Add varargs async test with Task and ValueTask<int>

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

src/tests/async/varargs/varargs.cs

@@ -0,0 +1,80 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.Runtime.CompilerServices;
+using System.Threading.Tasks;
+using Xunit;
+
+public class Async2Varargs
+{
+    [Fact]
+    public static void TestTaskDirectCall()
+    {
+        TaskWithArglist(42, __arglist(100, 200)).Wait();
+    }
+
+    [Fact]
+    public static void TestTaskAwait()
+    {
+        TestTaskAwaitAsync().Wait();
+    }
+
+    private static async Task TestTaskAwaitAsync()
+    {
+        await TaskWithArglist(42, __arglist(100, 200));
+    }
+
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    private static async Task TaskWithArglist(int fixedArg, __arglist)
+    {
+        await Task.Yield();
+        Assert.Equal(42, fixedArg);
+
+        ArgIterator args = new ArgIterator(__arglist);
+        Assert.Equal(2, args.GetRemainingCount());
+
+        int arg1 = __refvalue(args.GetNextArg(), int);
+        int arg2 = __refvalue(args.GetNextArg(), int);
+
+        Assert.Equal(100, arg1);
+        Assert.Equal(200, arg2);
+    }
+
+    [Fact]
+    public static void TestValueTaskDirectCall()
+    {
+        int result = ValueTaskWithArglist(42, __arglist(100, 200)).Result;
+        Assert.Equal(342, result);
+    }
+
+    [Fact]
+    public static void TestValueTaskAwait()
+    {
+        TestValueTaskAwaitAsync().Wait();
+    }
+
+    private static async Task TestValueTaskAwaitAsync()
+    {
+        int result = await ValueTaskWithArglist(42, __arglist(100, 200));
+        Assert.Equal(342, result);
+    }
+
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    private static async ValueTask<int> ValueTaskWithArglist(int fixedArg, __arglist)
+    {
+        await Task.Yield();
+        Assert.Equal(42, fixedArg);
+
+        ArgIterator args = new ArgIterator(__arglist);
+        Assert.Equal(2, args.GetRemainingCount());
+
+        int arg1 = __refvalue(args.GetNextArg(), int);
+        int arg2 = __refvalue(args.GetNextArg(), int);
+
+        Assert.Equal(100, arg1);
+        Assert.Equal(200, arg2);
+
+        return fixedArg + arg1 + arg2;
+    }
+}

src/tests/async/varargs/varargs.csproj

@@ -0,0 +1,5 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <ItemGroup>
+    <Compile Include="$(MSBuildProjectName).cs" />
+  </ItemGroup>
+</Project>