diff --git a/sledge/nonstdlib/dune b/sledge/nonstdlib/dune
index d09d84d7d..77848d72d 100644
--- a/sledge/nonstdlib/dune
+++ b/sledge/nonstdlib/dune
@@ -7,7 +7,7 @@
  (name NS)
  (public_name nonstdlib)
  (libraries containers containers-data core_kernel.fheap iter zarith trace)
- (flags (:standard))
+ (flags (:standard -w -no-cmx-file))
  (preprocess
   (pps ppx_sledge ppx_trace))
  (inline_tests))