Add regression test for issue 152

Author: dtolnay

tests/test.rs

@@ -1,6 +1,6 @@
 #![cfg_attr(
  async_trait_nightly_testing,
- feature(min_specialization, min_const_generics)
+ feature(min_specialization, min_const_generics, type_alias_impl_trait)
 )]
 #![allow(
  clippy::let_underscore_drop,
@@ -1278,3 +1278,25 @@ pub mod issue149 {
  }
  }
 }
+
+// https://github.com/dtolnay/async-trait/issues/152
+#[cfg(async_trait_nightly_testing)]
+pub mod issue152 {
+ use async_trait::async_trait;
+
+ #[async_trait]
+ trait Trait {
+ type Assoc;
+
+ async fn f(&self) -> Self::Assoc;
+ }
+
+ struct Struct;
+
+ #[async_trait]
+ impl Trait for Struct {
+ type Assoc = impl Sized;
+
+ async fn f(&self) -> Self::Assoc {}
+ }
+}