α : Type u
β : α → Type v
inst✝ : DecidableEq α
a : α
s : AList β
⊢ dlookup a s.entries = lookup a s ∧
    { entries := kerase a s.entries, nodupKeys := (_ : NodupKeys (kerase a s.entries)) } = erase a s
α : Type u
β : α → Type v
inst✝ : DecidableEq α
a : α
s : AList β
⊢ extract a s = (lookup a s, erase a s)
simp [extract]
no goals
α : Type u
β : α → Type v
inst✝ : DecidableEq α
a : α
s : AList β
⊢ dlookup a s.entries = lookup a s ∧
    { entries := kerase a s.entries, nodupKeys := (_ : NodupKeys (kerase a s.entries)) } = erase a s
constructor <;> rfl