diff --git a/src/test/ui/async-await/async-trait-fn-with-default-body.rs b/src/test/ui/async-await/async-trait-fn-with-default-body.rs
new file mode 100644
index 0000000000000..6fbcce7ce2740
--- /dev/null
+++ b/src/test/ui/async-await/async-trait-fn-with-default-body.rs
@@ -0,0 +1,18 @@
+// edition:2018
+
+// FIXME: enable the async_fn_in_trait feature in this test after 101665 is fixed and we can
+// actually test these.
+
+trait T {
+    async fn foo() {} //~ ERROR functions in traits cannot be declared `async`
+    //~^ ERROR mismatched types
+    async fn bar(&self) {} //~ ERROR functions in traits cannot be declared `async`
+    //~^ ERROR mismatched types
+    async fn baz() { //~ ERROR functions in traits cannot be declared `async`
+        //~^ ERROR mismatched types
+        // Nested item must not ICE.
+        fn a() {}
+    }
+}
+
+fn main() {}
diff --git a/src/test/ui/async-await/async-trait-fn-with-default-body.stderr b/src/test/ui/async-await/async-trait-fn-with-default-body.stderr
new file mode 100644
index 0000000000000..49d5258d12c27
--- /dev/null
+++ b/src/test/ui/async-await/async-trait-fn-with-default-body.stderr
@@ -0,0 +1,90 @@
+error[E0706]: functions in traits cannot be declared `async`
+  --> $DIR/async-trait-fn-with-default-body.rs:7:5
+   |
+LL |     async fn foo() {}
+   |     -----^^^^^^^^^
+   |     |
+   |     `async` because of this
+   |
+   = note: `async` trait functions are not currently supported
+   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
+   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
+   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
+
+error[E0706]: functions in traits cannot be declared `async`
+  --> $DIR/async-trait-fn-with-default-body.rs:9:5
+   |
+LL |     async fn bar(&self) {}
+   |     -----^^^^^^^^^^^^^^
+   |     |
+   |     `async` because of this
+   |
+   = note: `async` trait functions are not currently supported
+   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
+   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
+   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
+
+error[E0706]: functions in traits cannot be declared `async`
+  --> $DIR/async-trait-fn-with-default-body.rs:11:5
+   |
+LL |     async fn baz() {
+   |     -----^^^^^^^^^
+   |     |
+   |     `async` because of this
+   |
+   = note: `async` trait functions are not currently supported
+   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
+   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
+   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
+
+error[E0308]: mismatched types
+  --> $DIR/async-trait-fn-with-default-body.rs:7:20
+   |
+LL |     async fn foo() {}
+   |                    ^^ expected associated type, found opaque type
+   |
+  ::: $SRC_DIR/core/src/future/mod.rs:LL:COL
+   |
+LL | pub const fn from_generator<T>(gen: T) -> impl Future<Output = T::Return>
+   |                                           ------------------------------- the found opaque type
+   |
+   = note: expected associated type `impl Future<Output = ()>` (trait associated opaque type at <$DIR/async-trait-fn-with-default-body.rs:7:20>)
+                  found opaque type `impl Future<Output = ()>` (opaque type at <$SRC_DIR/core/src/future/mod.rs:LL:COL>)
+
+error[E0308]: mismatched types
+  --> $DIR/async-trait-fn-with-default-body.rs:9:25
+   |
+LL |     async fn bar(&self) {}
+   |                         ^^ expected associated type, found opaque type
+   |
+  ::: $SRC_DIR/core/src/future/mod.rs:LL:COL
+   |
+LL | pub const fn from_generator<T>(gen: T) -> impl Future<Output = T::Return>
+   |                                           ------------------------------- the found opaque type
+   |
+   = note: expected associated type `impl Future<Output = ()>` (trait associated opaque type at <$DIR/async-trait-fn-with-default-body.rs:9:25>)
+                  found opaque type `impl Future<Output = ()>` (opaque type at <$SRC_DIR/core/src/future/mod.rs:LL:COL>)
+
+error[E0308]: mismatched types
+  --> $DIR/async-trait-fn-with-default-body.rs:11:20
+   |
+LL |       async fn baz() {
+   |  ____________________^
+LL | |
+LL | |         // Nested item must not ICE.
+LL | |         fn a() {}
+LL | |     }
+   | |_____^ expected associated type, found opaque type
+   |
+  ::: $SRC_DIR/core/src/future/mod.rs:LL:COL
+   |
+LL |   pub const fn from_generator<T>(gen: T) -> impl Future<Output = T::Return>
+   |                                             ------------------------------- the found opaque type
+   |
+   = note: expected associated type `impl Future<Output = ()>` (trait associated opaque type at <$DIR/async-trait-fn-with-default-body.rs:11:20>)
+                  found opaque type `impl Future<Output = ()>` (opaque type at <$SRC_DIR/core/src/future/mod.rs:LL:COL>)
+
+error: aborting due to 6 previous errors
+
+Some errors have detailed explanations: E0308, E0706.
+For more information about an error, try `rustc --explain E0308`.
diff --git a/src/test/ui/async-await/async-trait-fn.rs b/src/test/ui/async-await/async-trait-fn.rs
index 0ea685986db40..a883a8f87b7ad 100644
--- a/src/test/ui/async-await/async-trait-fn.rs
+++ b/src/test/ui/async-await/async-trait-fn.rs
@@ -1,14 +1,17 @@
 // edition:2018
+// check-pass
+
+#![feature(async_fn_in_trait)] //~ WARN the feature `async_fn_in_trait` is incomplete
+
 trait T {
-    async fn foo() {} //~ ERROR functions in traits cannot be declared `async`
-    //~^ ERROR mismatched types
-    async fn bar(&self) {} //~ ERROR functions in traits cannot be declared `async`
-    //~^ ERROR mismatched types
-    async fn baz() { //~ ERROR functions in traits cannot be declared `async`
-        //~^ ERROR mismatched types
-        // Nested item must not ICE.
-        fn a() {}
-    }
+    async fn foo();
+    // async fn bar(&self);
+}
+
+struct Impl;
+
+impl T for Impl {
+    async fn foo() {}
 }
 
 fn main() {}
diff --git a/src/test/ui/async-await/async-trait-fn.stderr b/src/test/ui/async-await/async-trait-fn.stderr
index 4fa54c6e36960..32b83740aaf1d 100644
--- a/src/test/ui/async-await/async-trait-fn.stderr
+++ b/src/test/ui/async-await/async-trait-fn.stderr
@@ -1,90 +1,11 @@
-error[E0706]: functions in traits cannot be declared `async`
-  --> $DIR/async-trait-fn.rs:3:5
+warning: the feature `async_fn_in_trait` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/async-trait-fn.rs:4:12
    |
-LL |     async fn foo() {}
-   |     -----^^^^^^^^^
-   |     |
-   |     `async` because of this
+LL | #![feature(async_fn_in_trait)]
+   |            ^^^^^^^^^^^^^^^^^
    |
-   = note: `async` trait functions are not currently supported
-   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
+   = note: `#[warn(incomplete_features)]` on by default
    = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
-   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
 
-error[E0706]: functions in traits cannot be declared `async`
-  --> $DIR/async-trait-fn.rs:5:5
-   |
-LL |     async fn bar(&self) {}
-   |     -----^^^^^^^^^^^^^^
-   |     |
-   |     `async` because of this
-   |
-   = note: `async` trait functions are not currently supported
-   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
-   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
-   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
-
-error[E0706]: functions in traits cannot be declared `async`
-  --> $DIR/async-trait-fn.rs:7:5
-   |
-LL |     async fn baz() {
-   |     -----^^^^^^^^^
-   |     |
-   |     `async` because of this
-   |
-   = note: `async` trait functions are not currently supported
-   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
-   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
-   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
-
-error[E0308]: mismatched types
-  --> $DIR/async-trait-fn.rs:3:20
-   |
-LL |     async fn foo() {}
-   |                    ^^ expected associated type, found opaque type
-   |
-  ::: $SRC_DIR/core/src/future/mod.rs:LL:COL
-   |
-LL | pub const fn from_generator<T>(gen: T) -> impl Future<Output = T::Return>
-   |                                           ------------------------------- the found opaque type
-   |
-   = note: expected associated type `impl Future<Output = ()>` (trait associated opaque type at <$DIR/async-trait-fn.rs:3:20>)
-                  found opaque type `impl Future<Output = ()>` (opaque type at <$SRC_DIR/core/src/future/mod.rs:LL:COL>)
-
-error[E0308]: mismatched types
-  --> $DIR/async-trait-fn.rs:5:25
-   |
-LL |     async fn bar(&self) {}
-   |                         ^^ expected associated type, found opaque type
-   |
-  ::: $SRC_DIR/core/src/future/mod.rs:LL:COL
-   |
-LL | pub const fn from_generator<T>(gen: T) -> impl Future<Output = T::Return>
-   |                                           ------------------------------- the found opaque type
-   |
-   = note: expected associated type `impl Future<Output = ()>` (trait associated opaque type at <$DIR/async-trait-fn.rs:5:25>)
-                  found opaque type `impl Future<Output = ()>` (opaque type at <$SRC_DIR/core/src/future/mod.rs:LL:COL>)
-
-error[E0308]: mismatched types
-  --> $DIR/async-trait-fn.rs:7:20
-   |
-LL |       async fn baz() {
-   |  ____________________^
-LL | |
-LL | |         // Nested item must not ICE.
-LL | |         fn a() {}
-LL | |     }
-   | |_____^ expected associated type, found opaque type
-   |
-  ::: $SRC_DIR/core/src/future/mod.rs:LL:COL
-   |
-LL |   pub const fn from_generator<T>(gen: T) -> impl Future<Output = T::Return>
-   |                                             ------------------------------- the found opaque type
-   |
-   = note: expected associated type `impl Future<Output = ()>` (trait associated opaque type at <$DIR/async-trait-fn.rs:7:20>)
-                  found opaque type `impl Future<Output = ()>` (opaque type at <$SRC_DIR/core/src/future/mod.rs:LL:COL>)
-
-error: aborting due to 6 previous errors
+warning: 1 warning emitted
 
-Some errors have detailed explanations: E0308, E0706.
-For more information about an error, try `rustc --explain E0308`.