AsyncEnumerable.FirstOrDefault*Async: Fix signature for nullable.

Ix.NET/Source/System.Linq.Async.Queryable/System/Linq/AsyncQueryable.Generated.cs

@@ -1210,62 +1210,62 @@ namespace System.Linq
         
         private static MethodInfo? FirstOrDefaultAsync__TSource__2__0(Type TSource) =>
             (s_FirstOrDefaultAsync__TSource__2__0 ??
-            (s_FirstOrDefaultAsync__TSource__2__0 = new Func<IAsyncQueryable<object>, CancellationToken, ValueTask<object>>(FirstOrDefaultAsync<object>).GetMethodInfo()!.GetGenericMethodDefinition())).MakeGenericMethod(TSource);
+            (s_FirstOrDefaultAsync__TSource__2__0 = new Func<IAsyncQueryable<object>, CancellationToken, ValueTask<object?>>(FirstOrDefaultAsync<object>).GetMethodInfo()!.GetGenericMethodDefinition())).MakeGenericMethod(TSource);
 
-        public static ValueTask<TSource> FirstOrDefaultAsync<TSource>(this IAsyncQueryable<TSource> source, CancellationToken cancellationToken = default)
+        public static ValueTask<TSource?> FirstOrDefaultAsync<TSource>(this IAsyncQueryable<TSource> source, CancellationToken cancellationToken = default)
         {
             if (source == null)
                 throw new ArgumentNullException(nameof(source));
 
-            return source.Provider.ExecuteAsync<TSource>(Expression.Call(FirstOrDefaultAsync__TSource__2__0(typeof(TSource)), source.Expression, Expression.Constant(cancellationToken, typeof(CancellationToken))), cancellationToken);
+            return source.Provider.ExecuteAsync<TSource?>(Expression.Call(FirstOrDefaultAsync__TSource__2__0(typeof(TSource)), source.Expression, Expression.Constant(cancellationToken, typeof(CancellationToken))), cancellationToken);
         }
 
         private static MethodInfo? s_FirstOrDefaultAsync__TSource__3__0;
         
         private static MethodInfo? FirstOrDefaultAsync__TSource__3__0(Type TSource) =>
             (s_FirstOrDefaultAsync__TSource__3__0 ??
-            (s_FirstOrDefaultAsync__TSource__3__0 = new Func<IAsyncQueryable<object>, Expression<Func<object, bool>>, CancellationToken, ValueTask<object>>(FirstOrDefaultAsync<object>).GetMethodInfo()!.GetGenericMethodDefinition())).MakeGenericMethod(TSource);
+            (s_FirstOrDefaultAsync__TSource__3__0 = new Func<IAsyncQueryable<object>, Expression<Func<object, bool>>, CancellationToken, ValueTask<object?>>(FirstOrDefaultAsync<object>).GetMethodInfo()!.GetGenericMethodDefinition())).MakeGenericMethod(TSource);
 
-        public static ValueTask<TSource> FirstOrDefaultAsync<TSource>(this IAsyncQueryable<TSource> source, Expression<Func<TSource, bool>> predicate, CancellationToken cancellationToken = default)
+        public static ValueTask<TSource?> FirstOrDefaultAsync<TSource>(this IAsyncQueryable<TSource> source, Expression<Func<TSource, bool>> predicate, CancellationToken cancellationToken = default)
         {
             if (source == null)
                 throw new ArgumentNullException(nameof(source));
             if (predicate == null)
                 throw new ArgumentNullException(nameof(predicate));
 
-            return source.Provider.ExecuteAsync<TSource>(Expression.Call(FirstOrDefaultAsync__TSource__3__0(typeof(TSource)), source.Expression, predicate, Expression.Constant(cancellationToken, typeof(CancellationToken))), cancellationToken);
+            return source.Provider.ExecuteAsync<TSource?>(Expression.Call(FirstOrDefaultAsync__TSource__3__0(typeof(TSource)), source.Expression, predicate, Expression.Constant(cancellationToken, typeof(CancellationToken))), cancellationToken);
         }
 
         private static MethodInfo? s_FirstOrDefaultAwaitAsync__TSource__3__0;
         
         private static MethodInfo? FirstOrDefaultAwaitAsync__TSource__3__0(Type TSource) =>
             (s_FirstOrDefaultAwaitAsync__TSource__3__0 ??
-            (s_FirstOrDefaultAwaitAsync__TSource__3__0 = new Func<IAsyncQueryable<object>, Expression<Func<object, ValueTask<bool>>>, CancellationToken, ValueTask<object>>(FirstOrDefaultAwaitAsync<object>).GetMethodInfo()!.GetGenericMethodDefinition())).MakeGenericMethod(TSource);
+            (s_FirstOrDefaultAwaitAsync__TSource__3__0 = new Func<IAsyncQueryable<object>, Expression<Func<object, ValueTask<bool>>>, CancellationToken, ValueTask<object?>>(FirstOrDefaultAwaitAsync<object>).GetMethodInfo()!.GetGenericMethodDefinition())).MakeGenericMethod(TSource);
 
-        public static ValueTask<TSource> FirstOrDefaultAwaitAsync<TSource>(this IAsyncQueryable<TSource> source, Expression<Func<TSource, ValueTask<bool>>> predicate, CancellationToken cancellationToken = default)
+        public static ValueTask<TSource?> FirstOrDefaultAwaitAsync<TSource>(this IAsyncQueryable<TSource> source, Expression<Func<TSource, ValueTask<bool>>> predicate, CancellationToken cancellationToken = default)
         {
             if (source == null)
                 throw new ArgumentNullException(nameof(source));
             if (predicate == null)
                 throw new ArgumentNullException(nameof(predicate));
 
-            return source.Provider.ExecuteAsync<TSource>(Expression.Call(FirstOrDefaultAwaitAsync__TSource__3__0(typeof(TSource)), source.Expression, predicate, Expression.Constant(cancellationToken, typeof(CancellationToken))), cancellationToken);
+            return source.Provider.ExecuteAsync<TSource?>(Expression.Call(FirstOrDefaultAwaitAsync__TSource__3__0(typeof(TSource)), source.Expression, predicate, Expression.Constant(cancellationToken, typeof(CancellationToken))), cancellationToken);
         }
 
         private static MethodInfo? s_FirstOrDefaultAwaitWithCancellationAsync__TSource__3__0;
         
         private static MethodInfo? FirstOrDefaultAwaitWithCancellationAsync__TSource__3__0(Type TSource) =>
             (s_FirstOrDefaultAwaitWithCancellationAsync__TSource__3__0 ??
-            (s_FirstOrDefaultAwaitWithCancellationAsync__TSource__3__0 = new Func<IAsyncQueryable<object>, Expression<Func<object, CancellationToken, ValueTask<bool>>>, CancellationToken, ValueTask<object>>(FirstOrDefaultAwaitWithCancellationAsync<object>).GetMethodInfo()!.GetGenericMethodDefinition())).MakeGenericMethod(TSource);
+            (s_FirstOrDefaultAwaitWithCancellationAsync__TSource__3__0 = new Func<IAsyncQueryable<object>, Expression<Func<object, CancellationToken, ValueTask<bool>>>, CancellationToken, ValueTask<object?>>(FirstOrDefaultAwaitWithCancellationAsync<object>).GetMethodInfo()!.GetGenericMethodDefinition())).MakeGenericMethod(TSource);
 
-        public static ValueTask<TSource> FirstOrDefaultAwaitWithCancellationAsync<TSource>(this IAsyncQueryable<TSource> source, Expression<Func<TSource, CancellationToken, ValueTask<bool>>> predicate, CancellationToken cancellationToken = default)
+        public static ValueTask<TSource?> FirstOrDefaultAwaitWithCancellationAsync<TSource>(this IAsyncQueryable<TSource> source, Expression<Func<TSource, CancellationToken, ValueTask<bool>>> predicate, CancellationToken cancellationToken = default)
         {
             if (source == null)
                 throw new ArgumentNullException(nameof(source));
             if (predicate == null)
                 throw new ArgumentNullException(nameof(predicate));
 
-            return source.Provider.ExecuteAsync<TSource>(Expression.Call(FirstOrDefaultAwaitWithCancellationAsync__TSource__3__0(typeof(TSource)), source.Expression, predicate, Expression.Constant(cancellationToken, typeof(CancellationToken))), cancellationToken);
+            return source.Provider.ExecuteAsync<TSource?>(Expression.Call(FirstOrDefaultAwaitWithCancellationAsync__TSource__3__0(typeof(TSource)), source.Expression, predicate, Expression.Constant(cancellationToken, typeof(CancellationToken))), cancellationToken);
         }
 
         private static MethodInfo? s_GroupBy__TSource_TKey__2__0;

Ix.NET/Source/System.Linq.Async/System/Linq/AsyncEnumerable.AsyncOverloads.cs

@@ -28,7 +28,7 @@ namespace System.Linq
         public static ValueTask<decimal?> AverageAsync<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, ValueTask<decimal?>> selector, CancellationToken cancellationToken = default) => AverageAwaitAsyncCore<TSource>(source, selector, cancellationToken);
         public static ValueTask<int> CountAsync<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, ValueTask<bool>> predicate, CancellationToken cancellationToken = default) => CountAwaitAsyncCore<TSource>(source, predicate, cancellationToken);
         public static ValueTask<TSource> FirstAsync<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, ValueTask<bool>> predicate, CancellationToken cancellationToken = default) => FirstAwaitAsyncCore<TSource>(source, predicate, cancellationToken);
-        public static ValueTask<TSource> FirstOrDefaultAsync<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, ValueTask<bool>> predicate, CancellationToken cancellationToken = default) => FirstOrDefaultAwaitAsyncCore<TSource>(source, predicate, cancellationToken);
+        public static ValueTask<TSource?> FirstOrDefaultAsync<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, ValueTask<bool>> predicate, CancellationToken cancellationToken = default) => FirstOrDefaultAwaitAsyncCore<TSource>(source, predicate, cancellationToken);
         public static Task ForEachAsync<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, Task> action, CancellationToken cancellationToken = default) => ForEachAwaitAsyncCore<TSource>(source, action, cancellationToken);
         public static Task ForEachAsync<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, int, Task> action, CancellationToken cancellationToken = default) => ForEachAwaitAsyncCore<TSource>(source, action, cancellationToken);
         public static IAsyncEnumerable<IAsyncGrouping<TKey, TSource>> GroupBy<TSource, TKey>(this IAsyncEnumerable<TSource> source, Func<TSource, ValueTask<TKey>> keySelector) => GroupByAwaitCore<TSource, TKey>(source, keySelector);
@@ -128,7 +128,7 @@ namespace System.Linq
         public static ValueTask<decimal?> AverageAsync<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, CancellationToken, ValueTask<decimal?>> selector, CancellationToken cancellationToken = default) => AverageAwaitWithCancellationAsyncCore<TSource>(source, selector, cancellationToken);
         public static ValueTask<int> CountAsync<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, CancellationToken, ValueTask<bool>> predicate, CancellationToken cancellationToken = default) => CountAwaitWithCancellationAsyncCore<TSource>(source, predicate, cancellationToken);
         public static ValueTask<TSource> FirstAsync<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, CancellationToken, ValueTask<bool>> predicate, CancellationToken cancellationToken = default) => FirstAwaitWithCancellationAsyncCore<TSource>(source, predicate, cancellationToken);
-        public static ValueTask<TSource> FirstOrDefaultAsync<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, CancellationToken, ValueTask<bool>> predicate, CancellationToken cancellationToken = default) => FirstOrDefaultAwaitWithCancellationAsyncCore<TSource>(source, predicate, cancellationToken);
+        public static ValueTask<TSource?> FirstOrDefaultAsync<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, CancellationToken, ValueTask<bool>> predicate, CancellationToken cancellationToken = default) => FirstOrDefaultAwaitWithCancellationAsyncCore<TSource>(source, predicate, cancellationToken);
         public static Task ForEachAsync<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, CancellationToken, Task> action, CancellationToken cancellationToken) => ForEachAwaitWithCancellationAsyncCore<TSource>(source, action, cancellationToken);
         public static Task ForEachAsync<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, int, CancellationToken, Task> action, CancellationToken cancellationToken) => ForEachAwaitWithCancellationAsyncCore<TSource>(source, action, cancellationToken);
         public static IAsyncEnumerable<IAsyncGrouping<TKey, TSource>> GroupBy<TSource, TKey>(this IAsyncEnumerable<TSource> source, Func<TSource, CancellationToken, ValueTask<TKey>> keySelector) => GroupByAwaitWithCancellationCore<TSource, TKey>(source, keySelector);
@@ -435,7 +435,7 @@ namespace System.Linq
         /// <param name="cancellationToken">An optional cancellation token for cancelling the sequence at any time.</param>
         /// <returns>A ValueTask containing the first element in the sequence that satisfies the predicate, or a default value if no element satisfies the predicate.</returns>
         /// <exception cref="ArgumentNullException"><paramref name="source"/> or <paramref name="predicate"/> is <see langword="null"/>.</exception>
-        public static ValueTask<TSource> FirstOrDefaultAwaitAsync<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, ValueTask<bool>> predicate, CancellationToken cancellationToken = default) => FirstOrDefaultAwaitAsyncCore<TSource>(source, predicate, cancellationToken);
+        public static ValueTask<TSource?> FirstOrDefaultAwaitAsync<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, ValueTask<bool>> predicate, CancellationToken cancellationToken = default) => FirstOrDefaultAwaitAsyncCore<TSource>(source, predicate, cancellationToken);
 
         /// <summary>
         /// Invokes and awaits an asynchronous action on each element in the source sequence, and returns a task that is signaled when the sequence terminates.
@@ -1378,7 +1378,7 @@ namespace System.Linq
         public static ValueTask<decimal?> AverageAwaitWithCancellationAsync<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, CancellationToken, ValueTask<decimal?>> selector, CancellationToken cancellationToken = default) => AverageAwaitWithCancellationAsyncCore<TSource>(source, selector, cancellationToken);
         public static ValueTask<int> CountAwaitWithCancellationAsync<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, CancellationToken, ValueTask<bool>> predicate, CancellationToken cancellationToken = default) => CountAwaitWithCancellationAsyncCore<TSource>(source, predicate, cancellationToken);
         public static ValueTask<TSource> FirstAwaitWithCancellationAsync<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, CancellationToken, ValueTask<bool>> predicate, CancellationToken cancellationToken = default) => FirstAwaitWithCancellationAsyncCore<TSource>(source, predicate, cancellationToken);
-        public static ValueTask<TSource> FirstOrDefaultAwaitWithCancellationAsync<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, CancellationToken, ValueTask<bool>> predicate, CancellationToken cancellationToken = default) => FirstOrDefaultAwaitWithCancellationAsyncCore<TSource>(source, predicate, cancellationToken);
+        public static ValueTask<TSource?> FirstOrDefaultAwaitWithCancellationAsync<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, CancellationToken, ValueTask<bool>> predicate, CancellationToken cancellationToken = default) => FirstOrDefaultAwaitWithCancellationAsyncCore<TSource>(source, predicate, cancellationToken);
         public static Task ForEachAwaitWithCancellationAsync<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, CancellationToken, Task> action, CancellationToken cancellationToken) => ForEachAwaitWithCancellationAsyncCore<TSource>(source, action, cancellationToken);
         public static Task ForEachAwaitWithCancellationAsync<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, int, CancellationToken, Task> action, CancellationToken cancellationToken) => ForEachAwaitWithCancellationAsyncCore<TSource>(source, action, cancellationToken);
         public static IAsyncEnumerable<IAsyncGrouping<TKey, TSource>> GroupByAwaitWithCancellation<TSource, TKey>(this IAsyncEnumerable<TSource> source, Func<TSource, CancellationToken, ValueTask<TKey>> keySelector) => GroupByAwaitWithCancellationCore<TSource, TKey>(source, keySelector);

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

@@ -18,18 +18,18 @@ namespace System.Linq
         /// <param name="cancellationToken">The optional cancellation token to be used for cancelling the sequence at any time.</param>
         /// <returns>ValueTask containing the first element in the async-enumerable sequence, or a default value if no such element exists.</returns>
         /// <exception cref="ArgumentNullException"><paramref name="source"/> is null.</exception>
-        public static ValueTask<TSource> FirstOrDefaultAsync<TSource>(this IAsyncEnumerable<TSource> source, CancellationToken cancellationToken = default)
+        public static ValueTask<TSource?> FirstOrDefaultAsync<TSource>(this IAsyncEnumerable<TSource> source, CancellationToken cancellationToken = default)
         {
             if (source == null)
                 throw Error.ArgumentNull(nameof(source));
 
             return Core(source, cancellationToken);
 
-            static async ValueTask<TSource> Core(IAsyncEnumerable<TSource> source, CancellationToken cancellationToken)
+            static async ValueTask<TSource?> Core(IAsyncEnumerable<TSource> source, CancellationToken cancellationToken)
             {
                 var first = await TryGetFirst(source, cancellationToken).ConfigureAwait(false);
 
-                return first.HasValue ? first.Value : default!;
+                return first.HasValue ? first.Value : default;
             }
         }
 
@@ -42,7 +42,7 @@ namespace System.Linq
         /// <param name="cancellationToken">The optional cancellation token to be used for cancelling the sequence at any time.</param>
         /// <returns>ValueTask containing the first element in the async-enumerable sequence that satisfies the condition in the predicate, or a default value if no such element exists.</returns>
         /// <exception cref="ArgumentNullException"><paramref name="source"/> or <paramref name="predicate"/> is null.</exception>
-        public static ValueTask<TSource> FirstOrDefaultAsync<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, bool> predicate, CancellationToken cancellationToken = default)
+        public static ValueTask<TSource?> FirstOrDefaultAsync<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, bool> predicate, CancellationToken cancellationToken = default)
         {
             if (source == null)
                 throw Error.ArgumentNull(nameof(source));
@@ -51,15 +51,15 @@ namespace System.Linq
 
             return Core(source, predicate, cancellationToken);
 
-            static async ValueTask<TSource> Core(IAsyncEnumerable<TSource> source, Func<TSource, bool> predicate, CancellationToken cancellationToken)
+            static async ValueTask<TSource?> Core(IAsyncEnumerable<TSource> source, Func<TSource, bool> predicate, CancellationToken cancellationToken)
             {
                 var first = await TryGetFirst(source, predicate, cancellationToken).ConfigureAwait(false);
 
-                return first.HasValue ? first.Value : default!;
+                return first.HasValue ? first.Value : default;
             }
         }
 
-        internal static ValueTask<TSource> FirstOrDefaultAwaitAsyncCore<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, ValueTask<bool>> predicate, CancellationToken cancellationToken = default)
+        internal static ValueTask<TSource?> FirstOrDefaultAwaitAsyncCore<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, ValueTask<bool>> predicate, CancellationToken cancellationToken = default)
         {
             if (source == null)
                 throw Error.ArgumentNull(nameof(source));
@@ -68,16 +68,16 @@ namespace System.Linq
 
             return Core(source, predicate, cancellationToken);
 
-            static async ValueTask<TSource> Core(IAsyncEnumerable<TSource> source, Func<TSource, ValueTask<bool>> predicate, CancellationToken cancellationToken)
+            static async ValueTask<TSource?> Core(IAsyncEnumerable<TSource> source, Func<TSource, ValueTask<bool>> predicate, CancellationToken cancellationToken)
             {
                 var first = await TryGetFirst(source, predicate, cancellationToken).ConfigureAwait(false);
 
-                return first.HasValue ? first.Value : default!;
+                return first.HasValue ? first.Value : default;
             }
         }
 
 #if !NO_DEEP_CANCELLATION
-        internal static ValueTask<TSource> FirstOrDefaultAwaitWithCancellationAsyncCore<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, CancellationToken, ValueTask<bool>> predicate, CancellationToken cancellationToken = default)
+        internal static ValueTask<TSource?> FirstOrDefaultAwaitWithCancellationAsyncCore<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, CancellationToken, ValueTask<bool>> predicate, CancellationToken cancellationToken = default)
         {
             if (source == null)
                 throw Error.ArgumentNull(nameof(source));
@@ -86,11 +86,11 @@ namespace System.Linq
 
             return Core(source, predicate, cancellationToken);
 
-            static async ValueTask<TSource> Core(IAsyncEnumerable<TSource> source, Func<TSource, CancellationToken, ValueTask<bool>> predicate, CancellationToken cancellationToken)
+            static async ValueTask<TSource?> Core(IAsyncEnumerable<TSource> source, Func<TSource, CancellationToken, ValueTask<bool>> predicate, CancellationToken cancellationToken)
             {
                 var first = await TryGetFirst(source, predicate, cancellationToken).ConfigureAwait(false);
 
-                return first.HasValue ? first.Value : default!;
+                return first.HasValue ? first.Value : default;
             }
         }
 #endif