ArgMin and ArgMax can't work

[MarkZander]

I attempted to use ArgMin but got the following error:

No instance for (Bounded (Arg Number LocalTime))

And sure enough there is no Bounded instance for Arg which Min requires.

Nothing that another orphan instance won't work around.

[ekmett]

It works just fine.

If you want a Monoid you'll need a Bounded instance, but if you just want a Semigroup you don't.

I cannot give you a Bounded instance for Arg. Its ordering isn't structural. Period. That path cannot work. You hit a dead end.

You are looking for Option (ArgMax a b). This adds in a unit.

No orphan is required, just careful knowledge of what instance you are actually looking for.