bjornhellander · bjornhellander · Jul 10, 2026
diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
@@ -15,7 +15,7 @@ jobs:
       matrix:
         configuration: [ 'Debug', 'Release' ]
         os: [ 'windows-latest' ]
-        testversion: [ '6', '7', '8', '9', '10', '11', '12', '13', '14' ]
+        testversion: [ '6', '7', '8', '9', '10', '11', '12', '13', '14', '15' ]
       fail-fast: false
 
     runs-on: ${{ matrix.os }}

diff --git a/StyleCop.Analyzers/StyleCop.Analyzers.CodeFixes/Properties/AssemblyInfo.cs b/StyleCop.Analyzers/StyleCop.Analyzers.CodeFixes/Properties/AssemblyInfo.cs
@@ -21,4 +21,5 @@
 [assembly: InternalsVisibleTo("StyleCop.Analyzers.Test.CSharp12")]
 [assembly: InternalsVisibleTo("StyleCop.Analyzers.Test.CSharp13")]
 [assembly: InternalsVisibleTo("StyleCop.Analyzers.Test.CSharp14")]
+[assembly: InternalsVisibleTo("StyleCop.Analyzers.Test.CSharp15")]
 [assembly: InternalsVisibleTo("StyleCopTester")]
diff --git a/....Analyzers/StyleCop.Analyzers.Test.CSharp15/DocumentationRules/SA1600CSharp15UnitTests.cs b/....Analyzers/StyleCop.Analyzers.Test.CSharp15/DocumentationRules/SA1600CSharp15UnitTests.cs
@@ -0,0 +1,59 @@
+// Copyright (c) Contributors to the New StyleCop Analyzers project.
+// Licensed under the MIT License. See LICENSE in the project root for license information.
+
+namespace StyleCop.Analyzers.Test.CSharp15.DocumentationRules
+{
+    using Microsoft.CodeAnalysis.Testing;
+    using StyleCop.Analyzers.Test.CSharp14.DocumentationRules;
+    using static StyleCop.Analyzers.Test.CSharp6.Verifiers.StyleCopCodeFixVerifier<
+        StyleCop.Analyzers.DocumentationRules.SA1600ElementsMustBeDocumented,
+        StyleCop.Analyzers.DocumentationRules.SA1600CodeFixProvider>;
+
+    public partial class SA1600CSharp15UnitTests : SA1600CSharp14UnitTests
+    {
+        protected override DiagnosticResult[] GetExpectedResultTestRegressionMethodGlobalNamespace(string code)
+        {
+            if (code == "public void {|#0:TestMember|}() { }")
+            {
+                return new[]
+                {
+                    // /0/Test0.cs(4,1): error CS0106: The modifier 'public' is not valid for this item
+                    DiagnosticResult.CompilerError("CS0106").WithSpan(4, 1, 4, 7).WithArguments("public"),
+
+                    // /0/Test0.cs(4,1): error CS8805: Program using top-level statements must be an executable.
+                    DiagnosticResult.CompilerError("CS8805").WithSpan(4, 1, 4, 29),
+                };
+            }
+
+            if (code.StartsWith("public string {|#0:this"))
+            {
+                return new[]
+                {
+                    // /0/Test0.cs(4,15): error CS9348: A compilation unit cannot directly contain members such as fields, methods or properties
+                    DiagnosticResult.CompilerError("CS9348").WithSpan(4, 15, 4, 19),
+
+                    Diagnostic().WithLocation(0),
+                };
+            }
+
+            if (code.StartsWith("public string"))
+            {
+                return new[]
+                {
+                    // /0/Test0.cs(4,15): error CS9348: A compilation unit cannot directly contain members such as fields, methods or properties
+                    DiagnosticResult.CompilerError("CS9348").WithSpan(4, 15, 4, 25),
+
+                    Diagnostic().WithLocation(0),
+                };
+            }
+
+            return new[]
+            {
+                // /0/Test0.cs(4,27): error CS9348: A compilation unit cannot directly contain members such as fields, methods or properties
+                DiagnosticResult.CompilerError("CS9348").WithSpan(4, 27, 4, 37),
+
+                Diagnostic().WithLocation(0),
+            };
+        }
+    }
+}
diff --git a/StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp15/Properties/AssemblyInfo.cs b/StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp15/Properties/AssemblyInfo.cs
@@ -0,0 +1,12 @@
+// Copyright (c) Contributors to the New StyleCop Analyzers project.
+// Licensed under the MIT License. See LICENSE in the project root for license information.
+
+using System;
+using System.Runtime.InteropServices;
+
+[assembly: CLSCompliant(false)]
+
+// Setting ComVisible to false makes the types in this assembly not visible
+// to COM components.  If you need to access a type in this assembly from
+// COM, set the ComVisible attribute to true on that type.
+[assembly: ComVisible(false)]
diff --git a/StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp15/StyleCop.Analyzers.Test.CSharp15.csproj b/StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp15/StyleCop.Analyzers.Test.CSharp15.csproj
@@ -0,0 +1,27 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net48</TargetFramework>
+    <OutputType>Exe</OutputType>
+    <EnforceExtendedAnalyzerRules>false</EnforceExtendedAnalyzerRules>
+    <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
+    <GenerateBindingRedirectsOutputType>true</GenerateBindingRedirectsOutputType>
+  </PropertyGroup>
+
+  <PropertyGroup>
+    <CodeAnalysisRuleSet>..\StyleCop.Analyzers.Internal.ruleset</CodeAnalysisRuleSet>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="5.6.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.7.0" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="3.1.5" PrivateAssets="all" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\StyleCop.Analyzers.Test.CSharp14\StyleCop.Analyzers.Test.CSharp14.csproj" />
+    <ProjectReference Include="..\StyleCop.Analyzers.PrivateCodeFixes\StyleCop.Analyzers.PrivateCodeFixes.csproj" PrivateAssets="all" SetTargetFramework="TargetFramework=netstandard2.0" OutputItemType="Analyzer" ReferenceOutputAssembly="false" />
+  </ItemGroup>
+
+</Project>
diff --git a/StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp6/Properties/AssemblyInfo.cs b/StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp6/Properties/AssemblyInfo.cs
@@ -20,3 +20,4 @@
 [assembly: InternalsVisibleTo("StyleCop.Analyzers.Test.CSharp12")]
 [assembly: InternalsVisibleTo("StyleCop.Analyzers.Test.CSharp13")]
 [assembly: InternalsVisibleTo("StyleCop.Analyzers.Test.CSharp14")]
+[assembly: InternalsVisibleTo("StyleCop.Analyzers.Test.CSharp15")]
diff --git a/StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp6/Verifiers/StyleCopCodeFixVerifier`2.cs b/StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp6/Verifiers/StyleCopCodeFixVerifier`2.cs
@@ -368,6 +368,12 @@ private void UpdateGlobalAnalyzerConfig()
             // NOTE: If needed, this method can be temporarily updated to default to a preview version
             private LanguageVersion? GetDefaultLanguageVersion()
             {
+                // Temporary fix since c# 15 is not yet the default language version in the c# 15 test project.
+                if (LightupHelpers.SupportsCSharp15)
+                {
+                    return LanguageVersionEx.Preview;
+                }
+
                 return null;
             }
         }

diff --git a/StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp6/Verifiers/StyleCopDiagnosticVerifier`1.cs b/StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp6/Verifiers/StyleCopDiagnosticVerifier`1.cs
@@ -83,6 +83,12 @@ protected override ParseOptions CreateParseOptions()
             // NOTE: If needed, this method can be temporarily updated to default to a preview version
             private LanguageVersion? GetDefaultLanguageVersion()
             {
+                // Temporary fix since c# 15 is not yet the default language version in the c# 15 test project.
+                if (LightupHelpers.SupportsCSharp15)
+                {
+                    return LanguageVersionEx.Preview;
+                }
+
                 return null;
             }
         }

diff --git a/StyleCop.Analyzers/StyleCop.Analyzers/Lightup/LightupHelpers.cs b/StyleCop.Analyzers/StyleCop.Analyzers/Lightup/LightupHelpers.cs
@@ -58,6 +58,9 @@ private static readonly ConcurrentDictionary<Type, ConcurrentDictionary<Operatio
         public static bool SupportsCSharp14 { get; }
             = Enum.GetNames(typeof(LanguageVersion)).Contains(nameof(LanguageVersionEx.CSharp14));
 
+        public static bool SupportsCSharp15 { get; }
+            = Enum.GetNames(typeof(SyntaxKind)).Contains(nameof(SyntaxKindEx.UnionKeyword));
+
         public static bool SupportsIOperation => SupportsCSharp73;
 
         internal static bool CanWrapObject(object obj, Type underlyingType)

diff --git a/StyleCop.Analyzers/StyleCop.Analyzers/Lightup/SyntaxKindEx.cs b/StyleCop.Analyzers/StyleCop.Analyzers/Lightup/SyntaxKindEx.cs
@@ -17,6 +17,7 @@ internal static class SyntaxKindEx
         public const SyntaxKind UnmanagedKeyword = (SyntaxKind)8446;
         public const SyntaxKind RequiredKeyword = (SyntaxKind)8447;
         public const SyntaxKind FileKeyword = (SyntaxKind)8449;
+        public const SyntaxKind UnionKeyword = (SyntaxKind)8452;
         public const SyntaxKind NullableKeyword = (SyntaxKind)8486;
         public const SyntaxKind EnableKeyword = (SyntaxKind)8487;
         public const SyntaxKind WarningsKeyword = (SyntaxKind)8488;
@@ -74,5 +75,7 @@ internal static class SyntaxKindEx
         public const SyntaxKind RecordStructDeclaration = (SyntaxKind)9068;
         public const SyntaxKind CollectionExpression = (SyntaxKind)9076;
         public const SyntaxKind ExtensionBlockDeclaration = (SyntaxKind)9079;
+        public const SyntaxKind WithElement = (SyntaxKind)9081;
+        public const SyntaxKind UnionDeclaration = (SyntaxKind)9082;
     }
 }
diff --git a/StyleCop.Analyzers/StyleCop.Analyzers/Properties/AssemblyInfo.cs b/StyleCop.Analyzers/StyleCop.Analyzers/Properties/AssemblyInfo.cs
@@ -25,4 +25,5 @@
 [assembly: InternalsVisibleTo("StyleCop.Analyzers.Test.CSharp12")]
 [assembly: InternalsVisibleTo("StyleCop.Analyzers.Test.CSharp13")]
 [assembly: InternalsVisibleTo("StyleCop.Analyzers.Test.CSharp14")]
+[assembly: InternalsVisibleTo("StyleCop.Analyzers.Test.CSharp15")]
 [assembly: InternalsVisibleTo("StyleCopTester")]
diff --git a/StyleCopAnalyzers.sln b/StyleCopAnalyzers.sln
@@ -1,7 +1,7 @@
 
 Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio Version 18
-VisualStudioVersion = 18.6.11828.311 oobstable
+VisualStudioVersion = 18.6.11828.311
 MinimumVisualStudioVersion = 17.0.31903.59
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "StyleCop.Analyzers", "StyleCop.Analyzers\StyleCop.Analyzers\StyleCop.Analyzers.csproj", "{3B052737-06CE-4182-AE0F-08EB82DFA73E}"
 EndProject
@@ -279,6 +279,8 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "StyleCop.Analyzers.Test.CSh
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "StyleCop.Analyzers.Test.CSharp14", "StyleCop.Analyzers\StyleCop.Analyzers.Test.CSharp14\StyleCop.Analyzers.Test.CSharp14.csproj", "{2DBCAA9D-7302-D41B-67F7-3005BCC1281C}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "StyleCop.Analyzers.Test.CSharp15", "StyleCop.Analyzers\StyleCop.Analyzers.Test.CSharp15\StyleCop.Analyzers.Test.CSharp15.csproj", "{F86DD736-F70E-7311-18F0-CDE98C5F03C6}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -349,6 +351,10 @@ Global
 		{2DBCAA9D-7302-D41B-67F7-3005BCC1281C}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{2DBCAA9D-7302-D41B-67F7-3005BCC1281C}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{2DBCAA9D-7302-D41B-67F7-3005BCC1281C}.Release|Any CPU.Build.0 = Release|Any CPU
+		{F86DD736-F70E-7311-18F0-CDE98C5F03C6}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{F86DD736-F70E-7311-18F0-CDE98C5F03C6}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{F86DD736-F70E-7311-18F0-CDE98C5F03C6}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{F86DD736-F70E-7311-18F0-CDE98C5F03C6}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE