bug#50583: 27.2; test-completion should return non-nil

[Lars Ingebrigtsen]

Dmitry Gutov <dgutov@yandex.ru> writes:

> On 14.09.2021 16:25, Kevin Vigouroux via Bug reports for GNU Emacs,
> the Swiss army knife of text editors wrote:
>> In the following code, I assume that `test-completion' should return a
>> non-‘nil’ value because "foo" is a valid completion alternative.
>
> "foo" is not a member of the list '("foobar" "bar" "barfoo"), so
> that's not true.

The doc string here is vague, though:

Return non-nil if STRING is a valid completion.

So perhaps it could be clarified.  I think it wants to say something
like "if STRING is in COMPLETIONS", but since COMPLETIONS can be a
function, that's not quite right.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no