case step.refl.inst.refl e _  => exact absurd hp.symm $ ne_of_ssubset e.progress_ssubset
α : Type
inst✝ : Proper α
s s₁ s₂ s₂✝ : State α
n : State.Nontrivial s₂
e : s₂ ↓ᵢ| s₂✝
a_ih✝ : Steps s₂✝ s₂ → State.Nontrivial s₂✝ → s₂✝.tag = s₂.tag → s₂✝.progress = s₂.progress → s₂✝ = s₂
ht : s₂✝.tag = s₂.tag
hp : s₂✝.progress = s₂.progress
⊢ s₂✝ = s₂
no goals