Remove USE_AWAIT_FOREACH (always on now).

Ix.NET/Source/Directory.build.targets

@@ -19,10 +19,6 @@
     <DefineConstants>$(DefineConstants);USE_ASYNC_ITERATOR;HAS_ASYNCENUMERABLE;HAS_ASYNCDISPOSABLE;BCL_HAS_CONFIGUREAWAIT</DefineConstants>
   </PropertyGroup>
 
-  <PropertyGroup>
-    <DefineConstants>$(DefineConstants);USE_AWAIT_FOREACH</DefineConstants>
-  </PropertyGroup>
-
   <PropertyGroup>
     <Product>$(AssemblyName) ($(TargetFramework))</Product>
   </PropertyGroup>

Ix.NET/Source/System.Linq.Async/System/Linq/AsyncEnumerableHelpers.cs

@@ -112,26 +112,10 @@ namespace System.Collections.Generic
         {
             var set = new Set<T>(comparer);
 
-#if USE_AWAIT_FOREACH
             await foreach (T item in source.WithCancellation(cancellationToken).ConfigureAwait(false))
             {
                 set.Add(item);
             }
-#else
-            var e = source.GetAsyncEnumerator(cancellationToken);
-
-            try
-            {
-                while (await e.MoveNextAsync().ConfigureAwait(false))
-                {
-                    set.Add(e.Current);
-                }
-            }
-            finally
-            {
-                await e.DisposeAsync().ConfigureAwait(false);
-            }
-#endif
 
             return set;
         }

Ix.NET/Source/System.Linq.Async/System/Linq/Operators/Aggregate.cs

@@ -133,26 +133,10 @@ namespace System.Linq
             {
                 var acc = _seed;
 
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     acc = _accumulator(acc, item);
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        acc = _accumulator(acc, e.Current);
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return acc;
             }
@@ -171,26 +155,10 @@ namespace System.Linq
             {
                 var acc = _seed;
 
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     acc = await _accumulator(acc, item).ConfigureAwait(false);
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        acc = await _accumulator(acc, e.Current).ConfigureAwait(false);
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return acc;
             }
@@ -210,26 +178,10 @@ namespace System.Linq
             {
                 var acc = _seed;
 
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     acc = await _accumulator(acc, item, _cancellationToken).ConfigureAwait(false);
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        acc = await _accumulator(acc, e.Current, _cancellationToken).ConfigureAwait(false);
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return acc;
             }
@@ -251,26 +203,10 @@ namespace System.Linq
             {
                 var acc = _seed;
 
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     acc = _accumulator(acc, item);
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        acc = _accumulator(acc, e.Current);
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return _resultSelector(acc);
             }
@@ -291,26 +227,10 @@ namespace System.Linq
             {
                 var acc = _seed;
 
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     acc = await _accumulator(acc, item).ConfigureAwait(false);
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        acc = await _accumulator(acc, e.Current).ConfigureAwait(false);
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return await _resultSelector(acc).ConfigureAwait(false);
             }
@@ -332,26 +252,10 @@ namespace System.Linq
             {
                 var acc = _seed;
 
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     acc = await _accumulator(acc, item, _cancellationToken).ConfigureAwait(false);
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        acc = await _accumulator(acc, e.Current, _cancellationToken).ConfigureAwait(false);
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return await _resultSelector(acc, _cancellationToken).ConfigureAwait(false);
             }

Ix.NET/Source/System.Linq.Async/System/Linq/Operators/All.cs

@@ -21,7 +21,6 @@ namespace System.Linq
 
             static async Task<bool> Core(IAsyncEnumerable<TSource> _source, Func<TSource, bool> _predicate, CancellationToken _cancellationToken)
             {
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     if (!_predicate(item))
@@ -29,22 +28,6 @@ namespace System.Linq
                         return false;
                     }
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        if (!_predicate(e.Current))
-                            return false;
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return true;
             }
@@ -61,7 +44,6 @@ namespace System.Linq
 
             static async Task<bool> Core(IAsyncEnumerable<TSource> _source, Func<TSource, ValueTask<bool>> _predicate, CancellationToken _cancellationToken)
             {
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     if (!await _predicate(item).ConfigureAwait(false))
@@ -69,22 +51,6 @@ namespace System.Linq
                         return false;
                     }
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        if (!await _predicate(e.Current).ConfigureAwait(false))
-                            return false;
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return true;
             }
@@ -102,7 +68,6 @@ namespace System.Linq
 
             static async Task<bool> Core(IAsyncEnumerable<TSource> _source, Func<TSource, CancellationToken, ValueTask<bool>> _predicate, CancellationToken _cancellationToken)
             {
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     if (!await _predicate(item, _cancellationToken).ConfigureAwait(false))
@@ -110,22 +75,6 @@ namespace System.Linq
                         return false;
                     }
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        if (!await _predicate(e.Current, _cancellationToken).ConfigureAwait(false))
-                            return false;
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return true;
             }

Ix.NET/Source/System.Linq.Async/System/Linq/Operators/Any.cs

@@ -43,7 +43,6 @@ namespace System.Linq
 
             static async Task<bool> Core(IAsyncEnumerable<TSource> _source, Func<TSource, bool> _predicate, CancellationToken _cancellationToken)
             {
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     if (_predicate(item))
@@ -51,22 +50,6 @@ namespace System.Linq
                         return true;
                     }
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        if (_predicate(e.Current))
-                            return true;
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return false;
             }
@@ -83,7 +66,6 @@ namespace System.Linq
 
             static async Task<bool> Core(IAsyncEnumerable<TSource> _source, Func<TSource, ValueTask<bool>> _predicate, CancellationToken _cancellationToken)
             {
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     if (await _predicate(item).ConfigureAwait(false))
@@ -91,22 +73,6 @@ namespace System.Linq
                         return true;
                     }
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        if (await _predicate(e.Current).ConfigureAwait(false))
-                            return true;
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return false;
             }
@@ -124,7 +90,6 @@ namespace System.Linq
 
             static async Task<bool> Core(IAsyncEnumerable<TSource> _source, Func<TSource, CancellationToken, ValueTask<bool>> _predicate, CancellationToken _cancellationToken)
             {
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     if (await _predicate(item, _cancellationToken).ConfigureAwait(false))
@@ -132,22 +97,6 @@ namespace System.Linq
                         return true;
                     }
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        if (await _predicate(e.Current, _cancellationToken).ConfigureAwait(false))
-                            return true;
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return false;
             }

Ix.NET/Source/System.Linq.Async/System/Linq/Operators/AppendPrepend.cs

@@ -206,28 +206,11 @@ namespace System.Linq
                 }
                 else
                 {
-#if USE_AWAIT_FOREACH
                     await foreach (TSource item in _source.WithCancellation(cancellationToken).ConfigureAwait(false))
                     {
                         array[index] = item;
                         ++index;
                     }
-#else
-                    var en = _source.GetAsyncEnumerator(cancellationToken);
-
-                    try
-                    {
-                        while (await en.MoveNextAsync().ConfigureAwait(false))
-                        {
-                            array[index] = en.Current;
-                            ++index;
-                        }
-                    }
-                    finally
-                    {
-                        await en.DisposeAsync().ConfigureAwait(false);
-                    }
-#endif
                 }
 
                 if (_appending)
@@ -251,26 +234,10 @@ namespace System.Linq
                     list.Add(_item);
                 }
 
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(cancellationToken).ConfigureAwait(false))
                 {
                     list.Add(item);
                 }
-#else
-                var en = _source.GetAsyncEnumerator(cancellationToken);
-
-                try
-                {
-                    while (await en.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        list.Add(en.Current);
-                    }
-                }
-                finally
-                {
-                    await en.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 if (_appending)
                 {
@@ -428,28 +395,11 @@ namespace System.Linq
                 }
                 else
                 {
-#if USE_AWAIT_FOREACH
                     await foreach (TSource item in _source.WithCancellation(cancellationToken).ConfigureAwait(false))
                     {
                         array[index] = item;
                         ++index;
                     }
-#else
-                    var en = _source.GetAsyncEnumerator(cancellationToken);
-
-                    try
-                    {
-                        while (await en.MoveNextAsync().ConfigureAwait(false))
-                        {
-                            array[index] = en.Current;
-                            ++index;
-                        }
-                    }
-                    finally
-                    {
-                        await en.DisposeAsync().ConfigureAwait(false);
-                    }
-#endif
                 }
 
                 index = array.Length;
@@ -471,26 +421,10 @@ namespace System.Linq
                     list.Add(n.Item);
                 }
 
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(cancellationToken).ConfigureAwait(false))
                 {
                     list.Add(item);
                 }
-#else
-                var en = _source.GetAsyncEnumerator(cancellationToken);
-
-                try
-                {
-                    while (await en.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        list.Add(en.Current);
-                    }
-                }
-                finally
-                {
-                    await en.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 if (_appended != null)
                 {

Ix.NET/Source/System.Linq.Async/System/Linq/Operators/Concat.cs

@@ -84,26 +84,10 @@ namespace System.Linq
                         break;
                     }
 
-#if USE_AWAIT_FOREACH
                     await foreach (TSource item in source.WithCancellation(cancellationToken).ConfigureAwait(false))
                     {
                         list.Add(item);
                     }
-#else
-                    var e = source.GetAsyncEnumerator(cancellationToken);
-
-                    try
-                    {
-                        while (await e.MoveNextAsync().ConfigureAwait(false))
-                        {
-                            list.Add(e.Current);
-                        }
-                    }
-                    finally
-                    {
-                        await e.DisposeAsync().ConfigureAwait(false);
-                    }
-#endif
                 }
 
                 return list;

Ix.NET/Source/System.Linq.Async/System/Linq/Operators/Contains.cs

@@ -28,7 +28,6 @@ namespace System.Linq
 
                 static async Task<bool> Core(IAsyncEnumerable<TSource> _source, TSource _value, CancellationToken _cancellationToken)
                 {
-#if USE_AWAIT_FOREACH
                     await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                     {
                         if (EqualityComparer<TSource>.Default.Equals(item, _value))
@@ -36,24 +35,6 @@ namespace System.Linq
                             return true;
                         }
                     }
-#else
-                    var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                    try
-                    {
-                        while (await e.MoveNextAsync().ConfigureAwait(false))
-                        {
-                            if (EqualityComparer<TSource>.Default.Equals(e.Current, _value))
-                            {
-                                return true;
-                            }
-                        }
-                    }
-                    finally
-                    {
-                        await e.DisposeAsync().ConfigureAwait(false);
-                    }
-#endif
 
                     return false;
                 }
@@ -64,7 +45,6 @@ namespace System.Linq
 
                 static async Task<bool> Core(IAsyncEnumerable<TSource> _source, TSource _value, IEqualityComparer<TSource> _comparer, CancellationToken _cancellationToken)
                 {
-#if USE_AWAIT_FOREACH
                     await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                     {
                         if (_comparer.Equals(item, _value))
@@ -72,24 +52,6 @@ namespace System.Linq
                             return true;
                         }
                     }
-#else
-                    var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                    try
-                    {
-                        while (await e.MoveNextAsync().ConfigureAwait(false))
-                        {
-                            if (_comparer.Equals(e.Current, _value))
-                            {
-                                return true;
-                            }
-                        }
-                    }
-                    finally
-                    {
-                        await e.DisposeAsync().ConfigureAwait(false);
-                    }
-#endif
 
                     return false;
                 }

Ix.NET/Source/System.Linq.Async/System/Linq/Operators/Count.cs

@@ -32,7 +32,6 @@ namespace System.Linq
             {
                 var count = 0;
 
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     checked
@@ -40,24 +39,6 @@ namespace System.Linq
                         count++;
                     }
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        checked
-                        {
-                            count++;
-                        }
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return count;
             }
@@ -76,7 +57,6 @@ namespace System.Linq
             {
                 var count = 0;
 
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     if (_predicate(item))
@@ -87,27 +67,6 @@ namespace System.Linq
                         }
                     }
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        if (_predicate(e.Current))
-                        {
-                            checked
-                            {
-                                count++;
-                            }
-                        }
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return count;
             }
@@ -126,7 +85,6 @@ namespace System.Linq
             {
                 var count = 0;
 
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     if (await _predicate(item).ConfigureAwait(false))
@@ -137,27 +95,6 @@ namespace System.Linq
                         }
                     }
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        if (await _predicate(e.Current).ConfigureAwait(false))
-                        {
-                            checked
-                            {
-                                count++;
-                            }
-                        }
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return count;
             }
@@ -177,7 +114,6 @@ namespace System.Linq
             {
                 var count = 0;
 
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     if (await _predicate(item, _cancellationToken).ConfigureAwait(false))
@@ -188,27 +124,6 @@ namespace System.Linq
                         }
                     }
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        if (await _predicate(e.Current, _cancellationToken).ConfigureAwait(false))
-                        {
-                            checked
-                            {
-                                count++;
-                            }
-                        }
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return count;
             }

Ix.NET/Source/System.Linq.Async/System/Linq/Operators/ElementAt.cs

@@ -37,7 +37,6 @@ namespace System.Linq
 
                     if (_index >= 0)
                     {
-#if USE_AWAIT_FOREACH
                         await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                         {
                             if (_index == 0)
@@ -47,26 +46,6 @@ namespace System.Linq
 
                             _index--;
                         }
-#else
-                        var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                        try
-                        {
-                            while (await e.MoveNextAsync().ConfigureAwait(false))
-                            {
-                                if (_index == 0)
-                                {
-                                    return e.Current;
-                                }
-
-                                _index--;
-                            }
-                        }
-                        finally
-                        {
-                            await e.DisposeAsync().ConfigureAwait(false);
-                        }
-#endif
                     }
                 }
 

Ix.NET/Source/System.Linq.Async/System/Linq/Operators/ElementAtOrDefault.cs

@@ -40,7 +40,6 @@ namespace System.Linq
                     }
                     else
                     {
-#if USE_AWAIT_FOREACH
                         await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                         {
                             if (_index == 0)
@@ -50,26 +49,6 @@ namespace System.Linq
 
                             _index--;
                         }
-#else
-                        var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                        try
-                        {
-                            while (await e.MoveNextAsync().ConfigureAwait(false))
-                            {
-                                if (_index == 0)
-                                {
-                                    return e.Current;
-                                }
-
-                                _index--;
-                            }
-                        }
-                        finally
-                        {
-                            await e.DisposeAsync().ConfigureAwait(false);
-                        }
-#endif
                     }
                 }
 

Ix.NET/Source/System.Linq.Async/System/Linq/Operators/ForEach.cs

@@ -28,26 +28,10 @@ namespace System.Linq
 
             static async Task Core(IAsyncEnumerable<TSource> _source, Action<TSource> _action, CancellationToken _cancellationToken)
             {
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     _action(item);
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        _action(e.Current);
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
             }
         }
 
@@ -64,26 +48,10 @@ namespace System.Linq
             {
                 var index = 0;
 
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     _action(item, checked(index++));
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        _action(e.Current, checked(index++));
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
             }
         }
 
@@ -98,26 +66,10 @@ namespace System.Linq
 
             static async Task Core(IAsyncEnumerable<TSource> _source, Func<TSource, Task> _action, CancellationToken _cancellationToken)
             {
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     await _action(item).ConfigureAwait(false);
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        await _action(e.Current).ConfigureAwait(false);
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
             }
         }
 
@@ -127,26 +79,10 @@ namespace System.Linq
 
             static async Task Core(IAsyncEnumerable<TSource> _source, Func<TSource, CancellationToken, Task> _action, CancellationToken _cancellationToken)
             {
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     await _action(item, _cancellationToken).ConfigureAwait(false);
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        await _action(e.Current, _cancellationToken).ConfigureAwait(false);
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
             }
         }
 
@@ -163,26 +99,10 @@ namespace System.Linq
             {
                 var index = 0;
 
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     await _action(item, checked(index++)).ConfigureAwait(false);
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        await _action(e.Current, checked(index++)).ConfigureAwait(false);
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
             }
         }
 
@@ -199,26 +119,10 @@ namespace System.Linq
             {
                 var index = 0;
 
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     await _action(item, checked(index++), _cancellationToken).ConfigureAwait(false);
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        await _action(e.Current, checked(index++), _cancellationToken).ConfigureAwait(false);
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
             }
         }
     }

Ix.NET/Source/System.Linq.Async/System/Linq/Operators/LastOrDefault.cs

@@ -101,28 +101,11 @@ namespace System.Linq
                     var last = default(TSource);
                     var hasLast = false;
 
-#if USE_AWAIT_FOREACH
                     await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                     {
                         hasLast = true;
                         last = item;
                     }
-#else
-                    var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                    try
-                    {
-                        while (await e.MoveNextAsync().ConfigureAwait(false))
-                        {
-                            hasLast = true;
-                            last = e.Current;
-                        }
-                    }
-                    finally
-                    {
-                        await e.DisposeAsync().ConfigureAwait(false);
-                    }
-#endif
 
                     return hasLast ? new Maybe<TSource>(last) : new Maybe<TSource>();
                 }
@@ -136,7 +119,6 @@ namespace System.Linq
             var last = default(TSource);
             var hasLast = false;
 
-#if USE_AWAIT_FOREACH
             await foreach (TSource item in source.WithCancellation(cancellationToken).ConfigureAwait(false))
             {
                 if (predicate(item))
@@ -145,27 +127,6 @@ namespace System.Linq
                     last = item;
                 }
             }
-#else
-            var e = source.GetAsyncEnumerator(cancellationToken);
-
-            try
-            {
-                while (await e.MoveNextAsync().ConfigureAwait(false))
-                {
-                    var value = e.Current;
-
-                    if (predicate(value))
-                    {
-                        hasLast = true;
-                        last = value;
-                    }
-                }
-            }
-            finally
-            {
-                await e.DisposeAsync().ConfigureAwait(false);
-            }
-#endif
 
             return hasLast ? new Maybe<TSource>(last) : new Maybe<TSource>();
         }
@@ -175,7 +136,6 @@ namespace System.Linq
             var last = default(TSource);
             var hasLast = false;
 
-#if USE_AWAIT_FOREACH
             await foreach (TSource item in source.WithCancellation(cancellationToken).ConfigureAwait(false))
             {
                 if (await predicate(item).ConfigureAwait(false))
@@ -184,27 +144,6 @@ namespace System.Linq
                     last = item;
                 }
             }
-#else
-            var e = source.GetAsyncEnumerator(cancellationToken);
-
-            try
-            {
-                while (await e.MoveNextAsync().ConfigureAwait(false))
-                {
-                    var value = e.Current;
-
-                    if (await predicate(value).ConfigureAwait(false))
-                    {
-                        hasLast = true;
-                        last = value;
-                    }
-                }
-            }
-            finally
-            {
-                await e.DisposeAsync().ConfigureAwait(false);
-            }
-#endif
 
             return hasLast ? new Maybe<TSource>(last) : new Maybe<TSource>();
         }
@@ -215,7 +154,6 @@ namespace System.Linq
             var last = default(TSource);
             var hasLast = false;
 
-#if USE_AWAIT_FOREACH
             await foreach (TSource item in source.WithCancellation(cancellationToken).ConfigureAwait(false))
             {
                 if (await predicate(item, cancellationToken).ConfigureAwait(false))
@@ -224,27 +162,6 @@ namespace System.Linq
                     last = item;
                 }
             }
-#else
-            var e = source.GetAsyncEnumerator(cancellationToken);
-
-            try
-            {
-                while (await e.MoveNextAsync().ConfigureAwait(false))
-                {
-                    var value = e.Current;
-
-                    if (await predicate(value, cancellationToken).ConfigureAwait(false))
-                    {
-                        hasLast = true;
-                        last = value;
-                    }
-                }
-            }
-            finally
-            {
-                await e.DisposeAsync().ConfigureAwait(false);
-            }
-#endif
 
             return hasLast ? new Maybe<TSource>(last) : new Maybe<TSource>();
         }

Ix.NET/Source/System.Linq.Async/System/Linq/Operators/LongCount.cs

@@ -21,7 +21,6 @@ namespace System.Linq
             {
                 var count = 0L;
 
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     checked
@@ -29,24 +28,6 @@ namespace System.Linq
                         count++;
                     }
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        checked
-                        {
-                            count++;
-                        }
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return count;
             }
@@ -65,7 +46,6 @@ namespace System.Linq
             {
                 var count = 0L;
 
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     if (_predicate(item))
@@ -76,27 +56,6 @@ namespace System.Linq
                         }
                     }
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        if (_predicate(e.Current))
-                        {
-                            checked
-                            {
-                                count++;
-                            }
-                        }
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return count;
             }
@@ -115,7 +74,6 @@ namespace System.Linq
             {
                 var count = 0L;
 
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     if (await _predicate(item).ConfigureAwait(false))
@@ -126,27 +84,6 @@ namespace System.Linq
                         }
                     }
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        if (await _predicate(e.Current).ConfigureAwait(false))
-                        {
-                            checked
-                            {
-                                count++;
-                            }
-                        }
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return count;
             }
@@ -166,7 +103,6 @@ namespace System.Linq
             {
                 var count = 0L;
 
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     if (await _predicate(item, _cancellationToken).ConfigureAwait(false))
@@ -177,27 +113,6 @@ namespace System.Linq
                         }
                     }
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        if (await _predicate(e.Current, _cancellationToken).ConfigureAwait(false))
-                        {
-                            checked
-                            {
-                                count++;
-                            }
-                        }
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return count;
             }

Ix.NET/Source/System.Linq.Async/System/Linq/Operators/Lookup.cs

@@ -91,7 +91,6 @@ namespace System.Linq.Internal
 
             var lookup = new Lookup<TKey, TElement>(comparer);
 
-#if USE_AWAIT_FOREACH
             await foreach (TSource item in source.WithCancellation(cancellationToken).ConfigureAwait(false))
             {
                 var key = keySelector(item);
@@ -100,27 +99,6 @@ namespace System.Linq.Internal
                 var element = elementSelector(item);
                 group.Add(element);
             }
-#else
-            var enu = source.GetAsyncEnumerator(cancellationToken);
-
-            try
-            {
-                while (await enu.MoveNextAsync().ConfigureAwait(false))
-                {
-                    var item = enu.Current;
-
-                    var key = keySelector(item);
-                    var group = lookup.GetGrouping(key, create: true);
-
-                    var element = elementSelector(item);
-                    group.Add(element);
-                }
-            }
-            finally
-            {
-                await enu.DisposeAsync().ConfigureAwait(false);
-            }
-#endif
 
             return lookup;
         }
@@ -132,30 +110,11 @@ namespace System.Linq.Internal
 
             var lookup = new Lookup<TKey, TElement>(comparer);
 
-#if USE_AWAIT_FOREACH
             await foreach (TElement item in source.WithCancellation(cancellationToken).ConfigureAwait(false))
             {
                 var key = keySelector(item);
                 lookup.GetGrouping(key, create: true).Add(item);
             }
-#else
-            var enu = source.GetAsyncEnumerator(cancellationToken);
-
-            try
-            {
-                while (await enu.MoveNextAsync().ConfigureAwait(false))
-                {
-                    var item = enu.Current;
-
-                    var key = keySelector(item);
-                    lookup.GetGrouping(key, create: true).Add(item);
-                }
-            }
-            finally
-            {
-                await enu.DisposeAsync().ConfigureAwait(false);
-            }
-#endif
 
             return lookup;
         }
@@ -164,7 +123,6 @@ namespace System.Linq.Internal
         {
             var lookup = new Lookup<TKey, TElement>(comparer);
 
-#if USE_AWAIT_FOREACH
             await foreach (TElement item in source.WithCancellation(cancellationToken).ConfigureAwait(false))
             {
                 var key = keySelector(item);
@@ -173,27 +131,6 @@ namespace System.Linq.Internal
                     lookup.GetGrouping(key, create: true).Add(item);
                 }
             }
-#else
-            var enu = source.GetAsyncEnumerator(cancellationToken);
-
-            try
-            {
-                while (await enu.MoveNextAsync().ConfigureAwait(false))
-                {
-                    var item = enu.Current;
-
-                    var key = keySelector(item);
-                    if (key != null)
-                    {
-                        lookup.GetGrouping(key, create: true).Add(item);
-                    }
-                }
-            }
-            finally
-            {
-                await enu.DisposeAsync().ConfigureAwait(false);
-            }
-#endif
 
             return lookup;
         }
@@ -419,7 +356,6 @@ namespace System.Linq.Internal
 
             var lookup = new LookupWithTask<TKey, TElement>(comparer);
 
-#if USE_AWAIT_FOREACH
             await foreach (TSource item in source.WithCancellation(cancellationToken).ConfigureAwait(false))
             {
                 var key = await keySelector(item).ConfigureAwait(false);
@@ -428,27 +364,6 @@ namespace System.Linq.Internal
                 var element = await elementSelector(item).ConfigureAwait(false);
                 group.Add(element);
             }
-#else
-            var enu = source.GetAsyncEnumerator(cancellationToken);
-
-            try
-            {
-                while (await enu.MoveNextAsync().ConfigureAwait(false))
-                {
-                    var item = enu.Current;
-
-                    var key = await keySelector(item).ConfigureAwait(false);
-                    var group = lookup.GetGrouping(key, create: true);
-
-                    var element = await elementSelector(item).ConfigureAwait(false);
-                    group.Add(element);
-                }
-            }
-            finally
-            {
-                await enu.DisposeAsync().ConfigureAwait(false);
-            }
-#endif
 
             return lookup;
         }
@@ -462,7 +377,6 @@ namespace System.Linq.Internal
 
             var lookup = new LookupWithTask<TKey, TElement>(comparer);
 
-#if USE_AWAIT_FOREACH
             await foreach (TSource item in source.WithCancellation(cancellationToken).ConfigureAwait(false))
             {
                 var key = await keySelector(item, cancellationToken).ConfigureAwait(false);
@@ -471,27 +385,6 @@ namespace System.Linq.Internal
                 var element = await elementSelector(item, cancellationToken).ConfigureAwait(false);
                 group.Add(element);
             }
-#else
-            var enu = source.GetAsyncEnumerator(cancellationToken);
-
-            try
-            {
-                while (await enu.MoveNextAsync().ConfigureAwait(false))
-                {
-                    var item = enu.Current;
-
-                    var key = await keySelector(item, cancellationToken).ConfigureAwait(false);
-                    var group = lookup.GetGrouping(key, create: true);
-
-                    var element = await elementSelector(item, cancellationToken).ConfigureAwait(false);
-                    group.Add(element);
-                }
-            }
-            finally
-            {
-                await enu.DisposeAsync().ConfigureAwait(false);
-            }
-#endif
 
             return lookup;
         }
@@ -504,30 +397,11 @@ namespace System.Linq.Internal
 
             var lookup = new LookupWithTask<TKey, TElement>(comparer);
 
-#if USE_AWAIT_FOREACH
             await foreach (TElement item in source.WithCancellation(cancellationToken).ConfigureAwait(false))
             {
                 var key = await keySelector(item).ConfigureAwait(false);
                 lookup.GetGrouping(key, create: true).Add(item);
             }
-#else
-            var enu = source.GetAsyncEnumerator(cancellationToken);
-
-            try
-            {
-                while (await enu.MoveNextAsync().ConfigureAwait(false))
-                {
-                    var item = enu.Current;
-
-                    var key = await keySelector(item).ConfigureAwait(false);
-                    lookup.GetGrouping(key, create: true).Add(item);
-                }
-            }
-            finally
-            {
-                await enu.DisposeAsync().ConfigureAwait(false);
-            }
-#endif
 
             return lookup;
         }
@@ -540,30 +414,11 @@ namespace System.Linq.Internal
 
             var lookup = new LookupWithTask<TKey, TElement>(comparer);
 
-#if USE_AWAIT_FOREACH
             await foreach (TElement item in source.WithCancellation(cancellationToken).ConfigureAwait(false))
             {
                 var key = await keySelector(item, cancellationToken).ConfigureAwait(false);
                 lookup.GetGrouping(key, create: true).Add(item);
             }
-#else
-            var enu = source.GetAsyncEnumerator(cancellationToken);
-
-            try
-            {
-                while (await enu.MoveNextAsync().ConfigureAwait(false))
-                {
-                    var item = enu.Current;
-
-                    var key = await keySelector(item, cancellationToken).ConfigureAwait(false);
-                    lookup.GetGrouping(key, create: true).Add(item);
-                }
-            }
-            finally
-            {
-                await enu.DisposeAsync().ConfigureAwait(false);
-            }
-#endif
 
             return lookup;
         }
@@ -573,7 +428,6 @@ namespace System.Linq.Internal
         {
             var lookup = new LookupWithTask<TKey, TElement>(comparer);
 
-#if USE_AWAIT_FOREACH
             await foreach (TElement item in source.WithCancellation(cancellationToken).ConfigureAwait(false))
             {
                 var key = await keySelector(item).ConfigureAwait(false);
@@ -582,27 +436,6 @@ namespace System.Linq.Internal
                     lookup.GetGrouping(key, create: true).Add(item);
                 }
             }
-#else
-            var enu = source.GetAsyncEnumerator(cancellationToken);
-
-            try
-            {
-                while (await enu.MoveNextAsync().ConfigureAwait(false))
-                {
-                    var item = enu.Current;
-
-                    var key = await keySelector(item).ConfigureAwait(false);
-                    if (key != null)
-                    {
-                        lookup.GetGrouping(key, create: true).Add(item);
-                    }
-                }
-            }
-            finally
-            {
-                await enu.DisposeAsync().ConfigureAwait(false);
-            }
-#endif
 
             return lookup;
         }
@@ -612,7 +445,6 @@ namespace System.Linq.Internal
         {
             var lookup = new LookupWithTask<TKey, TElement>(comparer);
 
-#if USE_AWAIT_FOREACH
             await foreach (TElement item in source.WithCancellation(cancellationToken).ConfigureAwait(false))
             {
                 var key = await keySelector(item, cancellationToken).ConfigureAwait(false);
@@ -621,27 +453,6 @@ namespace System.Linq.Internal
                     lookup.GetGrouping(key, create: true).Add(item);
                 }
             }
-#else
-            var enu = source.GetAsyncEnumerator(cancellationToken);
-
-            try
-            {
-                while (await enu.MoveNextAsync().ConfigureAwait(false))
-                {
-                    var item = enu.Current;
-
-                    var key = await keySelector(item, cancellationToken).ConfigureAwait(false);
-                    if (key != null)
-                    {
-                        lookup.GetGrouping(key, create: true).Add(item);
-                    }
-                }
-            }
-            finally
-            {
-                await enu.DisposeAsync().ConfigureAwait(false);
-            }
-#endif
 
             return lookup;
         }

Ix.NET/Source/System.Linq.Async/System/Linq/Operators/SelectMany.cs

@@ -402,7 +402,6 @@ namespace System.Linq
                 {
                     var count = 0;
 
-#if USE_AWAIT_FOREACH
                     await foreach (var element in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                     {
                         checked
@@ -410,24 +409,6 @@ namespace System.Linq
                             count += await _selector(element).CountAsync().ConfigureAwait(false);
                         }
                     }
-#else
-                    var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                    try
-                    {
-                        while (await e.MoveNextAsync().ConfigureAwait(false))
-                        {
-                            checked
-                            {
-                                count += await _selector(e.Current).CountAsync().ConfigureAwait(false);
-                            }
-                        }
-                    }
-                    finally
-                    {
-                        await e.DisposeAsync().ConfigureAwait(false);
-                    }
-#endif
 
                     return count;
                 }
@@ -446,30 +427,12 @@ namespace System.Linq
             {
                 var list = new List<TResult>();
 
-#if USE_AWAIT_FOREACH
                 await foreach (var element in _source.WithCancellation(cancellationToken).ConfigureAwait(false))
                 {
                     var items = _selector(element);
 
                     await list.AddRangeAsync(items, cancellationToken).ConfigureAwait(false);
                 }
-#else
-                var e = _source.GetAsyncEnumerator(cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        var items = _selector(e.Current);
-
-                        await list.AddRangeAsync(items, cancellationToken).ConfigureAwait(false);
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return list;
             }
@@ -578,7 +541,6 @@ namespace System.Linq
                 {
                     var count = 0;
 
-#if USE_AWAIT_FOREACH
                     await foreach (var element in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                     {
                         var items = await _selector(element).ConfigureAwait(false);
@@ -588,26 +550,6 @@ namespace System.Linq
                             count += await items.CountAsync().ConfigureAwait(false);
                         }
                     }
-#else
-                    var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                    try
-                    {
-                        while (await e.MoveNextAsync().ConfigureAwait(false))
-                        {
-                            var items = await _selector(e.Current).ConfigureAwait(false);
-
-                            checked
-                            {
-                                count += await items.CountAsync().ConfigureAwait(false);
-                            }
-                        }
-                    }
-                    finally
-                    {
-                        await e.DisposeAsync().ConfigureAwait(false);
-                    }
-#endif
 
                     return count;
                 }
@@ -626,30 +568,12 @@ namespace System.Linq
             {
                 var list = new List<TResult>();
 
-#if USE_AWAIT_FOREACH
                 await foreach (var element in _source.WithCancellation(cancellationToken).ConfigureAwait(false))
                 {
                     var items = await _selector(element).ConfigureAwait(false);
 
                     await list.AddRangeAsync(items, cancellationToken).ConfigureAwait(false);
                 }
-#else
-                var e = _source.GetAsyncEnumerator(cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        var items = await _selector(e.Current).ConfigureAwait(false);
-
-                        await list.AddRangeAsync(items, cancellationToken).ConfigureAwait(false);
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return list;
             }
@@ -759,7 +683,6 @@ namespace System.Linq
                 {
                     var count = 0;
 
-#if USE_AWAIT_FOREACH
                     await foreach (var element in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                     {
                         var items = await _selector(element, _cancellationToken).ConfigureAwait(false);
@@ -769,26 +692,6 @@ namespace System.Linq
                             count += await items.CountAsync().ConfigureAwait(false);
                         }
                     }
-#else
-                    var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                    try
-                    {
-                        while (await e.MoveNextAsync().ConfigureAwait(false))
-                        {
-                            var items = await _selector(e.Current, _cancellationToken).ConfigureAwait(false);
-
-                            checked
-                            {
-                                count += await items.CountAsync().ConfigureAwait(false);
-                            }
-                        }
-                    }
-                    finally
-                    {
-                        await e.DisposeAsync().ConfigureAwait(false);
-                    }
-#endif
 
                     return count;
                 }
@@ -807,30 +710,12 @@ namespace System.Linq
             {
                 var list = new List<TResult>();
 
-#if USE_AWAIT_FOREACH
                 await foreach (var element in _source.WithCancellation(cancellationToken).ConfigureAwait(false))
                 {
                     var items = await _selector(element, cancellationToken).ConfigureAwait(false);
 
                     await list.AddRangeAsync(items, cancellationToken).ConfigureAwait(false);
                 }
-#else
-                var e = _source.GetAsyncEnumerator(cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        var items = await _selector(e.Current, cancellationToken).ConfigureAwait(false);
-
-                        await list.AddRangeAsync(items, cancellationToken).ConfigureAwait(false);
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return list;
             }

Ix.NET/Source/System.Linq.Async/System/Linq/Operators/Sum.Generated.tt

@@ -46,7 +46,6 @@ foreach (var o in os)
             {
                 var sum = <#=o.zero#>;
 
-#if USE_AWAIT_FOREACH
                 await foreach (<#=o.type#> value in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
 <#
@@ -67,37 +66,6 @@ else
 }
 #>
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-<#
-if (o.@checked)
-{
-#>
-                        checked
-                        {
-                            sum += e.Current<#=n#>;
-                        }
-<#
-}
-else
-{
-#>
-                        sum += e.Current<#=n#>;
-<#
-}
-#>
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return sum;
             }
@@ -116,7 +84,6 @@ else
             {
                 var sum = <#=o.zero#>;
 
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     var value = _selector(item);
@@ -139,39 +106,6 @@ else
 }
 #>
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        var value = _selector(e.Current);
-
-<#
-if (o.@checked)
-{
-#>
-                        checked
-                        {
-                            sum += value<#=n#>;
-                        }
-<#
-}
-else
-{
-#>
-                        sum += value<#=n#>;
-<#
-}
-#>
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return sum;
             }
@@ -190,7 +124,6 @@ else
             {
                 var sum = <#=o.zero#>;
 
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     var value = await _selector(item).ConfigureAwait(false);
@@ -213,39 +146,6 @@ else
 }
 #>
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        var value = await _selector(e.Current).ConfigureAwait(false);
-
-<#
-if (o.@checked)
-{
-#>
-                        checked
-                        {
-                            sum += value<#=n#>;
-                        }
-<#
-}
-else
-{
-#>
-                        sum += value<#=n#>;
-<#
-}
-#>
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return sum;
             }
@@ -265,7 +165,6 @@ else
             {
                 var sum = <#=o.zero#>;
 
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     var value = await _selector(item, _cancellationToken).ConfigureAwait(false);
@@ -288,39 +187,6 @@ else
 }
 #>
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        var value = await _selector(e.Current, _cancellationToken).ConfigureAwait(false);
-
-<#
-if (o.@checked)
-{
-#>
-                        checked
-                        {
-                            sum += value<#=n#>;
-                        }
-<#
-}
-else
-{
-#>
-                        sum += value<#=n#>;
-<#
-}
-#>
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return sum;
             }

Ix.NET/Source/System.Linq.Async/System/Linq/Operators/ToDictionary.cs

@@ -26,32 +26,12 @@ namespace System.Linq
             {
                 var d = new Dictionary<TKey, TSource>(_comparer);
 
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     var key = _keySelector(item);
 
                     d.Add(key, item);
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        var item = e.Current;
-
-                        var key = _keySelector(item);
-
-                        d.Add(key, item);
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return d;
             }
@@ -73,32 +53,12 @@ namespace System.Linq
             {
                 var d = new Dictionary<TKey, TSource>(_comparer);
 
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     var key = await _keySelector(item).ConfigureAwait(false);
 
                     d.Add(key, item);
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        var item = e.Current;
-
-                        var key = await _keySelector(item).ConfigureAwait(false);
-
-                        d.Add(key, item);
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return d;
             }
@@ -121,32 +81,12 @@ namespace System.Linq
             {
                 var d = new Dictionary<TKey, TSource>(_comparer);
 
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     var key = await _keySelector(item, _cancellationToken).ConfigureAwait(false);
 
                     d.Add(key, item);
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        var item = e.Current;
-
-                        var key = await _keySelector(item, _cancellationToken).ConfigureAwait(false);
-
-                        d.Add(key, item);
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return d;
             }
@@ -171,7 +111,6 @@ namespace System.Linq
             {
                 var d = new Dictionary<TKey, TElement>(_comparer);
 
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     var key = _keySelector(item);
@@ -179,26 +118,6 @@ namespace System.Linq
 
                     d.Add(key, value);
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        var item = e.Current;
-
-                        var key = _keySelector(item);
-                        var value = _elementSelector(item);
-
-                        d.Add(key, value);
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return d;
             }
@@ -222,7 +141,6 @@ namespace System.Linq
             {
                 var d = new Dictionary<TKey, TElement>(_comparer);
 
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     var key = await _keySelector(item).ConfigureAwait(false);
@@ -230,26 +148,6 @@ namespace System.Linq
 
                     d.Add(key, value);
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        var item = e.Current;
-
-                        var key = await _keySelector(item).ConfigureAwait(false);
-                        var value = await _elementSelector(item).ConfigureAwait(false);
-
-                        d.Add(key, value);
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return d;
             }
@@ -274,7 +172,6 @@ namespace System.Linq
             {
                 var d = new Dictionary<TKey, TElement>(_comparer);
 
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     var key = await _keySelector(item, _cancellationToken).ConfigureAwait(false);
@@ -282,26 +179,6 @@ namespace System.Linq
 
                     d.Add(key, value);
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        var item = e.Current;
-
-                        var key = await _keySelector(item, _cancellationToken).ConfigureAwait(false);
-                        var value = await _elementSelector(item, _cancellationToken).ConfigureAwait(false);
-
-                        d.Add(key, value);
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return d;
             }

Ix.NET/Source/System.Linq.Async/System/Linq/Operators/ToHashSet.cs

@@ -24,26 +24,10 @@ namespace System.Linq
             {
                 var set = new HashSet<TSource>(_comparer);
 
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     set.Add(item);
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        set.Add(e.Current);
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return set;
             }

Ix.NET/Source/System.Linq.Async/System/Linq/Operators/ToList.cs

@@ -24,26 +24,10 @@ namespace System.Linq
             {
                 var list = new List<TSource>();
 
-#if USE_AWAIT_FOREACH
                 await foreach (TSource item in _source.WithCancellation(_cancellationToken).ConfigureAwait(false))
                 {
                     list.Add(item);
                 }
-#else
-                var e = _source.GetAsyncEnumerator(_cancellationToken);
-
-                try
-                {
-                    while (await e.MoveNextAsync().ConfigureAwait(false))
-                    {
-                        list.Add(e.Current);
-                    }
-                }
-                finally
-                {
-                    await e.DisposeAsync().ConfigureAwait(false);
-                }
-#endif
 
                 return list;
             }

Ix.NET/Source/System.Linq.Async/System/Linq/Operators/Union.cs

@@ -162,26 +162,10 @@ namespace System.Linq
                         return set;
                     }
 
-#if USE_AWAIT_FOREACH
                     await foreach (TSource item in enumerable.WithCancellation(cancellationToken).ConfigureAwait(false))
                     {
                         set.Add(item);
                     }
-#else
-                    var e = enumerable.GetAsyncEnumerator(cancellationToken);
-
-                    try
-                    {
-                        while (await e.MoveNextAsync().ConfigureAwait(false))
-                        {
-                            set.Add(e.Current);
-                        }
-                    }
-                    finally
-                    {
-                        await e.DisposeAsync().ConfigureAwait(false);
-                    }
-#endif
                 }
             }
 

Ix.NET/Source/System.Linq.Async/System/Linq/Operators/Utilities.cs

@@ -38,26 +38,10 @@ namespace System.Linq
                 }
             }
 
-#if USE_AWAIT_FOREACH
             await foreach (var item in collection.WithCancellation(cancellationToken).ConfigureAwait(false))
             {
                 list.Add(item);
             }
-#else
-            var e = collection.GetAsyncEnumerator(cancellationToken);
-
-            try
-            {
-                while (await e.MoveNextAsync().ConfigureAwait(false))
-                {
-                    list.Add(e.Current);
-                }
-            }
-            finally
-            {
-                await e.DisposeAsync().ConfigureAwait(false);
-            }
-#endif
         }
     }
 }