Make cofe_subst slightly stronger by not re-infering the type.

modures/cofe.v

@@ -11,8 +11,8 @@ Hint Extern 0 (_ ={_}= _) => symmetry; assumption.
 Ltac cofe_subst :=
   repeat match goal with
   | _ => progress simplify_equality'
-  | H: @dist _ ?d ?n ?x _ |- _ => setoid_subst_aux (@dist _ d n) x
-  | H: @dist _ ?d ?n _ ?x |- _ => symmetry in H;setoid_subst_aux (@dist _ d n) x
+  | H:@dist ?A ?d ?n ?x _ |- _ => setoid_subst_aux (@dist A d n) x
+  | H:@dist ?A ?d ?n _ ?x |- _ => symmetry in H;setoid_subst_aux (@dist A d n) x
   end.
 
 Record chain (A : Type) `{Dist A} := {