Merge pull request #162 from dtolnay/select

Compatibility with tokio::select

Author: dtolnay

Cargo.toml

@@ -19,6 +19,7 @@ quote = "1.0"
 syn = { version = "1.0.61", features = ["full", "visit-mut"] }
 
 [dev-dependencies]
+futures = "0.3"
 rustversion = "1.0"
 tracing = "0.1.14"
 tracing-attributes = "0.1.14"

src/receiver.rs

@@ -151,9 +151,16 @@ impl VisitMut for ReplaceSelf {
 
     fn visit_item_mut(&mut self, i: &mut Item) {
         // Visit `macro_rules!` because locally defined macros can refer to
-        // `self`. Otherwise, do not recurse into nested items.
+        // `self`.
+        //
+        // Visit `futures::select` and similar select macros, which commonly
+        // appear syntactically like an item despite expanding to an expression.
+        //
+        // Otherwise, do not recurse into nested items.
         if let Item::Macro(i) = i {
-            if i.mac.path.is_ident("macro_rules") {
+            if i.mac.path.is_ident("macro_rules")
+                || i.mac.path.segments.last().unwrap().ident == "select"
+            {
                 self.visit_macro_mut(&mut i.mac)
             }
         }

tests/test.rs

@@ -1335,3 +1335,29 @@ pub mod issue158 {
         }
     }
 }
+
+// https://github.com/dtolnay/async-trait/issues/161
+#[allow(clippy::mut_mut)]
+pub mod issue161 {
+    use async_trait::async_trait;
+    use futures::future::FutureExt;
+    use std::sync::Arc;
+
+    #[async_trait]
+    pub trait Trait {
+        async fn f(self: Arc<Self>);
+    }
+
+    pub struct MyStruct(bool);
+
+    #[async_trait]
+    impl Trait for MyStruct {
+        async fn f(self: Arc<Self>) {
+            futures::select! {
+                _ = async {
+                    println!("{}", self.0);
+                }.fuse() => {}
+            }
+        }
+    }
+}