Merge pull request #237 from dtolnay/asyncyieldsasync

Suppress async_yields_async clippy correctness lint in generated code

Author: dtolnay

src/expand.rs

@@ -119,6 +119,7 @@ pub fn expand(input: &mut Item, is_local: bool) {
 fn lint_suppress_with_body() -> Attribute {
     parse_quote! {
         #[allow(
+            clippy::async_yields_async,
             clippy::let_unit_value,
             clippy::no_effect_underscore_binding,
             clippy::shadow_same,

tests/test.rs

@@ -1556,3 +1556,31 @@ pub mod issue234 {
         async fn f(Tuple { 1: _int, .. }: Tuple<Droppable, i32>) {}
     }
 }
+
+// https://github.com/dtolnay/async-trait/issues/236
+pub mod issue236 {
+    #![deny(clippy::async_yields_async)]
+    #![allow(clippy::manual_async_fn)]
+
+    use async_trait::async_trait;
+    use std::future::{self, Future, Ready};
+
+    // Does not trigger the lint.
+    pub async fn async_fn() -> Ready<()> {
+        future::ready(())
+    }
+
+    #[allow(clippy::async_yields_async)]
+    pub fn impl_future_fn() -> impl Future<Output = Ready<()>> {
+        async { future::ready(()) }
+    }
+
+    // The async_trait attribute turns the former into the latter, so we make it
+    // put its own allow(async_yeilds_async) to remain consistent with async fn.
+    #[async_trait]
+    pub trait Trait {
+        async fn f() -> Ready<()> {
+            future::ready(())
+        }
+    }
+}