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feat: improve SimpTheorem preprocessor

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Leonardo de Moura 2022-02-28 18:27:13 -08:00
parent e8fb0c96ac
commit 4e310ac63d
3 changed files with 24 additions and 0 deletions
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4
src/Init/SimpLemmas.lean
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@ -139,6 +139,10 @@ theorem dite_congr {s : Decidable b} [Decidable c]
@[simp] theorem Bool.beq_to_eq (a b : Bool) : ((a == b) = true) = (a = b) := by cases a <;> cases b <;> decide
@[simp] theorem Bool.not_beq_to_not_eq (a b : Bool) : ((!(a == b)) = true) = ¬(a = b) := by cases a <;> cases b <;> decide
theorem Bool.of_not_eq_true {b : Bool} : ¬ (b = true) → b = false := by cases b <;> decide
theorem Bool.of_not_eq_false {b : Bool} : ¬ (b = false) → b = true := by cases b <;> decide
@[simp] theorem Bool.not_eq_true (b : Bool) : (¬ (b = true)) = (b = false) := by cases b <;> decide
@[simp] theorem Bool.not_eq_false (b : Bool) : (¬ (b = false)) = (b = true) := by cases b <;> decide

9
src/Lean/Meta/Tactic/Simp/SimpTheorems.lean
View file

@ -153,12 +153,21 @@ where
else if let some (_, lhs, rhs) := type.ne? then
if inv then
throwError "invalid '←' modifier in rewrite rule to 'False'"
if rhs.isConstOf ``Bool.true then
return [(← mkAppM ``Bool.of_not_eq_true #[e], ← mkEq lhs (mkConst ``Bool.false))]
else if rhs.isConstOf ``Bool.false then
return [(← mkAppM ``Bool.of_not_eq_false #[e], ← mkEq lhs (mkConst ``Bool.true))]
let type ← mkEq (← mkEq lhs rhs) (mkConst ``False)
let e ← mkEqFalse e
return [(e, type)]
else if let some p := type.not? then
if inv then
throwError "invalid '←' modifier in rewrite rule to 'False'"
if let some (_, lhs, rhs) := p.eq? then
if rhs.isConstOf ``Bool.true then
return [(← mkAppM ``Bool.of_not_eq_true #[e], ← mkEq lhs (mkConst ``Bool.false))]
else if rhs.isConstOf ``Bool.false then
return [(← mkAppM ``Bool.of_not_eq_false #[e], ← mkEq lhs (mkConst ``Bool.true))]
let type ← mkEq p (mkConst ``False)
let e ← mkEqFalse e
return [(e, type)]

11
tests/lean/run/simpBool.lean Normal file
View file

@ -0,0 +1,11 @@
example (h : x ≠ true) : (x && y) = false := by
simp [h]
example (h : ¬ (x = true)) : (x && y) = false := by
simp [h]
example (h : x ≠ false) : (x && y) = y := by
simp [h]
example (h : ¬ (x = false)) : (x && y) = y := by
simp [h]