Code cleanup and formatting for System.Memory files. (#17451)

* Fix IDE0034 C# expression can be simplified (use of default)

* Remove unnecessary using statements

* IDE0012 C# Name can be simplified. String -> string

* IDE0041  C# Null check can be simplified

* Fix code formatting (limited to Span/System.Memory files).

* Address PR feedback - IDE0012 Name can be simplified (String -> string)

* Add back the necessary using statements and fix typo

* Fix comment typo and add necessary using statements

7 files changed, 91 insertions, 91 deletions

diff --git a/src/System.Private.CoreLib/src/System/Threading/Tasks/AsyncCausalityTracer.cs b/src/System.Private.CoreLib/src/System/Threading/Tasks/AsyncCausalityTracer.cs
index 0e4ed9bd64..d1bdd13ab9 100644
--- a/src/System.Private.CoreLib/src/System/Threading/Tasks/AsyncCausalityTracer.cs
+++ b/src/System.Private.CoreLib/src/System/Threading/Tasks/AsyncCausalityTracer.cs
@@ -150,7 +150,7 @@ namespace System.Threading.Tasks
                 s_TracerFactory = (WFD.IAsyncCausalityTracerStatics)factory;
 
                 EventRegistrationToken token = s_TracerFactory.add_TracingStatusChanged(new EventHandler<WFD.TracingStatusChangedEventArgs>(TracingStatusChangedHandler));
-                Debug.Assert(token != default(EventRegistrationToken), "EventRegistrationToken is null");
+                Debug.Assert(token != default, "EventRegistrationToken is null");
             }
             catch (Exception ex)
             {
diff --git a/src/System.Private.CoreLib/src/System/Threading/Tasks/FutureFactory.cs b/src/System.Private.CoreLib/src/System/Threading/Tasks/FutureFactory.cs
index 4615d43826..1eaa85a079 100644
--- a/src/System.Private.CoreLib/src/System/Threading/Tasks/FutureFactory.cs
+++ b/src/System.Private.CoreLib/src/System/Threading/Tasks/FutureFactory.cs
@@ -85,7 +85,7 @@ namespace System.Threading.Tasks
         /// cref="System.Threading.Tasks.TaskScheduler.Current">TaskScheduler.Current</see>).
         /// </remarks>
         public TaskFactory()
-            : this(default(CancellationToken), TaskCreationOptions.None, TaskContinuationOptions.None, null)
+            : this(default, TaskCreationOptions.None, TaskContinuationOptions.None, null)
         {
         }
 
@@ -130,7 +130,7 @@ namespace System.Threading.Tasks
         /// cref="System.Threading.Tasks.TaskScheduler.Current">TaskScheduler.Current</see>).
         /// </remarks>
         public TaskFactory(TaskScheduler scheduler) // null means to use TaskScheduler.Current
-            : this(default(CancellationToken), TaskCreationOptions.None, TaskContinuationOptions.None, scheduler)
+            : this(default, TaskCreationOptions.None, TaskContinuationOptions.None, scheduler)
         {
         }
 
@@ -161,7 +161,7 @@ namespace System.Threading.Tasks
         /// cref="System.Threading.Tasks.TaskScheduler.Current">TaskScheduler.Current</see>).
         /// </remarks>
         public TaskFactory(TaskCreationOptions creationOptions, TaskContinuationOptions continuationOptions)
-            : this(default(CancellationToken), creationOptions, continuationOptions, null)
+            : this(default, creationOptions, continuationOptions, null)
         {
         }
 
@@ -520,7 +520,7 @@ namespace System.Threading.Tasks
 
             Exception ex = null;
             OperationCanceledException oce = null;
-            TResult result = default(TResult);
+            TResult result = default;
 
             try
             {
@@ -690,7 +690,7 @@ namespace System.Threading.Tasks
                 FromAsyncCoreLogic(asyncResult, endFunction, endAction, promise, requiresSynchronization: true);
             }),
                 (object)null, null,
-                default(CancellationToken), TaskCreationOptions.None, InternalTaskOptions.None, null);
+                default, TaskCreationOptions.None, InternalTaskOptions.None, null);
 
             if (AsyncCausalityTracer.LoggingOn)
                 AsyncCausalityTracer.TraceOperationCreation(CausalityTraceLevel.Verbose, t.Id, "TaskFactory.FromAsync Callback", 0);
@@ -827,7 +827,7 @@ namespace System.Threading.Tasks
                 }
 
                 // Make sure we don't leave promise "dangling".
-                promise.TrySetResult(default(TResult));
+                promise.TrySetResult(default);
                 throw;
             }
 
@@ -948,7 +948,7 @@ namespace System.Threading.Tasks
                 }
 
                 // Make sure we don't leave promise "dangling".
-                promise.TrySetResult(default(TResult));
+                promise.TrySetResult(default);
                 throw;
             }
 
@@ -1077,7 +1077,7 @@ namespace System.Threading.Tasks
                 }
 
                 // Make sure we don't leave promise "dangling".
-                promise.TrySetResult(default(TResult));
+                promise.TrySetResult(default);
                 throw;
             }
 
@@ -1214,7 +1214,7 @@ namespace System.Threading.Tasks
                 }
 
                 // Make sure we don't leave the promise "dangling".
-                promise.TrySetResult(default(TResult));
+                promise.TrySetResult(default);
                 throw;
             }
 
@@ -1305,7 +1305,7 @@ namespace System.Threading.Tasks
                 // Grab the relevant state and then null it out so that the task doesn't hold onto the state unnecessarily
                 var thisRef = promise.m_thisRef;
                 var endMethod = promise.m_endMethod;
-                promise.m_thisRef = default(TInstance);
+                promise.m_thisRef = default;
                 promise.m_endMethod = null;
                 if (endMethod == null) ThrowHelper.ThrowArgumentException(ExceptionResource.InvalidOperation_WrongAsyncResultOrEndCalledMultiple, ExceptionArgument.asyncResult);
 
@@ -1374,7 +1374,7 @@ namespace System.Threading.Tasks
             TaskCreationOptions tco;
             InternalTaskOptions dontcare;
             Task.CreationOptionsFromContinuationOptions(continuationOptions, out tco, out dontcare);
-            return new Task<TResult>(true, default(TResult), tco, ct);
+            return new Task<TResult>(true, default, tco, ct);
         }
 
         //
@@ -1745,7 +1745,7 @@ namespace System.Threading.Tasks
                    (completedTasks, state) =>
                    {
                        completedTasks.NotifyDebuggerOfWaitCompletionIfNecessary();
-                       ((Action<Task[]>)state)(completedTasks.Result); return default(TResult);
+                       ((Action<Task[]>)state)(completedTasks.Result); return default;
                    },
                    continuationAction, scheduler, cancellationToken, continuationOptions);
             }
@@ -2062,7 +2062,7 @@ namespace System.Threading.Tasks
                 return starter.ContinueWith<TResult>(
                     //the following delegate avoids closure capture as much as possible
                     //completedTask.Result is the winning task; state == continuationAction
-                    (completedTask, state) => { ((Action<Task>)state)(completedTask.Result); return default(TResult); },
+                    (completedTask, state) => { ((Action<Task>)state)(completedTask.Result); return default; },
                     continuationAction, scheduler, cancellationToken, continuationOptions);
             }
         }
@@ -2133,7 +2133,7 @@ namespace System.Threading.Tasks
                 var action = (Action<Task<TAntecedentResult>>)state;
                 var arg = (Task<TAntecedentResult>)wrappedWinner.Result;
                 action(arg);
-                return default(TResult);
+                return default;
             };
 
         // ContinueWith delegate for TaskFactory<TResult>.ContinueWhenAllImpl<TAntecedentResult>(non-null continuationFunction)
@@ -2152,7 +2152,7 @@ namespace System.Threading.Tasks
                 wrappedAntecedents.NotifyDebuggerOfWaitCompletionIfNecessary();
                 var action = (Action<Task<TAntecedentResult>[]>)state;
                 action(wrappedAntecedents.Result);
-                return default(TResult);
+                return default;
             };
     }
 }
diff --git a/src/System.Private.CoreLib/src/System/Threading/Tasks/ProducerConsumerQueues.cs b/src/System.Private.CoreLib/src/System/Threading/Tasks/ProducerConsumerQueues.cs
index 1994c490d3..13347ec9fb 100644
--- a/src/System.Private.CoreLib/src/System/Threading/Tasks/ProducerConsumerQueues.cs
+++ b/src/System.Private.CoreLib/src/System/Threading/Tasks/ProducerConsumerQueues.cs
@@ -204,7 +204,7 @@ namespace System.Threading.Tasks
             if (first != segment.m_state.m_lastCopy)
             {
                 result = array[first];
-                array[first] = default(T); // Clear the slot to release the element
+                array[first] = default; // Clear the slot to release the element
                 segment.m_state.m_first = (first + 1) & (array.Length - 1);
                 return true;
             }
@@ -239,12 +239,12 @@ namespace System.Threading.Tasks
 
             if (first == segment.m_state.m_last)
             {
-                result = default(T);
+                result = default;
                 return false;
             }
 
             result = array[first];
-            array[first] = default(T); // Clear the slot to release the element
+            array[first] = default; // Clear the slot to release the element
             segment.m_state.m_first = (first + 1) & (segment.m_array.Length - 1);
             segment.m_state.m_lastCopy = segment.m_state.m_last; // Refresh m_lastCopy to ensure that m_first has not passed m_lastCopy
 
diff --git a/src/System.Private.CoreLib/src/System/Threading/Tasks/Task.cs b/src/System.Private.CoreLib/src/System/Threading/Tasks/Task.cs
index 8a288edb83..4b98612ab0 100644
--- a/src/System.Private.CoreLib/src/System/Threading/Tasks/Task.cs
+++ b/src/System.Private.CoreLib/src/System/Threading/Tasks/Task.cs
@@ -347,7 +347,7 @@ namespace System.Threading.Tasks
                 }
             }
 
-            TaskConstructorCore(null, state, default(CancellationToken), creationOptions, InternalTaskOptions.PromiseTask, null);
+            TaskConstructorCore(null, state, default, creationOptions, InternalTaskOptions.PromiseTask, null);
         }
 
         /// <summary>
@@ -356,7 +356,7 @@ namespace System.Threading.Tasks
         /// <param name="action">The delegate that represents the code to execute in the Task.</param>
         /// <exception cref="T:System.ArgumentNullException">The <paramref name="action"/> argument is null.</exception>
         public Task(Action action)
-            : this(action, null, null, default(CancellationToken), TaskCreationOptions.None, InternalTaskOptions.None, null)
+            : this(action, null, null, default, TaskCreationOptions.None, InternalTaskOptions.None, null)
         {
         }
 
@@ -391,7 +391,7 @@ namespace System.Threading.Tasks
         /// cref="T:System.Threading.Tasks.TaskCreationOptions"/>.
         /// </exception>
         public Task(Action action, TaskCreationOptions creationOptions)
-            : this(action, null, Task.InternalCurrentIfAttached(creationOptions), default(CancellationToken), creationOptions, InternalTaskOptions.None, null)
+            : this(action, null, Task.InternalCurrentIfAttached(creationOptions), default, creationOptions, InternalTaskOptions.None, null)
         {
         }
 
@@ -429,7 +429,7 @@ namespace System.Threading.Tasks
         /// The <paramref name="action"/> argument is null.
         /// </exception>
         public Task(Action<object> action, object state)
-            : this(action, state, null, default(CancellationToken), TaskCreationOptions.None, InternalTaskOptions.None, null)
+            : this(action, state, null, default, TaskCreationOptions.None, InternalTaskOptions.None, null)
         {
         }
 
@@ -467,7 +467,7 @@ namespace System.Threading.Tasks
         /// cref="T:System.Threading.Tasks.TaskCreationOptions"/>.
         /// </exception>
         public Task(Action<object> action, object state, TaskCreationOptions creationOptions)
-            : this(action, state, Task.InternalCurrentIfAttached(creationOptions), default(CancellationToken), creationOptions, InternalTaskOptions.None, null)
+            : this(action, state, Task.InternalCurrentIfAttached(creationOptions), default, creationOptions, InternalTaskOptions.None, null)
         {
         }
 
@@ -1132,7 +1132,7 @@ namespace System.Threading.Tasks
                     // Also if we queued the task above, the task may not be done yet.
                     if (waitForCompletion && !IsCompleted)
                     {
-                        SpinThenBlockingWait(Timeout.Infinite, default(CancellationToken));
+                        SpinThenBlockingWait(Timeout.Infinite, default);
                     }
                 }
                 catch (Exception e)
@@ -1414,7 +1414,7 @@ namespace System.Threading.Tasks
             get
             {
                 var props = Volatile.Read(ref m_contingentProperties);
-                return (props == null) ? default(CancellationToken) : props.m_cancellationToken;
+                return (props == null) ? default : props.m_cancellationToken;
             }
         }
 
@@ -1533,7 +1533,7 @@ namespace System.Threading.Tasks
         public static TaskFactory Factory { get; } = new TaskFactory();
 
         /// <summary>Gets a task that's already been completed successfully.</summary>
-        public static Task CompletedTask { get; } = new Task(false, (TaskCreationOptions)InternalTaskOptions.DoNotDispose, default(CancellationToken));
+        public static Task CompletedTask { get; } = new Task(false, (TaskCreationOptions)InternalTaskOptions.DoNotDispose, default);
 
         /// <summary>
         /// Provides an event that can be used to wait for completion.
@@ -2697,7 +2697,7 @@ namespace System.Threading.Tasks
 #if DEBUG
             bool waitResult =
 #endif
-            Wait(Timeout.Infinite, default(CancellationToken));
+            Wait(Timeout.Infinite, default);
 
 #if DEBUG
             Debug.Assert(waitResult, "expected wait to succeed");
@@ -2731,7 +2731,7 @@ namespace System.Threading.Tasks
                 ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.timeout);
             }
 
-            return Wait((int)totalMilliseconds, default(CancellationToken));
+            return Wait((int)totalMilliseconds, default);
         }
 
 
@@ -2773,7 +2773,7 @@ namespace System.Threading.Tasks
         /// </exception>
         public bool Wait(int millisecondsTimeout)
         {
-            return Wait(millisecondsTimeout, default(CancellationToken));
+            return Wait(millisecondsTimeout, default);
         }
 
 
@@ -3142,11 +3142,11 @@ namespace System.Threading.Tasks
             RecordInternalCancellationRequest();
 
             Debug.Assert((Options & (TaskCreationOptions)InternalTaskOptions.PromiseTask) != 0, "Task.RecordInternalCancellationRequest(CancellationToken) only valid for promise-style task");
-            Debug.Assert(m_contingentProperties.m_cancellationToken == default(CancellationToken));
+            Debug.Assert(m_contingentProperties.m_cancellationToken == default);
 
             // Store the supplied cancellation token as this task's token.
             // Waiting on this task will then result in an OperationCanceledException containing this token.
-            if (tokenToRecord != default(CancellationToken))
+            if (tokenToRecord != default)
             {
                 m_contingentProperties.m_cancellationToken = tokenToRecord;
             }
@@ -3401,7 +3401,7 @@ namespace System.Threading.Tasks
         /// </exception>
         public Task ContinueWith(Action<Task> continuationAction)
         {
-            return ContinueWith(continuationAction, TaskScheduler.Current, default(CancellationToken), TaskContinuationOptions.None);
+            return ContinueWith(continuationAction, TaskScheduler.Current, default, TaskContinuationOptions.None);
         }
 
         /// <summary>
@@ -3453,7 +3453,7 @@ namespace System.Threading.Tasks
         /// </exception>
         public Task ContinueWith(Action<Task> continuationAction, TaskScheduler scheduler)
         {
-            return ContinueWith(continuationAction, scheduler, default(CancellationToken), TaskContinuationOptions.None);
+            return ContinueWith(continuationAction, scheduler, default, TaskContinuationOptions.None);
         }
 
         /// <summary>
@@ -3486,7 +3486,7 @@ namespace System.Threading.Tasks
         /// </exception>
         public Task ContinueWith(Action<Task> continuationAction, TaskContinuationOptions continuationOptions)
         {
-            return ContinueWith(continuationAction, TaskScheduler.Current, default(CancellationToken), continuationOptions);
+            return ContinueWith(continuationAction, TaskScheduler.Current, default, continuationOptions);
         }
 
         /// <summary>
@@ -3587,7 +3587,7 @@ namespace System.Threading.Tasks
         /// </exception>
         public Task ContinueWith(Action<Task, Object> continuationAction, Object state)
         {
-            return ContinueWith(continuationAction, state, TaskScheduler.Current, default(CancellationToken), TaskContinuationOptions.None);
+            return ContinueWith(continuationAction, state, TaskScheduler.Current, default, TaskContinuationOptions.None);
         }
 
         /// <summary>
@@ -3641,7 +3641,7 @@ namespace System.Threading.Tasks
         /// </exception>
         public Task ContinueWith(Action<Task, Object> continuationAction, Object state, TaskScheduler scheduler)
         {
-            return ContinueWith(continuationAction, state, scheduler, default(CancellationToken), TaskContinuationOptions.None);
+            return ContinueWith(continuationAction, state, scheduler, default, TaskContinuationOptions.None);
         }
 
         /// <summary>
@@ -3675,7 +3675,7 @@ namespace System.Threading.Tasks
         /// </exception>
         public Task ContinueWith(Action<Task, Object> continuationAction, Object state, TaskContinuationOptions continuationOptions)
         {
-            return ContinueWith(continuationAction, state, TaskScheduler.Current, default(CancellationToken), continuationOptions);
+            return ContinueWith(continuationAction, state, TaskScheduler.Current, default, continuationOptions);
         }
 
         /// <summary>
@@ -3780,7 +3780,7 @@ namespace System.Threading.Tasks
         /// </exception>
         public Task<TResult> ContinueWith<TResult>(Func<Task, TResult> continuationFunction)
         {
-            return ContinueWith<TResult>(continuationFunction, TaskScheduler.Current, default(CancellationToken),
+            return ContinueWith<TResult>(continuationFunction, TaskScheduler.Current, default,
                 TaskContinuationOptions.None);
         }
 
@@ -3840,7 +3840,7 @@ namespace System.Threading.Tasks
         /// </exception>
         public Task<TResult> ContinueWith<TResult>(Func<Task, TResult> continuationFunction, TaskScheduler scheduler)
         {
-            return ContinueWith<TResult>(continuationFunction, scheduler, default(CancellationToken), TaskContinuationOptions.None);
+            return ContinueWith<TResult>(continuationFunction, scheduler, default, TaskContinuationOptions.None);
         }
 
         /// <summary>
@@ -3876,7 +3876,7 @@ namespace System.Threading.Tasks
         /// </exception>
         public Task<TResult> ContinueWith<TResult>(Func<Task, TResult> continuationFunction, TaskContinuationOptions continuationOptions)
         {
-            return ContinueWith<TResult>(continuationFunction, TaskScheduler.Current, default(CancellationToken), continuationOptions);
+            return ContinueWith<TResult>(continuationFunction, TaskScheduler.Current, default, continuationOptions);
         }
 
         /// <summary>
@@ -3983,7 +3983,7 @@ namespace System.Threading.Tasks
         /// </exception>
         public Task<TResult> ContinueWith<TResult>(Func<Task, Object, TResult> continuationFunction, Object state)
         {
-            return ContinueWith<TResult>(continuationFunction, state, TaskScheduler.Current, default(CancellationToken),
+            return ContinueWith<TResult>(continuationFunction, state, TaskScheduler.Current, default,
                 TaskContinuationOptions.None);
         }
 
@@ -4045,7 +4045,7 @@ namespace System.Threading.Tasks
         /// </exception>
         public Task<TResult> ContinueWith<TResult>(Func<Task, Object, TResult> continuationFunction, Object state, TaskScheduler scheduler)
         {
-            return ContinueWith<TResult>(continuationFunction, state, scheduler, default(CancellationToken), TaskContinuationOptions.None);
+            return ContinueWith<TResult>(continuationFunction, state, scheduler, default, TaskContinuationOptions.None);
         }
 
         /// <summary>
@@ -4082,7 +4082,7 @@ namespace System.Threading.Tasks
         /// </exception>
         public Task<TResult> ContinueWith<TResult>(Func<Task, Object, TResult> continuationFunction, Object state, TaskContinuationOptions continuationOptions)
         {
-            return ContinueWith<TResult>(continuationFunction, state, TaskScheduler.Current, default(CancellationToken), continuationOptions);
+            return ContinueWith<TResult>(continuationFunction, state, TaskScheduler.Current, default, continuationOptions);
         }
 
         /// <summary>
@@ -4490,7 +4490,7 @@ namespace System.Threading.Tasks
 #if DEBUG
             bool waitResult =
 #endif
-            WaitAllCore(tasks, Timeout.Infinite, default(CancellationToken));
+            WaitAllCore(tasks, Timeout.Infinite, default);
 
 #if DEBUG
             Debug.Assert(waitResult, "expected wait to succeed");
@@ -4535,7 +4535,7 @@ namespace System.Threading.Tasks
                 ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.timeout);
             }
 
-            return WaitAllCore(tasks, (int)totalMilliseconds, default(CancellationToken));
+            return WaitAllCore(tasks, (int)totalMilliseconds, default);
         }
 
         /// <summary>
@@ -4567,7 +4567,7 @@ namespace System.Threading.Tasks
         [MethodImpl(MethodImplOptions.NoOptimization)]  // this is needed for the parallel debugger
         public static bool WaitAll(Task[] tasks, int millisecondsTimeout)
         {
-            return WaitAllCore(tasks, millisecondsTimeout, default(CancellationToken));
+            return WaitAllCore(tasks, millisecondsTimeout, default);
         }
 
         /// <summary>
@@ -4883,7 +4883,7 @@ namespace System.Threading.Tasks
         [MethodImpl(MethodImplOptions.NoOptimization)]  // this is needed for the parallel debugger
         public static int WaitAny(params Task[] tasks)
         {
-            int waitResult = WaitAnyCore(tasks, Timeout.Infinite, default(CancellationToken));
+            int waitResult = WaitAnyCore(tasks, Timeout.Infinite, default);
             Debug.Assert(tasks.Length == 0 || waitResult != -1, "expected wait to succeed");
             return waitResult;
         }
@@ -4922,7 +4922,7 @@ namespace System.Threading.Tasks
                 ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.timeout);
             }
 
-            return WaitAnyCore(tasks, (int)totalMilliseconds, default(CancellationToken));
+            return WaitAnyCore(tasks, (int)totalMilliseconds, default);
         }
 
         /// <summary>
@@ -4979,7 +4979,7 @@ namespace System.Threading.Tasks
         [MethodImpl(MethodImplOptions.NoOptimization)]  // this is needed for the parallel debugger
         public static int WaitAny(Task[] tasks, int millisecondsTimeout)
         {
-            return WaitAnyCore(tasks, millisecondsTimeout, default(CancellationToken));
+            return WaitAnyCore(tasks, millisecondsTimeout, default);
         }
 
         /// <summary>
@@ -5130,7 +5130,7 @@ namespace System.Threading.Tasks
         {
             if (!cancellationToken.IsCancellationRequested)
                 ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.cancellationToken);
-            return new Task<TResult>(true, default(TResult), TaskCreationOptions.None, cancellationToken);
+            return new Task<TResult>(true, default, TaskCreationOptions.None, cancellationToken);
         }
 
         /// <summary>Creates a <see cref="Task{TResult}"/> that's completed due to cancellation with the specified exception.</summary>
@@ -5162,7 +5162,7 @@ namespace System.Threading.Tasks
         /// </exception>
         public static Task Run(Action action)
         {
-            return Task.InternalStartNew(null, action, null, default(CancellationToken), TaskScheduler.Default,
+            return Task.InternalStartNew(null, action, null, default, TaskScheduler.Default,
                 TaskCreationOptions.DenyChildAttach, InternalTaskOptions.None);
         }
 
@@ -5194,7 +5194,7 @@ namespace System.Threading.Tasks
         /// </exception>
         public static Task<TResult> Run<TResult>(Func<TResult> function)
         {
-            return Task<TResult>.StartNew(null, function, default(CancellationToken),
+            return Task<TResult>.StartNew(null, function, default,
                 TaskCreationOptions.DenyChildAttach, InternalTaskOptions.None, TaskScheduler.Default);
         }
 
@@ -5227,7 +5227,7 @@ namespace System.Threading.Tasks
         /// </exception>
         public static Task Run(Func<Task> function)
         {
-            return Run(function, default(CancellationToken));
+            return Run(function, default);
         }
 
 
@@ -5275,7 +5275,7 @@ namespace System.Threading.Tasks
         /// </exception>
         public static Task<TResult> Run<TResult>(Func<Task<TResult>> function)
         {
-            return Run(function, default(CancellationToken));
+            return Run(function, default);
         }
 
         /// <summary>
@@ -5326,7 +5326,7 @@ namespace System.Threading.Tasks
         /// </remarks>
         public static Task Delay(TimeSpan delay)
         {
-            return Delay(delay, default(CancellationToken));
+            return Delay(delay, default);
         }
 
         /// <summary>
@@ -5370,7 +5370,7 @@ namespace System.Threading.Tasks
         /// </remarks>
         public static Task Delay(int millisecondsDelay)
         {
-            return Delay(millisecondsDelay, default(CancellationToken));
+            return Delay(millisecondsDelay, default);
         }
 
         /// <summary>
@@ -5467,7 +5467,7 @@ namespace System.Threading.Tasks
                     {
                         RemoveFromActiveTasks(this.Id);
                     }
-                    setSucceeded = TrySetResult(default(VoidTaskResult));
+                    setSucceeded = TrySetResult(default);
                 }
 
                 // If we set the value, also clean up.
@@ -5705,7 +5705,7 @@ namespace System.Threading.Tasks
                         {
                             RemoveFromActiveTasks(this.Id);
                         }
-                        TrySetResult(default(VoidTaskResult));
+                        TrySetResult(default);
                     }
                 }
                 Debug.Assert(m_count >= 0, "Count should never go below 0");
@@ -5849,7 +5849,7 @@ namespace System.Threading.Tasks
         {
             Debug.Assert(tasks != null, "Expected a non-null tasks array");
             return (tasks.Length == 0) ? // take shortcut if there are no tasks upon which to wait
-                new Task<TResult[]>(false, new TResult[0], TaskCreationOptions.None, default(CancellationToken)) :
+                new Task<TResult[]>(false, new TResult[0], TaskCreationOptions.None, default) :
                 new WhenAllPromise<TResult>(tasks);
         }
 
@@ -6081,7 +6081,7 @@ namespace System.Threading.Tasks
             Task<Task> intermediate = WhenAny((Task[])tasks);
 
             // Return a continuation task with the correct result type
-            return intermediate.ContinueWith(Task<TResult>.TaskWhenAnyCast, default(CancellationToken),
+            return intermediate.ContinueWith(Task<TResult>.TaskWhenAnyCast, default,
                 TaskContinuationOptions.ExecuteSynchronously | TaskContinuationOptions.DenyChildAttach, TaskScheduler.Default);
         }
 
@@ -6110,7 +6110,7 @@ namespace System.Threading.Tasks
             Task<Task> intermediate = WhenAny((IEnumerable<Task>)tasks);
 
             // Return a continuation task with the correct result type
-            return intermediate.ContinueWith(Task<TResult>.TaskWhenAnyCast, default(CancellationToken),
+            return intermediate.ContinueWith(Task<TResult>.TaskWhenAnyCast, default,
                 TaskContinuationOptions.ExecuteSynchronously | TaskContinuationOptions.DenyChildAttach, TaskScheduler.Default);
         }
         #endregion
@@ -6672,7 +6672,7 @@ namespace System.Threading.Tasks
                         RemoveFromActiveTasks(this.Id);
                     }
 
-                    result = TrySetResult(taskTResult != null ? taskTResult.Result : default(TResult));
+                    result = TrySetResult(taskTResult != null ? taskTResult.Result : default);
                     break;
             }
             return result;
@@ -6688,7 +6688,7 @@ namespace System.Threading.Tasks
             // If the inner task is null, the proxy should be canceled.
             if (task == null)
             {
-                TrySetCanceled(default(CancellationToken));
+                TrySetCanceled(default);
                 _state = STATE_DONE; // ... and record that we are done
             }
 
diff --git a/src/System.Private.CoreLib/src/System/Threading/Tasks/TaskContinuation.cs b/src/System.Private.CoreLib/src/System/Threading/Tasks/TaskContinuation.cs
index 3f72500ce4..dc63a67ddb 100644
--- a/src/System.Private.CoreLib/src/System/Threading/Tasks/TaskContinuation.cs
+++ b/src/System.Private.CoreLib/src/System/Threading/Tasks/TaskContinuation.cs
@@ -29,7 +29,7 @@ namespace System.Threading.Tasks
 
         public ContinuationTaskFromTask(
             Task antecedent, Delegate action, object state, TaskCreationOptions creationOptions, InternalTaskOptions internalOptions) :
-            base(action, state, Task.InternalCurrentIfAttached(creationOptions), default(CancellationToken), creationOptions, internalOptions, null)
+            base(action, state, Task.InternalCurrentIfAttached(creationOptions), default, creationOptions, internalOptions, null)
         {
             Debug.Assert(action is Action<Task> || action is Action<Task, object>,
                 "Invalid delegate type in ContinuationTaskFromTask");
@@ -76,7 +76,7 @@ namespace System.Threading.Tasks
 
         public ContinuationResultTaskFromTask(
             Task antecedent, Delegate function, object state, TaskCreationOptions creationOptions, InternalTaskOptions internalOptions) :
-            base(function, state, Task.InternalCurrentIfAttached(creationOptions), default(CancellationToken), creationOptions, internalOptions, null)
+            base(function, state, Task.InternalCurrentIfAttached(creationOptions), default, creationOptions, internalOptions, null)
         {
             Debug.Assert(function is Func<Task, TResult> || function is Func<Task, object, TResult>,
                 "Invalid delegate type in ContinuationResultTaskFromTask");
@@ -123,7 +123,7 @@ namespace System.Threading.Tasks
 
         public ContinuationTaskFromResultTask(
             Task<TAntecedentResult> antecedent, Delegate action, object state, TaskCreationOptions creationOptions, InternalTaskOptions internalOptions) :
-            base(action, state, Task.InternalCurrentIfAttached(creationOptions), default(CancellationToken), creationOptions, internalOptions, null)
+            base(action, state, Task.InternalCurrentIfAttached(creationOptions), default, creationOptions, internalOptions, null)
         {
             Debug.Assert(action is Action<Task<TAntecedentResult>> || action is Action<Task<TAntecedentResult>, object>,
                 "Invalid delegate type in ContinuationTaskFromResultTask");
@@ -170,7 +170,7 @@ namespace System.Threading.Tasks
 
         public ContinuationResultTaskFromResultTask(
             Task<TAntecedentResult> antecedent, Delegate function, object state, TaskCreationOptions creationOptions, InternalTaskOptions internalOptions) :
-            base(function, state, Task.InternalCurrentIfAttached(creationOptions), default(CancellationToken), creationOptions, internalOptions, null)
+            base(function, state, Task.InternalCurrentIfAttached(creationOptions), default, creationOptions, internalOptions, null)
         {
             Debug.Assert(function is Func<Task<TAntecedentResult>, TResult> || function is Func<Task<TAntecedentResult>, object, TResult>,
                 "Invalid delegate type in ContinuationResultTaskFromResultTask");
@@ -557,7 +557,7 @@ namespace System.Threading.Tasks
             Debug.Assert(scheduler != null);
 
             return new Task(
-                action, state, null, default(CancellationToken),
+                action, state, null, default,
                 TaskCreationOptions.None, InternalTaskOptions.QueuedByRuntime, scheduler)
             {
                 CapturedContext = m_capturedContext
diff --git a/src/System.Private.CoreLib/src/System/Threading/Tasks/TaskFactory.cs b/src/System.Private.CoreLib/src/System/Threading/Tasks/TaskFactory.cs
index 875d47b1e7..94c449d4ac 100644
--- a/src/System.Private.CoreLib/src/System/Threading/Tasks/TaskFactory.cs
+++ b/src/System.Private.CoreLib/src/System/Threading/Tasks/TaskFactory.cs
@@ -75,7 +75,7 @@ namespace System.Threading.Tasks
         /// cref="System.Threading.Tasks.TaskScheduler.Current">TaskScheduler.Current</see>).
         /// </remarks>
         public TaskFactory()
-            : this(default(CancellationToken), TaskCreationOptions.None, TaskContinuationOptions.None, null)
+            : this(default, TaskCreationOptions.None, TaskContinuationOptions.None, null)
         {
         }
 
@@ -120,7 +120,7 @@ namespace System.Threading.Tasks
         /// cref="System.Threading.Tasks.TaskScheduler.Current">TaskScheduler.Current</see>).
         /// </remarks>
         public TaskFactory(TaskScheduler scheduler) // null means to use TaskScheduler.Current
-            : this(default(CancellationToken), TaskCreationOptions.None, TaskContinuationOptions.None, scheduler)
+            : this(default, TaskCreationOptions.None, TaskContinuationOptions.None, scheduler)
         {
         }
 
@@ -151,7 +151,7 @@ namespace System.Threading.Tasks
         /// cref="System.Threading.Tasks.TaskScheduler.Current">TaskScheduler.Current</see>).
         /// </remarks>
         public TaskFactory(TaskCreationOptions creationOptions, TaskContinuationOptions continuationOptions)
-            : this(default(CancellationToken), creationOptions, continuationOptions, null)
+            : this(default, creationOptions, continuationOptions, null)
         {
         }
 
diff --git a/src/System.Private.CoreLib/src/System/Threading/Tasks/future.cs b/src/System.Private.CoreLib/src/System/Threading/Tasks/future.cs
index f9199d35cc..352572bd90 100644
--- a/src/System.Private.CoreLib/src/System/Threading/Tasks/future.cs
+++ b/src/System.Private.CoreLib/src/System/Threading/Tasks/future.cs
@@ -95,7 +95,7 @@ namespace System.Threading.Tasks
 
         // Construct a pre-completed Task<TResult>
         internal Task(TResult result) :
-            base(false, TaskCreationOptions.None, default(CancellationToken))
+            base(false, TaskCreationOptions.None, default)
         {
             m_result = result;
         }
@@ -127,7 +127,7 @@ namespace System.Threading.Tasks
         /// The <paramref name="function"/> argument is null.
         /// </exception>
         public Task(Func<TResult> function)
-            : this(function, null, default(CancellationToken),
+            : this(function, null, default,
                 TaskCreationOptions.None, InternalTaskOptions.None, null)
         {
         }
@@ -172,7 +172,7 @@ namespace System.Threading.Tasks
         /// cref="T:System.Threading.Tasks.TaskCreationOptions"/>.
         /// </exception>
         public Task(Func<TResult> function, TaskCreationOptions creationOptions)
-            : this(function, Task.InternalCurrentIfAttached(creationOptions), default(CancellationToken), creationOptions, InternalTaskOptions.None, null)
+            : this(function, Task.InternalCurrentIfAttached(creationOptions), default, creationOptions, InternalTaskOptions.None, null)
         {
         }
 
@@ -215,7 +215,7 @@ namespace System.Threading.Tasks
         /// The <paramref name="function"/> argument is null.
         /// </exception>
         public Task(Func<object, TResult> function, object state)
-            : this(function, state, null, default(CancellationToken),
+            : this(function, state, null, default,
                 TaskCreationOptions.None, InternalTaskOptions.None, null)
         {
         }
@@ -261,7 +261,7 @@ namespace System.Threading.Tasks
         /// cref="T:System.Threading.Tasks.TaskCreationOptions"/>.
         /// </exception>
         public Task(Func<object, TResult> function, object state, TaskCreationOptions creationOptions)
-            : this(function, state, Task.InternalCurrentIfAttached(creationOptions), default(CancellationToken),
+            : this(function, state, Task.InternalCurrentIfAttached(creationOptions), default,
                     creationOptions, InternalTaskOptions.None, null)
         {
         }
@@ -484,7 +484,7 @@ namespace System.Threading.Tasks
         internal TResult GetResultCore(bool waitCompletionNotification)
         {
             // If the result has not been calculated yet, wait for it.
-            if (!IsCompleted) InternalWait(Timeout.Infinite, default(CancellationToken)); // won't throw if task faulted or canceled; that's handled below
+            if (!IsCompleted) InternalWait(Timeout.Infinite, default); // won't throw if task faulted or canceled; that's handled below
 
             // Notify the debugger of the wait completion if it's requested such a notification
             if (waitCompletionNotification) NotifyDebuggerOfWaitCompletionIfNecessary();
@@ -663,7 +663,7 @@ namespace System.Threading.Tasks
         /// </exception>
         public Task ContinueWith(Action<Task<TResult>> continuationAction)
         {
-            return ContinueWith(continuationAction, TaskScheduler.Current, default(CancellationToken), TaskContinuationOptions.None);
+            return ContinueWith(continuationAction, TaskScheduler.Current, default, TaskContinuationOptions.None);
         }
 
 
@@ -717,7 +717,7 @@ namespace System.Threading.Tasks
         /// </exception>
         public Task ContinueWith(Action<Task<TResult>> continuationAction, TaskScheduler scheduler)
         {
-            return ContinueWith(continuationAction, scheduler, default(CancellationToken), TaskContinuationOptions.None);
+            return ContinueWith(continuationAction, scheduler, default, TaskContinuationOptions.None);
         }
 
         /// <summary>
@@ -750,7 +750,7 @@ namespace System.Threading.Tasks
         /// </exception>
         public Task ContinueWith(Action<Task<TResult>> continuationAction, TaskContinuationOptions continuationOptions)
         {
-            return ContinueWith(continuationAction, TaskScheduler.Current, default(CancellationToken), continuationOptions);
+            return ContinueWith(continuationAction, TaskScheduler.Current, default, continuationOptions);
         }
 
         /// <summary>
@@ -852,7 +852,7 @@ namespace System.Threading.Tasks
         /// </exception>
         public Task ContinueWith(Action<Task<TResult>, Object> continuationAction, Object state)
         {
-            return ContinueWith(continuationAction, state, TaskScheduler.Current, default(CancellationToken), TaskContinuationOptions.None);
+            return ContinueWith(continuationAction, state, TaskScheduler.Current, default, TaskContinuationOptions.None);
         }
 
 
@@ -908,7 +908,7 @@ namespace System.Threading.Tasks
         /// </exception>
         public Task ContinueWith(Action<Task<TResult>, Object> continuationAction, Object state, TaskScheduler scheduler)
         {
-            return ContinueWith(continuationAction, state, scheduler, default(CancellationToken), TaskContinuationOptions.None);
+            return ContinueWith(continuationAction, state, scheduler, default, TaskContinuationOptions.None);
         }
 
         /// <summary>
@@ -942,7 +942,7 @@ namespace System.Threading.Tasks
         /// </exception>
         public Task ContinueWith(Action<Task<TResult>, Object> continuationAction, Object state, TaskContinuationOptions continuationOptions)
         {
-            return ContinueWith(continuationAction, state, TaskScheduler.Current, default(CancellationToken), continuationOptions);
+            return ContinueWith(continuationAction, state, TaskScheduler.Current, default, continuationOptions);
         }
 
         /// <summary>
@@ -1048,7 +1048,7 @@ namespace System.Threading.Tasks
         /// </exception>
         public Task<TNewResult> ContinueWith<TNewResult>(Func<Task<TResult>, TNewResult> continuationFunction)
         {
-            return ContinueWith<TNewResult>(continuationFunction, TaskScheduler.Current, default(CancellationToken), TaskContinuationOptions.None);
+            return ContinueWith<TNewResult>(continuationFunction, TaskScheduler.Current, default, TaskContinuationOptions.None);
         }
 
 
@@ -1107,7 +1107,7 @@ namespace System.Threading.Tasks
         /// </exception>
         public Task<TNewResult> ContinueWith<TNewResult>(Func<Task<TResult>, TNewResult> continuationFunction, TaskScheduler scheduler)
         {
-            return ContinueWith<TNewResult>(continuationFunction, scheduler, default(CancellationToken), TaskContinuationOptions.None);
+            return ContinueWith<TNewResult>(continuationFunction, scheduler, default, TaskContinuationOptions.None);
         }
 
         /// <summary>
@@ -1149,7 +1149,7 @@ namespace System.Threading.Tasks
         /// </exception>
         public Task<TNewResult> ContinueWith<TNewResult>(Func<Task<TResult>, TNewResult> continuationFunction, TaskContinuationOptions continuationOptions)
         {
-            return ContinueWith<TNewResult>(continuationFunction, TaskScheduler.Current, default(CancellationToken), continuationOptions);
+            return ContinueWith<TNewResult>(continuationFunction, TaskScheduler.Current, default, continuationOptions);
         }
 
         /// <summary>
@@ -1264,7 +1264,7 @@ namespace System.Threading.Tasks
         /// </exception>
         public Task<TNewResult> ContinueWith<TNewResult>(Func<Task<TResult>, Object, TNewResult> continuationFunction, Object state)
         {
-            return ContinueWith<TNewResult>(continuationFunction, state, TaskScheduler.Current, default(CancellationToken), TaskContinuationOptions.None);
+            return ContinueWith<TNewResult>(continuationFunction, state, TaskScheduler.Current, default, TaskContinuationOptions.None);
         }
 
 
@@ -1327,7 +1327,7 @@ namespace System.Threading.Tasks
         public Task<TNewResult> ContinueWith<TNewResult>(Func<Task<TResult>, Object, TNewResult> continuationFunction, Object state,
             TaskScheduler scheduler)
         {
-            return ContinueWith<TNewResult>(continuationFunction, state, scheduler, default(CancellationToken), TaskContinuationOptions.None);
+            return ContinueWith<TNewResult>(continuationFunction, state, scheduler, default, TaskContinuationOptions.None);
         }
 
         /// <summary>
@@ -1371,7 +1371,7 @@ namespace System.Threading.Tasks
         public Task<TNewResult> ContinueWith<TNewResult>(Func<Task<TResult>, Object, TNewResult> continuationFunction, Object state,
             TaskContinuationOptions continuationOptions)
         {
-            return ContinueWith<TNewResult>(continuationFunction, state, TaskScheduler.Current, default(CancellationToken), continuationOptions);
+            return ContinueWith<TNewResult>(continuationFunction, state, TaskScheduler.Current, default, continuationOptions);
         }
 
         /// <summary>
@@ -1544,7 +1544,7 @@ namespace System.Threading.Tasks
             m_task = task;
         }
 
-        public TResult Result { get { return m_task.Status == TaskStatus.RanToCompletion ? m_task.Result : default(TResult); } }
+        public TResult Result { get { return m_task.Status == TaskStatus.RanToCompletion ? m_task.Result : default; } }
         public object AsyncState { get { return m_task.AsyncState; } }
         public TaskCreationOptions CreationOptions { get { return m_task.CreationOptions; } }
         public Exception Exception { get { return m_task.Exception; } }