Update SA1010 to accept whitespace before collection initializers

#3687

Author: bjornhellander

StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp12/SpacingRules/SA1010CSharp12UnitTests.cs

@@ -3,9 +3,47 @@
 
 namespace StyleCop.Analyzers.Test.CSharp12.SpacingRules
 {
+    using System.Threading;
+    using System.Threading.Tasks;
+    using Microsoft.CodeAnalysis.Testing;
     using StyleCop.Analyzers.Test.CSharp11.SpacingRules;
+    using Xunit;
+
+    using static StyleCop.Analyzers.Test.Verifiers.StyleCopCodeFixVerifier<
+        StyleCop.Analyzers.SpacingRules.SA1010OpeningSquareBracketsMustBeSpacedCorrectly,
+        StyleCop.Analyzers.SpacingRules.TokenSpacingCodeFixProvider>;
 
     public partial class SA1010CSharp12UnitTests : SA1010CSharp11UnitTests
     {
+        [Fact]
+        [WorkItem(3687, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3687")]
+        public async Task TestCollectionExpressionAsync()
+        {
+            var testCode = $@"
+using System.Collections.Generic;
+
+namespace TestNamespace
+{{
+    public class TestClass
+    {{
+        protected static readonly int[] DefaultMetadataPaths = [1, 2];
+
+        public void TestMethod(List<int> x, int y)
+        {{
+            List<int> foo = [];
+            foo = [42];
+            foo = [..x, y];
+            Bar([1 ,2, 3]);
+        }}
+        
+        public void Bar(int[] x)
+        {{
+        }}
+    }}
+}}
+";
+
+            await VerifyCSharpDiagnosticAsync(testCode, DiagnosticResult.EmptyDiagnosticResults, CancellationToken.None).ConfigureAwait(false);
+        }
     }
 }

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

@@ -69,5 +69,6 @@ internal static class SyntaxKindEx
         public const SyntaxKind RecordDeclaration = (SyntaxKind)9063;
         public const SyntaxKind FunctionPointerUnmanagedCallingConventionList = (SyntaxKind)9066;
         public const SyntaxKind RecordStructDeclaration = (SyntaxKind)9068;
+        public const SyntaxKind CollectionExpression = (SyntaxKind)9076;
     }
 }

StyleCop.Analyzers/StyleCop.Analyzers/SpacingRules/SA1010OpeningSquareBracketsMustBeSpacedCorrectly.cs

@@ -100,7 +100,7 @@ private static void HandleOpenBracketToken(SyntaxTreeAnalysisContext context, Sy
             }
 
             if (!firstInLine && precededBySpace && !ignorePrecedingSpaceProblem &&
-                !IsPartOfIndexInitializer(token) && !IsPartOfListPattern(token))
+                !IsPartOfIndexInitializer(token) && !IsPartOfListPattern(token) && !IsPartOfCollectionExpression(token))
             {
                 // Opening square bracket should {not be preceded} by a space.
                 context.ReportDiagnostic(Diagnostic.Create(DescriptorNotPreceded, token.GetLocation(), TokenSpacingProperties.RemovePreceding));
@@ -128,5 +128,10 @@ private static bool IsPartOfListPattern(SyntaxToken token)
         {
             return token.Parent.IsKind(SyntaxKindEx.ListPattern);
         }
+
+        private static bool IsPartOfCollectionExpression(SyntaxToken token)
+        {
+            return token.Parent.IsKind(SyntaxKindEx.CollectionExpression);
+        }
     }
 }