misc/multistream-select: Cleanup trait bounds and remove unused file (#2067)

* misc/multistream-select: Remove unused file error.rs

* misc/multistream-select: Remove unnecessary trait bounds

misc/multistream-select/src/dialer_select.rs

@@ -128,23 +128,14 @@ where
 /// A `Future` returned by [`dialer_select_proto_serial`] which negotiates
 /// a protocol iteratively by considering one protocol after the other.
 #[pin_project::pin_project]
-pub struct DialerSelectSeq<R, I>
-where
-    R: AsyncRead + AsyncWrite,
-    I: Iterator,
-    I::Item: AsRef<[u8]>
-{
+pub struct DialerSelectSeq<R, I: Iterator> {
     // TODO: It would be nice if eventually N = I::Item = Protocol.
     protocols: iter::Peekable<I>,
     state: SeqState<R, I::Item>,
     version: Version,
 }
 
-enum SeqState<R, N>
-where
-    R: AsyncRead + AsyncWrite,
-    N: AsRef<[u8]>
-{
+enum SeqState<R, N> {
     SendHeader { io: MessageIO<R>, },
     SendProtocol { io: MessageIO<R>, protocol: N },
     FlushProtocol { io: MessageIO<R>, protocol: N },
@@ -274,22 +265,13 @@ where
 /// a protocol selectively by considering all supported protocols of the remote
 /// "in parallel".
 #[pin_project::pin_project]
-pub struct DialerSelectPar<R, I>
-where
-    R: AsyncRead + AsyncWrite,
-    I: Iterator,
-    I::Item: AsRef<[u8]>
-{
+pub struct DialerSelectPar<R, I: Iterator> {
     protocols: I,
     state: ParState<R, I::Item>,
     version: Version,
 }
 
-enum ParState<R, N>
-where
-    R: AsyncRead + AsyncWrite,
-    N: AsRef<[u8]>
-{
+enum ParState<R, N> {
     SendHeader { io: MessageIO<R> },
     SendProtocolsRequest { io: MessageIO<R> },
     Flush { io: MessageIO<R> },

misc/multistream-select/src/error.rs

@@ -1,27 +0,0 @@
-// Copyright 2017 Parity Technologies (UK) Ltd.
-//
-// Permission is hereby granted, free of charge, to any person obtaining a
-// copy of this software and associated documentation files (the "Software"),
-// to deal in the Software without restriction, including without limitation
-// the rights to use, copy, modify, merge, publish, distribute, sublicense,
-// and/or sell copies of the Software, and to permit persons to whom the
-// Software is furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in
-// all copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
-// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
-// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
-// DEALINGS IN THE SOFTWARE.
-
-//! Main `ProtocolChoiceError` error.
-
-pub use crate::protocol::ProtocolError;
-
-use std::error::Error;
-use std::{fmt, io};
-

misc/multistream-select/src/listener_select.rs

@@ -65,11 +65,7 @@ where
 /// The `Future` returned by [`listener_select_proto`] that performs a
 /// multistream-select protocol negotiation on an underlying I/O stream.
 #[pin_project::pin_project]
-pub struct ListenerSelectFuture<R, N>
-where
-    R: AsyncRead + AsyncWrite,
-    N: AsRef<[u8]>
-{
+pub struct ListenerSelectFuture<R, N> {
     // TODO: It would be nice if eventually N = Protocol, which has a
     // few more implications on the API.
     protocols: SmallVec<[(N, Protocol); 8]>,
@@ -83,11 +79,7 @@ where
     last_sent_na: bool,
 }
 
-enum State<R, N>
-where
-    R: AsyncRead + AsyncWrite,
-    N: AsRef<[u8]>
-{
+enum State<R, N> {
     RecvHeader { io: MessageIO<R> },
     SendHeader { io: MessageIO<R> },
     RecvMessage { io: MessageIO<R> },