Allow switch arms to start a line with an open brace

Fixes #57854
dotnet · Sep 19, 2023 · 920fc47 · 920fc47
1 parent dc3d069
commit 920fc47
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Showing 2 changed files with 70 additions and 12 deletions.
diff --git a/src/Workspaces/CSharpTest/Formatting/FormattingTests.cs b/src/Workspaces/CSharpTest/Formatting/FormattingTests.cs
@@ -10086,6 +10086,44 @@ public bool IsFoo(A a)
 }", changedOptionSet: changingOptions);
         }
 
+        [Fact, Trait(Traits.Feature, Traits.Features.Formatting)]
+        [WorkItem(57854, "https://github.com/dotnet/roslyn/issues/57854")]
+        public async Task NewLinesForBraces_PropertyPatternClauses_NonDefaultInSwitchExpression()
+        {
+            var changingOptions = new OptionsCollection(LanguageNames.CSharp)
+            {
+                { NewLineBeforeOpenBrace, NewLineBeforeOpenBrace.DefaultValue.WithFlagValue(NewLineBeforeOpenBracePlacement.ObjectCollectionArrayInitializers, false) },
+            };
+            await AssertFormatAsync(
+                @"
+class A
+{
+    public string Name { get; }
+
+    public bool IsFoo(A a)
+    {
+        return a switch {
+            { Name: ""foo"" } => true,
+            _ => false,
+        };
+    }
+}",
+                @"
+class A
+{
+    public string Name { get; }
+
+    public bool IsFoo(A a)
+    {
+        return a switch
+        {
+            { Name: ""foo"" } => true,
+            _ => false,
+        };
+    }
+}", changedOptionSet: changingOptions);
+        }
+
         [Theory, CombinatorialData]
         [WorkItem("https://github.com/dotnet/roslyn/issues/52413")]
         public async Task NewLinesForBraces_PropertyPatternClauses_SingleLine(bool option)

diff --git a/...ilitiesAndExtensions/Compiler/CSharp/Formatting/Rules/NewLineUserSettingFormattingRule.cs b/...ilitiesAndExtensions/Compiler/CSharp/Formatting/Rules/NewLineUserSettingFormattingRule.cs
@@ -127,18 +127,38 @@ private static bool IsControlBlock(SyntaxNode node)
             }
 
             // new { - Object Initialization, or with { - Record with initializer, or is { - property pattern clauses
-            if (currentToken.IsKind(SyntaxKind.OpenBraceToken) &&
-                currentToken.Parent.Kind() is
-                    SyntaxKind.ObjectInitializerExpression or
-                    SyntaxKind.CollectionInitializerExpression or
-                    SyntaxKind.ArrayInitializerExpression or
-                    SyntaxKind.ImplicitArrayCreationExpression or
-                    SyntaxKind.WithInitializerExpression or
-                    SyntaxKind.PropertyPatternClause)
-            {
-                if (!_options.NewLines.HasFlag(NewLinePlacement.BeforeOpenBraceInObjectCollectionArrayInitializers))
-                {
-                    operation = CreateAdjustSpacesOperation(1, AdjustSpacesOption.ForceSpaces);
+            if (currentToken.IsKind(SyntaxKind.OpenBraceToken))
+            {
+                if (currentToken.Parent.Kind() is SyntaxKind.ObjectInitializerExpression
+                    or SyntaxKind.CollectionInitializerExpression
+                    or SyntaxKind.ArrayInitializerExpression
+                    or SyntaxKind.ImplicitArrayCreationExpression
+                    or SyntaxKind.WithInitializerExpression)
+                {
+                    if (!_options.NewLines.HasFlag(NewLinePlacement.BeforeOpenBraceInObjectCollectionArrayInitializers))
+                    {
+                        operation = CreateAdjustSpacesOperation(1, AdjustSpacesOption.ForceSpaces);
+                    }
+                }
+                else if (currentToken.Parent.IsKind(SyntaxKind.PropertyPatternClause))
+                {
+                    if (!_options.NewLines.HasFlag(NewLinePlacement.BeforeOpenBraceInObjectCollectionArrayInitializers))
+                    {
+                        // Allow property patterns in switch expressions to start on their own line:
+                        //
+                        // var x = y switch {
+                        //    { Value: true } => false,    ⬅️ This line starts with an open brace
+                        //    _ => true,
+                        // };
+                        var isFirstTokenOfSwitchArm = currentToken.Parent.IsParentKind(SyntaxKind.RecursivePattern, out RecursivePatternSyntax? recursivePattern)
+                            && recursivePattern.IsParentKind(SyntaxKind.SwitchExpressionArm, out SwitchExpressionArmSyntax? switchExpressionArm)
+                            && switchExpressionArm.GetFirstToken() == currentToken;
+
+                        var spacesOption = isFirstTokenOfSwitchArm
+                            ? AdjustSpacesOption.ForceSpacesIfOnSingleLine
+                            : AdjustSpacesOption.ForceSpaces;
+                        operation = CreateAdjustSpacesOperation(1, spacesOption);
+                    }
                 }
             }