Update SA1137 to also consider init accessors

#3668

Author: bjornhellander

StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp9/ReadabilityRules/SA1137CSharp9UnitTests.cs

@@ -3,9 +3,61 @@
 
 namespace StyleCop.Analyzers.Test.CSharp9.ReadabilityRules
 {
+    using System.Threading.Tasks;
+    using Microsoft.CodeAnalysis.Testing;
     using StyleCop.Analyzers.Test.CSharp8.ReadabilityRules;
+    using Xunit;
+    using static StyleCop.Analyzers.Test.Verifiers.StyleCopCodeFixVerifier<
+        StyleCop.Analyzers.ReadabilityRules.SA1137ElementsShouldHaveTheSameIndentation,
+        StyleCop.Analyzers.ReadabilityRules.IndentationCodeFixProvider>;
 
     public class SA1137CSharp9UnitTests : SA1137CSharp8UnitTests
     {
+        [Fact]
+        [WorkItem(3668, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3668")]
+        public async Task TestInitAccessorAttributeListAsync()
+        {
+            string testCode = @"
+using System;
+
+class TestClass
+{
+    int Property
+    {
+        [My]
+[| |][My]
+        init { }
+    }
+}
+
+[AttributeUsage(AttributeTargets.All, AllowMultiple = true)]
+class MyAttribute : Attribute { }
+";
+
+            string fixedCode = @"
+using System;
+
+class TestClass
+{
+    int Property
+    {
+        [My]
+        [My]
+        init { }
+    }
+}
+
+[AttributeUsage(AttributeTargets.All, AllowMultiple = true)]
+class MyAttribute : Attribute { }
+";
+
+            var test = new CSharpTest
+            {
+                ReferenceAssemblies = ReferenceAssemblies.Net.Net50,
+                TestCode = testCode,
+                FixedCode = fixedCode,
+            };
+            await test.RunAsync().ConfigureAwait(false);
+        }
     }
 }

StyleCop.Analyzers/StyleCop.Analyzers/Lightup/SyntaxKindEx.cs

@@ -62,6 +62,7 @@ internal static class SyntaxKindEx
         public const SyntaxKind NullableDirectiveTrivia = (SyntaxKind)9055;
         public const SyntaxKind FunctionPointerType = (SyntaxKind)9056;
         public const SyntaxKind FunctionPointerParameter = (SyntaxKind)9057;
+        public const SyntaxKind InitAccessorDeclaration = (SyntaxKind)9060;
         public const SyntaxKind WithExpression = (SyntaxKind)9061;
         public const SyntaxKind WithInitializerExpression = (SyntaxKind)9062;
         public const SyntaxKind RecordDeclaration = (SyntaxKind)9063;

StyleCop.Analyzers/StyleCop.Analyzers/ReadabilityRules/SA1137ElementsShouldHaveTheSameIndentation.cs

@@ -336,6 +336,7 @@ private static void AddMemberAndAttributes(ImmutableList<SyntaxNode>.Builder ele
 
             case SyntaxKind.GetAccessorDeclaration:
             case SyntaxKind.SetAccessorDeclaration:
+            case SyntaxKindEx.InitAccessorDeclaration:
             case SyntaxKind.AddAccessorDeclaration:
             case SyntaxKind.RemoveAccessorDeclaration:
             case SyntaxKind.UnknownAccessorDeclaration: