diff --git a/src/util/warning.ml b/src/util/warning.ml
index a44af1295271c13fd3e4d253922e6efe6d341b0c..c2b2398647ad5df3f6557802849f1eeb1743ffb9 100644
--- a/src/util/warning.ml
+++ b/src/util/warning.ml
@@ -21,6 +21,8 @@ let set_hook = (:=) hook
 let emit ?loc p =
   let b = Buffer.create 100 in
   let fmt = formatter_of_buffer b in
+  pp_set_margin fmt 1000000000;
+  pp_open_box fmt 0;
   let handle fmt =
-    Format.pp_print_flush fmt (); !hook ?loc (Buffer.contents b) in
+    pp_print_flush fmt (); !hook ?loc (Buffer.contents b) in
   kfprintf handle fmt p