diff --git a/src/plugins/wp/cil2cfg.ml b/src/plugins/wp/cil2cfg.ml
index 861d41295e4efda49df284417e93b66f98ec434d..97e047cd573495d6d055cb161efa44aa7722bc58 100644
--- a/src/plugins/wp/cil2cfg.ml
+++ b/src/plugins/wp/cil2cfg.ml
@@ -1395,7 +1395,7 @@ struct
   type dot = {
     name: string;
     chan: out_channel;
-    fmt : Stdlib__format.formatter;
+    fmt : Format.formatter;
   }
 
   let create kf =