diff --git a/src/Lean/Meta/Tactic/Grind/Propagate.lean b/src/Lean/Meta/Tactic/Grind/Propagate.lean index 14a3a786ef84..42d1135a14f0 100644 --- a/src/Lean/Meta/Tactic/Grind/Propagate.lean +++ b/src/Lean/Meta/Tactic/Grind/Propagate.lean @@ -99,6 +99,8 @@ builtin_grind_propagator propagateNotUp ↑Not := fun e => do else if (← isEqTrue a) then -- a = True → (Not a) = False pushEqFalse e <| mkApp2 (mkConst ``Lean.Grind.not_eq_of_eq_true) a (← mkEqTrueProof a) + else if (← isEqv e a) then + closeGoal <| mkApp2 (mkConst ``Lean.Grind.false_of_not_eq_self) a (← mkEqProof e a) /-- Propagates truth values downwards for a negation expression `Not a` based on the truth value of `Not a`. diff --git a/tests/lean/run/grind_propagate_connectives.lean b/tests/lean/run/grind_propagate_connectives.lean index e4f4a020dc68..6cb042ae1bba 100644 --- a/tests/lean/run/grind_propagate_connectives.lean +++ b/tests/lean/run/grind_propagate_connectives.lean @@ -103,3 +103,6 @@ example (p q r : Prop) : p ∨ (q ↔ r) → ¬r → q → False := by grind on_failure do Lean.logInfo "hello world" fallback + +example (a b : Nat) : (a = b) = (b = a) := by + grind