diff --git a/src/test/ui/unboxed-closures/issue-30906.nll.stderr b/src/test/ui/unboxed-closures/issue-30906.nll.stderr
new file mode 100644
index 0000000000000..5a2cbab9a1500
--- /dev/null
+++ b/src/test/ui/unboxed-closures/issue-30906.nll.stderr
@@ -0,0 +1,8 @@
+error: higher-ranked subtype error
+  --> $DIR/issue-30906.rs:15:5
+   |
+LL |     test(Compose(f, |_| {}));
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+