6 files changed, 21 insertions, 2 deletions
diff --git a/src/doc/unstable-book/src/library-features/async-fn-traits.md b/src/doc/unstable-book/src/library-features/async-fn-traits.md
new file mode 100644
index 00000000000..e1c3f067e5b
--- /dev/null
+++ b/src/doc/unstable-book/src/library-features/async-fn-traits.md
@@ -0,0 +1,13 @@
+# `async_fn_traits`
+
+See Also: [`fn_traits`](../library-features/fn-traits.md)
+
+----
+
+The `async_fn_traits` feature allows for implementation of the [`AsyncFn*`] traits
+for creating custom closure-like types that return futures.
+
+[`AsyncFn*`]: ../../std/ops/trait.AsyncFn.html
+
+The main difference to the `Fn*` family of traits is that `AsyncFn` can return a future
+that borrows from itself (`FnOnce::Output` has no lifetime parameters, while `AsyncFn::CallFuture` does).
diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index bd1d68e7074..3bac71dbc24 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -2286,6 +2286,7 @@ pub(crate) fn clean_middle_ty<'tcx>(
         }
 
         ty::Closure(..) => panic!("Closure"),
+        ty::CoroutineClosure(..) => panic!("CoroutineClosure"),
         ty::Coroutine(..) => panic!("Coroutine"),
         ty::Placeholder(..) => panic!("Placeholder"),
         ty::CoroutineWitness(..) => panic!("CoroutineWitness"),
diff --git a/src/librustdoc/passes/collect_intra_doc_links.rs b/src/librustdoc/passes/collect_intra_doc_links.rs
index a75d9bee304..fe02611b5d4 100644
--- a/src/librustdoc/passes/collect_intra_doc_links.rs
+++ b/src/librustdoc/passes/collect_intra_doc_links.rs
@@ -503,6 +503,7 @@ impl<'a, 'tcx> LinkCollector<'a, 'tcx> {
             }
             ty::Alias(..)
             | ty::Closure(..)
+            | ty::CoroutineClosure(..)
             | ty::Coroutine(..)
             | ty::CoroutineWitness(..)
             | ty::Dynamic(..)
diff --git a/src/tools/clippy/clippy_lints/src/dereference.rs b/src/tools/clippy/clippy_lints/src/dereference.rs
index 8ff54dfcfa0..194cf69ea7e 100644
--- a/src/tools/clippy/clippy_lints/src/dereference.rs
+++ b/src/tools/clippy/clippy_lints/src/dereference.rs
@@ -881,6 +881,7 @@ impl TyCoercionStability {
                 | ty::Coroutine(..)
                 | ty::CoroutineWitness(..)
                 | ty::Closure(..)
+                | ty::CoroutineClosure(..)
                 | ty::Never
                 | ty::Tuple(_)
                 | ty::Alias(ty::Projection, _) => Self::Deref,
diff --git a/src/tools/clippy/clippy_lints/src/utils/author.rs b/src/tools/clippy/clippy_lints/src/utils/author.rs
index b26ebe5cee3..288df0fd663 100644
--- a/src/tools/clippy/clippy_lints/src/utils/author.rs
+++ b/src/tools/clippy/clippy_lints/src/utils/author.rs
@@ -490,6 +490,9 @@ impl<'a, 'tcx> PrintVisitor<'a, 'tcx> {
                             format!("ClosureKind::Coroutine(CoroutineKind::Coroutine(Movability::{movability:?})")
                         },
                     },
+                    ClosureKind::CoroutineClosure(desugaring) => format!(
+                        "ClosureKind::CoroutineClosure(CoroutineDesugaring::{desugaring:?})"
+                    ),
                 };
 
                 let ret_ty = match fn_decl.output {
diff --git a/src/tools/clippy/tests/ui/author/blocks.stdout b/src/tools/clippy/tests/ui/author/blocks.stdout
index 8c4d71e68f8..579f137f861 100644
--- a/src/tools/clippy/tests/ui/author/blocks.stdout
+++ b/src/tools/clippy/tests/ui/author/blocks.stdout
@@ -40,10 +40,10 @@ if let ExprKind::Block(block, None) = expr.kind
 {
     // report your lint here
 }
-if let ExprKind::Closure { capture_clause: CaptureBy::Value { .. }, fn_decl: fn_decl, body: body_id, closure_kind: ClosureKind::Closure, .. } = expr.kind
+if let ExprKind::Closure { capture_clause: CaptureBy::Value { .. }, fn_decl: fn_decl, body: body_id, closure_kind: ClosureKind::CoroutineClosure(CoroutineDesugaring::Async), .. } = expr.kind
     && let FnRetTy::DefaultReturn(_) = fn_decl.output
     && expr1 = &cx.tcx.hir().body(body_id).value
-    && let ExprKind::Closure { capture_clause: CaptureBy::Value { .. }, fn_decl: fn_decl1, body: body_id1, closure_kind: ClosureKind::Coroutine(CoroutineKind::Desugared(CoroutineDesugaring::Async, CoroutineSource::Closure)), .. } = expr1.kind
+    && let ExprKind::Closure { capture_clause: CaptureBy::Ref, fn_decl: fn_decl1, body: body_id1, closure_kind: ClosureKind::Coroutine(CoroutineKind::Desugared(CoroutineDesugaring::Async, CoroutineSource::Closure)), .. } = expr1.kind
     && let FnRetTy::DefaultReturn(_) = fn_decl1.output
     && expr2 = &cx.tcx.hir().body(body_id1).value
     && let ExprKind::Block(block, None) = expr2.kind