Fix async closures in CTFE

compiler/rustc_const_eval/src/interpret/util.rs

@@ -34,6 +34,7 @@ fn visit_ty(&mut self, ty: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
             match *ty.kind() {
                 ty::Param(_) => ControlFlow::Break(FoundParam),
                 ty::Closure(def_id, args)
+                | ty::CoroutineClosure(def_id, args, ..)
                 | ty::Coroutine(def_id, args, ..)
                 | ty::FnDef(def_id, args) => {
                     let instance = ty::InstanceDef::Item(def_id);

compiler/rustc_const_eval/src/interpret/validity.rs

@@ -236,8 +236,8 @@ fn aggregate_field_path_elem(&mut self, layout: TyAndLayout<'tcx>, field: usize)
 
         // Now we know we are projecting to a field, so figure out which one.
         match layout.ty.kind() {
-            // coroutines and closures.
-            ty::Closure(def_id, _) | ty::Coroutine(def_id, _) => {
+            // coroutines, closures, and coroutine-closures all have upvars that may be named.
+            ty::Closure(def_id, _) | ty::Coroutine(def_id, _) | ty::CoroutineClosure(def_id, _) => {
                 let mut name = None;
                 // FIXME this should be more descriptive i.e. CapturePlace instead of CapturedVar
                 // https://github.com/rust-lang/project-rfc-2229/issues/46

src/tools/miri/tests/pass/async-closure.rs

@@ -0,0 +1,40 @@
+#![feature(async_closure, noop_waker, async_fn_traits)]
+
+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);
+    let ctx = &mut Context::from_waker(Waker::noop());
+
+    loop {
+        match fut.as_mut().poll(ctx) {
+            Poll::Pending => {}
+            Poll::Ready(t) => break t,
+        }
+    }
+}
+
+async fn call_once(f: impl async FnOnce(DropMe)) {
+    f(DropMe("world")).await;
+}
+
+#[derive(Debug)]
+struct DropMe(&'static str);
+
+impl Drop for DropMe {
+    fn drop(&mut self) {
+        println!("{}", self.0);
+    }
+}
+
+pub fn main() {
+    block_on(async {
+        let b = DropMe("hello");
+        let async_closure = async move |a: DropMe| {
+            println!("{a:?} {b:?}");
+        };
+        call_once(async_closure).await;
+    });
+}

src/tools/miri/tests/pass/async-closure.stdout

@@ -0,0 +1,3 @@
+DropMe("world") DropMe("hello")
+world
+hello