simpl_subst in vcgen

(Fixes #4)

theories/vcgen/vcg_solver.v

@@ -10,24 +10,20 @@ Import env_notations.
 Section vcg_continue.
   Context `{amonadG Σ}.
 
-  Class FromKnownLocs (Γls : penv) (E_old : known_locs) (E_new : known_locs) :=
-    from_known_locs: True. (*dom Γls ⊂ (elem_of E_old) disj_Union (elem_of E) *)
+  Class FromKnownLocs (Γls : penv) (E_old : known_locs) (E_new : known_locs).
+  (*dom Γls ⊂ (elem_of E_old) disj_Union (elem_of E) *)
 
   Global Instance from_known_locs_Nil E_old:
     FromKnownLocs [] E_old [].
-  Proof. done. Qed.
 
   Global Instance from_known_locs_old_cons Γls E_old E_new x q v l i:
     LocLookup E_old l i →
     FromKnownLocs Γls E_old E_new →
     FromKnownLocs (PenvItem l x q v :: Γls) E_old E_new.
-  Proof. done. Qed.
 
   Global Instance from_known_locs_new_cons Γls E_old E_new x q v l:
     FromKnownLocs Γls E_old E_new →
     FromKnownLocs (PenvItem l x q v :: Γls) E_old (l :: E_new) | 100.
-  Proof. done. Qed.
-
 
   Lemma tac_vcg_sound Γs_in Γs_out Γls Γp m c e R Φ E de :
     MapstoListFromEnv Γs_in Γs_out Γls →
@@ -94,7 +90,7 @@ Ltac vcg_solver :=
   | apply _              (* Reify the expression *)
   | vm_compute[reflexivity]; try done (* Prove that the reified expression is well-formed *)
   | done                 (* Prove that the environment is well-formed  *)
-  | simpl ].
+  | simpl; simpl_subst ].
 
 Ltac vcg_continue :=
   eapply tac_exists_known_locs;