split_ifs <;> tauto
case h.e'_2
σ σ' : VarName → VarName
X : DefName
xs : List VarName
binders : Finset VarName
h1 : ∀ v ∉ binders, σ v = σ' v
x : VarName
a✝ : x ∈ xs
⊢ (if x ∉ binders then σ x else x) = if x ∉ binders then σ' x else x
no goals