Update Tokio to Rust 2018 (#1082)

tokio-threadpool/tests/threadpool.rs

@@ -1,24 +1,21 @@
-extern crate env_logger;
-extern crate futures;
-extern crate tokio_executor;
-extern crate tokio_threadpool;
-
-use tokio_executor::park::{Park, Unpark};
-use tokio_threadpool::park::{DefaultPark, DefaultUnpark};
-use tokio_threadpool::*;
+#![deny(warnings, rust_2018_idioms)]
 
 use futures::future::lazy;
 use futures::{Async, Future, Poll, Sink, Stream};
-
 use std::cell::Cell;
 use std::sync::atomic::Ordering::Relaxed;
 use std::sync::atomic::*;
 use std::sync::{mpsc, Arc};
 use std::time::Duration;
+use tokio_executor::park::{Park, Unpark};
+use tokio_threadpool::park::{DefaultPark, DefaultUnpark};
+use tokio_threadpool::*;
 
 thread_local!(static FOO: Cell<u32> = Cell::new(0));
 
-fn ignore_results<F: Future + Send + 'static>(f: F) -> Box<Future<Item = (), Error = ()> + Send> {
+fn ignore_results<F: Future + Send + 'static>(
+    f: F,
+) -> Box<dyn Future<Item = (), Error = ()> + Send> {
     Box::new(f.map(|_| ()).map_err(|_| ()))
 }
 
@@ -129,7 +126,7 @@ fn force_shutdown_drops_futures() {
                 b.fetch_add(1, Relaxed);
             })
             .build();
-        let mut tx = pool.sender().clone();
+        let tx = pool.sender().clone();
 
         tx.spawn(Never(num_drop.clone())).unwrap();
 
@@ -188,7 +185,7 @@ fn drop_threadpool_drops_futures() {
                 b.fetch_add(1, Relaxed);
             })
             .build();
-        let mut tx = pool.sender().clone();
+        let tx = pool.sender().clone();
 
         tx.spawn(Never(num_drop.clone())).unwrap();
 
@@ -217,7 +214,7 @@ fn many_oneshot_futures() {
 
     for _ in 0..50 {
         let pool = ThreadPool::new();
-        let mut tx = pool.sender().clone();
+        let tx = pool.sender().clone();
         let cnt = Arc::new(AtomicUsize::new(0));
 
         for _ in 0..NUM {
@@ -249,7 +246,7 @@ fn many_multishot_futures() {
 
     for _ in 0..50 {
         let pool = ThreadPool::new();
-        let mut pool_tx = pool.sender().clone();
+        let pool_tx = pool.sender().clone();
 
         let mut start_txs = Vec::with_capacity(TRACKS);
         let mut final_rxs = Vec::with_capacity(TRACKS);