lean4-htt/tests/elab/exfalsoBug.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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2.2 KiB
Text

namespace Ex1
def f (n : Nat) : Option { r : Nat // r ≤ n } :=
match n with
| 0 => some ⟨0, Nat.le_refl _⟩
| n+1 => match f n with
| some ⟨m, h₁⟩ =>
have : m < n+1 := Nat.lt_of_le_of_lt h₁ (Nat.lt_succ_self _)
match f m with
| some ⟨r, h₂⟩ => some ⟨r, Nat.le_trans h₂ (Nat.le_trans h₁ (Nat.le_succ _))⟩
| none => none
| none => none
end Ex1
namespace Ex2
def f (n : Nat) : Option { r : Nat // r ≤ n } :=
if h : n = 0 then
some ⟨0, h ▸ Nat.le_refl _⟩
else
match f (n-1) with
| some ⟨m, h₁⟩ =>
have : m < n := Nat.lt_of_le_of_lt h₁ (Nat.pred_lt h)
match f m with
| some ⟨r, h₂⟩ => some ⟨r, Nat.le_trans h₂ (Nat.le_trans h₁ (Nat.pred_le _))⟩
| none => none
| none => none
end Ex2
namespace Ex3
def f' (n : Nat) : Option { r : Nat // r ≤ n } :=
match n with
| 0 => some ⟨0, Nat.le_refl _⟩
| n+1 => match f' n with
| some ⟨m, h₁⟩ =>
have : m < n+1 := Nat.lt_of_le_of_lt h₁ (Nat.lt_succ_self _)
match f' m with
| some ⟨r, h₂⟩ => some ⟨r, Nat.le_trans h₂ (Nat.le_trans h₁ (Nat.le_succ _))⟩
| none => none
| none => none
theorem f'_ne_none (n : Nat) : f' n ≠ none := by
match n with
| 0 => simp [f']
| n+1 =>
simp [f']
have ih₁ := f'_ne_none n
split
next m h₁ he =>
have : m < n+1 := Nat.lt_of_le_of_lt h₁ (Nat.lt_succ_self _)
have ih₂ := f'_ne_none m
split
next => simp
next h => contradiction
next => contradiction
def f (n : Nat) : Option Nat :=
match f' n with
| some r => some r.1
| none => none
theorem f_eq (n : Nat) :
f n = match n with
| 0 => some 0
| n => match f (n - 1) with
| some m => f m
| none => none := by
unfold f
split
next r h =>
revert h
split <;> try simp [f']
next => intro h; subst h; simp
next hne =>
cases n <;> simp [f']
next => contradiction
next n _ =>
split <;> try simp
next r hrn h₁ =>
split <;> simp
next => intro he; subst he; simp [*]
next h_eq_none =>
have hne := f'_ne_none n
contradiction
end Ex3