diff --git a/actix-http/src/error.rs b/actix-http/src/error.rs
index 92efd572d..203656bdd 100644
--- a/actix-http/src/error.rs
+++ b/actix-http/src/error.rs
@@ -44,6 +44,7 @@ impl Error {
 }
 
 /// Errors that can generate responses.
+// TODO: add std::error::Error bound when replacement for Box<dyn Error> is found
 pub trait ResponseError: fmt::Debug + fmt::Display {
     /// Returns appropriate status code for error.
     ///
diff --git a/actix-http/src/ws/mod.rs b/actix-http/src/ws/mod.rs
index 22df2b4ff..3571bb379 100644
--- a/actix-http/src/ws/mod.rs
+++ b/actix-http/src/ws/mod.rs
@@ -25,7 +25,7 @@ pub use self::frame::Parser;
 pub use self::proto::{hash_key, CloseCode, CloseReason, OpCode};
 
 /// WebSocket protocol errors.
-#[derive(Debug, Display, From, Error)]
+#[derive(Debug, Display, Error, From)]
 pub enum ProtocolError {
     /// Received an unmasked frame from client.
     #[display(fmt = "Received an unmasked frame from client.")]
@@ -71,7 +71,7 @@ pub enum ProtocolError {
 impl ResponseError for ProtocolError {}
 
 /// WebSocket handshake errors
-#[derive(PartialEq, Debug, Display)]
+#[derive(Debug, PartialEq, Display, Error)]
 pub enum HandshakeError {
     /// Only get method is allowed.
     #[display(fmt = "Method not allowed.")]