bug#11360: ERC completion case-sensitive

[Stefan Monnier]

>>> erc-completion-ignore-case or completion-ignore-case is t. A specific
>>> setting seems like a good idea because presumably some people will want
>>> case-insensitive completion in erc but not elsewhere.
>> 
>> There are 2 notions of "case-sensitivity" when it comes to completion:
>> - whether the case is semantically significant in the end result
>> (i.e. is "FirstName" another user than "firstname"?).
>> - whether the user wants "FirstName" be considered as a valid candidate
>> for completion of "fir".
>> 
>> The current completion code somewhat conflates the two, but in terms of
>> "what should Emacs do" the difference is important.  Of course, the
>> second consideration only applies when the first is true.
>> 
>> So: is the case semantically significant, here?

> irc retains case, but it doesn't use it to distinguish.  That is, if you
> have a nick "Larsi", you can't have a nick "larsi".

Thanks, so we should indeed use completion-table-case-fold (and make it
work).


        Stefan


PS: but in the mean time, setting completion-ignore-case buffer-locally
is the better fix for emacs-25.