rcases e with (_ | e) <;> simp
α : Type u_1
α₁ : Type u_2
α₂ : Type u_3
β : Type u_4
γ : Type u_5
σ : Type u_6
τ : Type u_7
inst✝⁶ : Primcodable α
inst✝⁵ : Primcodable α₁
inst✝⁴ : Primcodable α₂
inst✝³ : Primcodable β
inst✝² : Primcodable γ
inst✝¹ : Primcodable σ
inst✝ : Primcodable τ
a : α
as : List α
e : ℕ
⊢ decode e = some (a :: as) → decode e.pred.unpair.1 = some a ∧ decode e.pred.unpair.2 = some as
case succ
α : Type u_1
α₁ : Type u_2
α₂ : Type u_3
β : Type u_4
γ : Type u_5
σ : Type u_6
τ : Type u_7
inst✝⁶ : Primcodable α
inst✝⁵ : Primcodable α₁
inst✝⁴ : Primcodable α₂
inst✝³ : Primcodable β
inst✝² : Primcodable γ
inst✝¹ : Primcodable σ
inst✝ : Primcodable τ
a : α
as : List α
e : ℕ
⊢ (Seq.seq (Option.map (fun x x_1 => x :: x_1) (decode e.unpair.1)) fun x => decode e.unpair.2) = some (a :: as) →
    decode e.unpair.1 = some a ∧ decode e.unpair.2 = some as