Add OverloadResolutionPriorityAttribute to AsyncEnumerable overloads with CancellationToken

Co-authored-by: stephentoub <[email protected]>

Author: Copilot

src/libraries/System.Linq.AsyncEnumerable/src/System.Linq.AsyncEnumerable.csproj

@@ -88,10 +88,15 @@
     <Compile Include="System\Linq\Sequence.cs" />
   </ItemGroup>
 
-  <ItemGroup Condition="!$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net9.0'))">
+  <ItemGroup>
     <Compile Include="$(CoreLibSharedDir)System\Runtime\CompilerServices\OverloadResolutionPriorityAttribute.cs" />
   </ItemGroup>
 
+  <PropertyGroup>
+    <!-- Suppress warning about duplicate OverloadResolutionPriorityAttribute when building for net10.0 -->
+    <NoWarn>$(NoWarn);CS0436</NoWarn>
+  </PropertyGroup>
+
   <ItemGroup Condition="'$(TargetFramework)' == '$(NetCoreAppCurrent)'">
     <ProjectReference Include="$(LibrariesProjectRoot)System.Collections\src\System.Collections.csproj" />
     <ProjectReference Include="$(LibrariesProjectRoot)System.Linq\src\System.Linq.csproj" />

src/libraries/System.Linq.AsyncEnumerable/src/System/Linq/AggregateAsync.cs

@@ -60,6 +60,7 @@ static async ValueTask<TSource> Impl(
         /// <exception cref="ArgumentNullException"><paramref name="source"/> is <see langword="null"/>.</exception>
         /// <exception cref="ArgumentNullException"><paramref name="func"/> is <see langword="null"/>.</exception>
         /// <exception cref="InvalidOperationException"><paramref name="source"/> contains no elements.</exception>
+        [OverloadResolutionPriority(1)]
         public static ValueTask<TSource> AggregateAsync<TSource>(
             this IAsyncEnumerable<TSource> source,
             Func<TSource, TSource, CancellationToken, ValueTask<TSource>> func,
@@ -139,6 +140,7 @@ static async ValueTask<TAccumulate> Impl(
         /// <returns>The final accumulator value.</returns>
         /// <exception cref="ArgumentNullException"><paramref name="source"/> is <see langword="null"/>.</exception>
         /// <exception cref="ArgumentNullException"><paramref name="func"/> is <see langword="null"/>.</exception>
+        [OverloadResolutionPriority(1)]
         public static ValueTask<TAccumulate> AggregateAsync<TSource, TAccumulate>(
             this IAsyncEnumerable<TSource> source, TAccumulate seed,
             Func<TAccumulate, TSource, CancellationToken, ValueTask<TAccumulate>> func,
@@ -229,6 +231,7 @@ static async ValueTask<TResult> Impl(
         /// <exception cref="ArgumentNullException"><paramref name="source"/> is <see langword="null"/>.</exception>
         /// <exception cref="ArgumentNullException"><paramref name="func"/> is <see langword="null"/>.</exception>
         /// <exception cref="ArgumentNullException"><paramref name="resultSelector"/> is <see langword="null"/>.</exception>
+        [OverloadResolutionPriority(1)]
         public static ValueTask<TResult> AggregateAsync<TSource, TAccumulate, TResult>(
             this IAsyncEnumerable<TSource> source,
             TAccumulate seed,

src/libraries/System.Linq.AsyncEnumerable/src/System/Linq/AggregateBy.cs

@@ -101,6 +101,7 @@ static async IAsyncEnumerable<KeyValuePair<TKey, TAccumulate>> Impl(
         /// <exception cref="ArgumentNullException"><paramref name="source"/> is <see langword="null"/>.</exception>
         /// <exception cref="ArgumentNullException"><paramref name="keyComparer"/> is <see langword="null"/>.</exception>
         /// <exception cref="ArgumentNullException"><paramref name="func"/> is <see langword="null"/>.</exception>
+        [OverloadResolutionPriority(1)]
         public static IAsyncEnumerable<KeyValuePair<TKey, TAccumulate>> AggregateBy<TSource, TKey, TAccumulate>(
             this IAsyncEnumerable<TSource> source,
             Func<TSource, CancellationToken, ValueTask<TKey>> keySelector,
@@ -240,6 +241,7 @@ static async IAsyncEnumerable<KeyValuePair<TKey, TAccumulate>> Impl(
         /// <exception cref="ArgumentNullException"><paramref name="keyComparer"/> is <see langword="null"/>.</exception>
         /// <exception cref="ArgumentNullException"><paramref name="seedSelector"/> is <see langword="null"/>.</exception>
         /// <exception cref="ArgumentNullException"><paramref name="func"/> is <see langword="null"/>.</exception>
+        [OverloadResolutionPriority(1)]
         public static IAsyncEnumerable<KeyValuePair<TKey, TAccumulate>> AggregateBy<TSource, TKey, TAccumulate>(
             this IAsyncEnumerable<TSource> source,
             Func<TSource, CancellationToken, ValueTask<TKey>> keySelector,

src/libraries/System.Linq.AsyncEnumerable/src/System/Linq/AllAsync.cs

@@ -21,6 +21,7 @@ public static partial class AsyncEnumerable
         /// </returns>
         /// <exception cref="ArgumentNullException"><paramref name="source"/> is <see langword="null"/>.</exception>
         /// <exception cref="ArgumentNullException"><paramref name="predicate"/> is <see langword="null"/>.</exception>
+        [OverloadResolutionPriority(1)]
         public static ValueTask<bool> AllAsync<TSource>(
             this IAsyncEnumerable<TSource> source,
             Func<TSource, bool> predicate,

src/libraries/System.Linq.AsyncEnumerable/src/System/Linq/AnyAsync.cs

@@ -16,6 +16,7 @@ public static partial class AsyncEnumerable
         /// <param name="cancellationToken">The <see cref="CancellationToken"/> to monitor for cancellation requests. The default is <see cref="CancellationToken.None"/>.</param>
         /// <returns><see langword="true"/> if the source sequence contains any elements; otherwise, <see langword="false"/>.</returns>
         /// <exception cref="ArgumentNullException"><paramref name="source"/> is <see langword="null"/>.</exception>
+        [OverloadResolutionPriority(1)]
         public static ValueTask<bool> AnyAsync<TSource>(
             this IAsyncEnumerable<TSource> source,
             CancellationToken cancellationToken = default)

src/libraries/System.Linq.AsyncEnumerable/src/System/Linq/CountAsync.cs

@@ -17,6 +17,7 @@ public static partial class AsyncEnumerable
         /// <returns>The number of elements in the input sequence.</returns>
         /// <exception cref="ArgumentNullException"><paramref name="source"/> is <see langword="null"/>.</exception>
         /// <exception cref="OverflowException">The number of elements in source is larger than <see cref="int.MaxValue"/> (via the returned task).</exception>
+        [OverloadResolutionPriority(1)]
         public static ValueTask<int> CountAsync<TSource>(
             this IAsyncEnumerable<TSource> source,
             CancellationToken cancellationToken = default)
@@ -118,6 +119,7 @@ static async ValueTask<int> Impl(
         /// <param name="cancellationToken">The <see cref="CancellationToken"/> to monitor for cancellation requests. The default is <see cref="CancellationToken.None"/>.</param>
         /// <returns>The number of elements in the input sequence that satisfy the condition in the predicate function.</returns>
         /// <exception cref="ArgumentNullException"><paramref name="source"/> is <see langword="null"/>.</exception>
+        [OverloadResolutionPriority(1)]
         public static ValueTask<long> LongCountAsync<TSource>(
             this IAsyncEnumerable<TSource> source,
             CancellationToken cancellationToken = default)

src/libraries/System.Linq.AsyncEnumerable/src/System/Linq/CountBy.cs

@@ -71,6 +71,7 @@ static async IAsyncEnumerable<KeyValuePair<TKey, int>> Impl(
         /// <returns>An enumerable containing the frequencies of each key occurrence in <paramref name="source"/>.</returns>
         /// <exception cref="ArgumentNullException"><paramref name="source"/> is <see langword="null"/>.</exception>
         /// <exception cref="ArgumentNullException"><paramref name="keySelector"/> is <see langword="null"/>.</exception>
+        [OverloadResolutionPriority(1)]
         public static IAsyncEnumerable<KeyValuePair<TKey, int>> CountBy<TSource, TKey>(
             this IAsyncEnumerable<TSource> source,
             Func<TSource, CancellationToken, ValueTask<TKey>> keySelector,

src/libraries/System.Linq.AsyncEnumerable/src/System/Linq/DistinctBy.cs

@@ -74,6 +74,7 @@ static async IAsyncEnumerable<TSource> Impl(
         /// </remarks>
         /// <exception cref="ArgumentNullException"><paramref name="source"/> is <see langword="null"/>.</exception>
         /// <exception cref="ArgumentNullException"><paramref name="keySelector"/> is <see langword="null"/>.</exception>
+        [OverloadResolutionPriority(1)]
         public static IAsyncEnumerable<TSource> DistinctBy<TSource, TKey>(
             this IAsyncEnumerable<TSource> source,
             Func<TSource, CancellationToken, ValueTask<TKey>> keySelector,

src/libraries/System.Linq.AsyncEnumerable/src/System/Linq/ExceptBy.cs

@@ -83,6 +83,7 @@ static async IAsyncEnumerable<TSource> Impl(
         /// <exception cref="ArgumentNullException"><paramref name="first"/> is <see langword="null"/>.</exception>
         /// <exception cref="ArgumentNullException"><paramref name="second"/> is <see langword="null"/>.</exception>
         /// <exception cref="ArgumentNullException"><paramref name="keySelector"/> is <see langword="null"/>.</exception>
+        [OverloadResolutionPriority(1)]
         public static IAsyncEnumerable<TSource> ExceptBy<TSource, TKey>(
             this IAsyncEnumerable<TSource> first,
             IAsyncEnumerable<TKey> second,

src/libraries/System.Linq.AsyncEnumerable/src/System/Linq/FirstAsync.cs

@@ -91,6 +91,7 @@ static async ValueTask<TSource> Impl(
         /// The source sequence is empty, or no element in the sequence satisfies
         /// the condition in predicate (via the returned task).
         /// </exception>
+        [OverloadResolutionPriority(1)]
         public static ValueTask<TSource> FirstAsync<TSource>(
             this IAsyncEnumerable<TSource> source,
             Func<TSource, CancellationToken, ValueTask<bool>> predicate,
@@ -185,6 +186,7 @@ static async ValueTask<TSource> Impl(
         /// </returns>
         /// <exception cref="ArgumentNullException"><paramref name="source" /> is <see langword="null" />.</exception>
         /// <exception cref="ArgumentNullException"><paramref name="predicate" /> is <see langword="null" />.</exception>
+        [OverloadResolutionPriority(1)]
         public static ValueTask<TSource?> FirstOrDefaultAsync<TSource>(
             this IAsyncEnumerable<TSource> source,
             Func<TSource, CancellationToken, ValueTask<bool>> predicate,
@@ -237,6 +239,7 @@ static async ValueTask<TSource> Impl(
         /// <returns><paramref name="defaultValue" /> if <paramref name="source" /> is empty or if no element passes the test specified by <paramref name="predicate" />; otherwise, the first element in <paramref name="source" /> that passes the test specified by <paramref name="predicate" />.</returns>
         /// <exception cref="ArgumentNullException"><paramref name="source" /> is <see langword="null" />.</exception>
         /// <exception cref="ArgumentNullException"><paramref name="predicate" /> is <see langword="null" />.</exception>
+        [OverloadResolutionPriority(1)]
         public static ValueTask<TSource> FirstOrDefaultAsync<TSource>(
             this IAsyncEnumerable<TSource> source,
             Func<TSource, CancellationToken, ValueTask<bool>> predicate,