Update SA1008OpeningParenthesisMustBeSpacedCorrectly to disallow a leading space before a lambda in a collection expression

StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp12/SpacingRules/SA1008CSharp12UnitTests.cs

@@ -72,5 +72,88 @@ await VerifyCSharpFixAsync(
                 fixedCode,
                 CancellationToken.None).ConfigureAwait(false);
         }
+
+        [Fact]
+        [WorkItem(3931, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3931")]
+        public async Task TestParenthesizedLambdaInCollectionExpressionAsync()
+        {
+            var testCode = @"
+class TestClass
+{
+    private System.Action[] actions = [ [|(|]) => {}];
+}
+";
+
+            var fixedCode = @"
+class TestClass
+{
+    private System.Action[] actions = [() => {}];
+}
+";
+
+            await VerifyCSharpFixAsync(testCode, DiagnosticResult.EmptyDiagnosticResults, fixedCode, CancellationToken.None).ConfigureAwait(false);
+        }
+
+        [Fact]
+        [WorkItem(3931, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3931")]
+        public async Task TestLambdaAfterCommaInCollectionExpressionAsync()
+        {
+            var testCode = @"
+class TestClass
+{
+    private System.Func<int, int, int>[] functions = [(x, y) => x + y,{|#0:(|}x, y) => x - y];
+}
+";
+
+            var fixedCode = @"
+class TestClass
+{
+    private System.Func<int, int, int>[] functions = [(x, y) => x + y, (x, y) => x - y];
+}
+";
+
+            var expected = Diagnostic(DescriptorPreceded).WithLocation(0);
+            await VerifyCSharpFixAsync(testCode, expected, fixedCode, CancellationToken.None).ConfigureAwait(false);
+        }
+
+        [Fact]
+        [WorkItem(3931, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3931")]
+        public async Task TestLambdaAfterSpreadInCollectionExpressionAsync()
+        {
+            var testCode = @"
+class TestClass
+{
+    private static System.Func<int, int, int>[] existing = [(x, y) => x + y];
+    private System.Func<int, int, int>[] functions = [..existing,{|#0:(|}x, y) => x - y];
+}
+";
+
+            var fixedCode = @"
+class TestClass
+{
+    private static System.Func<int, int, int>[] existing = [(x, y) => x + y];
+    private System.Func<int, int, int>[] functions = [..existing, (x, y) => x - y];
+}
+";
+
+            var expected = Diagnostic(DescriptorPreceded).WithLocation(0);
+            await VerifyCSharpFixAsync(testCode, expected, fixedCode, CancellationToken.None).ConfigureAwait(false);
+        }
+
+        [Fact]
+        [WorkItem(3931, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3931")]
+        public async Task TestLambdaWithBracketOnPreviousLineAsync()
+        {
+            var testCode = @"
+class TestClass
+{
+    private System.Func<int, int, int>[] functions = [
+        (x, y) => x + y
+    ];
+}
+";
+
+            await VerifyCSharpDiagnosticAsync(testCode, DiagnosticResult.EmptyDiagnosticResults, CancellationToken.None).ConfigureAwait(false);
+        }
     }
 }

StyleCop.Analyzers/StyleCop.Analyzers.Test/SpacingRules/SA1008UnitTests.cs

@@ -1895,6 +1895,34 @@ public void TestMethod1()
             await VerifyCSharpFixAsync(testCode, expectedDiagnostics, fixedTestCode, CancellationToken.None).ConfigureAwait(false);
         }
 
+        [Fact]
+        [WorkItem(3931, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3931")]
+        public async Task TestLambdaInCollectionInitializerAsync()
+        {
+            var testCode = @"
+using System;
+using System.Collections.Generic;
+
+class TestClass
+{
+    private List<Action<int, int>> actions = new List<Action<int, int>>() {{|#0:(|}x, y) => { } };
+}
+";
+
+            var fixedCode = @"
+using System;
+using System.Collections.Generic;
+
+class TestClass
+{
+    private List<Action<int, int>> actions = new List<Action<int, int>>() { (x, y) => { } };
+}
+";
+
+            var expected = Diagnostic(DescriptorPreceded).WithLocation(0);
+            await VerifyCSharpFixAsync(testCode, expected, fixedCode, CancellationToken.None).ConfigureAwait(false);
+        }
+
         /// <summary>
         /// Verifies that multi-line comments are handled properly.
         /// </summary>

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

@@ -248,7 +248,8 @@ private static void HandleOpenParenToken(SyntaxTreeAnalysisContext context, Synt
 
             case SyntaxKind.ParameterList:
                 var partOfLambdaExpression = token.Parent.Parent.IsKind(SyntaxKind.ParenthesizedLambdaExpression);
-                haveLeadingSpace = partOfLambdaExpression;
+                var startOfCollectionExpression = prevToken.IsKind(SyntaxKind.OpenBracketToken) && prevToken.Parent.IsKind(SyntaxKindEx.CollectionExpression);
+                haveLeadingSpace = partOfLambdaExpression && !startOfCollectionExpression;
                 break;
 
             case SyntaxKindEx.TupleType: