From: Eric Wong <normalperson@...>
Date: 2014-03-27T01:23:23+00:00
Subject: [ruby-core:61707] Re: [ruby-trunk - Bug #9680] [Open] String#sub and siblings should not use regex when String pattern is passed

I had an idea to replace the current reg_cache with memoization for
converting string literals, but never got around to it.  That would
also reduce garbage while preserving $& compatibility.