Fix SA1119 handling of switch expression within member access expressions

Fixes #3200

Author: sharwell

StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp8/MaintainabilityRules/SA1119CSharp8UnitTests.cs

@@ -116,5 +116,43 @@ public void TestMethod(int n, object a, object b)
 
             await VerifyCSharpFixAsync(LanguageVersion.CSharp8, testCode, expected, fixedCode, CancellationToken.None).ConfigureAwait(false);
         }
+
+        [Theory]
+        [InlineData(".ToString()")]
+        [InlineData("?.ToString()")]
+        [InlineData("[0]")]
+        [InlineData("?[0]")]
+        [WorkItem(3171, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3171")]
+        public async Task TestSwitchExpressionFollowedByDereferenceAsync(string operation)
+        {
+            string testCode = $@"
+public class Foo
+{{
+    public object TestMethod(int n, string a, string b)
+    {{
+        return (n switch {{ 1 => a, 2 => b }}){operation};
+    }}
+}}
+";
+
+            await VerifyCSharpDiagnosticAsync(LanguageVersion.CSharp8, testCode, DiagnosticResult.EmptyDiagnosticResults, CancellationToken.None).ConfigureAwait(false);
+        }
+
+        [Fact]
+        [WorkItem(3171, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3171")]
+        public async Task TestSwitchExpressionFollowedByPointerDereferenceAsync()
+        {
+            string testCode = @"
+public class Foo
+{
+    public unsafe string TestMethod(int n, byte* a, byte* b)
+    {
+        return (n switch { 1 => a, 2 => b })->ToString();
+    }
+}
+";
+
+            await VerifyCSharpDiagnosticAsync(LanguageVersion.CSharp8, testCode, DiagnosticResult.EmptyDiagnosticResults, CancellationToken.None).ConfigureAwait(false);
+        }
     }
 }

StyleCop.Analyzers/StyleCop.Analyzers/MaintainabilityRules/SA1119StatementMustNotUseUnnecessaryParenthesis.cs

@@ -10,6 +10,7 @@ namespace StyleCop.Analyzers.MaintainabilityRules
     using Microsoft.CodeAnalysis.CSharp;
     using Microsoft.CodeAnalysis.CSharp.Syntax;
     using Microsoft.CodeAnalysis.Diagnostics;
+    using StyleCop.Analyzers.DocumentationRules;
     using StyleCop.Analyzers.Helpers;
     using StyleCop.Analyzers.Lightup;
 
@@ -132,6 +133,11 @@ private static void HandleParenthesizedExpression(SyntaxNodeAnalysisContext cont
                         return;
                     }
 
+                    if (IsSwitchExpressionExpressionOfMemberAccess(node))
+                    {
+                        return;
+                    }
+
                     ReportDiagnostic(context, node);
                 }
                 else
@@ -221,6 +227,22 @@ private static bool IsSwitchExpressionPrecededByTypeCast(ParenthesizedExpression
             return previousToken.IsKind(SyntaxKind.CloseParenToken) && previousToken.Parent.IsKind(SyntaxKind.CastExpression);
         }
 
+        private static bool IsSwitchExpressionExpressionOfMemberAccess(ParenthesizedExpressionSyntax node)
+        {
+            if (!node.Expression.IsKind(SyntaxKindEx.SwitchExpression))
+            {
+                return false;
+            }
+
+            return node.Parent switch
+            {
+                MemberAccessExpressionSyntax memberAccessExpression => memberAccessExpression.Expression == node,
+                ConditionalAccessExpressionSyntax conditionalAccessExpression => conditionalAccessExpression.Expression == node,
+                ElementAccessExpressionSyntax elementAccessExpression => elementAccessExpression.Expression == node,
+                _ => false,
+            };
+        }
+
         private static void ReportDiagnostic(SyntaxNodeAnalysisContext context, ParenthesizedExpressionSyntax node)
         {
             context.ReportDiagnostic(Diagnostic.Create(Descriptor, node.GetLocation()));