diff --git a/src/sync/mutex.rs b/src/sync/mutex.rs
index 8ae51ad..673eb83 100644
--- a/src/sync/mutex.rs
+++ b/src/sync/mutex.rs
@@ -10,7 +10,7 @@ use crate::future::Future;
 use crate::task::{Context, Poll, Waker};
 
 /// Set if the mutex is locked.
-const LOCK: usize = 1 << 0;
+const LOCK: usize = 1;
 
 /// Set if there are tasks blocked on the mutex.
 const BLOCKED: usize = 1 << 1;
diff --git a/src/sync/rwlock.rs b/src/sync/rwlock.rs
index 36f475b..55a29fc 100644
--- a/src/sync/rwlock.rs
+++ b/src/sync/rwlock.rs
@@ -10,7 +10,7 @@ use crate::future::Future;
 use crate::task::{Context, Poll, Waker};
 
 /// Set if a write lock is held.
-const WRITE_LOCK: usize = 1 << 0;
+const WRITE_LOCK: usize = 1;
 
 /// Set if there are read operations blocked on the lock.
 const BLOCKED_READS: usize = 1 << 1;
diff --git a/src/task/block_on.rs b/src/task/block_on.rs
index 2d49dca..f585693 100644
--- a/src/task/block_on.rs
+++ b/src/task/block_on.rs
@@ -69,12 +69,11 @@ where
         let future = task_local::add_finalizer(future);
 
         let future = async move {
-            let res = future.await;
+            future.await;
             trace!("block_on completed", {
                 parent_id: parent_id,
                 child_id: child_id,
             });
-            res
         };
 
         // Pin the future onto the stack.
diff --git a/src/task/blocking.rs b/src/task/blocking.rs
index 41177bc..8f4277c 100644
--- a/src/task/blocking.rs
+++ b/src/task/blocking.rs
@@ -135,7 +135,7 @@ fn random(n: u32) -> u32 {
     use std::num::Wrapping;
 
     thread_local! {
-        static RNG: Cell<Wrapping<u32>> = Cell::new(Wrapping(1406868647));
+        static RNG: Cell<Wrapping<u32>> = Cell::new(Wrapping(1_406_868_647));
     }
 
     RNG.with(|rng| {
@@ -152,6 +152,6 @@ fn random(n: u32) -> u32 {
         //
         // Author: Daniel Lemire
         // Source: https://lemire.me/blog/2016/06/27/a-fast-alternative-to-the-modulo-reduction/
-        ((x.0 as u64).wrapping_mul(n as u64) >> 32) as u32
+        ((u64::from(x.0)).wrapping_mul(u64::from(n)) >> 32) as u32
     })
 }
diff --git a/src/task/builder.rs b/src/task/builder.rs
index 630876c..a43b42b 100644
--- a/src/task/builder.rs
+++ b/src/task/builder.rs
@@ -4,7 +4,7 @@ use crate::future::Future;
 use crate::io;
 
 /// Task builder that configures the settings of a new task.
-#[derive(Debug)]
+#[derive(Debug, Default)]
 pub struct Builder {
     pub(crate) name: Option<String>,
 }