lean4-htt/tests/lean/run/issue10775.lean
2025-10-24 14:54:36 +00:00

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set_option linter.unusedVariables false
opaque R : (n m : Int) → Type
axiom mkR : Nat → R n m
noncomputable def d : ∀ (n m : Int), R n m
| .ofNat n, .ofNat m => mkR 0
| .negSucc n, .negSucc m => mkR 0
| .negSucc 0, .ofNat 0 => mkR 0
| .ofNat _, .negSucc _ => mkR 0
| .negSucc _, .ofNat _ => mkR 0
/--
error: unsolved goals
case refine_1
⊢ ∀ (n m : Nat), ¬↑n + 1 = ↑m → mkR 0 = mkR 0
case refine_2
⊢ ∀ (n m : Nat), ¬Int.negSucc n + 1 = Int.negSucc m → mkR 0 = mkR 0
case refine_3
⊢ ¬0 = 0 → mkR 0 = mkR 0
case refine_4
⊢ ∀ (a a_1 : Nat), ¬↑a + 1 = Int.negSucc a_1 → mkR 0 = mkR 0
case refine_5
⊢ ∀ (a a_1 : Nat), (a = 0 → a_1 = 0 → False) → ¬Int.negSucc a + 1 = ↑a_1 → mkR 0 = mkR 0
-/
#guard_msgs in
example : (n m : Int) → (hnm : n + 1 ≠ m) → d n m = mkR 0 := by
refine d.fun_cases_unfolding (motive := fun n m r => (n + 1 ≠ m) → r = mkR 0)
?_ ?_ ?_ ?_ ?_ <;> dsimp
/--
error: unsolved goals
case case1
n✝ m✝ : Nat
hnm : Int.ofNat n✝ + 1 ≠ Int.ofNat m✝
⊢ d (Int.ofNat n✝) (Int.ofNat m✝) = mkR 0
case case2
n✝ m✝ : Nat
hnm : Int.negSucc n✝ + 1 ≠ Int.negSucc m✝
⊢ d (Int.negSucc n✝) (Int.negSucc m✝) = mkR 0
case case3
hnm : Int.negSucc 0 + 1 ≠ Int.ofNat 0
⊢ d (Int.negSucc 0) (Int.ofNat 0) = mkR 0
case case4
a✝¹ a✝ : Nat
hnm : Int.ofNat a✝¹ + 1 ≠ Int.negSucc a✝
⊢ d (Int.ofNat a✝¹) (Int.negSucc a✝) = mkR 0
case case5
a✝¹ a✝ : Nat
x✝ : a✝¹ = 0 → a✝ = 0 → False
hnm : Int.negSucc a✝¹ + 1 ≠ Int.ofNat a✝
⊢ d (Int.negSucc a✝¹) (Int.ofNat a✝) = mkR 0
-/
#guard_msgs in
example : (n m : Int) → (hnm : n + 1 ≠ m) → d n m = mkR 0 := by
intros n m hnm
fun_cases d
-- set_option trace.Elab.induction true in
/--
error: unsolved goals
case case1
n✝ m✝ : Nat
hnm : Int.ofNat n✝ + 1 ≠ Int.ofNat m✝
⊢ d (Int.ofNat n✝) (Int.ofNat m✝) = mkR 0
case case2
n✝ m✝ : Nat
hnm : Int.negSucc n✝ + 1 ≠ Int.negSucc m✝
⊢ d (Int.negSucc n✝) (Int.negSucc m✝) = mkR 0
case case3
hnm : Int.negSucc 0 + 1 ≠ Int.ofNat 0
⊢ d (Int.negSucc 0) (Int.ofNat 0) = mkR 0
case case4
a✝¹ a✝ : Nat
hnm : Int.ofNat a✝¹ + 1 ≠ Int.negSucc a✝
⊢ d (Int.ofNat a✝¹) (Int.negSucc a✝) = mkR 0
case case5
a✝¹ a✝ : Nat
x✝ : a✝¹ = 0 → a✝ = 0 → False
hnm : Int.negSucc a✝¹ + 1 ≠ Int.ofNat a✝
⊢ d (Int.negSucc a✝¹) (Int.ofNat a✝) = mkR 0
-/
#guard_msgs(pass trace, all) in
example : (n m : Int) → (hnm : n + 1 ≠ m) → d n m = mkR 0 := by
intros n m hnm
cases n, m using d.fun_cases_unfolding
/--
error: unsolved goals
case case1
n✝ m✝ : Nat
hnm : Int.ofNat n✝ + 1 ≠ Int.ofNat m✝
⊢ mkR 0 = mkR 0
case case2
n✝ m✝ : Nat
hnm : Int.negSucc n✝ + 1 ≠ Int.negSucc m✝
⊢ mkR 0 = mkR 0
case case3
hnm : Int.negSucc 0 + 1 ≠ Int.ofNat 0
⊢ mkR 0 = mkR 0
case case4
a✝¹ a✝ : Nat
hnm : Int.ofNat a✝¹ + 1 ≠ Int.negSucc a✝
⊢ mkR 0 = mkR 0
case case5
a✝¹ a✝ : Nat
x✝ : a✝¹ = 0 → a✝ = 0 → False
hnm : Int.negSucc a✝¹ + 1 ≠ Int.ofNat a✝
⊢ mkR 0 = mkR 0
-/
#guard_msgs(pass trace, all) in
example : (n m : Int) → (hnm : n + 1 ≠ m) → d n m = mkR 0 := by
intros n m hnm
induction n, m using d.fun_cases_unfolding