diff --git a/tests/ui/needless_pass_by_ref_mut.rs b/tests/ui/needless_pass_by_ref_mut.rs
index 5e7280995c6..27e1fc075bb 100644
--- a/tests/ui/needless_pass_by_ref_mut.rs
+++ b/tests/ui/needless_pass_by_ref_mut.rs
@@ -91,15 +91,79 @@ impl<T> Mut<T> {
 // Should not warn.
 fn unused(_: &mut u32, _b: &mut u8) {}
 
-fn main() {
-    let mut u = 0;
-    let mut v = vec![0];
-    foo(&mut v, &0, &mut u);
-    foo2(&mut v);
-    foo3(&mut v);
-    foo4(&mut v);
-    foo5(&mut v);
-    alias_check(&mut v);
-    alias_check2(&mut v);
-    println!("{u}");
+// Should not warn.
+async fn f1(x: &mut i32) {
+    *x += 1;
+}
+// Should not warn.
+async fn f2(x: &mut i32, y: String) {
+    *x += 1;
+}
+// Should not warn.
+async fn f3(x: &mut i32, y: String, z: String) {
+    *x += 1;
+}
+// Should not warn.
+async fn f4(x: &mut i32, y: i32) {
+    *x += 1;
+}
+// Should not warn.
+async fn f5(x: i32, y: &mut i32) {
+    *y += 1;
+}
+// Should not warn.
+async fn f6(x: i32, y: &mut i32, z: &mut i32) {
+    *y += 1;
+    *z += 1;
+}
+// Should not warn.
+async fn f7(x: &mut i32, y: i32, z: &mut i32, a: i32) {
+    *x += 1;
+    *z += 1;
+}
+
+// Should warn.
+async fn a1(x: &mut i32) {
+    println!("{:?}", x);
+}
+// Should warn.
+async fn a2(x: &mut i32, y: String) {
+    println!("{:?}", x);
+}
+// Should warn.
+async fn a3(x: &mut i32, y: String, z: String) {
+    println!("{:?}", x);
+}
+// Should warn.
+async fn a4(x: &mut i32, y: i32) {
+    println!("{:?}", x);
+}
+// Should warn.
+async fn a5(x: i32, y: &mut i32) {
+    println!("{:?}", x);
+}
+// Should warn.
+async fn a6(x: i32, y: &mut i32) {
+    println!("{:?}", x);
+}
+// Should warn.
+async fn a7(x: i32, y: i32, z: &mut i32) {
+    println!("{:?}", z);
+}
+// Should warn.
+async fn a8(x: i32, a: &mut i32, y: i32, z: &mut i32) {
+    println!("{:?}", z);
+}
+
+fn main() {
+    // let mut u = 0;
+    // let mut v = vec![0];
+    // foo(&mut v, &0, &mut u);
+    // foo2(&mut v);
+    // foo3(&mut v);
+    // foo4(&mut v);
+    // foo5(&mut v);
+    // alias_check(&mut v);
+    // alias_check2(&mut v);
+    // println!("{u}");
 }
diff --git a/tests/ui/needless_pass_by_ref_mut.stderr b/tests/ui/needless_pass_by_ref_mut.stderr
index 5e9d80bb6c4..caf47bbce86 100644
--- a/tests/ui/needless_pass_by_ref_mut.stderr
+++ b/tests/ui/needless_pass_by_ref_mut.stderr
@@ -24,5 +24,59 @@ error: this argument is a mutable reference, but not used mutably
 LL |     fn badger(&mut self, vec: &mut Vec<i32>) -> usize {
    |                               ^^^^^^^^^^^^^ help: consider changing to: `&Vec<i32>`
 
-error: aborting due to 4 previous errors
+error: this argument is a mutable reference, but not used mutably
+  --> $DIR/needless_pass_by_ref_mut.rs:126:16
+   |
+LL | async fn a1(x: &mut i32) {
+   |                ^^^^^^^^ help: consider changing to: `&i32`
+
+error: this argument is a mutable reference, but not used mutably
+  --> $DIR/needless_pass_by_ref_mut.rs:130:16
+   |
+LL | async fn a2(x: &mut i32, y: String) {
+   |                ^^^^^^^^ help: consider changing to: `&i32`
+
+error: this argument is a mutable reference, but not used mutably
+  --> $DIR/needless_pass_by_ref_mut.rs:134:16
+   |
+LL | async fn a3(x: &mut i32, y: String, z: String) {
+   |                ^^^^^^^^ help: consider changing to: `&i32`
+
+error: this argument is a mutable reference, but not used mutably
+  --> $DIR/needless_pass_by_ref_mut.rs:138:16
+   |
+LL | async fn a4(x: &mut i32, y: i32) {
+   |                ^^^^^^^^ help: consider changing to: `&i32`
+
+error: this argument is a mutable reference, but not used mutably
+  --> $DIR/needless_pass_by_ref_mut.rs:142:24
+   |
+LL | async fn a5(x: i32, y: &mut i32) {
+   |                        ^^^^^^^^ help: consider changing to: `&i32`
+
+error: this argument is a mutable reference, but not used mutably
+  --> $DIR/needless_pass_by_ref_mut.rs:146:24
+   |
+LL | async fn a6(x: i32, y: &mut i32) {
+   |                        ^^^^^^^^ help: consider changing to: `&i32`
+
+error: this argument is a mutable reference, but not used mutably
+  --> $DIR/needless_pass_by_ref_mut.rs:150:32
+   |
+LL | async fn a7(x: i32, y: i32, z: &mut i32) {
+   |                                ^^^^^^^^ help: consider changing to: `&i32`
+
+error: this argument is a mutable reference, but not used mutably
+  --> $DIR/needless_pass_by_ref_mut.rs:154:24
+   |
+LL | async fn a8(x: i32, a: &mut i32, y: i32, z: &mut i32) {
+   |                        ^^^^^^^^ help: consider changing to: `&i32`
+
+error: this argument is a mutable reference, but not used mutably
+  --> $DIR/needless_pass_by_ref_mut.rs:154:45
+   |
+LL | async fn a8(x: i32, a: &mut i32, y: i32, z: &mut i32) {
+   |                                             ^^^^^^^^ help: consider changing to: `&i32`
+
+error: aborting due to 13 previous errors