diff --git a/src/programs/pgm_main.ml b/src/programs/pgm_main.ml
index 4ded374bdef12aa1bc9093261a7b8857b05568cf..92e71c19d6ae2355f1cdcd8984a746da08b9ac95 100644
--- a/src/programs/pgm_main.ml
+++ b/src/programs/pgm_main.ml
@@ -36,6 +36,7 @@ let add_module ?(type_only=false) env penv lmod m =
   Mstr.add id.id m lmod
 
 let retrieve penv c =
+  assert false (*TODO*)
 
 let pgm_env_of_env =
   let h = Env.Wenv.create 17 in