Upgrade rust/crates/async-trait to 0.1.38

Change-Id: I894c990c19b1ac3d74e4bf002cf581b9875e730e
diff --git a/tests/test.rs b/tests/test.rs
index 3ea2d15..4ecab07 100644
--- a/tests/test.rs
+++ b/tests/test.rs
@@ -706,6 +706,8 @@
 
 // https://github.com/dtolnay/async-trait/issues/83
 pub mod issue83 {
+    #![allow(clippy::needless_arbitrary_self_type)]
+
     use async_trait::async_trait;
 
     #[async_trait]
@@ -959,3 +961,20 @@
         async fn load(&self, _key: &str) {}
     }
 }
+
+// https://github.com/dtolnay/async-trait/issues/120
+mod issue120 {
+    #![deny(clippy::trivially_copy_pass_by_ref)]
+
+    use async_trait::async_trait;
+
+    #[async_trait]
+    trait Trait {
+        async fn f(&self);
+    }
+
+    #[async_trait]
+    impl Trait for () {
+        async fn f(&self) {}
+    }
+}