Add support for outlining switch expressions

src/EditorFeatures/CSharpTest/Structure/SwitchExpressionStructureTests.cs

@@ -0,0 +1,38 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Threading.Tasks;
+using Microsoft.CodeAnalysis.CSharp.Structure;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.Structure;
+using Microsoft.CodeAnalysis.Test.Utilities;
+using Roslyn.Test.Utilities;
+using Xunit;
+
+namespace Microsoft.CodeAnalysis.Editor.CSharp.UnitTests.Structure;
+
+[Trait(Traits.Feature, Traits.Features.Outlining)]
+public sealed class SwitchExpressionStructureTests : AbstractCSharpSyntaxNodeStructureTests<SwitchExpressionSyntax>
+{
+    internal override AbstractSyntaxStructureProvider CreateProvider() => new SwitchExpressionStructureProvider();
+
+    [Fact, WorkItem("https://github.com/dotnet/roslyn/issues/69357")]
+    public async Task TestSwitchExpression1()
+    {
+        var code = """
+            class C
+            {
+                void M(int i)
+                {
+                    var v = {|hint:$$i switch{|textspan:
+                    {
+                    }|}|}
+                }
+            }
+            """;
+
+        await VerifyBlockSpansAsync(code,
+            Region("textspan", "hint", CSharpStructureHelpers.Ellipsis, autoCollapse: false));
+    }
+}

src/EditorFeatures/CSharpTest/Structure/SwitchStatementStructureTests.cs

@@ -11,11 +11,12 @@
 
 namespace Microsoft.CodeAnalysis.Editor.CSharp.UnitTests.Structure;
 
-public class SwitchStatementStructureTests : AbstractCSharpSyntaxNodeStructureTests<SwitchStatementSyntax>
+[Trait(Traits.Feature, Traits.Features.Outlining)]
+public sealed class SwitchStatementStructureTests : AbstractCSharpSyntaxNodeStructureTests<SwitchStatementSyntax>
 {
     internal override AbstractSyntaxStructureProvider CreateProvider() => new SwitchStatementStructureProvider();
 
-    [Fact, Trait(Traits.Feature, Traits.Features.Outlining)]
+    [Fact]
     public async Task TestSwitchStatement1()
     {
         var code = """
@@ -34,7 +35,7 @@ await VerifyBlockSpansAsync(code,
             Region("textspan", "hint", CSharpStructureHelpers.Ellipsis, autoCollapse: false));
     }
 
-    [Fact, Trait(Traits.Feature, Traits.Features.Outlining)]
+    [Fact]
     public async Task TestSwitchStatement2()
     {
         var code = """

src/Features/CSharp/Portable/Structure/CSharpBlockStructureProvider.cs

@@ -47,6 +47,7 @@ private static ImmutableDictionary<Type, ImmutableArray<AbstractSyntaxStructureP
         builder.Add<RegionDirectiveTriviaSyntax, RegionDirectiveStructureProvider>();
         builder.Add<SimpleLambdaExpressionSyntax, SimpleLambdaExpressionStructureProvider>();
         builder.Add<StructDeclarationSyntax, TypeDeclarationStructureProvider>();
+        builder.Add<SwitchExpressionSyntax, SwitchExpressionStructureProvider>();
         builder.Add<SwitchStatementSyntax, SwitchStatementStructureProvider>();
         builder.Add<LiteralExpressionSyntax, StringLiteralExpressionStructureProvider>();
         builder.Add<InterpolatedStringExpressionSyntax, InterpolatedStringExpressionStructureProvider>();

src/Features/CSharp/Portable/Structure/Providers/SwitchExpressionStructureProvider.cs

@@ -0,0 +1,28 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Threading;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.PooledObjects;
+using Microsoft.CodeAnalysis.Structure;
+using Microsoft.CodeAnalysis.Text;
+
+namespace Microsoft.CodeAnalysis.CSharp.Structure;
+
+internal sealed class SwitchExpressionStructureProvider : AbstractSyntaxNodeStructureProvider<SwitchExpressionSyntax>
+{
+    protected override void CollectBlockSpans(
+        SyntaxToken previousToken,
+        SwitchExpressionSyntax node,
+        ArrayBuilder<BlockSpan> spans,
+        BlockStructureOptions options,
+        CancellationToken cancellationToken)
+    {
+        spans.Add(new BlockSpan(
+            isCollapsible: true,
+            textSpan: TextSpan.FromBounds(node.SwitchKeyword.Span.End, node.CloseBraceToken.Span.End),
+            hintSpan: node.Span,
+            type: BlockTypes.Conditional));
+    }
+}

src/Features/CSharp/Portable/Structure/Providers/SwitchStatementStructureProvider.cs

@@ -10,7 +10,7 @@
 
 namespace Microsoft.CodeAnalysis.CSharp.Structure;
 
-internal class SwitchStatementStructureProvider : AbstractSyntaxNodeStructureProvider<SwitchStatementSyntax>
+internal sealed class SwitchStatementStructureProvider : AbstractSyntaxNodeStructureProvider<SwitchStatementSyntax>
 {
     protected override void CollectBlockSpans(
         SyntaxToken previousToken,