1 files changed, 12 insertions, 0 deletions

diff --git a/tests/ui/issues/issue-40510-1.rs b/tests/ui/issues/issue-40510-1.rs
new file mode 100644
index 00000000000..ca53dcd9b41
--- /dev/null
+++ b/tests/ui/issues/issue-40510-1.rs
@@ -0,0 +1,12 @@
+#![allow(unused)]
+
+fn f() {
+    let mut x: Box<()> = Box::new(());
+
+    || {
+        &mut x
+    };
+    //~^^ ERROR captured variable cannot escape `FnMut` closure body
+}
+
+fn main() {}