| C.AImplicit _ -> assert false
| C.AAppl (_, []) -> assert false
-and xats frm vs =
- let map v = F.fprintf frm "{%a}" xat v in
- List.iter map vs
+and xats frm = function
+ | [] -> F.fprintf frm "{}"
+ | vs ->
+ let map v = F.fprintf frm "{%a}" xat v in
+ List.iter map vs
in
xat frm t