FR: Throw a warning if password line in cnf file contains hash character (#)

When I have a # character in my password, and try to use a .cnf file for auto login, the parser seems to strip all characters after the hash in the cnf file.
I believe it's some kind of "comment stripper" in the code that's the culprit.
Since the # char is perfectly valid for passwords everywhere else (working in php, entered on command line, etc), the mysql client should at least yield a warning when finding a comment char in a password in some cnf file.