simp_all
case some.nil
α : Type u_1
hd : α
val✝ : List α × α
ho : [].getSnoc? = some val✝
ih : ∀ {xs : List α} {x : α}, val✝ = (xs, x) ↔ [] = xs ++ [x]
⊢ False
case some.nil
α : Type u_1
hd : α
val✝ : List α × α
ho : [].getSnoc? = some val✝
ih : ∀ {xs : List α} {x : α}, ¬val✝ = (xs, x)
⊢ False