Callbacks of the Switch methods are flagged with InstantHandleAttribute

Author: PawelGerr

Directory.Build.props

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <Copyright>(c) $([System.DateTime]::Now.Year), Pawel Gerr. All rights reserved.</Copyright>
-    <VersionPrefix>9.6.2</VersionPrefix>
+    <VersionPrefix>9.7.0</VersionPrefix>
     <Authors>Pawel Gerr</Authors>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <PackageProjectUrl>https://github.com/PawelGerr/Thinktecture.Runtime.Extensions</PackageProjectUrl>

docs

@@ -449,7 +449,7 @@ private void GenerateSwitchForAction(bool withState, bool isPartially)
       if (isPartially)
       {
          _sb.Append(@"
-         global::System.Action<");
+         [global::JetBrains.Annotations.InstantHandleAttribute] global::System.Action<");
 
          if (withState)
             _sb.Append("TState, ");
@@ -465,7 +465,7 @@ private void GenerateSwitchForAction(bool withState, bool isPartially)
             _sb.Append(",");
 
          _sb.Append(@"
-         global::System.Action<");
+         [global::JetBrains.Annotations.InstantHandleAttribute] global::System.Action<");
 
          if (withState)
             _sb.Append("TState, ");
@@ -607,7 +607,7 @@ private void GenerateSwitchForFunc(bool withState, bool isPartially)
       if (isPartially)
       {
          _sb.Append(@"
-         global::System.Func<");
+         [global::JetBrains.Annotations.InstantHandleAttribute] global::System.Func<");
 
          if (withState)
             _sb.Append("TState, ");
@@ -625,7 +625,7 @@ private void GenerateSwitchForFunc(bool withState, bool isPartially)
          _sb.Append(@"
          ");
 
-         _sb.Append("global::System.Func<");
+         _sb.Append("[global::JetBrains.Annotations.InstantHandleAttribute] global::System.Func<");
 
          if (withState)
             _sb.Append("TState, ");

src/Thinktecture.Runtime.Extensions.SourceGenerator/CodeAnalysis/AdHocUnions/AdHocUnionCodeGenerator.cs

@@ -6,7 +6,7 @@ namespace Thinktecture.CodeAnalysis.AdHocUnions;
 public class AdHocUnionSourceGenerator : ThinktectureSourceGeneratorBase, IIncrementalGenerator
 {
    public AdHocUnionSourceGenerator()
-      : base(15_000)
+      : base(20_000)
    {
    }
 

src/Thinktecture.Runtime.Extensions.SourceGenerator/CodeAnalysis/AdHocUnions/AdHocUnionSourceGenerator.cs

@@ -0,0 +1,89 @@
+namespace Thinktecture.CodeAnalysis.Annotations;
+
+[Generator]
+public class AnnotationsSourceGenerator : ThinktectureSourceGeneratorBase, IIncrementalGenerator
+{
+   public AnnotationsSourceGenerator()
+      : base(1)
+   {
+   }
+
+   public void Initialize(IncrementalGeneratorInitializationContext context)
+   {
+      var options = GetGeneratorOptions(context);
+
+      var annotationsCheck = context.MetadataReferencesProvider
+                                    .Select((reference, _) => HasJetbrainsAnnotations(reference))
+                                    .Collect();
+
+      context.RegisterSourceOutput(
+         annotationsCheck.Combine(options)
+                         .SelectMany((tuple, _) => tuple.Left.Any(hasAnnotations => hasAnnotations) || !tuple.Right.GenerateJetbrainsAnnotations ? ImmutableArray<bool>.Empty : [false]),
+         (ctx, _) => AddAnnotations(ctx));
+   }
+
+   private bool HasJetbrainsAnnotations(MetadataReference reference)
+   {
+      try
+      {
+         return reference.GetModules().Any(module => module.Name == "JetBrains.Annotations.dll");
+      }
+      catch
+      {
+         return false;
+      }
+   }
+
+   private void AddAnnotations(SourceProductionContext ctx)
+   {
+      ctx.AddSource("Thinktecture.Annotations.g.cs",
+                    """
+                    /* MIT License
+
+                    Copyright (c) 2025 JetBrains http://www.jetbrains.com
+
+                    Permission is hereby granted, free of charge, to any person obtaining a copy
+                    of this software and associated documentation files (the "Software"), to deal
+                    in the Software without restriction, including without limitation the rights
+                    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+                    copies of the Software, and to permit persons to whom the Software is
+                    furnished to do so, subject to the following conditions:
+
+                    The above copyright notice and this permission notice shall be included in all
+                    copies or substantial portions of the Software.
+
+                    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+                    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+                    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+                    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+                    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+                    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+                    SOFTWARE. */
+
+                    using System;
+
+                    // ReSharper disable once CheckNamespace
+                    namespace JetBrains.Annotations;
+
+                    /// <summary>
+                    /// Tells the code analysis engine if the parameter is completely handled when the invoked method is on stack.
+                    /// If the parameter is of the delegate type - indicates that the delegate can only be invoked during the method
+                    /// execution. The delegate can be invoked zero or multiple times, but not stored to some field and invoked later,
+                    /// when the containing method is no longer on the execution stack.
+                    /// If the parameter is of the enumerable type - indicates that it is enumerated while the method is executed.
+                    /// If <see cref="RequireAwait"/> is true - the attribute will only take effect if the method invocation
+                    /// is located under the <c>await</c> expression.
+                    /// </summary>
+                    [AttributeUsage(AttributeTargets.Parameter)]
+                    internal sealed class InstantHandleAttribute : Attribute
+                    {
+                       /// <summary>
+                       /// Requires the method invocation to be used under the <c>await</c> expression for this attribute to take effect.
+                       /// Can be used for delegate/enumerable parameters of <c>async</c> methods.
+                       /// </summary>
+                       public bool RequireAwait { get; set; }
+                    }
+                    """
+      );
+   }
+}

src/Thinktecture.Runtime.Extensions.SourceGenerator/CodeAnalysis/Annotations/AnnotationsSourceGenerator.cs

@@ -36,6 +36,7 @@ public static class Methods
    public static class Configuration
    {
       public const string COUNTER = "build_property.ThinktectureRuntimeExtensions_SourceGenerator_Counter";
+      public const string GENERATE_JETBRAINS_ANNOTATIONS = "build_property.ThinktectureRuntimeExtensions_SourceGenerator_GenerateJetBrainsAnnotations";
       public const string LOG_FILE_PATH = "build_property.ThinktectureRuntimeExtensions_SourceGenerator_LogFilePath";
       public const string LOG_FILE_PATH_UNIQUE = "build_property.ThinktectureRuntimeExtensions_SourceGenerator_LogFilePathMustBeUnique";
       public const string LOG_LEVEL = "build_property.ThinktectureRuntimeExtensions_SourceGenerator_LogLevel";

src/Thinktecture.Runtime.Extensions.SourceGenerator/CodeAnalysis/Constants.cs

@@ -3,13 +3,15 @@ namespace Thinktecture.CodeAnalysis;
 public sealed class GeneratorOptions : IEquatable<GeneratorOptions>
 {
    public bool CounterEnabled { get; }
+   public bool GenerateJetbrainsAnnotations { get; }
    public LoggingOptions? Logging { get; }
 
-   public GeneratorOptions(
-      bool counterEnabled,
-      LoggingOptions? logging)
+   public GeneratorOptions(bool counterEnabled,
+                           bool generateJetbrainsAnnotations,
+                           LoggingOptions? logging)
    {
       CounterEnabled = counterEnabled;
+      GenerateJetbrainsAnnotations = generateJetbrainsAnnotations;
       Logging = logging;
    }
 
@@ -22,6 +24,7 @@ public bool Equals(GeneratorOptions? other)
          return true;
 
       return CounterEnabled == other.CounterEnabled
+             && GenerateJetbrainsAnnotations == other.GenerateJetbrainsAnnotations
              && Logging.EqualsTo(other.Logging);
    }
 
@@ -34,7 +37,9 @@ public override int GetHashCode()
    {
       unchecked
       {
-         return (CounterEnabled.GetHashCode() * 397) ^ Logging.GetHashCode();
+         return (CounterEnabled.GetHashCode() * 397)
+                ^ (GenerateJetbrainsAnnotations.GetHashCode() * 397)
+                ^ Logging.GetHashCode();
       }
    }
 }

src/Thinktecture.Runtime.Extensions.SourceGenerator/CodeAnalysis/GeneratorOptions.cs

@@ -266,7 +266,7 @@ private void GenerateSwitchForAction(bool withState, bool isPartially, IReadOnly
       if (isPartially)
       {
          _sb.Append(@"
-      global::System.Action<");
+      [global::JetBrains.Annotations.InstantHandleAttribute] global::System.Action<");
 
          if (withState)
             _sb.Append("TState, ");
@@ -282,7 +282,7 @@ private void GenerateSwitchForAction(bool withState, bool isPartially, IReadOnly
             _sb.Append(",");
 
          _sb.Append(@"
-      global::System.Action<");
+      [global::JetBrains.Annotations.InstantHandleAttribute] global::System.Action<");
 
          if (withState)
             _sb.Append("TState, ");
@@ -425,7 +425,7 @@ private void GenerateSwitchForFunc(bool withState, bool isPartially, IReadOnlyLi
       if (isPartially)
       {
          _sb.Append(@"
-      global::System.Func<");
+      [global::JetBrains.Annotations.InstantHandleAttribute] global::System.Func<");
 
          if (withState)
             _sb.Append("TState, ");
@@ -441,7 +441,7 @@ private void GenerateSwitchForFunc(bool withState, bool isPartially, IReadOnlyLi
             _sb.Append(",");
 
          _sb.Append(@"
-      global::System.Func<");
+      [global::JetBrains.Annotations.InstantHandleAttribute] global::System.Func<");
 
          if (withState)
             _sb.Append("TState, ");

src/Thinktecture.Runtime.Extensions.SourceGenerator/CodeAnalysis/RegularUnions/RegularUnionCodeGenerator.cs

@@ -6,7 +6,7 @@ namespace Thinktecture.CodeAnalysis.RegularUnions;
 public class RegularUnionSourceGenerator : ThinktectureSourceGeneratorBase, IIncrementalGenerator
 {
    public RegularUnionSourceGenerator()
-      : base(20_000)
+      : base(25_000)
    {
    }
 

src/Thinktecture.Runtime.Extensions.SourceGenerator/CodeAnalysis/RegularUnions/RegularUnionSourceGenerator.cs

@@ -424,7 +424,7 @@ private void GenerateSwitchForAction(bool withState, bool isPartially)
       if (isPartially)
       {
          _sb.Append(@"
-         global::System.Action<");
+         [global::JetBrains.Annotations.InstantHandleAttribute] global::System.Action<");
 
          if (withState)
             _sb.Append("TState, ");
@@ -438,7 +438,7 @@ private void GenerateSwitchForAction(bool withState, bool isPartially)
             _sb.Append(",");
 
          _sb.Append(@"
-         global::System.Action");
+         [global::JetBrains.Annotations.InstantHandleAttribute] global::System.Action");
 
          if (withState)
             _sb.Append("<TState>");
@@ -568,7 +568,7 @@ private void GenerateSwitchForFunc(bool withState, bool isPartially)
       if (isPartially)
       {
          _sb.Append(@"
-         global::System.Func<");
+         [global::JetBrains.Annotations.InstantHandleAttribute] global::System.Func<");
 
          if (withState)
             _sb.Append("TState, ");
@@ -584,7 +584,7 @@ private void GenerateSwitchForFunc(bool withState, bool isPartially)
          _sb.Append(@"
          ");
 
-         _sb.Append("global::System.Func<");
+         _sb.Append("[global::JetBrains.Annotations.InstantHandleAttribute] global::System.Func<");
 
          if (withState)
             _sb.Append("TState, ");