diff --git a/src/usexp/jbuild_lexer.boot.ml b/src/usexp/jbuild_lexer.boot.ml
new file mode 100644
index 00000000..e0671e6d
--- /dev/null
+++ b/src/usexp/jbuild_lexer.boot.ml
@@ -0,0 +1 @@
+let token _ = failwith "Unused during bootstrap"