diff --git a/Cargo.toml b/Cargo.toml
index 555944c..3024b36 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -5,7 +5,7 @@ authors = ["David Tolnay <dtolnay@gmail.com>"]
 categories = ["asynchronous", "no-std"]
 description = "Type erasure for async trait methods"
 documentation = "https://docs.rs/async-trait"
-edition = "2018"
+edition = "2021"
 keywords = ["async"]
 license = "MIT OR Apache-2.0"
 repository = "https://github.com/dtolnay/async-trait"
diff --git a/src/receiver.rs b/src/receiver.rs
index 6de5090..f5791bf 100644
--- a/src/receiver.rs
+++ b/src/receiver.rs
@@ -1,5 +1,4 @@
 use proc_macro2::{Group, Span, TokenStream, TokenTree};
-use std::iter::FromIterator;
 use syn::visit_mut::{self, VisitMut};
 use syn::{
     Block, ExprPath, Ident, Item, Macro, Pat, PatIdent, Path, Receiver, Signature, Token, TypePath,
diff --git a/tests/test.rs b/tests/test.rs
index 285377a..cc0f4ff 100644
--- a/tests/test.rs
+++ b/tests/test.rs
@@ -873,7 +873,7 @@ pub mod issue89 {
     }
 
     #[async_trait]
-    impl Trait for Send + Sync {
+    impl Trait for dyn Send + Sync {
         async fn f(&self) {}
     }