induction scope <;> simp
α σ : Type
ε : σ → Type
δ : Dialect α σ ε
name : SSAVal
scope : SSAScope δ
⊢ getT name scope = none → ∀ (τ : MLIRType δ), get name scope τ = none
case cons
α σ : Type
ε : σ → Type
δ : Dialect α σ ε
name : SSAVal
head✝ : SSAVal × (τ : MLIRType δ) × MLIRType.eval τ
tail✝ : List (SSAVal × (τ : MLIRType δ) × MLIRType.eval τ)
tail_ih✝ : getT name tail✝ = none → ∀ (τ : MLIRType δ), get name tail✝ τ = none
⊢ (if head✝.fst = name then some head✝.2 else getT name tail✝) = none →
    ∀ (τ : MLIRType δ),
      (if head✝.fst = name then
          if h : head✝.2.fst = τ then
            some
              (cast
                (_ :
                  (match head✝.2.fst with
                    | MLIRType.float a => Float
                    | MLIRType.int signedness sz => FinInt sz
                    | MLIRType.tensor1d => Tensor1D
                    | MLIRType.tensor2d => Tensor2D
                    | MLIRType.tensor4d => Tensor4D
                    | MLIRType.index => ℤ
                    | MLIRType.undefined a => Unit
                    | MLIRType.extended σ => ε σ
                    | MLIRType.erased => Unit) =
                    match τ with
                    | MLIRType.float a => Float
                    | MLIRType.int signedness sz => FinInt sz
                    | MLIRType.tensor1d => Tensor1D
                    | MLIRType.tensor2d => Tensor2D
                    | MLIRType.tensor4d => Tensor4D
                    | MLIRType.index => ℤ
                    | MLIRType.undefined a => Unit
                    | MLIRType.extended σ => ε σ
                    | MLIRType.erased => Unit)
                head✝.2.snd)
          else none
        else get name tail✝ τ) =
        none