Fix SA1008 and SA1012 for pattern matching tuples

Fixes #3141

Author: sharwell

StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp8/SpacingRules/SA1008CSharp8UnitTests.cs

@@ -73,5 +73,41 @@ await VerifyCSharpFixAsync(
                 fixedCode,
                 CancellationToken.None).ConfigureAwait(false);
         }
+
+        [Fact]
+        [WorkItem(3141, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3141")]
+        public async Task TestInPropertyPatternsAsync()
+        {
+            var testCode = @"
+class C
+{
+    void M((string A, string B) tuple)
+    {
+        _ = tuple is{|#0:(|} { Length: 1 }, { Length: 2 });
+    }
+}
+";
+            var fixedCode = @"
+class C
+{
+    void M((string A, string B) tuple)
+    {
+        _ = tuple is ({ Length: 1 }, { Length: 2 });
+    }
+}
+";
+            DiagnosticResult[] expectedResults =
+            {
+                Diagnostic(DescriptorPreceded).WithLocation(0),
+                Diagnostic(DescriptorNotFollowed).WithLocation(0),
+            };
+
+            await VerifyCSharpFixAsync(
+                LanguageVersion.CSharp8,
+                testCode,
+                expectedResults,
+                fixedCode,
+                CancellationToken.None).ConfigureAwait(false);
+        }
     }
 }

StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp8/SpacingRules/SA1012CSharp8UnitTests.cs

@@ -3,9 +3,62 @@
 
 namespace StyleCop.Analyzers.Test.CSharp8.SpacingRules
 {
+    using System.Threading;
+    using System.Threading.Tasks;
+    using Microsoft.CodeAnalysis.CSharp;
+    using Microsoft.CodeAnalysis.Testing;
     using StyleCop.Analyzers.Test.CSharp7.SpacingRules;
+    using Xunit;
+    using static StyleCop.Analyzers.Test.Verifiers.StyleCopCodeFixVerifier<
+        StyleCop.Analyzers.SpacingRules.SA1012OpeningBracesMustBeSpacedCorrectly,
+        StyleCop.Analyzers.SpacingRules.TokenSpacingCodeFixProvider>;
 
     public class SA1012CSharp8UnitTests : SA1012CSharp7UnitTests
     {
+        [Fact]
+        [WorkItem(3141, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3141")]
+        public async Task TestInPropertyPatternsAsync()
+        {
+            var testCode = @"
+class C
+{
+    void M((string A, string B) tuple)
+    {
+        _ = tuple is ( {|#0:{|}Length: 1 },{|#1:{|}Length: 2 });
+    }
+}
+";
+            var fixedCode = @"
+class C
+{
+    void M((string A, string B) tuple)
+    {
+        _ = tuple is ({ Length: 1 }, { Length: 2 });
+    }
+}
+";
+
+            DiagnosticResult[] expectedResults =
+            {
+                // /0/Test0.cs(6,24): warning SA1012: Opening brace should be followed by a space
+                Diagnostic().WithLocation(0).WithArguments(string.Empty, "followed"),
+
+                // /0/Test0.cs(6,24): warning SA1012: Opening brace should not be preceded by a space
+                Diagnostic().WithLocation(0).WithArguments(" not", "preceded"),
+
+                // /0/Test0.cs(6,37): warning SA1012: Opening brace should be followed by a space
+                Diagnostic().WithLocation(1).WithArguments(string.Empty, "followed"),
+
+                // /0/Test0.cs(6,37): warning SA1012: Opening brace should be preceded by a space
+                Diagnostic().WithLocation(1).WithArguments(string.Empty, "preceded"),
+            };
+
+            await VerifyCSharpFixAsync(
+                LanguageVersion.CSharp8,
+                testCode,
+                expectedResults,
+                fixedCode,
+                CancellationToken.None).ConfigureAwait(false);
+        }
     }
 }

StyleCop.Analyzers/StyleCop.Analyzers/SpacingRules/SA1008OpeningParenthesisMustBeSpacedCorrectly.cs

@@ -184,6 +184,10 @@ private static void HandleOpenParenToken(SyntaxTreeAnalysisContext context, Synt
                 haveLeadingSpace = true;
                 break;
 
+            case SyntaxKindEx.PositionalPatternClause:
+                haveLeadingSpace = prevToken.IsKind(SyntaxKind.IsKeyword);
+                break;
+
             case SyntaxKind.ArgumentList:
             case SyntaxKind.AttributeArgumentList:
             case SyntaxKind.CheckedExpression:

StyleCop.Analyzers/StyleCop.Analyzers/SpacingRules/SA1012OpeningBracesMustBeSpacedCorrectly.cs

@@ -10,6 +10,7 @@ namespace StyleCop.Analyzers.SpacingRules
     using Microsoft.CodeAnalysis.CSharp.Syntax;
     using Microsoft.CodeAnalysis.Diagnostics;
     using StyleCop.Analyzers.Helpers;
+    using StyleCop.Analyzers.Lightup;
 
     /// <summary>
     /// An opening brace within a C# element is not spaced correctly.
@@ -88,13 +89,22 @@ private static void HandleOpenBraceToken(SyntaxTreeAnalysisContext context, Synt
                 return;
             }
 
+            bool expectPrecedingSpace = true;
+            if (token.Parent.IsKind(SyntaxKindEx.PropertyPatternClause)
+                && token.GetPreviousToken() is { RawKind: (int)SyntaxKind.OpenParenToken, Parent: { RawKind: (int)SyntaxKindEx.PositionalPatternClause } })
+            {
+                // value is ({ P: 0 }, { P: 0 })
+                expectPrecedingSpace = false;
+            }
+
             bool precededBySpace = token.IsFirstInLine() || token.IsPrecededByWhitespace(context.CancellationToken);
 
-            if (!precededBySpace)
+            if (precededBySpace != expectPrecedingSpace)
             {
                 // Opening brace should{} be {preceded} by a space.
-                var properties = TokenSpacingProperties.InsertPreceding;
-                context.ReportDiagnostic(Diagnostic.Create(Descriptor, token.GetLocation(), properties, string.Empty, "preceded"));
+                // Opening brace should{ not} be {preceded} by a space.
+                var properties = expectPrecedingSpace ? TokenSpacingProperties.InsertPreceding : TokenSpacingProperties.RemovePrecedingPreserveLayout;
+                context.ReportDiagnostic(Diagnostic.Create(Descriptor, token.GetLocation(), properties, expectPrecedingSpace ? string.Empty : " not", "preceded"));
             }
 
             if (!token.IsLastInLine() && !followedBySpace)