Add regression test for #95719

tests/ui/type-alias-impl-trait/send-bound-nested-async-95719.rs

@@ -0,0 +1,53 @@
+// Regression test for <https://github.com/rust-lang/rust/issues/95719>.
+// The `Send` bound of a GAT `impl Future` was lost when the future was
+// wrapped in another `async fn`, failing with "the parameter type `G` may
+// not live long enough".
+//@ check-pass
+//@ edition: 2021
+
+#![feature(impl_trait_in_assoc_type)]
+
+use std::future::Future;
+
+pub trait Get: Send + Sync {
+    type Ret<'a>: Future<Output = usize> + Send + 'a
+    where
+        Self: 'a;
+    fn get<'a>(&'a self) -> Self::Ret<'a>
+    where
+        Self: 'a;
+}
+
+impl Get for usize {
+    type Ret<'a>
+        = impl Future<Output = usize> + Send + 'a
+    where
+        Self: 'a;
+
+    fn get<'a>(&'a self) -> Self::Ret<'a>
+    where
+        Self: 'a,
+    {
+        async move { *self }
+    }
+}
+
+fn is_send<R, F: Future<Output = R> + Send>(_f: &F) -> bool {
+    true
+}
+
+async fn wrap<G: Get>(g: &G) -> usize {
+    let fut = g.get();
+    assert!(is_send(&fut));
+    fut.await
+}
+
+async fn wrap_wrap<G: Get>(g: &G) -> usize {
+    let fut = wrap(g);
+    assert!(is_send(&fut));
+    fut.await
+}
+
+fn main() {
+    let _ = wrap_wrap(&0usize);
+}