1 files changed, 59 insertions, 0 deletions
diff --git a/tests/ui/layout/post-mono-layout-cycle-2.rs b/tests/ui/layout/post-mono-layout-cycle-2.rs
new file mode 100644
index 00000000000..356f1e777c7
--- /dev/null
+++ b/tests/ui/layout/post-mono-layout-cycle-2.rs
@@ -0,0 +1,59 @@
+//@ build-fail
+//@ edition: 2021
+
+#![feature(async_closure, noop_waker)]
+
+use std::future::Future;
+use std::pin::pin;
+use std::task::*;
+
+pub fn block_on<T>(fut: impl Future<Output = T>) -> T {
+    let mut fut = pin!(fut);
+    // Poll loop, just to test the future...
+    let ctx = &mut Context::from_waker(Waker::noop());
+
+    loop {
+        match fut.as_mut().poll(ctx) {
+            Poll::Pending => {}
+            Poll::Ready(t) => break t,
+        }
+    }
+}
+
+trait Blah {
+    async fn iter<T>(&mut self, iterator: T)
+    where
+        T: IntoIterator<Item = ()>;
+}
+
+impl Blah for () {
+    async fn iter<T>(&mut self, iterator: T)
+    //~^ ERROR recursion in an async fn requires boxing
+    where
+        T: IntoIterator<Item = ()>,
+    {
+        Blah::iter(self, iterator).await
+    }
+}
+
+struct Wrap<T: Blah> {
+    t: T,
+}
+
+impl<T: Blah> Wrap<T>
+where
+    T: Blah,
+{
+    async fn ice(&mut self) {
+        //~^ ERROR a cycle occurred during layout computation
+        let arr: [(); 0] = [];
+        self.t.iter(arr.into_iter()).await;
+    }
+}
+
+fn main() {
+    block_on(async {
+        let mut t = Wrap { t: () };
+        t.ice();
+    })
+}