Issue #17030 has been updated by shyouhei (Shyouhei Urabe).


Yes but E#grep's allocating MatchData is by spec.  You can observe `$&` etc. by passing a block to it.

```ruby
p %w[q w e r].grep(/./) { $~ }
```

So this is at least a breaking change.

----------------------------------------
Bug #17030: Enumerable#grep{_v} should be optimized for Regexp
https://bugs.ruby-lang.org/issues/17030#change-86539

* Author: marcandre (Marc-Andre Lafortune)
* Status: Open
* Priority: Normal
* Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN
----------------------------------------
Currently:

```ruby
array.select { |e| e.match?(REGEXP) }

# about 3x faster and 6x more memory efficient than
array.grep(REGEXP)
```

This is because `grep` calls `Regexp#===` which creates useless `MatchData`



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