Theorem: Nat.xor_assoc (Algdata/Data/Nat/Bits.lean)

State before:
l m n : Nat
⊢ (false != false) = false
Tactic:
decide
State after:
no goals

State before:
l m n : Nat
a b c : Bool
⊢ ((a != b) != c) = (a != (b != c))
Tactic:
cases a <;> cases b <;> cases c <;> decide
State after:
no goals