Fix SA1023 for C# 9 function pointer parameters

Author: nxtn

StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp9/SpacingRules/SA1023CSharp9UnitTests.cs

@@ -3,9 +3,66 @@
 
 namespace StyleCop.Analyzers.Test.CSharp9.SpacingRules
 {
+    using System.Threading;
+    using System.Threading.Tasks;
+    using Microsoft.CodeAnalysis.Testing;
     using StyleCop.Analyzers.Test.CSharp8.SpacingRules;
+    using Xunit;
+    using static StyleCop.Analyzers.SpacingRules.SA1023DereferenceAndAccessOfSymbolsMustBeSpacedCorrectly;
+    using static StyleCop.Analyzers.Test.Verifiers.StyleCopCodeFixVerifier<
+        StyleCop.Analyzers.SpacingRules.SA1023DereferenceAndAccessOfSymbolsMustBeSpacedCorrectly,
+        StyleCop.Analyzers.SpacingRules.TokenSpacingCodeFixProvider>;
 
     public class SA1023CSharp9UnitTests : SA1023CSharp8UnitTests
     {
+        [Fact]
+        public async Task TestFunctionPointerParameterValidSpacingAsync()
+        {
+            var testCode = @"public class TestClass
+{
+    unsafe delegate*<int*> FuncPtr;
+}
+";
+
+            await VerifyCSharpDiagnosticAsync(testCode, DiagnosticResult.EmptyDiagnosticResults, CancellationToken.None).ConfigureAwait(false);
+        }
+
+        [Fact]
+        public async Task TestFunctionPointerParameterInvalidPrecedingSpaceAsync()
+        {
+            var testCode = @"public class TestClass
+{
+    unsafe delegate*<int *> FuncPtr;
+}
+";
+
+            var fixedCode = @"public class TestClass
+{
+    unsafe delegate*<int*> FuncPtr;
+}
+";
+
+            var expected = Diagnostic(DescriptorNotPreceded).WithLocation(3, 26);
+            await VerifyCSharpFixAsync(testCode, expected, fixedCode, CancellationToken.None).ConfigureAwait(false);
+        }
+
+        [Fact]
+        public async Task TestFunctionPointerParameterInvalidTrailingSpaceAsync()
+        {
+            var testCode = @"public class TestClass
+{
+    unsafe delegate*<int* > FuncPtr;
+}
+";
+
+            var fixedCode = @"public class TestClass
+{
+    unsafe delegate*<int*> FuncPtr;
+}
+";
+
+            var expected = Diagnostic(DescriptorNotFollowed).WithLocation(3, 25);
+            await VerifyCSharpFixAsync(testCode, expected, fixedCode, CancellationToken.None).ConfigureAwait(false);
+        }
     }
 }

StyleCop.Analyzers/StyleCop.Analyzers/Lightup/SyntaxKindEx.cs

@@ -49,6 +49,7 @@ internal static class SyntaxKindEx
         public const SyntaxKind ImplicitStackAllocArrayCreationExpression = (SyntaxKind)9053;
         public const SyntaxKind SuppressNullableWarningExpression = (SyntaxKind)9054;
         public const SyntaxKind NullableDirectiveTrivia = (SyntaxKind)9055;
+        public const SyntaxKind FunctionPointerParameter = (SyntaxKind)9057;
         public const SyntaxKind WithInitializerExpression = (SyntaxKind)9062;
         public const SyntaxKind RecordDeclaration = (SyntaxKind)9063;
     }

StyleCop.Analyzers/StyleCop.Analyzers/SpacingRules/SA1023DereferenceAndAccessOfSymbolsMustBeSpacedCorrectly.cs

@@ -10,6 +10,7 @@ namespace StyleCop.Analyzers.SpacingRules
     using Microsoft.CodeAnalysis.CSharp;
     using Microsoft.CodeAnalysis.Diagnostics;
     using StyleCop.Analyzers.Helpers;
+    using StyleCop.Analyzers.Lightup;
 
     /// <summary>
     /// A dereference symbol or an access-of symbol within a C# element is not spaced correctly.
@@ -113,6 +114,13 @@ private static void HandleAsteriskToken(SyntaxTreeAnalysisContext context, Synta
             bool allowTrailingSpace;
             switch (token.Parent.Kind())
             {
+            case SyntaxKind.PointerType when token.Parent.Parent.IsKind(SyntaxKindEx.FunctionPointerParameter):
+                allowAtLineStart = true;
+                allowAtLineEnd = true;
+                allowPrecedingSpace = false;
+                allowTrailingSpace = false;
+                break;
+
             case SyntaxKind.PointerType:
                 allowAtLineStart = false;
                 allowAtLineEnd = true;