lean4-htt/tests/lean/run/4920.lean
jrr6 62f14514da
refactor: update built-in tactic error messages (#9633)
This PR updates various error messages produced by or associated with
built-in tactics and adapts their formatting to current conventions.
2025-07-31 14:16:57 +00:00

51 lines
1.4 KiB
Text

def Vect (n: Nat) (A: Type u) := {l: List A // l.length = n}
def Vect.cons (a: A) (v: Vect n A): Vect (n + 1) A :=
⟨a::v.val, by simp [v.property]⟩
instance: GetElem (Vect n A) Nat A (λ _ i => i < n) where
getElem vec i _ := match vec with | ⟨l, _⟩ => l[i]
set_option pp.mvars false
/--
error: Type mismatch
xm[i]
has type
Vect m A
but is expected to have type
A
---
error: Type mismatch: After simplification, term
ih
has type
i < as.length
of sort `Prop` but is expected to have type
?_
of sort `Type _`
---
error: failed to prove index is valid, possible solutions:
- Use `have`-expressions to prove the index is valid
- Use `a[i]!` notation instead, runtime check is performed, and 'Panic' error message is produced if index is not valid
- Use `a[i]?` notation instead, result is an `Option` type
- Use `a[i]'h` notation instead, where `h` is a proof that index is valid
A : Type _
m i j : Nat
as : List A
xm : List (Vect m A)
h0 : xm.length = as.length
ih : i < (List.zipWith cons as xm).length
jh : j < m
⊢ ?_ sorry j
-/
#guard_msgs in
theorem Vect.aux
{as: List A} {xm: List (Vect m A)}
(h0: xm.length = as.length)
(ih: i < (List.zipWith cons as xm).length)
(jh: j < m)
: ((List.zipWith cons as xm)[i])[j + 1] =
xm[i]'(by simpa[h0] using ih)[j] := by
-- Correct syntax requires an extra pair of parentheses:
-- (xm[i]'(by simpa[h0] using ih))[j]
-- but `lean` should not crash.
sorry