1 files changed, 3 insertions, 3 deletions
diff --git a/src/mscorlib/src/System/Threading/Tasks/TaskCompletionSource.cs b/src/mscorlib/src/System/Threading/Tasks/TaskCompletionSource.cs
index 8b1dd2a62f..320f704f09 100644
--- a/src/mscorlib/src/System/Threading/Tasks/TaskCompletionSource.cs
+++ b/src/mscorlib/src/System/Threading/Tasks/TaskCompletionSource.cs
@@ -12,6 +12,7 @@
 // =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
 
 using System;
+using System.Diagnostics;
 using System.Diagnostics.Contracts;
 using System.Collections.Generic;
 using System.Runtime.CompilerServices;
@@ -47,7 +48,6 @@ namespace System.Threading.Tasks
     /// </remarks>
     /// <typeparam name="TResult">The type of the result value assocatied with this <see
     /// cref="TaskCompletionSource{TResult}"/>.</typeparam>
-    [HostProtection(Synchronization = true, ExternalThreading = true)]
     public class TaskCompletionSource<TResult>
     {
         private readonly Task<TResult> m_task;
@@ -209,9 +209,9 @@ namespace System.Threading.Tasks
         /// <remarks>Unlike the public methods, this method doesn't currently validate that its arguments are correct.</remarks>
         internal bool TrySetException(IEnumerable<ExceptionDispatchInfo> exceptions)
         {
-            Contract.Assert(exceptions != null);
+            Debug.Assert(exceptions != null);
 #if DEBUG
-            foreach(var edi in exceptions) Contract.Assert(edi != null, "Contents must be non-null");
+            foreach(var edi in exceptions) Debug.Assert(edi != null, "Contents must be non-null");
 #endif
 
             bool rval = m_task.TrySetException(exceptions);