Update SA1413 for pattern matching

Author: sharwell

StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp8/MaintainabilityRules/SA1413CSharp8UnitTests.cs

@@ -1,8 +1,6 @@
 // Copyright (c) Tunnel Vision Laboratories, LLC. All Rights Reserved.
 // Licensed under the MIT License. See LICENSE in the project root for license information.
 
-#nullable disable
-
 namespace StyleCop.Analyzers.Test.CSharp8.MaintainabilityRules
 {
     using System.Threading;
@@ -54,6 +52,53 @@ public void TestMethod(int input)
         }
     }
 }
+";
+
+            await VerifyCSharpFixAsync(testCode, DiagnosticResult.EmptyDiagnosticResults, fixedCode, CancellationToken.None).ConfigureAwait(false);
+        }
+
+        [Fact]
+        [WorkItem(3003, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3003")]
+        public async Task TestPropertyPatternAsync()
+        {
+            var testCode = @"
+public class TestClass
+{
+    public bool Test1(SomeType value) => value is SomeType { X: 1, Y: 2 };
+    public bool Test2(SomeType value) => value is SomeType { X: 1, Y: 2, };
+    public bool Test3(SomeType value) => value is SomeType
+    {
+        X: 1,
+        [|Y: 2|]
+    };
+}
+
+public class SomeType
+{
+    public int X { get; set; }
+
+    public int Y { get; set; }
+}
+";
+
+            var fixedCode = @"
+public class TestClass
+{
+    public bool Test1(SomeType value) => value is SomeType { X: 1, Y: 2 };
+    public bool Test2(SomeType value) => value is SomeType { X: 1, Y: 2, };
+    public bool Test3(SomeType value) => value is SomeType
+    {
+        X: 1,
+        Y: 2,
+    };
+}
+
+public class SomeType
+{
+    public int X { get; set; }
+
+    public int Y { get; set; }
+}
 ";
 
             await VerifyCSharpFixAsync(testCode, DiagnosticResult.EmptyDiagnosticResults, fixedCode, CancellationToken.None).ConfigureAwait(false);

StyleCop.Analyzers/StyleCop.Analyzers/MaintainabilityRules/SA1413UseTrailingCommasInMultiLineInitializers.cs

@@ -62,6 +62,7 @@ internal class SA1413UseTrailingCommasInMultiLineInitializers : DiagnosticAnalyz
         private static readonly Action<SyntaxNodeAnalysisContext> HandleAnonymousObjectInitializerAction = HandleAnonymousObjectInitializer;
         private static readonly Action<SyntaxNodeAnalysisContext> HandleEnumDeclarationAction = HandleEnumDeclaration;
         private static readonly Action<SyntaxNodeAnalysisContext> HandleSwitchExpressionAction = HandleSwitchExpression;
+        private static readonly Action<SyntaxNodeAnalysisContext> HandlePropertyPatternClauseAction = HandlePropertyPatternClause;
 
         private static readonly ImmutableArray<SyntaxKind> ObjectInitializerKinds =
             ImmutableArray.Create(SyntaxKind.ObjectInitializerExpression, SyntaxKind.ArrayInitializerExpression, SyntaxKind.CollectionInitializerExpression, SyntaxKindEx.WithInitializerExpression);
@@ -80,6 +81,7 @@ public override void Initialize(AnalysisContext context)
             context.RegisterSyntaxNodeAction(HandleAnonymousObjectInitializerAction, SyntaxKind.AnonymousObjectCreationExpression);
             context.RegisterSyntaxNodeAction(HandleEnumDeclarationAction, SyntaxKind.EnumDeclaration);
             context.RegisterSyntaxNodeAction(HandleSwitchExpressionAction, SyntaxKindEx.SwitchExpression);
+            context.RegisterSyntaxNodeAction(HandlePropertyPatternClauseAction, SyntaxKindEx.PropertyPatternClause);
         }
 
         private static void HandleEnumDeclaration(SyntaxNodeAnalysisContext context)
@@ -138,5 +140,19 @@ private static void HandleSwitchExpression(SyntaxNodeAnalysisContext context)
                 context.ReportDiagnostic(Diagnostic.Create(Descriptor, switchExpression.Arms.Last().SyntaxNode.GetLocation()));
             }
         }
+
+        private static void HandlePropertyPatternClause(SyntaxNodeAnalysisContext context)
+        {
+            var propertyPatternClause = (PropertyPatternClauseSyntaxWrapper)context.Node;
+            if (propertyPatternClause.SyntaxNode == null || !propertyPatternClause.SyntaxNode.SpansMultipleLines())
+            {
+                return;
+            }
+
+            if (propertyPatternClause.Subpatterns.SeparatorCount < propertyPatternClause.Subpatterns.Count)
+            {
+                context.ReportDiagnostic(Diagnostic.Create(Descriptor, propertyPatternClause.Subpatterns.Last().SyntaxNode.GetLocation()));
+            }
+        }
     }
 }

documentation/SA1413.md

@@ -55,7 +55,9 @@ var x = new Barnacle
 };
 ```
 
-This diagnostic is also reported for other forms of comma-separated list, such as enum members.
+This diagnostic is also reported for other forms of comma-separated list, such as enum members. Starting with C# 8.0, it
+also applies to switch expression arm lists and the subpatterns inside multi-line property patterns—add a trailing comma
+to the last arm or subpattern when they span multiple lines.
 
 ## How to fix violations