Fix scope for uPred_const.

program_logic/upred.v

@@ -208,7 +208,7 @@ Arguments uPred_holds {_} _%I _ _.
 Arguments uPred_entails _ _%I _%I.
 Notation "P ⊑ Q" := (uPred_entails P%I Q%I) (at level 70) : C_scope.
 Notation "(⊑)" := uPred_entails (only parsing) : C_scope.
-Notation "■ φ" := (uPred_const φ) (at level 20) : uPred_scope.
+Notation "■ φ" := (uPred_const φ%type) (at level 20) : uPred_scope.
 Notation "'False'" := (uPred_const False) : uPred_scope.
 Notation "'True'" := (uPred_const True) : uPred_scope.
 Infix "∧" := uPred_and : uPred_scope.