lean4-htt/src/Init/Data/Fin
Kyle Miller 28cf146d00
fix: make sure monad lift coercion elaborator has no side effects (#6024)
This PR fixes a bug where the monad lift coercion elaborator would
partially unify expressions even if they were not monads. This could be
taken advantage of to propagate information that could help elaboration
make progress, for example the first `change` worked because the monad
lift coercion elaborator was unifying `@Eq _ _` with `@Eq (Nat × Nat)
p`:
```lean
example (p : Nat × Nat) : p = p := by
  change _ = ⟨_, _⟩ -- used to work (yielding `p = (p.fst, p.snd)`), now it doesn't
  change ⟨_, _⟩ = _ -- never worked
```
As such, this is a breaking change; you may need to adjust expressions
to include additional implicit arguments.
2024-11-13 16:22:31 +00:00
..
Basic.lean chore: deprecate duplicated Fin.size_pos (#6025) 2024-11-11 04:06:13 +00:00
Bitwise.lean feat: USize.and_toNat (#4629) 2024-07-03 01:28:36 +00:00
Fold.lean chore: upstream lemmas about Fin.foldX (#5937) 2024-11-04 00:52:59 +00:00
Iterate.lean chore: fix spelling mistakes in src/Init/ (#5427) 2024-09-23 21:09:58 +00:00
Lemmas.lean fix: make sure monad lift coercion elaborator has no side effects (#6024) 2024-11-13 16:22:31 +00:00
Log2.lean feat: log2 for Fin and UInts 2022-11-29 01:05:06 +01:00