lean4-htt/tests/elab/fin_coercions.lean
Garmelon 08eb78a5b2
chore: switch to new test/bench suite (#12590)
This PR sets up the new integrated test/bench suite. It then migrates
all benchmarks and some related tests to the new suite. There's also
some documentation and some linting.

For now, a lot of the old tests are left alone so this PR doesn't become
even larger than it already is. Eventually, all tests should be migrated
to the new suite though so there isn't a confusing mix of two systems.
2026-02-25 13:51:53 +00:00

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Text

set_option pp.mvars false
-- We first verify that there is no global coercion from `Nat` to `Fin n`.
-- Such a coercion would frequently introduce unexpected modular arithmetic.
/--
error: Type mismatch
n
has type
Nat
but is expected to have type
Fin 3
---
info: fun n => sorry : (n : Nat) → ?_ n
-/
#guard_msgs in #check fun (n : Nat) => (n : Fin 3)
-- This instance is available via `open Fin.NatCast in ...`
section
open Fin.NatCast
variable (m : Nat) (n : Fin 3)
/-- info: n < ↑m : Prop -/
#guard_msgs in #check n < m
end
example (x : Fin (n + 1)) (h : x < n) : Fin (n + 1) := x.succ.castLT (by simp [h])