apply congrArg Array.mk
α : Type u
as : Array α
h✝ : size as > 0
l : List α
h : size { data := l } > 0
⊢ { data := List.dropLast l ++ [List.getLast l (_ : { data := l }.data ≠ [])] } = { data := l }
α : Type u
as : Array α
h✝ : size as > 0
l : List α
h : size { data := l } > 0
⊢ List.dropLast l ++ [List.getLast l (_ : { data := l }.data ≠ [])] = l