Add support for collapsing => expression bodies.

src/Features/CSharp/Portable/CSharpFeatures.csproj

@@ -55,6 +55,7 @@
     <Compile Include="..\..\..\Compilers\CSharp\Portable\Syntax\LambdaUtilities.cs">
       <Link>InternalUtilities\LambdaUtilities.cs</Link>
     </Compile>
+    <Compile Include="Structure\Providers\ArrowExpressionClauseStructureProvider.cs" />
     <Compile Include="ConvertToInterpolatedString\CSharpConvertConcatenationToInterpolatedStringRefactoringProvider.cs" />
     <Compile Include="Structure\Providers\InitializerExpressionStructureProvider.cs" />
     <Compile Include="UseCoalesceExpression\CSharpUseCoalesceExpressionForNullableDiagnosticAnalyzer.cs" />

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

@@ -7,7 +7,6 @@
 
 namespace Microsoft.CodeAnalysis.CSharp.Structure
 {
-
     internal class CSharpBlockStructureProvider : AbstractBlockStructureProvider
     {
         private static ImmutableDictionary<Type, ImmutableArray<AbstractSyntaxStructureProvider>> CreateDefaultNodeProviderMap()
@@ -16,6 +15,7 @@ internal class CSharpBlockStructureProvider : AbstractBlockStructureProvider
 
             builder.Add<AccessorDeclarationSyntax, AccessorDeclarationStructureProvider>();
             builder.Add<AnonymousMethodExpressionSyntax, AnonymousMethodExpressionStructureProvider>();
+            builder.Add<ArrowExpressionClauseSyntax, ArrowExpressionClauseStructureProvider>();
             builder.Add<BlockSyntax, BlockSyntaxStructureProvider>();
             builder.Add<ClassDeclarationSyntax, TypeDeclarationStructureProvider, MetadataAsSource.MetadataTypeDeclarationStructureProvider>();
             builder.Add<CompilationUnitSyntax, CompilationUnitStructureProvider>();

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

+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+using System.Threading;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.Options;
+using Microsoft.CodeAnalysis.Structure;
+using Microsoft.CodeAnalysis.Text;
+
+namespace Microsoft.CodeAnalysis.CSharp.Structure
+{
+    internal class ArrowExpressionClauseStructureProvider : AbstractSyntaxNodeStructureProvider<ArrowExpressionClauseSyntax>
+    {
+        protected override void CollectBlockSpans(
+            ArrowExpressionClauseSyntax node,
+            ArrayBuilder<BlockSpan> spans,
+            OptionSet options,
+            CancellationToken cancellationToken)
+        {
+            var previousToken = node.ArrowToken.GetPreviousToken();
+            spans.Add(new BlockSpan(
+                isCollapsible: true,
+                textSpan: TextSpan.FromBounds(previousToken.Span.End, node.Span.End),
+                hintSpan: node.Parent.Span,
+                type: BlockTypes.Member));
+        }
+    }
+}
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