http://www.perlmonks.org?node_id=1128006


in reply to Re^2: Strange behavior with List::Util qw{first} on perl >= 5.20
in thread Strange behavior with List::Util qw{first} on perl >= 5.20

There's something fishy about $_. It's a TEMP with REFCNT=1. I believe that means it's a mortal. If so, that means noone claims a reference to $_, but first still uses it after the callback returns. This points to a bug in List::Util.

That said, the inplace lc($_)[1] should probably only happen in void context.


  1. This is the first I've ever heard about this!