Flesh out a few more tests

tests/ui/async-await/async-closures/async-fn-once-for-async-fn.rs

@@ -8,11 +8,15 @@
 
 fn main() {
     block_on::block_on(async {
-        let x = async || {};
-
         async fn needs_async_fn_once(x: impl async FnOnce()) {
             x().await;
         }
-        needs_async_fn_once(x).await;
+
+        needs_async_fn_once(async || {}).await;
+
+        needs_async_fn_once(|| async {}).await;
+
+        async fn foo() {}
+        needs_async_fn_once(foo).await;
     });
 }

tests/ui/async-await/async-closures/move-is-async-fn.rs

@@ -2,7 +2,7 @@
 //@ edition:2021
 //@ build-pass
 
-#![feature(async_closure)]
+#![feature(async_closure, async_fn_traits)]
 
 extern crate block_on;
 
@@ -15,7 +15,11 @@ fn main() {
         c().await;
         c().await;
 
-        fn is_static<T: 'static>(_: T) {}
+        fn is_static<T: 'static>(_: &T) {}
-        is_static(c);
+        is_static(&c);
+
+        // Check that `<{async fn} as AsyncFnOnce>::CallOnceFuture` owns its captures.
+        fn call_once<F: async FnOnce()>(f: F) -> F::CallOnceFuture { f() }
+        is_static(&call_once(c));
     });
 }

tests/ui/async-await/async-closures/refd.rs

@@ -2,8 +2,6 @@
 //@ edition:2021
 //@ build-pass
 
-// check that `&{async-closure}` implements `AsyncFn`.
-
 #![feature(async_closure)]
 
 extern crate block_on;
@@ -13,6 +11,15 @@
 fn main() {
     block_on::block_on(async {
         async fn call_once(x: impl async Fn()) { x().await }
-        call_once(&async || {}).await
+
+        // check that `&{async-closure}` implements `async Fn`.
+        call_once(&async || {}).await;
+
+        // check that `&{closure}` implements `async Fn`.
+        call_once(&|| async {}).await;
+
+        // check that `&fndef` implements `async Fn`.
+        async fn foo() {}
+        call_once(&foo).await;
     });
 }

tests/ui/async-await/async-fn/project.rs

@@ -0,0 +1,12 @@
+//@ edition:2018
+//@ revisions: current next
+//@[next] compile-flags: -Znext-solver
+//@ check-pass
+
+#![feature(async_closure, unboxed_closures, async_fn_traits)]
+
+fn project<F: async Fn<()>>(_: F) -> Option<F::Output> { None }
+
+fn main() {
+    let x: Option<i32> = project(|| async { 1i32 });
+}