Import async-trait crate.

Bug: 164106399
Bug: 158290206
Test: mm
Change-Id: I0c4a491b785134e4ac1d5572e5ff94b8699dc0bc
diff --git a/tests/ui/self-span.rs b/tests/ui/self-span.rs
new file mode 100644
index 0000000..b01f247
--- /dev/null
+++ b/tests/ui/self-span.rs
@@ -0,0 +1,30 @@
+use async_trait::async_trait;
+
+pub struct S {}
+
+pub enum E {
+    V {},
+}
+
+#[async_trait]
+pub trait Trait {
+    async fn method(self);
+}
+
+#[async_trait]
+impl Trait for S {
+    async fn method(self) {
+        let _: () = self;
+        let _: Self = Self;
+    }
+}
+
+#[async_trait]
+impl Trait for E {
+    async fn method(self) {
+        let _: () = self;
+        let _: Self = Self::V;
+    }
+}
+
+fn main() {}