chore: deny warnings for doc tests (#1539)

tokio-executor/src/executor.rs

@@ -149,7 +149,7 @@ impl dyn Executor {
     ///     println!("running on the executor");
     /// })).unwrap();
     ///
-    /// handle.map(|_| println!("the future has completed"));
+    /// let handle = handle.map(|_| println!("the future has completed"));
     /// # }
     /// ```
     pub fn spawn_with_handle<Fut>(

tokio-executor/src/lib.rs

@@ -6,7 +6,10 @@
     unreachable_pub
 )]
 #![deny(intra_doc_link_resolution_failure)]
-#![doc(test(no_crate_inject, attr(deny(rust_2018_idioms))))]
+#![doc(test(
+    no_crate_inject,
+    attr(deny(warnings, rust_2018_idioms), allow(dead_code, unused_variables))
+))]
 
 //! Task execution related traits and utilities.
 //!

tokio-executor/src/threadpool/blocking.rs

@@ -104,7 +104,7 @@ pub struct BlockingError {
 ///         // from the context of a `Future` implementation. Since we don't
 ///         // have a complicated requirement, we can use `poll_fn` in this
 ///         // case.
-///         poll_fn(move |_| {
+///         let _ = poll_fn(move |_| {
 ///             blocking(|| {
 ///                 let msg = rx.recv().unwrap();
 ///                 println!("message = {}", msg);

tokio-executor/src/typed.rs

@@ -63,7 +63,7 @@ use crate::SpawnError;
 ///             if item.is_none() { break; }
 ///         }
 ///
-///         self.tx.take().unwrap().send(()).map_err(|_| ());
+///         let _ = self.tx.take().unwrap().send(()).map_err(|_| ());
 ///         Poll::Ready(())
 ///     }
 /// }