug, because variables prefixed by `_` (including `_` itself) are supposed to be used in cases where you are ignoring the values.  There are other cases where `_` prefixed variables are special:

```ruby
def a(b, b) end   # SyntaxError
def a(_b, _b) end # no error
```


----------------------------------------
Bug #18629: block args array splatting assigns to higher scope _ var
https://bugs.ruby-lang.org/issues/18629#change-96825

* Author: Nakilon (Victor Maslov)
* Status: Open
* Priority: Normal
* ruby -v: 3.0.2
* Backport: 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN
----------------------------------------
``` ruby
v = 1; [[2]].each{ |(v)| }; p v
_ = 1; [[2]].each{ |(_)| }; p _
```
prints
```
1
2
```
You can see here that `v` is still `1` but `_` isn't shadowed properly and is being assigned `2`.
Reproducible from 2.3.8 to 3.0.2 (macOS rbenv)



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