Fix CS0169 and Could not load file or assembly Microsoft.Bcl.AsyncInterfaces

Author: timcassell

samples/BenchmarkDotNet.Samples/BenchmarkDotNet.Samples.csproj

@@ -26,6 +26,7 @@
     <PackageReference Include="System.IO.Hashing" Version="$(SihVersion)" />
   </ItemGroup>
   <ItemGroup>
+    <PackageReference Include="Microsoft.Bcl.AsyncInterfaces" Version="10.0.1" />
     <PackageReference Include="System.Drawing.Common" Version="10.0.1" />
     <!-- The Test SDK is required only for the VSTest Adapter to work -->
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.0.1" />

src/BenchmarkDotNet/Code/CodeGenerator.cs

@@ -32,13 +32,16 @@ internal static string Generate(BuildPartition buildPartition, CodeGenBenchmarkR
             {
                 var benchmark = buildInfo.BenchmarkCase;
 
-                string benchmarkTypeCode = GetDeclarationsProvider(benchmark)
+                var declarationsProvider = GetDeclarationsProvider(benchmark);
+                var extraFields = declarationsProvider.GetExtraFields();
+
+                string benchmarkTypeCode = declarationsProvider
                     .ReplaceTemplate(new SmartStringBuilder(ResourceHelper.LoadTemplate("BenchmarkType.txt")))
                     .Replace("$ID$", buildInfo.Id.ToString())
                     .Replace("$JobSetDefinition$", GetJobsSetDefinition(benchmark))
                     .Replace("$ParamsContent$", GetParamsContent(benchmark))
                     .Replace("$ArgumentsDefinition$", GetArgumentsDefinition(benchmark))
-                    .Replace("$DeclareArgumentFields$", GetDeclareArgumentFields(benchmark))
+                    .Replace("$DeclareFieldsContainer$", GetDeclareFieldsContainer(benchmark, buildInfo.Id, extraFields))
                     .Replace("$InitializeArgumentFields$", GetInitializeArgumentFields(benchmark))
                     .Replace("$EngineFactoryType$", GetEngineFactoryTypeName(benchmark))
                     .Replace("$RunExtraIteration$", buildInfo.Config.HasExtraIterationDiagnoser(benchmark) ? "true" : "false")
@@ -144,11 +147,48 @@ private static string GetArgumentsDefinition(BenchmarkCase benchmarkCase)
                 benchmarkCase.Descriptor.WorkloadMethod.GetParameters()
                     .Select((parameter, index) => $"{GetParameterModifier(parameter)} {parameter.ParameterType.GetCorrectCSharpTypeName()} arg{index}"));
 
-        private static string GetDeclareArgumentFields(BenchmarkCase benchmarkCase)
-            => string.Join(
-                Environment.NewLine,
-                benchmarkCase.Descriptor.WorkloadMethod.GetParameters()
-                    .Select((parameter, index) => $"public {GetFieldType(parameter.ParameterType, benchmarkCase.Parameters.GetArgument(parameter.Name!)).GetCorrectCSharpTypeName()} __argField{index};"));
+        private static string GetDeclareFieldsContainer(BenchmarkCase benchmarkCase, BenchmarkId benchmarkId, string[] extraFields)
+        {
+            var fields = benchmarkCase.Descriptor.WorkloadMethod.GetParameters()
+                .Select((parameter, index) => $"public {GetFieldType(parameter.ParameterType, benchmarkCase.Parameters.GetArgument(parameter.Name!)).GetCorrectCSharpTypeName()} __argField{index};")
+                .Concat(extraFields)
+                .ToArray();
+
+            // Prevent CS0169
+            if (fields.Length == 0)
+            {
+                return string.Empty;
+            }
+
+            // Wrapper struct is necessary because of error CS4004: Cannot await in an unsafe context
+            var sb = new StringBuilder();
+            sb.AppendLine("""
+                    [global::System.Runtime.InteropServices.StructLayout(global::System.Runtime.InteropServices.LayoutKind.Auto)]
+                    private unsafe struct FieldsContainer
+                    {
+            """);
+            foreach (var field in fields)
+            {
+                sb.AppendLine($"            {field}");
+            }
+            sb.AppendLine("            }");
+            sb.AppendLine();
+            sb.AppendLine($"        private global::BenchmarkDotNet.Autogenerated.Runnable_{benchmarkId.Value}.FieldsContainer __fieldsContainer;");
+            return sb.ToString();
+        }
+
+        /*
+         
+        [global::System.Runtime.InteropServices.StructLayout(global::System.Runtime.InteropServices.LayoutKind.Auto)]
+        private unsafe struct FieldsContainer
+        {
+            $DeclareArgumentFields$
+            $ExtraFields$
+        }
+
+        private global::BenchmarkDotNet.Autogenerated.Runnable_$ID$.FieldsContainer __fieldsContainer;
+        
+         */
 
         private static string GetInitializeArgumentFields(BenchmarkCase benchmarkCase)
             => string.Join(

src/BenchmarkDotNet/Code/DeclarationsProvider.cs

@@ -26,6 +26,8 @@ internal abstract class DeclarationsProvider(BenchmarkCase benchmark)
         protected BenchmarkCase Benchmark { get; } = benchmark;
         protected Descriptor Descriptor => Benchmark.Descriptor;
 
+        public abstract string[] GetExtraFields();
+
         public SmartStringBuilder ReplaceTemplate(SmartStringBuilder smartStringBuilder)
         {
             Replace(smartStringBuilder, Descriptor.GlobalSetupMethod, "$GlobalSetupModifiers$", "$GlobalSetupImpl$", false);
@@ -98,6 +100,8 @@ protected string GetPassArgumentsDirect()
 
     internal class SyncDeclarationsProvider(BenchmarkCase benchmark) : DeclarationsProvider(benchmark)
     {
+        public override string[] GetExtraFields() => [];
+
         protected override string PrependExtraGlobalCleanupImpl(string impl) => impl;
 
         protected override SmartStringBuilder ReplaceCore(SmartStringBuilder smartStringBuilder)
@@ -152,7 +156,6 @@ protected override SmartStringBuilder ReplaceCore(SmartStringBuilder smartString
             """;
 
             return smartStringBuilder
-                .Replace("$ExtraFields$", string.Empty)
                 .Replace("$CoreImpl$", coreImpl);
         }
 
@@ -177,6 +180,13 @@ private string GetPassArguments()
 
     internal class AsyncDeclarationsProvider(BenchmarkCase benchmark) : DeclarationsProvider(benchmark)
     {
+        public override string[] GetExtraFields() =>
+        [
+            $"public {typeof(WorkloadContinuerAndValueTaskSource).GetCorrectCSharpTypeName()} workloadContinuerAndValueTaskSource;",
+            $"public {typeof(IClock).GetCorrectCSharpTypeName()} clock;",
+            "public long invokeCount;"
+        ];
+
         protected override string PrependExtraGlobalCleanupImpl(string impl)
             => $"""
             this.__fieldsContainer.workloadContinuerAndValueTaskSource?.Complete();
@@ -263,11 +273,6 @@ private async void __StartWorkload()
             """;
 
             return smartStringBuilder
-                .Replace("$ExtraFields$", $"""
-                    public {typeof(WorkloadContinuerAndValueTaskSource).GetCorrectCSharpTypeName()} workloadContinuerAndValueTaskSource;
-                                public global::Perfolizer.Horology.IClock clock;
-                                public long invokeCount;
-                    """)
                 .Replace("$CoreImpl$", coreImpl);
         }
 

src/BenchmarkDotNet/Templates/BenchmarkType.txt

@@ -68,15 +68,7 @@
             $ParamsContent$
         }
 
-        // Necessary because of error CS4004: Cannot await in an unsafe context
-        [global::System.Runtime.InteropServices.StructLayout(global::System.Runtime.InteropServices.LayoutKind.Auto)]
-        private unsafe struct FieldsContainer
-        {
-            $DeclareArgumentFields$
-            $ExtraFields$
-        }
-
-        private global::BenchmarkDotNet.Autogenerated.Runnable_$ID$.FieldsContainer __fieldsContainer;
+        $DeclareFieldsContainer$
 
         private $GlobalSetupModifiers$ global::System.Threading.Tasks.ValueTask __GlobalSetup()
         {