chore: bump nightly version used in CI (#2178)

This requires fixing a few warnings.

azure-pipelines.yml

@@ -3,7 +3,7 @@ pr: ["master"]
 
 variables:
   RUSTFLAGS: -Dwarnings
-  nightly: nightly-2019-11-16
+  nightly: nightly-2020-01-25
 
 jobs:
 # Test top level crate

tokio-macros/src/lib.rs

@@ -14,6 +14,9 @@
 
 //! Macros for use with Tokio
 
+// This `extern` is required for older `rustc` versions but newer `rustc`
+// versions warn about the unused `extern crate`.
+#[allow(unused_extern_crates)]
 extern crate proc_macro;
 
 mod entry;

tokio/src/time/driver/atomic_stack.rs

@@ -103,7 +103,7 @@ impl Iterator for AtomicStackEntries {
         let entry = unsafe { Arc::from_raw(self.ptr) };
 
         // Update `self.ptr` to point to the next element of the stack
-        self.ptr = unsafe { (*entry.next_atomic.get()) };
+        self.ptr = unsafe { *entry.next_atomic.get() };
 
         // Unset the queued flag
         let res = entry.queued.fetch_and(false, SeqCst);

tokio/src/time/driver/entry.rs

@@ -143,12 +143,12 @@ impl Entry {
     /// The current entry state as known by the timer. This is not the value of
     /// `state`, but lets the timer know how to converge its state to `state`.
     pub(crate) fn when_internal(&self) -> Option<u64> {
-        unsafe { (*self.when.get()) }
+        unsafe { *self.when.get() }
     }
 
     pub(crate) fn set_when_internal(&self, when: Option<u64>) {
         unsafe {
-            (*self.when.get()) = when;
+            *self.when.get() = when;
         }
     }
 

tokio/src/time/wheel/level.rs

@@ -217,7 +217,7 @@ impl<T> fmt::Debug for Level<T> {
 }
 
 fn occupied_bit(slot: usize) -> u64 {
-    (1 << slot)
+    1 << slot
 }
 
 fn slot_range(level: usize) -> u64 {