Reordering GroupBy overloads.

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

@@ -11,18 +11,26 @@ namespace System.Linq
 {
     public static partial class AsyncEnumerable
     {
-        public static IAsyncEnumerable<IAsyncGrouping<TKey, TElement>> GroupBy<TSource, TKey, TElement>(this IAsyncEnumerable<TSource> source, Func<TSource, TKey> keySelector, Func<TSource, TElement> elementSelector, IEqualityComparer<TKey> comparer)
+        public static IAsyncEnumerable<IAsyncGrouping<TKey, TSource>> GroupBy<TSource, TKey>(this IAsyncEnumerable<TSource> source, Func<TSource, TKey> keySelector)
+        {
+            if (source == null)
+                throw new ArgumentNullException(nameof(source));
+            if (keySelector == null)
+                throw new ArgumentNullException(nameof(keySelector));
+
+            return new GroupedAsyncEnumerable<TSource, TKey>(source, keySelector, EqualityComparer<TKey>.Default);
+        }
+
+        public static IAsyncEnumerable<IAsyncGrouping<TKey, TSource>> GroupBy<TSource, TKey>(this IAsyncEnumerable<TSource> source, Func<TSource, TKey> keySelector, IEqualityComparer<TKey> comparer)
         {
             if (source == null)
                 throw new ArgumentNullException(nameof(source));
             if (keySelector == null)
                 throw new ArgumentNullException(nameof(keySelector));
-            if (elementSelector == null)
-                throw new ArgumentNullException(nameof(elementSelector));
             if (comparer == null)
                 throw new ArgumentNullException(nameof(comparer));
 
-            return new GroupedAsyncEnumerable<TSource, TKey, TElement>(source, keySelector, elementSelector, comparer);
+            return new GroupedAsyncEnumerable<TSource, TKey>(source, keySelector, comparer);
         }
 
         public static IAsyncEnumerable<IAsyncGrouping<TKey, TElement>> GroupBy<TSource, TKey, TElement>(this IAsyncEnumerable<TSource> source, Func<TSource, TKey> keySelector, Func<TSource, TElement> elementSelector)
@@ -37,42 +45,44 @@ namespace System.Linq
             return source.GroupBy(keySelector, elementSelector, EqualityComparer<TKey>.Default);
         }
 
-        public static IAsyncEnumerable<IAsyncGrouping<TKey, TSource>> GroupBy<TSource, TKey>(this IAsyncEnumerable<TSource> source, Func<TSource, TKey> keySelector, IEqualityComparer<TKey> comparer)
+        public static IAsyncEnumerable<IAsyncGrouping<TKey, TElement>> GroupBy<TSource, TKey, TElement>(this IAsyncEnumerable<TSource> source, Func<TSource, TKey> keySelector, Func<TSource, TElement> elementSelector, IEqualityComparer<TKey> comparer)
         {
             if (source == null)
                 throw new ArgumentNullException(nameof(source));
             if (keySelector == null)
                 throw new ArgumentNullException(nameof(keySelector));
+            if (elementSelector == null)
+                throw new ArgumentNullException(nameof(elementSelector));
             if (comparer == null)
                 throw new ArgumentNullException(nameof(comparer));
 
-            return new GroupedAsyncEnumerable<TSource, TKey>(source, keySelector, comparer);
+            return new GroupedAsyncEnumerable<TSource, TKey, TElement>(source, keySelector, elementSelector, comparer);
         }
 
-        public static IAsyncEnumerable<IAsyncGrouping<TKey, TSource>> GroupBy<TSource, TKey>(this IAsyncEnumerable<TSource> source, Func<TSource, TKey> keySelector)
+        public static IAsyncEnumerable<TResult> GroupBy<TSource, TKey, TResult>(this IAsyncEnumerable<TSource> source, Func<TSource, TKey> keySelector, Func<TKey, IAsyncEnumerable<TSource>, TResult> resultSelector)
         {
             if (source == null)
                 throw new ArgumentNullException(nameof(source));
             if (keySelector == null)
                 throw new ArgumentNullException(nameof(keySelector));
+            if (resultSelector == null)
+                throw new ArgumentNullException(nameof(resultSelector));
 
-            return new GroupedAsyncEnumerable<TSource, TKey>(source, keySelector, EqualityComparer<TKey>.Default);
+            return GroupBy(source, keySelector, resultSelector, EqualityComparer<TKey>.Default);
         }
 
-        public static IAsyncEnumerable<TResult> GroupBy<TSource, TKey, TElement, TResult>(this IAsyncEnumerable<TSource> source, Func<TSource, TKey> keySelector, Func<TSource, TElement> elementSelector, Func<TKey, IAsyncEnumerable<TElement>, TResult> resultSelector, IEqualityComparer<TKey> comparer)
+        public static IAsyncEnumerable<TResult> GroupBy<TSource, TKey, TResult>(this IAsyncEnumerable<TSource> source, Func<TSource, TKey> keySelector, Func<TKey, IAsyncEnumerable<TSource>, TResult> resultSelector, IEqualityComparer<TKey> comparer)
         {
             if (source == null)
                 throw new ArgumentNullException(nameof(source));
             if (keySelector == null)
                 throw new ArgumentNullException(nameof(keySelector));
-            if (elementSelector == null)
-                throw new ArgumentNullException(nameof(elementSelector));
             if (resultSelector == null)
                 throw new ArgumentNullException(nameof(resultSelector));
             if (comparer == null)
                 throw new ArgumentNullException(nameof(comparer));
 
-            return source.GroupBy(keySelector, elementSelector, comparer).Select(g => resultSelector(g.Key, g));
+            return new GroupedResultAsyncEnumerable<TSource, TKey, TResult>(source, keySelector, resultSelector, comparer);
         }
 
         public static IAsyncEnumerable<TResult> GroupBy<TSource, TKey, TElement, TResult>(this IAsyncEnumerable<TSource> source, Func<TSource, TKey> keySelector, Func<TSource, TElement> elementSelector, Func<TKey, IAsyncEnumerable<TElement>, TResult> resultSelector)
@@ -89,30 +99,20 @@ namespace System.Linq
             return source.GroupBy(keySelector, elementSelector, EqualityComparer<TKey>.Default).Select(g => resultSelector(g.Key, g));
         }
 
-        public static IAsyncEnumerable<TResult> GroupBy<TSource, TKey, TResult>(this IAsyncEnumerable<TSource> source, Func<TSource, TKey> keySelector, Func<TKey, IAsyncEnumerable<TSource>, TResult> resultSelector, IEqualityComparer<TKey> comparer)
+        public static IAsyncEnumerable<TResult> GroupBy<TSource, TKey, TElement, TResult>(this IAsyncEnumerable<TSource> source, Func<TSource, TKey> keySelector, Func<TSource, TElement> elementSelector, Func<TKey, IAsyncEnumerable<TElement>, TResult> resultSelector, IEqualityComparer<TKey> comparer)
         {
             if (source == null)
                 throw new ArgumentNullException(nameof(source));
             if (keySelector == null)
                 throw new ArgumentNullException(nameof(keySelector));
+            if (elementSelector == null)
+                throw new ArgumentNullException(nameof(elementSelector));
             if (resultSelector == null)
                 throw new ArgumentNullException(nameof(resultSelector));
             if (comparer == null)
                 throw new ArgumentNullException(nameof(comparer));
 
-            return new GroupedResultAsyncEnumerable<TSource, TKey, TResult>(source, keySelector, resultSelector, comparer);
-        }
-
-        public static IAsyncEnumerable<TResult> GroupBy<TSource, TKey, TResult>(this IAsyncEnumerable<TSource> source, Func<TSource, TKey> keySelector, Func<TKey, IAsyncEnumerable<TSource>, TResult> resultSelector)
-        {
-            if (source == null)
-                throw new ArgumentNullException(nameof(source));
-            if (keySelector == null)
-                throw new ArgumentNullException(nameof(keySelector));
-            if (resultSelector == null)
-                throw new ArgumentNullException(nameof(resultSelector));
-
-            return GroupBy(source, keySelector, resultSelector, EqualityComparer<TKey>.Default);
+            return source.GroupBy(keySelector, elementSelector, comparer).Select(g => resultSelector(g.Key, g));
         }
 
         internal sealed class GroupedResultAsyncEnumerable<TSource, TKey, TResult> : AsyncIterator<TResult>, IIListProvider<TResult>