select AsyncFn traits during overloaded call op

Author: compiler-errors

compiler/rustc_hir/src/lang_items.rs

@@ -208,6 +208,10 @@ language_item_table! {
     FnMut,                   sym::fn_mut,              fn_mut_trait,               Target::Trait,          GenericRequirement::Exact(1);
     FnOnce,                  sym::fn_once,             fn_once_trait,              Target::Trait,          GenericRequirement::Exact(1);
 
+    AsyncFn,                 sym::async_fn,            async_fn_trait,             Target::Trait,          GenericRequirement::Exact(1);
+    AsyncFnMut,              sym::async_fn_mut,        async_fn_mut_trait,         Target::Trait,          GenericRequirement::Exact(1);
+    AsyncFnOnce,             sym::async_fn_once,       async_fn_once_trait,        Target::Trait,          GenericRequirement::Exact(1);
+
     FnOnceOutput,            sym::fn_once_output,      fn_once_output,             Target::AssocTy,        GenericRequirement::None;
 
     Iterator,                sym::iterator,            iterator_trait,             Target::Trait,          GenericRequirement::Exact(0);

compiler/rustc_hir_typeck/src/callee.rs

@@ -220,6 +220,17 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             (self.tcx.lang_items().fn_trait(), Ident::with_dummy_span(sym::call), true),
             (self.tcx.lang_items().fn_mut_trait(), Ident::with_dummy_span(sym::call_mut), true),
             (self.tcx.lang_items().fn_once_trait(), Ident::with_dummy_span(sym::call_once), false),
+            (self.tcx.lang_items().async_fn_trait(), Ident::with_dummy_span(sym::async_call), true),
+            (
+                self.tcx.lang_items().async_fn_mut_trait(),
+                Ident::with_dummy_span(sym::async_call_mut),
+                true,
+            ),
+            (
+                self.tcx.lang_items().async_fn_once_trait(),
+                Ident::with_dummy_span(sym::async_call_once),
+                false,
+            ),
         ] {
             let Some(trait_def_id) = opt_trait_def_id else { continue };
 

compiler/rustc_span/src/symbol.rs

@@ -423,8 +423,14 @@ symbols! {
         assume,
         assume_init,
         async_await,
+        async_call,
+        async_call_mut,
+        async_call_once,
         async_closure,
+        async_fn,
         async_fn_in_trait,
+        async_fn_mut,
+        async_fn_once,
         async_fn_track_caller,
         async_for_loop,
         async_iterator,

library/core/src/ops/async_function.rs

@@ -8,6 +8,7 @@ use crate::marker::Tuple;
 #[rustc_paren_sugar]
 #[fundamental]
 #[must_use = "async closures are lazy and do nothing unless called"]
+#[cfg_attr(not(bootstrap), lang = "async_fn")]
 pub trait AsyncFn<Args: Tuple>: AsyncFnMut<Args> {
     /// Future returned by [`AsyncFn::async_call`].
     #[unstable(feature = "async_fn_traits", issue = "none")]
@@ -27,6 +28,7 @@ pub trait AsyncFn<Args: Tuple>: AsyncFnMut<Args> {
 #[rustc_paren_sugar]
 #[fundamental]
 #[must_use = "async closures are lazy and do nothing unless called"]
+#[cfg_attr(not(bootstrap), lang = "async_fn_mut")]
 pub trait AsyncFnMut<Args: Tuple>: AsyncFnOnce<Args> {
     /// Future returned by [`AsyncFnMut::async_call_mut`].
     #[unstable(feature = "async_fn_traits", issue = "none")]
@@ -46,6 +48,7 @@ pub trait AsyncFnMut<Args: Tuple>: AsyncFnOnce<Args> {
 #[rustc_paren_sugar]
 #[fundamental]
 #[must_use = "async closures are lazy and do nothing unless called"]
+#[cfg_attr(not(bootstrap), lang = "async_fn_once")]
 pub trait AsyncFnOnce<Args: Tuple> {
     /// Future returned by [`AsyncFnOnce::async_call_once`].
     #[unstable(feature = "async_fn_traits", issue = "none")]

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

@@ -8,7 +8,7 @@ use std::ops::AsyncFn;
 async fn foo() {}
 
 async fn call_asyncly(f: impl AsyncFn(i32) -> i32) -> i32 {
-    f.async_call((1i32,)).await
+    f(1).await
 }
 
 fn main() {