feat: generalize basic Inhabited/Nonempty instances from Monad to Applicative#12041
Open
fgdorais wants to merge 3 commits intoleanprover:masterfrom
Open
feat: generalize basic Inhabited/Nonempty instances from Monad to Applicative#12041fgdorais wants to merge 3 commits intoleanprover:masterfrom
fgdorais wants to merge 3 commits intoleanprover:masterfrom
Conversation
fgdorais
changed the title
github-actions
Bot
added
the
toolchain-available
|
Mathlib CI status (docs):
|
Collaborator
|
Reference manual CI status:
|
eric-wieser
reviewed
Jan 19, 2026
eric-wieser
reviewed
Jan 19, 2026
| seqLeft := fun a b => Seq.seq (Functor.map (Function.const _) a) b | ||
| seqRight := fun a b => Seq.seq (Functor.map (Function.const _ id) a) b | ||
|
|
||
| instance {α : Type u} {f : Type u → Type v} [Applicative f] : Inhabited (α → f α) where |
Contributor
There was a problem hiding this comment.
Note this forms a diamond with the instance below (and the instance that sets default = fun i => default for pi types).
It would probably be better to demote this to Nonempty to avoid this risk.
Contributor
Author
There was a problem hiding this comment.
Makes sense but that would be a regression. I wouldn't do that without maintainer input.
Co-authored-by: Eric Wieser <wieser.eric@gmail.com>
Contributor
Author
|
changelog-library |
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
3 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
This PR generalizes basic derived
Inhabited/Nonemptyinstances fromMonadtoApplicative.Closes #12042