lean4-htt/tests/elab/matchtac.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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theorem tst1 {α : Type} {p : Prop} (xs : List α) (h₁ : (a : α) → (as : List α) → xs = a :: as → p) (h₂ : xs = [] → p) : p :=
by match (generalizing := false) h : xs with
| [] => exact h₂ h
| z::zs => apply h₁ z zs; assumption
theorem tst1' {α : Type} {p : Prop} (xs : List α) (h₁ : (a : α) → (as : List α) → xs = a :: as → p) (h₂ : xs = [] → p) : p :=
by match xs with
| [] => exact h₂ rfl
| z::zs => exact h₁ z zs rfl
theorem tst2 {α : Type} {p : Prop} (xs : List α) (h₁ : (a : α) → (as : List α) → xs = a :: as → p) (h₂ : xs = [] → p) : p :=
by match (generalizing := false) h:xs with
| [] => ?nilCase
| z::zs => ?consCase;
case consCase => exact h₁ z zs h;
case nilCase => exact h₂ h
def tst3 {α β γ : Type} (h : α × β × γ) : β × α × γ :=
by {
match h with
| (a, b, c) => exact (b, a, c)
}
theorem tst4 {α : Type} {p : Prop} (xs : List α) (h₁ : (a : α) → (as : List α) → xs = a :: as → p) (h₂ : xs = [] → p) : p := by
match (generalizing := false) h : xs with
| [] => _
| z::zs => _
case match_2 => exact h₁ z zs h
exact h₂ h
theorem tst5 {p q r} (h : p q r) : r q p:= by
match h with
| Or.inl h => exact Or.inr (Or.inr h)
| Or.inr (Or.inl h) => ?c1
| Or.inr (Or.inr h) => ?c2
case c2 =>
apply Or.inl
assumption
case c1 =>
apply Or.inr
apply Or.inl
assumption
theorem tst6 {p q r} (h : p q r) : r q p:= by
match h with
| Or.inl h => exact Or.inr (Or.inr h)
| Or.inr (Or.inl h) => ?c1
| Or.inr (Or.inr h) =>
apply Or.inl
assumption
case c1 => apply Or.inr; apply Or.inl; assumption
theorem tst7 {p q r} (h : p q r) : r q p:=
by match h with
| Or.inl h =>
exact Or.inr (Or.inr h)
| Or.inr (Or.inl h) =>
apply Or.inr;
apply Or.inl;
assumption
| Or.inr (Or.inr h) =>
apply Or.inl;
assumption
inductive ListLast.{u} {α : Type u} : List α → Type u
| empty : ListLast []
| nonEmpty : (as : List α) → (a : α) → ListLast (as ++ [a])
axiom last {α} (xs : List α) : ListLast xs
axiom back {α} [Inhabited α] (xs : List α) : α
axiom popBack {α} : List α → List α
axiom backEq {α} [Inhabited α] : (xs : List α) → (x : α) → back (xs ++ [x]) = x
axiom popBackEq {α} : (xs : List α) → (x : α) → popBack (xs ++ [x]) = xs
theorem tst8 {α} [Inhabited α] (xs : List α) : xs ≠ [] → xs = popBack xs ++ [back xs] :=
match (generalizing := false) xs, h:last xs with
| _, ListLast.empty => fun h => absurd rfl h
| _, ListLast.nonEmpty ys y => fun _ => sorry
theorem tst9 {α} [Inhabited α] (xs : List α) : xs ≠ [] → xs = popBack xs ++ [back xs] := by
match (generalizing := false) xs, h:last xs with
| _, ListLast.empty => intro h; exact absurd rfl h
| _, ListLast.nonEmpty ys y => intro; rw [popBackEq, backEq]
theorem tst8' {α} [Inhabited α] (xs : List α) : xs ≠ [] → xs = popBack xs ++ [back xs] :=
match xs, last xs with
| _, ListLast.empty => fun h => absurd rfl h
| _, ListLast.nonEmpty ys y => fun _ => sorry
theorem tst8'' {α} [Inhabited α] (xs : List α) (h : xs ≠ []) : xs = popBack xs ++ [back xs] :=
match xs, last xs with
| _, ListLast.empty => absurd rfl h
| _, ListLast.nonEmpty ys y => sorry
example (xs : List α) : xs = xs := by
match xs with
| [] | [x] | x::x'::xs => rfl