rw [ih]
α : Type u_1
p✝ : α → Prop
inst✝¹ : DecidablePred p✝
p : α → Prop
inst✝ : DecidablePred p
x : α
xs : List α
ih : ∀ (i : (List.sublist p xs).Index), (unsublist p i).val = i.val.val
i : (List.sublist p (x :: xs)).Index
hx : ¬p x
⊢ (unsublist p (⋯ ▸ i)).val = i.val.val
α : Type u_1
p✝ : α → Prop
inst✝¹ : DecidablePred p✝
p : α → Prop
inst✝ : DecidablePred p
x : α
xs : List α
ih : ∀ (i : (List.sublist p xs).Index), (unsublist p i).val = i.val.val
i : (List.sublist p (x :: xs)).Index
hx : ¬p x
⊢ (⋯ ▸ i).val.val = i.val.val