∀ {α : Type u_1} {r : Std.Ric α} [inst : LE α] [inst_1 : DecidableLE α] [inst_2 : Std.PRange.Least? α]
  [inst_3 : Std.PRange.UpwardEnumerable α] [inst_4 : Std.PRange.LawfulUpwardEnumerableLE α]
  [inst_5 : Std.PRange.LawfulUpwardEnumerableLeast? α] [inst_6 : Std.Rxc.IsAlwaysFinite α]
  [inst_7 : Std.PRange.LawfulUpwardEnumerable α] {m : Type u_1 → Type u_2} [inst_8 : Monad m] [LawfulMonad m]
  {γ : Type u_1} {init : γ} {f : (a : α) → a ∈ r → γ → m (ForInStep γ)},
  forIn' r init f = forIn' (Std.PRange.UpwardEnumerable.least...=r.upper) init fun a ha acc => f a ⋯ acc