We aren't enumerating arguments but values for an argument, so the name
should reflect that.
This will be important as part of #1807 when we have more specific
attribute names.
This is mostly about avoiding criterion's build times when just
developing clap itself.
I'm assuming the derive test changed because criterion's clap v2 isn't
in the dependency tree anymore.
This will make it easier to divide off parser logic for adding in
actions.
This does mean we can't provide error reporting on bad values with
`bool` but
- We should have also been doing that for `from_flag`
- We'll be dropping this soon in clap4 anyways
For clap 3, its opt-in as a precaution against breaking
compatibility in some weird cases.
This does require the types to implement `Clone`.
Fixes#3734Fixes#3496Fixes#3589
