Merge pull request #235 from dtolnay/patterns

Make expansion of nested `_` and `..` patterns edition independent

Author: dtolnay

src/expand.rs

@@ -403,7 +403,10 @@ fn transform_block(context: Context, sig: &mut Signature, block: &mut Block) {
                     } else {
                         quote! {
                             #(#attrs)*
-                            let #pat = #ident;
+                            let #pat = {
+                                let #ident = #ident;
+                                #ident
+                            };
                         }
                     }
                 }

tests/test.rs

@@ -2,6 +2,7 @@
     async_trait_nightly_testing,
     feature(min_specialization, type_alias_impl_trait)
 )]
+#![deny(rust_2021_compatibility)]
 #![allow(
     clippy::let_unit_value,
     clippy::missing_panics_doc,
@@ -1523,3 +1524,35 @@ pub mod issue232 {
         async fn take_ref(&self, (_a, _b, _c): &(T, T, T)) {}
     }
 }
+
+// https://github.com/dtolnay/async-trait/issues/234
+pub mod issue234 {
+    use async_trait::async_trait;
+
+    pub struct Droppable;
+
+    impl Drop for Droppable {
+        fn drop(&mut self) {}
+    }
+
+    pub struct Tuple<T, U>(T, U);
+
+    #[async_trait]
+    pub trait Trait {
+        async fn f(arg: Tuple<Droppable, i32>);
+    }
+
+    pub struct UnderscorePattern;
+
+    #[async_trait]
+    impl Trait for UnderscorePattern {
+        async fn f(Tuple(_, _int): Tuple<Droppable, i32>) {}
+    }
+
+    pub struct DotDotPattern;
+
+    #[async_trait]
+    impl Trait for DotDotPattern {
+        async fn f(Tuple { 1: _int, .. }: Tuple<Droppable, i32>) {}
+    }
+}