Consider synthetic closure bodies to be typeck children

compiler/rustc_middle/src/ty/util.rs

@@ -571,7 +571,10 @@ impl<'tcx> TyCtxt<'tcx> {
     /// Returns `true` if `def_id` refers to a definition that does not have its own
     /// type-checking context, i.e. closure, coroutine or inline const.
     pub fn is_typeck_child(self, def_id: DefId) -> bool {
-        matches!(self.def_kind(def_id), DefKind::Closure | DefKind::InlineConst)
+        matches!(
+            self.def_kind(def_id),
+            DefKind::Closure | DefKind::InlineConst | DefKind::SyntheticCoroutineBody
+        )
     }
 
     /// Returns `true` if `def_id` refers to a trait (i.e., `trait Foo { ... }`).

tests/ui/async-await/async-closures/debuginfo-by-move-body.rs

@@ -0,0 +1,19 @@
+//@ aux-build:block-on.rs
+//@ edition: 2021
+//@ build-pass
+//@ compile-flags: -Cdebuginfo=2
+
+#![feature(async_closure)]
+
+extern crate block_on;
+
+async fn call_once(f: impl async FnOnce()) {
+    f().await;
+}
+
+pub fn main() {
+    block_on::block_on(async {
+        let async_closure = async move || {};
+        call_once(async_closure).await;
+    });
+}