bug#3687: 23.1.50; inconsistency in multibyte eight-bit regexps

[Eli Zaretskii <eliz@gnu.org>]

> Date: Fri, 26 Jun 2009 18:56:50 +0900 (JST)
> From: YAMAMOTO Mitsuharu <mituharu@math.s.chiba-u.ac.jp>
> Cc: 
> 
> The following results look inconsistent:
> 
>   (string-match (string-to-multibyte "\x80") (string-to-multibyte "\x80"))
>   => 0
>   (string-match (string-to-multibyte "\x80") "\x80")
>   => nil
> 
>   (string-match (string-to-multibyte "[\x80]") (string-to-multibyte "\x80"))
>   => nil
>   (string-match (string-to-multibyte "[\x80]") "\x80")
>   => 0

Please tell why you think they are inconsistent.  More importantly,
please show real-life examples of code or situations where this gets
in your way.  This area is full of subtleties and gotchas, and in
general the current code does what it does because it needs to cater
to many different practical situations.

There could still be bugs, of course.