diff --git a/src/plugins/e-acsl/visit.ml b/src/plugins/e-acsl/visit.ml
index 82302b4394afc838bc1324efff8e8a35fd9c345c..5cff01c8156b74d7bcb315f615c6d7f03e991dd8 100644
--- a/src/plugins/e-acsl/visit.ml
+++ b/src/plugins/e-acsl/visit.ml
@@ -497,6 +497,8 @@ end
 let do_visit ?(prj=Project.current ()) generate =
   let vis = new e_acsl_visitor prj generate in
   first_global := true;
+  (* explicit type annotation in order to check that no new method is introduced
+     by error *)
   (vis : Visitor.frama_c_visitor)
 
 (*