diff --git a/tests/test.rs b/tests/test.rs
index 348f3f9..2bca1fc 100644
--- a/tests/test.rs
+++ b/tests/test.rs
@@ -6,6 +6,7 @@
     clippy::let_underscore_drop,
     clippy::let_unit_value,
     clippy::missing_panics_doc,
+    clippy::missing_safety_doc,
     clippy::needless_return,
     clippy::trivially_copy_pass_by_ref,
     clippy::unused_async
@@ -1376,3 +1377,15 @@
 
     pub fn test(_t: &dyn Trait) {}
 }
+
+// https://github.com/dtolnay/async-trait/issues/183
+pub mod issue183 {
+    #![deny(clippy::shadow_same)]
+
+    use async_trait::async_trait;
+
+    #[async_trait]
+    trait Foo {
+        async fn foo(_n: i32) {}
+    }
+}
diff --git a/tests/ui/bare-trait-object.stderr b/tests/ui/bare-trait-object.stderr
index f6374eb..6670c48 100644
--- a/tests/ui/bare-trait-object.stderr
+++ b/tests/ui/bare-trait-object.stderr
@@ -1,13 +1,13 @@
 error: trait objects without an explicit `dyn` are deprecated
-  --> $DIR/bare-trait-object.rs:11:16
+  --> tests/ui/bare-trait-object.rs:11:16
    |
 11 | impl Trait for Send + Sync {
    |                ^^^^^^^^^^^ help: use `dyn`: `dyn Send + Sync`
    |
 note: the lint level is defined here
-  --> $DIR/bare-trait-object.rs:1:9
+  --> tests/ui/bare-trait-object.rs:1:9
    |
 1  | #![deny(bare_trait_objects)]
    |         ^^^^^^^^^^^^^^^^^^
    = warning: this is accepted in the current edition (Rust 2018) but is a hard error in Rust 2021!
-   = note: for more information, see issue #80165 <https://github.com/rust-lang/rust/issues/80165>
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
diff --git a/tests/ui/delimiter-span.stderr b/tests/ui/delimiter-span.stderr
index 6120262..a13985d 100644
--- a/tests/ui/delimiter-span.stderr
+++ b/tests/ui/delimiter-span.stderr
@@ -1,5 +1,5 @@
 error: no rules expected the token `{`
-  --> $DIR/delimiter-span.rs:17:16
+  --> tests/ui/delimiter-span.rs:17:16
    |
 3  | macro_rules! picky {
    | ------------------ when calling this macro
@@ -8,7 +8,7 @@
    |                ^ no rules expected this token in macro call
 
 error: no rules expected the token `{`
-  --> $DIR/delimiter-span.rs:18:16
+  --> tests/ui/delimiter-span.rs:18:16
    |
 3  | macro_rules! picky {
    | ------------------ when calling this macro
diff --git a/tests/ui/lifetime-span.stderr b/tests/ui/lifetime-span.stderr
index ddfb267..aad25a7 100644
--- a/tests/ui/lifetime-span.stderr
+++ b/tests/ui/lifetime-span.stderr
@@ -1,5 +1,5 @@
 error[E0726]: implicit elided lifetime not allowed here
-  --> $DIR/lifetime-span.rs:12:6
+  --> tests/ui/lifetime-span.rs:12:6
    |
 12 | impl Trait for A {
    |      ^^^^^- help: indicate the anonymous lifetime: `<'_>`
@@ -7,7 +7,7 @@
    = note: assuming a `'static` lifetime...
 
 error[E0107]: this trait takes 0 lifetime arguments but 1 lifetime argument was supplied
-  --> $DIR/lifetime-span.rs:32:10
+  --> tests/ui/lifetime-span.rs:32:10
    |
 32 | impl<'r> Trait2<'r> for B {
    |          ^^^^^^---- help: remove these generics
@@ -15,13 +15,13 @@
    |          expected 0 lifetime arguments
    |
 note: trait defined here, with 0 lifetime parameters
-  --> $DIR/lifetime-span.rs:22:11
+  --> tests/ui/lifetime-span.rs:22:11
    |
 22 | pub trait Trait2 {
    |           ^^^^^^
 
 error[E0195]: lifetime parameters or bounds on method `method` do not match the trait declaration
-  --> $DIR/lifetime-span.rs:13:14
+  --> tests/ui/lifetime-span.rs:13:14
    |
 8  |     async fn method(&'r self);
    |              ---------------- lifetimes in impl do not match this method in trait
@@ -30,7 +30,7 @@
    |              ^^^^^^^^^^^^^ lifetimes do not match method in trait
 
 error[E0195]: lifetime parameters or bounds on method `method` do not match the trait declaration
-  --> $DIR/lifetime-span.rs:18:14
+  --> tests/ui/lifetime-span.rs:18:14
    |
 8  |     async fn method(&'r self);
    |              ---------------- lifetimes in impl do not match this method in trait
@@ -39,7 +39,7 @@
    |              ^^^^^^^^^^^^^ lifetimes do not match method in trait
 
 error[E0195]: lifetime parameters or bounds on method `method` do not match the trait declaration
-  --> $DIR/lifetime-span.rs:33:14
+  --> tests/ui/lifetime-span.rs:33:14
    |
 23 |     async fn method<'r>(&'r self);
    |                    ---- lifetimes in impl do not match this method in trait
diff --git a/tests/ui/missing-async-in-impl.rs b/tests/ui/missing-async-in-impl.rs
new file mode 100644
index 0000000..3a5f58c
--- /dev/null
+++ b/tests/ui/missing-async-in-impl.rs
@@ -0,0 +1,15 @@
+use async_trait::async_trait;
+
+#[async_trait]
+pub trait Trait {
+    async fn method();
+}
+
+pub struct Struct;
+
+#[async_trait]
+impl Trait for Struct {
+    fn method() {}
+}
+
+fn main() {}
diff --git a/tests/ui/missing-async-in-impl.stderr b/tests/ui/missing-async-in-impl.stderr
new file mode 100644
index 0000000..e461c85
--- /dev/null
+++ b/tests/ui/missing-async-in-impl.stderr
@@ -0,0 +1,8 @@
+error[E0195]: lifetime parameters or bounds on method `method` do not match the trait declaration
+  --> tests/ui/missing-async-in-impl.rs:12:14
+   |
+5  |     async fn method();
+   |              -------- lifetimes in impl do not match this method in trait
+...
+12 |     fn method() {}
+   |              ^ lifetimes do not match method in trait
diff --git a/tests/ui/missing-async-in-trait.rs b/tests/ui/missing-async-in-trait.rs
new file mode 100644
index 0000000..56fea7a
--- /dev/null
+++ b/tests/ui/missing-async-in-trait.rs
@@ -0,0 +1,15 @@
+use async_trait::async_trait;
+
+#[async_trait]
+pub trait Trait {
+    fn method();
+}
+
+pub struct Struct;
+
+#[async_trait]
+impl Trait for Struct {
+    async fn method() {}
+}
+
+fn main() {}
diff --git a/tests/ui/missing-async-in-trait.stderr b/tests/ui/missing-async-in-trait.stderr
new file mode 100644
index 0000000..c92c38d
--- /dev/null
+++ b/tests/ui/missing-async-in-trait.stderr
@@ -0,0 +1,8 @@
+error[E0195]: lifetime parameters or bounds on method `method` do not match the trait declaration
+  --> tests/ui/missing-async-in-trait.rs:12:14
+   |
+5  |     fn method();
+   |              - lifetimes in impl do not match this method in trait
+...
+12 |     async fn method() {}
+   |              ^^^^^^^^ lifetimes do not match method in trait
diff --git a/tests/ui/missing-body.stderr b/tests/ui/missing-body.stderr
index 2d9b09c..e6ddb42 100644
--- a/tests/ui/missing-body.stderr
+++ b/tests/ui/missing-body.stderr
@@ -1,5 +1,5 @@
 error: associated function in `impl` without body
-  --> $DIR/missing-body.rs:12:5
+  --> tests/ui/missing-body.rs:12:5
    |
 12 |     async fn f(&self);
    |     ^^^^^^^^^^^^^^^^^-
diff --git a/tests/ui/must-use.stderr b/tests/ui/must-use.stderr
index c09a51e..1b97055 100644
--- a/tests/ui/must-use.stderr
+++ b/tests/ui/must-use.stderr
@@ -1,11 +1,11 @@
 error: unused return value of `Interface::f` that must be used
-  --> $DIR/must-use.rs:18:5
+  --> tests/ui/must-use.rs:18:5
    |
 18 |     Thing.f();
    |     ^^^^^^^^^^
    |
 note: the lint level is defined here
-  --> $DIR/must-use.rs:1:9
+  --> tests/ui/must-use.rs:1:9
    |
 1  | #![deny(unused_must_use)]
    |         ^^^^^^^^^^^^^^^
diff --git a/tests/ui/self-span.stderr b/tests/ui/self-span.stderr
index 9ea1bbe..2690791 100644
--- a/tests/ui/self-span.stderr
+++ b/tests/ui/self-span.stderr
@@ -1,5 +1,5 @@
 error[E0308]: mismatched types
-  --> $DIR/self-span.rs:17:21
+  --> tests/ui/self-span.rs:17:21
    |
 17 |         let _: () = self;
    |                --   ^^^^ expected `()`, found struct `S`
@@ -7,13 +7,13 @@
    |                expected due to this
 
 error: the `Self` constructor can only be used with tuple or unit structs
-  --> $DIR/self-span.rs:18:23
+  --> tests/ui/self-span.rs:18:23
    |
 18 |         let _: Self = Self;
    |                       ^^^^ help: use curly brackets: `Self { /* fields */ }`
 
 error[E0308]: mismatched types
-  --> $DIR/self-span.rs:25:21
+  --> tests/ui/self-span.rs:25:21
    |
 25 |         let _: () = self;
    |                --   ^^^^ expected `()`, found enum `E`
@@ -21,7 +21,7 @@
    |                expected due to this
 
 error[E0533]: expected unit struct, unit variant or constant, found struct variant `Self::V`
-  --> $DIR/self-span.rs:26:23
+  --> tests/ui/self-span.rs:26:23
    |
 26 |         let _: Self = Self::V;
    |                       ^^^^^^^
diff --git a/tests/ui/send-not-implemented.stderr b/tests/ui/send-not-implemented.stderr
index 473a31b..8004de6 100644
--- a/tests/ui/send-not-implemented.stderr
+++ b/tests/ui/send-not-implemented.stderr
@@ -1,5 +1,5 @@
 error: future cannot be sent between threads safely
-  --> $DIR/send-not-implemented.rs:8:26
+  --> tests/ui/send-not-implemented.rs:8:26
    |
 8  |       async fn test(&self) {
    |  __________________________^
@@ -9,9 +9,9 @@
 12 | |     }
    | |_____^ future created by async block is not `Send`
    |
-   = help: within `impl Future`, the trait `Send` is not implemented for `MutexGuard<'_, ()>`
+   = help: within `impl Future<Output = [async output]>`, the trait `Send` is not implemented for `MutexGuard<'_, ()>`
 note: future is not `Send` as this value is used across an await
-  --> $DIR/send-not-implemented.rs:11:9
+  --> tests/ui/send-not-implemented.rs:11:9
    |
 10 |         let _guard = mutex.lock().unwrap();
    |             ------ has type `MutexGuard<'_, ()>` which is not `Send`
@@ -22,7 +22,7 @@
    = note: required for the cast to the object type `dyn Future<Output = ()> + Send`
 
 error: future cannot be sent between threads safely
-  --> $DIR/send-not-implemented.rs:14:38
+  --> tests/ui/send-not-implemented.rs:14:38
    |
 14 |       async fn test_ret(&self) -> bool {
    |  ______________________________________^
@@ -33,9 +33,9 @@
 19 | |     }
    | |_____^ future created by async block is not `Send`
    |
-   = help: within `impl Future`, the trait `Send` is not implemented for `MutexGuard<'_, ()>`
+   = help: within `impl Future<Output = [async output]>`, the trait `Send` is not implemented for `MutexGuard<'_, ()>`
 note: future is not `Send` as this value is used across an await
-  --> $DIR/send-not-implemented.rs:17:9
+  --> tests/ui/send-not-implemented.rs:17:9
    |
 16 |         let _guard = mutex.lock().unwrap();
    |             ------ has type `MutexGuard<'_, ()>` which is not `Send`
diff --git a/tests/ui/unreachable.rs b/tests/ui/unreachable.rs
index f546a58..cac2826 100644
--- a/tests/ui/unreachable.rs
+++ b/tests/ui/unreachable.rs
@@ -12,8 +12,8 @@
 #[async_trait]
 pub trait TraitFoo {
     async fn f() {
-        let y = unimplemented!();
-        let z = y;
+        let _y = unimplemented!();
+        let _z = _y;
     }
 }
 
diff --git a/tests/ui/unreachable.stderr b/tests/ui/unreachable.stderr
index 0b74692..08595e5 100644
--- a/tests/ui/unreachable.stderr
+++ b/tests/ui/unreachable.stderr
@@ -1,13 +1,13 @@
 error: unreachable statement
-  --> $DIR/unreachable.rs:16:9
+  --> tests/ui/unreachable.rs:16:9
    |
-15 |         let y = unimplemented!();
-   |                 ---------------- any code following this expression is unreachable
-16 |         let z = y;
-   |         ^^^^^^^^^^ unreachable statement
+15 |         let _y = unimplemented!();
+   |                  ---------------- any code following this expression is unreachable
+16 |         let _z = _y;
+   |         ^^^^^^^^^^^^ unreachable statement
    |
 note: the lint level is defined here
-  --> $DIR/unreachable.rs:1:9
+  --> tests/ui/unreachable.rs:1:9
    |
 1  | #![deny(warnings)]
    |         ^^^^^^^^
diff --git a/tests/ui/unsupported-self.stderr b/tests/ui/unsupported-self.stderr
index c98807e..1493945 100644
--- a/tests/ui/unsupported-self.stderr
+++ b/tests/ui/unsupported-self.stderr
@@ -1,5 +1,5 @@
 error: the `Self` constructor can only be used with tuple or unit structs
-  --> $DIR/unsupported-self.rs:11:17
+  --> tests/ui/unsupported-self.rs:11:17
    |
 11 |         let _ = Self;
    |                 ^^^^