1 files changed, 25 insertions, 0 deletions
diff --git a/src/test/ui/async-await/feature-gate-async_fn_in_trait.rs b/src/test/ui/async-await/feature-gate-async_fn_in_trait.rs
new file mode 100644
index 000000000..792f378cb
--- /dev/null
+++ b/src/test/ui/async-await/feature-gate-async_fn_in_trait.rs
@@ -0,0 +1,25 @@
+// edition:2021
+
+// RPITIT is not enough to allow use of async functions
+#![allow(incomplete_features)]
+#![feature(return_position_impl_trait_in_trait)]
+
+trait T {
+    async fn foo(); //~ ERROR functions in traits cannot be declared `async`
+}
+
+// Both return_position_impl_trait_in_trait and async_fn_in_trait are required for this (see also
+// feature-gate-return_position_impl_trait_in_trait.rs)
+trait T2 {
+    async fn foo() -> impl Sized; //~ ERROR functions in traits cannot be declared `async`
+}
+
+trait T3 {
+    fn foo() -> impl std::future::Future<Output = ()>;
+}
+
+impl T3 for () {
+    async fn foo() {} //~ ERROR functions in traits cannot be declared `async`
+}
+
+fn main() {}