bin/176444: strange behaviour of the $(( )) form in sh(1)

[jilles at FreeBSD.org]

Synopsis: strange behaviour of the $(( )) form in sh(1)

Responsible-Changed-From-To: freebsd-bugs->jilles
Responsible-Changed-By: jilles
Responsible-Changed-When: Sat Mar 2 23:55:19 UTC 2013
Responsible-Changed-Why: 
sh(1) is my area.

It is indeed unfortunate that $((++a)) is so insidiously broken.
I don't know yet whether to fix it by implementing the operators
or by adding error detection.

http://www.freebsd.org/cgi/query-pr.cgi?pr=176444