diff --git a/src/lib_rules.ml b/src/lib_rules.ml
index a1de06a0..1c52e6e0 100644
--- a/src/lib_rules.ml
+++ b/src/lib_rules.ml
@@ -1,6 +1,7 @@
 open Import
 open Build.O
 open Dune_file
+open! No_io
 
 module SC = Super_context