remove NO_VARIANCE as no longer needed

Ix.NET/Source/System.Interactive.Async.Providers/IAsyncQueryable.cs

@@ -31,11 +31,7 @@ namespace System.Linq
     /// Asynchronous enumerable sequence represented by an expression tree.
     /// </summary>
     /// <typeparam name="T">The type of the elements in the sequence.</typeparam>
-    public interface IAsyncQueryable<
-#if !NO_VARIANCE
-out
-#endif
-        T> : IAsyncEnumerable<T>, IAsyncQueryable
+    public interface IAsyncQueryable<out T> : IAsyncEnumerable<T>, IAsyncQueryable
     {
     }
 }

Ix.NET/Source/System.Interactive.Async.Providers/IOrderedAsyncQueryable.cs

@@ -14,11 +14,7 @@ namespace System.Linq
     /// Ordered asynchronous enumerable sequence represented by an expression tree.
     /// </summary>
     /// <typeparam name="T">The type of the elements in the sequence.</typeparam>
-    public interface IOrderedAsyncQueryable<
-#if !NO_VARIANCE
-out
-#endif
-        T> : IAsyncQueryable<T>
+    public interface IOrderedAsyncQueryable<out T> : IAsyncQueryable<T>
     {
     }
 }

Ix.NET/Source/System.Interactive.Async/IAsyncEnumerable.cs

@@ -1,25 +1,25 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the Apache 2.0 License.
 // See the LICENSE file in the project root for more information. 
+
 using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
 
 namespace System.Collections.Generic
 {
     /// <summary>
-    /// Asynchronous version of the IEnumerable&lt;T&gt; interface, allowing elements of the
-    /// enumerable sequence to be retrieved asynchronously.
+    ///     Asynchronous version of the IEnumerable&lt;T&gt; interface, allowing elements of the
+    ///     enumerable sequence to be retrieved asynchronously.
     /// </summary>
     /// <typeparam name="T">Element type.</typeparam>
-    public interface IAsyncEnumerable<
-#if !NO_VARIANCE
-out
-#endif
-        T>
+    public interface IAsyncEnumerable<out T>
     {
         /// <summary>
-        /// Gets an asynchronous enumerator over the sequence.
+        ///     Gets an asynchronous enumerator over the sequence.
         /// </summary>
         /// <returns>Enumerator for asynchronous enumeration over the sequence.</returns>
         IAsyncEnumerator<T> GetEnumerator();
     }
-}
+}

Ix.NET/Source/System.Interactive.Async/IAsyncEnumerator.cs

@@ -1,36 +1,35 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the Apache 2.0 License.
 // See the LICENSE file in the project root for more information. 
+
 using System;
-using System.Threading.Tasks;
+using System.Collections.Generic;
+using System.Linq;
 using System.Threading;
+using System.Threading.Tasks;
 
 namespace System.Collections.Generic
 {
     /// <summary>
-    /// Asynchronous version of the IEnumerator&lt;T&gt; interface, allowing elements to be
-    /// retrieved asynchronously.
+    ///     Asynchronous version of the IEnumerator&lt;T&gt; interface, allowing elements to be
+    ///     retrieved asynchronously.
     /// </summary>
     /// <typeparam name="T">Element type.</typeparam>
-    public interface IAsyncEnumerator<
-#if !NO_VARIANCE
-out
-#endif
-        T> : IDisposable
+    public interface IAsyncEnumerator<out T> : IDisposable
     {
         /// <summary>
-        /// Advances the enumerator to the next element in the sequence, returning the result asynchronously.
+        ///     Gets the current element in the iteration.
+        /// </summary>
+        T Current { get; }
+
+        /// <summary>
+        ///     Advances the enumerator to the next element in the sequence, returning the result asynchronously.
         /// </summary>
         /// <param name="cancellationToken">Cancellation token that can be used to cancel the operation.</param>
         /// <returns>
-        /// Task containing the result of the operation: true if the enumerator was successfully advanced 
-        /// to the next element; false if the enumerator has passed the end of the sequence.
+        ///     Task containing the result of the operation: true if the enumerator was successfully advanced
+        ///     to the next element; false if the enumerator has passed the end of the sequence.
         /// </returns>
         Task<bool> MoveNext(CancellationToken cancellationToken);
-
-        /// <summary>
-        /// Gets the current element in the iteration.
-        /// </summary>
-        T Current { get; }
     }
-}
+}

Ix.NET/Source/System.Interactive.Async/IAsyncGrouping.cs

@@ -1,21 +1,16 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the Apache 2.0 License.
 // See the LICENSE file in the project root for more information. 
+
 using System;
 using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
 
 namespace System.Linq
 {
-    public interface IAsyncGrouping<
-#if !NO_VARIANCE
-        out 
-#endif
-        TKey,
-#if !NO_VARIANCE
-        out 
-#endif
-        TElement> : IAsyncEnumerable<TElement>
+    public interface IAsyncGrouping<out TKey, out TElement> : IAsyncEnumerable<TElement>
     {
         TKey Key { get; }
     }
-}
+}

Ix.NET/Source/System.Interactive.Async/IOrderedAsyncEnumerable.cs

@@ -6,11 +6,7 @@ using System.Collections.Generic;
 
 namespace System.Linq
 {
-    public interface IOrderedAsyncEnumerable<
-#if !NO_VARIANCE
-out 
-#endif
-        TElement> : IAsyncEnumerable<TElement>
+    public interface IOrderedAsyncEnumerable<out TElement> : IAsyncEnumerable<TElement>
     {
         IOrderedAsyncEnumerable<TElement> CreateOrderedEnumerable<TKey>(Func<TElement, TKey> keySelector, IComparer<TKey> comparer, bool descending);
     }