foo : Π A [H], A → A
foo' : Π {A} [H] {x}, A
foo ℕ 10 : ℕ
definition test : ∀ {A : Type} [H : inhabited A], @foo' ℕ nat.is_inhabited (@has_add.add ℕ nat_has_add 5 5) = 10 :=
λ A H, @rfl ℕ (@foo' ℕ nat.is_inhabited (@has_add.add ℕ nat_has_add 5 5))