On 08.04.2021 22:46, Drew Adams wrote:
>> Another approach would be to add a new "extra property"
>> or metadata element which will say "don't remove duplicates".
> 
> I mentioned variable `icicle-transform-function', whose
> most common values are `icicle-remove-duplicates' and
> nil (which means don't remove dups).
> 
> (Like such a variable, completion metadata is an
> aggregate operation: it applies to a set of completions,
> not to just this or that completion.)
> 
> `icicle-transform-function' is applied to all candidates,
> and it can do anything.

A general completion table does specify any `icicle-transform-function`, 
and it wouldn't know how.

Some standard, cross-frontend approach would be required.

>> I do think it's questionable, though, to include
>> completions that are hard to distinguish.
> 
> Don't confuse looking different in *Completions*, at the
> outset and always, with easy to distinguish.  There are
> other ways to make them appear different - from mode-line
> to ephemeral appearance changes in *Completions*.  There
> is more than one way to skin this cat.

Ephemeral appearance changes could be good enough. Or icons, like on the 
attached video.