Theorem: Set.subset_refl (GMLInit/Data/Set/Subset.lean)

State before:
α : Sort u_1
s✝ t u s : Set α
⊢ s.Subset s
Tactic:
intro x hs
State after:
α : Sort u_1
s✝ t u s : Set α
x : α
hs : x ∈ s
⊢ x ∈ s

State before:
α : Sort u_1
s✝ t u s : Set α
x : α
hs : x ∈ s
⊢ x ∈ s
Tactic:
exact hs
State after:
no goals