Update SA1110 for target-typed new

Author: sharwell

StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp9/ReadabilityRules/SA1110CSharp9UnitTests.cs

@@ -130,6 +130,48 @@ public async Task TestPrimaryConstructorBaseListWithoutParametersAsync(string ty
             await VerifyCSharpFixAsync(testCode, expected, fixedCode, CancellationToken.None).ConfigureAwait(false);
         }
 
+        [Fact]
+        [WorkItem(3972, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3972")]
+        public async Task TestTargetTypedNewOpeningParenthesisOnNextLineAsync()
+        {
+            var testCode = @"
+class TestClass
+{
+    public TestClass(int value)
+    {
+    }
+}
+
+class Test
+{
+    void M()
+    {
+        TestClass value = new
+            {|#0:(|}1);
+    }
+}";
+
+            var fixedCode = @"
+class TestClass
+{
+    public TestClass(int value)
+    {
+    }
+}
+
+class Test
+{
+    void M()
+    {
+        TestClass value = new(
+            1);
+    }
+}";
+
+            var expected = Diagnostic().WithLocation(0);
+            await VerifyCSharpFixAsync(testCode, expected, fixedCode, CancellationToken.None).ConfigureAwait(false);
+        }
+
         protected virtual DiagnosticResult[] GetExpectedResultTestPrimaryConstructor()
         {
             return new[]

StyleCop.Analyzers/StyleCop.Analyzers/ReadabilityRules/SA1110OpeningParenthesisMustBeOnDeclarationLine.cs

@@ -60,6 +60,7 @@ internal class SA1110OpeningParenthesisMustBeOnDeclarationLine : DiagnosticAnaly
         private static readonly Action<SyntaxNodeAnalysisContext> ConstructorDeclarationAction = HandleConstructorDeclaration;
         private static readonly Action<SyntaxNodeAnalysisContext> InvocationExpressionAction = HandleInvocationExpression;
         private static readonly Action<SyntaxNodeAnalysisContext> ObjectCreationExpressionAction = HandleObjectCreationExpression;
+        private static readonly Action<SyntaxNodeAnalysisContext> ImplicitObjectCreationExpressionAction = HandleImplicitObjectCreationExpression;
         private static readonly Action<SyntaxNodeAnalysisContext> IndexerDeclarationAction = HandleIndexerDeclaration;
         private static readonly Action<SyntaxNodeAnalysisContext> ElementAccessExpressionAction = HandleElementAccessExpression;
         private static readonly Action<SyntaxNodeAnalysisContext> AttributeAction = HandleAttribute;
@@ -86,6 +87,7 @@ public override void Initialize(AnalysisContext context)
             context.RegisterSyntaxNodeAction(ConstructorDeclarationAction, SyntaxKind.ConstructorDeclaration);
             context.RegisterSyntaxNodeAction(InvocationExpressionAction, SyntaxKind.InvocationExpression);
             context.RegisterSyntaxNodeAction(ObjectCreationExpressionAction, SyntaxKind.ObjectCreationExpression);
+            context.RegisterSyntaxNodeAction(ImplicitObjectCreationExpressionAction, SyntaxKindEx.ImplicitObjectCreationExpression);
             context.RegisterSyntaxNodeAction(IndexerDeclarationAction, SyntaxKind.IndexerDeclaration);
             context.RegisterSyntaxNodeAction(ElementAccessExpressionAction, SyntaxKind.ElementAccessExpression);
             context.RegisterSyntaxNodeAction(AttributeAction, SyntaxKind.Attribute);
@@ -258,6 +260,24 @@ private static void HandleObjectCreationExpression(SyntaxNodeAnalysisContext con
             }
         }
 
+        private static void HandleImplicitObjectCreationExpression(SyntaxNodeAnalysisContext context)
+        {
+            var implicitObjectCreation = (ImplicitObjectCreationExpressionSyntaxWrapper)context.Node;
+            if (implicitObjectCreation.NewKeyword.IsMissing)
+            {
+                return;
+            }
+
+            var argumentList = implicitObjectCreation.ArgumentList;
+
+            if (argumentList != null
+                && !argumentList.OpenParenToken.IsMissing)
+            {
+                bool preserveLayout = argumentList.Arguments.Any();
+                CheckIfLocationOfPreviousTokenAndOpenTokenAreTheSame(context, argumentList.OpenParenToken, preserveLayout);
+            }
+        }
+
         private static SyntaxToken? GetIdentifier(ObjectCreationExpressionSyntax objectCreationExpressionSyntax)
         {
             switch (objectCreationExpressionSyntax.Type.Kind())

documentation/SA1110.md

@@ -25,6 +25,9 @@ not placed on the same line as the method or indexer name.
 A violation of this rule occurs when the opening bracket of a method or indexer call or declaration is not placed on the
 same line as the method or indexer. The following examples show correct placement of the opening bracket:
 
+This rule also applies to constructor invocations and object creation expressions, including target-typed `new` expressions
+introduced in C# 9. In all of these cases, the `(` should appear on the same line as the `new` keyword.
+
 ```csharp
 public string JoinName(string first, string last)
 {