Update SA1000 to handle checked operator declarations correctly

#3478

Author: bjornhellander

StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp11/SpacingRules/SA1000CSharp11UnitTests.cs

@@ -3,9 +3,48 @@
 
 namespace StyleCop.Analyzers.Test.CSharp11.SpacingRules
 {
+    using System.Threading;
+    using System.Threading.Tasks;
     using StyleCop.Analyzers.Test.CSharp10.SpacingRules;
+    using Xunit;
+
+    using static StyleCop.Analyzers.Test.Verifiers.StyleCopCodeFixVerifier<
+        StyleCop.Analyzers.SpacingRules.SA1000KeywordsMustBeSpacedCorrectly,
+        StyleCop.Analyzers.SpacingRules.TokenSpacingCodeFixProvider>;
 
     public class SA1000CSharp11UnitTests : SA1000CSharp10UnitTests
     {
+        [Fact]
+        public async Task TestCheckedOperatorDeclarationAsync()
+        {
+            // NOTE: A checked operator requires a non-checked operator as well
+            // NOTE: Implicit conversion operators can not be checked
+            var testCode = @"
+public class MyClass
+{
+    public static MyClass operator {|#0:checked|}-(MyClass x) => x;
+    public static MyClass operator -(MyClass x) => x;
+
+    public static explicit operator {|#1:checked|}@MyClass(int i) => new MyClass();
+    public static explicit operator MyClass(int i) => new MyClass();
+}";
+
+            var fixedCode = @"
+public class MyClass
+{
+    public static MyClass operator checked -(MyClass x) => x;
+    public static MyClass operator -(MyClass x) => x;
+
+    public static explicit operator checked @MyClass(int i) => new MyClass();
+    public static explicit operator MyClass(int i) => new MyClass();
+}";
+
+            var expected = new[]
+            {
+                Diagnostic().WithArguments("checked", string.Empty, "followed").WithLocation(0),
+                Diagnostic().WithArguments("checked", string.Empty, "followed").WithLocation(1),
+            };
+            await VerifyCSharpFixAsync(testCode, expected, fixedCode, CancellationToken.None).ConfigureAwait(false);
+        }
     }
 }

StyleCop.Analyzers/StyleCop.Analyzers/SpacingRules/SA1000KeywordsMustBeSpacedCorrectly.cs

@@ -119,13 +119,23 @@ private static void HandleSyntaxTree(SyntaxTreeAnalysisContext context)
 
                 case SyntaxKind.CheckedKeyword:
                 case SyntaxKind.UncheckedKeyword:
-                    if (token.GetNextToken().IsKind(SyntaxKind.OpenBraceToken))
+                    switch (token.Parent.Kind())
                     {
+                    case SyntaxKind.CheckedStatement:
+                    case SyntaxKind.UncheckedStatement:
+                    case SyntaxKind.OperatorDeclaration:
+                    case SyntaxKind.ConversionOperatorDeclaration:
                         HandleRequiredSpaceToken(ref context, token);
-                    }
-                    else
-                    {
+                        break;
+
+                    case SyntaxKind.CheckedExpression:
+                    case SyntaxKind.UncheckedExpression:
                         HandleDisallowedSpaceToken(ref context, token);
+                        break;
+
+                    default:
+                        // So far an unknown case, so we have no opinion yet
+                        break;
                     }
 
                     break;