From stdpp Require Import binders strings stringmap.
From iris.base_logic Require Import lib.iprop.
Require Import lang.
Goal ∀ {Σ} (P Q : iProp Σ), ⊢ P -∗ P.
move=> Σ P Q.
apply: (check_program_spec (Lam "x" (Var "x"))).
rewrite /check_program; simpl.
done.
Qed.
Goal ∀ {Σ} (P Q : iProp Σ), ⊢ P -∗ Q -∗ Q ∗ P.
move=> Σ P Q.
apply: (check_program_spec (Lam "x" (Lam "y" (Pair (Var "y") (Var "x"))))).
rewrite /check_program; simpl.
done.
Qed.