Update SA1500 for pattern matching

Author: sharwell

StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp8/LayoutRules/SA1500CSharp8UnitTests.cs

@@ -3,9 +3,117 @@
 
 namespace StyleCop.Analyzers.Test.CSharp8.LayoutRules
 {
+    using System.Threading;
+    using System.Threading.Tasks;
+    using Microsoft.CodeAnalysis.Testing;
     using StyleCop.Analyzers.Test.CSharp7.LayoutRules;
+    using StyleCop.Analyzers.Test.Helpers;
+    using Xunit;
+    using static StyleCop.Analyzers.Test.Verifiers.StyleCopCodeFixVerifier<
+        StyleCop.Analyzers.LayoutRules.SA1500BracesForMultiLineStatementsMustNotShareLine,
+        StyleCop.Analyzers.LayoutRules.SA1500CodeFixProvider>;
 
     public partial class SA1500CSharp8UnitTests : SA1500CSharp7UnitTests
     {
+        [Fact]
+        [WorkItem(3003, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3003")]
+        public async Task TestSwitchExpressionBracesMustOwnLineAsync()
+        {
+            var testCode = @"
+public class TestClass
+{
+    public int Test(Item value)
+    {
+        return value switch {|#0:{|}
+            { Prop: 1 } => 1,
+            _ => 0 {|#1:}|};
+    }
+}
+
+public class Item
+{
+    public int Prop { get; set; }
+}
+";
+
+            var fixedCode = @"
+public class TestClass
+{
+    public int Test(Item value)
+    {
+        return value switch
+        {
+            { Prop: 1 } => 1,
+            _ => 0
+        };
+    }
+}
+
+public class Item
+{
+    public int Prop { get; set; }
+}
+";
+
+            DiagnosticResult[] expectedDiagnostics =
+            {
+                Diagnostic().WithLocation(0),
+                Diagnostic().WithLocation(1),
+            };
+
+            await VerifyCSharpFixAsync(testCode, expectedDiagnostics, fixedCode, CancellationToken.None).ConfigureAwait(false);
+        }
+
+        [Fact]
+        [WorkItem(3003, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3003")]
+        public async Task TestPropertyPatternBracesMustOwnLineAsync()
+        {
+            var testCode = @"
+public class TestClass
+{
+    public bool Test(object value)
+    {
+        return value is TestType {|#0:{|} A: 1,
+            B: 2 {|#1:}|};
+    }
+}
+
+public class TestType
+{
+    public int A { get; set; }
+
+    public int B { get; set; }
+}
+";
+
+            var fixedCode = @"
+public class TestClass
+{
+    public bool Test(object value)
+    {
+        return value is TestType
+        {
+            A: 1,
+            B: 2
+        };
+    }
+}
+
+public class TestType
+{
+    public int A { get; set; }
+
+    public int B { get; set; }
+}
+";
+
+            DiagnosticResult[] expectedDiagnostics =
+            {
+                Diagnostic().WithLocation(0),
+                Diagnostic().WithLocation(1),
+            };
+
+            await VerifyCSharpFixAsync(testCode, expectedDiagnostics, fixedCode, CancellationToken.None).ConfigureAwait(false);
+        }
     }
 }

StyleCop.Analyzers/StyleCop.Analyzers/LayoutRules/SA1500BracesForMultiLineStatementsMustNotShareLine.cs

@@ -79,6 +79,8 @@ internal class SA1500BracesForMultiLineStatementsMustNotShareLine : DiagnosticAn
         private static readonly Action<SyntaxNodeAnalysisContext, StyleCopSettings> SwitchStatementAction = HandleSwitchStatement;
         private static readonly Action<SyntaxNodeAnalysisContext, StyleCopSettings> InitializerExpressionAction = HandleInitializerExpression;
         private static readonly Action<SyntaxNodeAnalysisContext, StyleCopSettings> AnonymousObjectCreationExpressionAction = HandleAnonymousObjectCreationExpression;
+        private static readonly Action<SyntaxNodeAnalysisContext, StyleCopSettings> SwitchExpressionAction = HandleSwitchExpression;
+        private static readonly Action<SyntaxNodeAnalysisContext, StyleCopSettings> PropertyPatternClauseAction = HandlePropertyPatternClause;
 
         /// <inheritdoc/>
         public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics { get; } =
@@ -99,6 +101,8 @@ public override void Initialize(AnalysisContext context)
                 context.RegisterSyntaxNodeAction(SwitchStatementAction, SyntaxKind.SwitchStatement);
                 context.RegisterSyntaxNodeAction(InitializerExpressionAction, SyntaxKinds.InitializerExpression);
                 context.RegisterSyntaxNodeAction(AnonymousObjectCreationExpressionAction, SyntaxKind.AnonymousObjectCreationExpression);
+                context.RegisterSyntaxNodeAction(SwitchExpressionAction, SyntaxKindEx.SwitchExpression);
+                context.RegisterSyntaxNodeAction(PropertyPatternClauseAction, SyntaxKindEx.PropertyPatternClause);
             });
         }
 
@@ -144,6 +148,18 @@ private static void HandleAnonymousObjectCreationExpression(SyntaxNodeAnalysisCo
             CheckBraces(context, settings, syntax.OpenBraceToken, syntax.CloseBraceToken);
         }
 
+        private static void HandleSwitchExpression(SyntaxNodeAnalysisContext context, StyleCopSettings settings)
+        {
+            var syntax = (SwitchExpressionSyntaxWrapper)context.Node;
+            CheckBraces(context, settings, syntax.OpenBraceToken, syntax.CloseBraceToken);
+        }
+
+        private static void HandlePropertyPatternClause(SyntaxNodeAnalysisContext context, StyleCopSettings settings)
+        {
+            var syntax = (PropertyPatternClauseSyntaxWrapper)context.Node;
+            CheckBraces(context, settings, syntax.OpenBraceToken, syntax.CloseBraceToken);
+        }
+
         private static void CheckBraces(SyntaxNodeAnalysisContext context, StyleCopSettings settings, SyntaxToken openBraceToken, SyntaxToken closeBraceToken)
         {
             if (openBraceToken.IsKind(SyntaxKind.None) || closeBraceToken.IsKind(SyntaxKind.None))

documentation/SA1500.md

@@ -57,6 +57,10 @@ public object Method()
 }
 ```
 
+Starting with C# 8.0, this rule also applies to braces introduced by switch expressions and property patterns. When the
+arms or pattern contents span multiple lines, the `{` and `}` for the switch expression or property pattern must appear
+on their own lines.
+
 ## How to fix violations
 
 To fix a violation of this rule, ensure that both the opening and closing braces are placed on their own line, and do not share the line with any other code, other than comments.