Adding C# & VB MergeNestedIfStatementsCodeRefactoringProvider

src/Features/CSharp/Portable/SplitIntoNestedIfStatements/CSharpMergeNestedIfStatementsCodeRefactoringProvider.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.Collections.Immutable;
+using System.Composition;
+using Microsoft.CodeAnalysis.CodeRefactorings;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.Editing;
+using Microsoft.CodeAnalysis.SplitIntoNestedIfStatements;
+
+namespace Microsoft.CodeAnalysis.CSharp.SplitIntoNestedIfStatements
+{
+    [ExportCodeRefactoringProvider(LanguageNames.CSharp, Name = PredefinedCodeRefactoringProviderNames.MergeNestedIfStatements), Shared]
+    internal sealed class CSharpMergeNestedIfStatementsCodeRefactoringProvider
+        : AbstractMergeNestedIfStatementsCodeRefactoringProvider<IfStatementSyntax>
+    {
+        protected override string IfKeywordText => SyntaxFacts.GetText(SyntaxKind.IfKeyword);
+
+        protected override bool IsTokenOfIfStatement(SyntaxToken token, out IfStatementSyntax ifStatement)
+        {
+            if (token.Parent is IfStatementSyntax s)
+            {
+                ifStatement = s;
+                return true;
+            }
+
+            ifStatement = null;
+            return false;
+        }
+
+        protected override bool IsFirstStatementOfIfStatement(SyntaxNode statement, out IfStatementSyntax ifStatement)
+        {
+            if (statement.Parent is IfStatementSyntax s1 && s1.Statement == statement)
+            {
+                ifStatement = s1;
+                return true;
+            }
+
+            if (statement.Parent is BlockSyntax block && block.Statements.FirstOrDefault() == statement &&
+                block.Parent is IfStatementSyntax s2 && s2.Statement == block)
+            {
+                ifStatement = s2;
+                return true;
+            }
+
+            ifStatement = null;
+            return false;
+        }
+
+        protected override ImmutableArray<SyntaxNode> GetElseClauses(IfStatementSyntax ifStatement)
+        {
+            return ImmutableArray.Create<SyntaxNode>(ifStatement.Else);
+        }
+
+        protected override IfStatementSyntax MergeIfStatements(IfStatementSyntax outerIfStatement, IfStatementSyntax innerIfStatement, SyntaxGenerator generator)
+        {
+            var newCondition = SyntaxFactory.BinaryExpression(
+                SyntaxKind.LogicalAndExpression,
+                (ExpressionSyntax)generator.AddParentheses(outerIfStatement.Condition),
+                (ExpressionSyntax)generator.AddParentheses(innerIfStatement.Condition));
+            return outerIfStatement.WithCondition(newCondition).WithStatement(innerIfStatement.Statement);
+        }
+    }
+}

src/Features/Core/Portable/CodeRefactorings/PredefinedCodeRefactoringProviderNames.cs

@@ -26,6 +26,7 @@ internal static class PredefinedCodeRefactoringProviderNames
         public const string MoveDeclarationNearReference = "Move Declaration Near Reference Code Action Provider";
         public const string SimplifyLambda = "Simplify Lambda Code Action Provider";
         public const string ConvertToInterpolatedString = "Convert To Interpolated String Code Action Provider";
+        public const string MergeNestedIfStatements = "Merge Nested If Statements Code Action Provider";
         public const string MoveTypeToFile = "Move Type To File Code Action Provider";
         public const string ReplaceDocCommentTextWithTag = "Replace Documentation Comment Text With Tag Code Action Provider";
         public const string SplitIntoNestedIfStatements = "Split Into Nested If Statements Code Action Provider";

src/Features/Core/Portable/FeaturesResources.Designer.cs

@@ -2233,6 +2233,15 @@ internal class FeaturesResources {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Merge nested &apos;{0}&apos; statements.
+        /// </summary>
+        internal static string Merge_nested_0_statements {
+            get {
+                return ResourceManager.GetString("Merge_nested_0_statements", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to method.
         /// </summary>

src/Features/Core/Portable/FeaturesResources.resx

@@ -1472,4 +1472,7 @@ This version used in: {2}</value>
   <data name="Split_into_nested_0_statements" xml:space="preserve">
     <value>Split into nested '{0}' statements</value>
   </data>
+  <data name="Merge_nested_0_statements" xml:space="preserve">
+    <value>Merge nested '{0}' statements</value>
+  </data>
 </root>
\ No newline at end of file

src/Features/Core/Portable/SplitIntoNestedIfStatements/AbstractMergeNestedIfStatementsCodeRefactoringProvider.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;
+using System.Collections.Immutable;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.CodeAnalysis.CodeActions;
+using Microsoft.CodeAnalysis.CodeRefactorings;
+using Microsoft.CodeAnalysis.Editing;
+using Microsoft.CodeAnalysis.Formatting;
+using Microsoft.CodeAnalysis.LanguageServices;
+using Microsoft.CodeAnalysis.Shared.Extensions;
+using Microsoft.CodeAnalysis.Text;
+using Microsoft.CodeAnalysis.Utilities;
+using Roslyn.Utilities;
+
+namespace Microsoft.CodeAnalysis.SplitIntoNestedIfStatements
+{
+    internal abstract class AbstractMergeNestedIfStatementsCodeRefactoringProvider<
+        TIfStatementSyntax> : CodeRefactoringProvider
+        where TIfStatementSyntax : SyntaxNode
+    {
+        protected abstract string IfKeywordText { get; }
+
+        protected abstract bool IsTokenOfIfStatement(SyntaxToken token, out TIfStatementSyntax ifStatement);
+
+        protected abstract bool IsFirstStatementOfIfStatement(SyntaxNode statement, out TIfStatementSyntax ifStatement);
+
+        protected abstract ImmutableArray<SyntaxNode> GetElseClauses(TIfStatementSyntax ifStatement);
+
+        protected abstract TIfStatementSyntax MergeIfStatements(TIfStatementSyntax outerIfStatement, TIfStatementSyntax innerIfStatement, SyntaxGenerator generator);
+
+        public sealed override async Task ComputeRefactoringsAsync(CodeRefactoringContext context)
+        {
+            var root = await context.Document.GetSyntaxRootAsync(context.CancellationToken).ConfigureAwait(false);
+            var token = root.FindToken(context.Span.Start);
+
+            if (context.Span.Length > 0 &&
+                context.Span != token.Span)
+            {
+                return;
+            }
+
+            if (IsTokenOfIfStatement(token, out var ifStatement) &&
+                IsFirstStatementOfIfStatement(ifStatement, out var parentIfStatement) &&
+                await CanBeMergedAsync(context.Document, parentIfStatement, ifStatement, context.CancellationToken))
+            {
+                context.RegisterRefactoring(
+                    new MyCodeAction(
+                        c => FixAsync(context.Document, context.Span, c),
+                        IfKeywordText));
+            }
+        }
+
+        private async Task<Document> FixAsync(Document document, TextSpan span, CancellationToken cancellationToken)
+        {
+            var root = await document.GetSyntaxRootAsync(cancellationToken).ConfigureAwait(false);
+            var token = root.FindToken(span.Start);
+
+            Contract.ThrowIfFalse(IsTokenOfIfStatement(token, out var ifStatement));
+            Contract.ThrowIfFalse(IsFirstStatementOfIfStatement(ifStatement, out var parentIfStatement));
+
+            var newIfStatement = MergeIfStatements(parentIfStatement, ifStatement, document.GetLanguageService<SyntaxGenerator>());
+
+            var newRoot = root.ReplaceNode(parentIfStatement, newIfStatement.WithAdditionalAnnotations(Formatter.Annotation));
+            return document.WithSyntaxRoot(newRoot);
+        }
+
+        private async Task<bool> CanBeMergedAsync(
+            Document document,
+            TIfStatementSyntax outerIfStatement,
+            TIfStatementSyntax innerIfStatement,
+            CancellationToken cancellationToken)
+        {
+            var syntaxFacts = document.GetLanguageService<ISyntaxFactsService>();
+
+            if (!GetElseClauses(outerIfStatement).SequenceEqual(GetElseClauses(innerIfStatement), syntaxFacts.AreEquivalent))
+            {
+                return false;
+            }
+
+            var statements = syntaxFacts.GetStatementContainerStatements(innerIfStatement.Parent);
+            if (statements.Count == 1)
+            {
+                // There are no other statements below the inner if statement. Merging is OK.
+                return true;
+            }
+            else
+            {
+                // There are statements below the inner if statement. We can merge if
+                // 1. these statements exist below the outer if as well, and
+                // 2. control flow can't reach after the end of these statements (otherwise, they would get executed twice).
+                // This will typically look like a single return, break, continue or a throw statement.
+
+                if (!syntaxFacts.IsStatementContainer(outerIfStatement.Parent))
+                {
+                    // This shouldn't happen, but let's be cautious.
+                    return false;
+                }
+
+                var outerStatements = syntaxFacts.GetStatementContainerStatements(outerIfStatement.Parent);
+                var outerIfStatementIndex = outerStatements.IndexOf(outerIfStatement);
+
+                var remainingStatements = statements.Skip(1);
+                var remainingOuterStatements = outerStatements.Skip(outerIfStatementIndex + 1);
+
+                if (!remainingStatements.SequenceEqual(remainingOuterStatements.Take(statements.Count - 1), syntaxFacts.AreEquivalent))
+                {
+                    return false;
+                }
+
+                var semanticModel = await document.GetSemanticModelAsync(cancellationToken).ConfigureAwait(false);
+                var controlFlow = semanticModel.AnalyzeControlFlow(statements.First(), statements.Last());
+
+                return !controlFlow.EndPointIsReachable;
+            }
+        }
+
+        private sealed class MyCodeAction : CodeAction.DocumentChangeAction
+        {
+            public MyCodeAction(Func<CancellationToken, Task<Document>> createChangedDocument, string ifKeywordText)
+                : base(string.Format(FeaturesResources.Merge_nested_0_statements, ifKeywordText), createChangedDocument)
+            {
+            }
+        }
+    }
+}

src/Features/Core/Portable/xlf/FeaturesResources.cs.xlf

@@ -107,6 +107,11 @@
         <target state="new">Introduce query variable</target>
         <note />
       </trans-unit>
+      <trans-unit id="Merge_nested_0_statements">
+        <source>Merge nested '{0}' statements</source>
+        <target state="new">Merge nested '{0}' statements</target>
+        <note />
+      </trans-unit>
       <trans-unit id="Private_member_0_can_be_removed_as_the_value_assigned_to_it_is_never_read">
         <source>Private member '{0}' can be removed as the value assigned to it is never read.</source>
         <target state="new">Private member '{0}' can be removed as the value assigned to it is never read.</target>

src/Features/Core/Portable/xlf/FeaturesResources.de.xlf

@@ -107,6 +107,11 @@
         <target state="new">Introduce query variable</target>
         <note />
       </trans-unit>
+      <trans-unit id="Merge_nested_0_statements">
+        <source>Merge nested '{0}' statements</source>
+        <target state="new">Merge nested '{0}' statements</target>
+        <note />
+      </trans-unit>
       <trans-unit id="Private_member_0_can_be_removed_as_the_value_assigned_to_it_is_never_read">
         <source>Private member '{0}' can be removed as the value assigned to it is never read.</source>
         <target state="new">Private member '{0}' can be removed as the value assigned to it is never read.</target>

src/Features/Core/Portable/xlf/FeaturesResources.es.xlf

@@ -107,6 +107,11 @@
         <target state="new">Introduce query variable</target>
         <note />
       </trans-unit>
+      <trans-unit id="Merge_nested_0_statements">
+        <source>Merge nested '{0}' statements</source>
+        <target state="new">Merge nested '{0}' statements</target>
+        <note />
+      </trans-unit>
       <trans-unit id="Private_member_0_can_be_removed_as_the_value_assigned_to_it_is_never_read">
         <source>Private member '{0}' can be removed as the value assigned to it is never read.</source>
         <target state="new">Private member '{0}' can be removed as the value assigned to it is never read.</target>

src/Features/Core/Portable/xlf/FeaturesResources.fr.xlf

@@ -107,6 +107,11 @@
         <target state="new">Introduce query variable</target>
         <note />
       </trans-unit>
+      <trans-unit id="Merge_nested_0_statements">
+        <source>Merge nested '{0}' statements</source>
+        <target state="new">Merge nested '{0}' statements</target>
+        <note />
+      </trans-unit>
       <trans-unit id="Private_member_0_can_be_removed_as_the_value_assigned_to_it_is_never_read">
         <source>Private member '{0}' can be removed as the value assigned to it is never read.</source>
         <target state="new">Private member '{0}' can be removed as the value assigned to it is never read.</target>

src/Features/Core/Portable/xlf/FeaturesResources.it.xlf

@@ -107,6 +107,11 @@
         <target state="new">Introduce query variable</target>
         <note />
       </trans-unit>
+      <trans-unit id="Merge_nested_0_statements">
+        <source>Merge nested '{0}' statements</source>
+        <target state="new">Merge nested '{0}' statements</target>
+        <note />
+      </trans-unit>
       <trans-unit id="Private_member_0_can_be_removed_as_the_value_assigned_to_it_is_never_read">
         <source>Private member '{0}' can be removed as the value assigned to it is never read.</source>
         <target state="new">Private member '{0}' can be removed as the value assigned to it is never read.</target>

src/Features/Core/Portable/xlf/FeaturesResources.ja.xlf

@@ -107,6 +107,11 @@
         <target state="new">Introduce query variable</target>
         <note />
       </trans-unit>
+      <trans-unit id="Merge_nested_0_statements">
+        <source>Merge nested '{0}' statements</source>
+        <target state="new">Merge nested '{0}' statements</target>
+        <note />
+      </trans-unit>
       <trans-unit id="Private_member_0_can_be_removed_as_the_value_assigned_to_it_is_never_read">
         <source>Private member '{0}' can be removed as the value assigned to it is never read.</source>
         <target state="new">Private member '{0}' can be removed as the value assigned to it is never read.</target>

src/Features/Core/Portable/xlf/FeaturesResources.ko.xlf

@@ -107,6 +107,11 @@
         <target state="new">Introduce query variable</target>
         <note />
       </trans-unit>
+      <trans-unit id="Merge_nested_0_statements">
+        <source>Merge nested '{0}' statements</source>
+        <target state="new">Merge nested '{0}' statements</target>
+        <note />
+      </trans-unit>
       <trans-unit id="Private_member_0_can_be_removed_as_the_value_assigned_to_it_is_never_read">
         <source>Private member '{0}' can be removed as the value assigned to it is never read.</source>
         <target state="new">Private member '{0}' can be removed as the value assigned to it is never read.</target>

src/Features/Core/Portable/xlf/FeaturesResources.pl.xlf

@@ -107,6 +107,11 @@
         <target state="new">Introduce query variable</target>
         <note />
       </trans-unit>
+      <trans-unit id="Merge_nested_0_statements">
+        <source>Merge nested '{0}' statements</source>
+        <target state="new">Merge nested '{0}' statements</target>
+        <note />
+      </trans-unit>
       <trans-unit id="Private_member_0_can_be_removed_as_the_value_assigned_to_it_is_never_read">
         <source>Private member '{0}' can be removed as the value assigned to it is never read.</source>
         <target state="new">Private member '{0}' can be removed as the value assigned to it is never read.</target>

src/Features/Core/Portable/xlf/FeaturesResources.pt-BR.xlf

@@ -107,6 +107,11 @@
         <target state="new">Introduce query variable</target>
         <note />
       </trans-unit>
+      <trans-unit id="Merge_nested_0_statements">
+        <source>Merge nested '{0}' statements</source>
+        <target state="new">Merge nested '{0}' statements</target>
+        <note />
+      </trans-unit>
       <trans-unit id="Private_member_0_can_be_removed_as_the_value_assigned_to_it_is_never_read">
         <source>Private member '{0}' can be removed as the value assigned to it is never read.</source>
         <target state="new">Private member '{0}' can be removed as the value assigned to it is never read.</target>

src/Features/Core/Portable/xlf/FeaturesResources.ru.xlf

@@ -107,6 +107,11 @@
         <target state="new">Introduce query variable</target>
         <note />
       </trans-unit>
+      <trans-unit id="Merge_nested_0_statements">
+        <source>Merge nested '{0}' statements</source>
+        <target state="new">Merge nested '{0}' statements</target>
+        <note />
+      </trans-unit>
       <trans-unit id="Private_member_0_can_be_removed_as_the_value_assigned_to_it_is_never_read">
         <source>Private member '{0}' can be removed as the value assigned to it is never read.</source>
         <target state="new">Private member '{0}' can be removed as the value assigned to it is never read.</target>

src/Features/Core/Portable/xlf/FeaturesResources.tr.xlf

@@ -107,6 +107,11 @@
         <target state="new">Introduce query variable</target>
         <note />
       </trans-unit>
+      <trans-unit id="Merge_nested_0_statements">
+        <source>Merge nested '{0}' statements</source>
+        <target state="new">Merge nested '{0}' statements</target>
+        <note />
+      </trans-unit>
       <trans-unit id="Private_member_0_can_be_removed_as_the_value_assigned_to_it_is_never_read">
         <source>Private member '{0}' can be removed as the value assigned to it is never read.</source>
         <target state="new">Private member '{0}' can be removed as the value assigned to it is never read.</target>

src/Features/Core/Portable/xlf/FeaturesResources.zh-Hans.xlf

@@ -107,6 +107,11 @@
         <target state="new">Introduce query variable</target>
         <note />
       </trans-unit>
+      <trans-unit id="Merge_nested_0_statements">
+        <source>Merge nested '{0}' statements</source>
+        <target state="new">Merge nested '{0}' statements</target>
+        <note />
+      </trans-unit>
       <trans-unit id="Private_member_0_can_be_removed_as_the_value_assigned_to_it_is_never_read">
         <source>Private member '{0}' can be removed as the value assigned to it is never read.</source>
         <target state="new">Private member '{0}' can be removed as the value assigned to it is never read.</target>

src/Features/Core/Portable/xlf/FeaturesResources.zh-Hant.xlf

@@ -107,6 +107,11 @@
         <target state="new">Introduce query variable</target>
         <note />
       </trans-unit>
+      <trans-unit id="Merge_nested_0_statements">
+        <source>Merge nested '{0}' statements</source>
+        <target state="new">Merge nested '{0}' statements</target>
+        <note />
+      </trans-unit>
       <trans-unit id="Private_member_0_can_be_removed_as_the_value_assigned_to_it_is_never_read">
         <source>Private member '{0}' can be removed as the value assigned to it is never read.</source>
         <target state="new">Private member '{0}' can be removed as the value assigned to it is never read.</target>

src/Features/VisualBasic/Portable/SplitIntoNestedIfStatements/VisualBasicMergeNestedIfStatementsCodeRefactoringProvider.vb

+' Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+Imports System.Collections.Immutable
+Imports System.Composition
+Imports Microsoft.CodeAnalysis.CodeRefactorings
+Imports Microsoft.CodeAnalysis.Editing
+Imports Microsoft.CodeAnalysis.SplitIntoNestedIfStatements
+Imports Microsoft.CodeAnalysis.VisualBasic.Syntax
+
+Namespace Microsoft.CodeAnalysis.VisualBasic.SplitIntoNestedIfStatements
+    <ExportCodeRefactoringProvider(LanguageNames.VisualBasic, Name:=PredefinedCodeRefactoringProviderNames.MergeNestedIfStatements), [Shared]>
+    Friend NotInheritable Class VisualBasicMergeNestedIfStatementsCodeRefactoringProvider
+        Inherits AbstractMergeNestedIfStatementsCodeRefactoringProvider(Of MultiLineIfBlockSyntax)
+
+        Protected Overrides ReadOnly Property IfKeywordText As String = SyntaxFacts.GetText(SyntaxKind.IfKeyword)
+
+        Protected Overrides Function IsTokenOfIfStatement(token As SyntaxToken, ByRef ifStatement As MultiLineIfBlockSyntax) As Boolean
+            If TypeOf token.Parent Is IfStatementSyntax AndAlso TypeOf token.Parent.Parent Is MultiLineIfBlockSyntax Then
+                ifStatement = DirectCast(token.Parent.Parent, MultiLineIfBlockSyntax)
+                Return True
+            End If
+
+            ifStatement = Nothing
+            Return False
+        End Function
+
+        Protected Overrides Function IsFirstStatementOfIfStatement(statement As SyntaxNode, ByRef ifStatement As MultiLineIfBlockSyntax) As Boolean
+            If TypeOf statement.Parent Is MultiLineIfBlockSyntax Then
+                ifStatement = DirectCast(statement.Parent, MultiLineIfBlockSyntax)
+                Return ifStatement.Statements.FirstOrDefault() Is statement
+            End If
+
+            ifStatement = Nothing
+            Return False
+        End Function
+
+        Protected Overrides Function GetElseClauses(ifStatement As MultiLineIfBlockSyntax) As ImmutableArray(Of SyntaxNode)
+            Return ImmutableArray.ToImmutableArray(Of SyntaxNode)(ifStatement.ElseIfBlocks).Add(ifStatement.ElseBlock)
+        End Function
+
+        Protected Overrides Function MergeIfStatements(outerIfBlock As MultiLineIfBlockSyntax, innerIfBlock As MultiLineIfBlockSyntax, generator As SyntaxGenerator) As MultiLineIfBlockSyntax
+            Dim newCondition = SyntaxFactory.BinaryExpression(SyntaxKind.AndAlsoExpression,
+                                                              DirectCast(generator.AddParentheses(outerIfBlock.IfStatement.Condition), ExpressionSyntax),
+                                                              SyntaxFactory.Token(SyntaxKind.AndAlsoKeyword),
+                                                              DirectCast(generator.AddParentheses(innerIfBlock.IfStatement.Condition), ExpressionSyntax))
+            Return outerIfBlock.WithIfStatement(outerIfBlock.IfStatement.WithCondition(newCondition)).WithStatements(innerIfBlock.Statements)
+        End Function
+    End Class
+End Namespace

src/Workspaces/CSharp/Portable/LanguageServices/CSharpSyntaxFactsService.cs

@@ -1895,14 +1895,31 @@ public SyntaxNode GetValueOfEqualsValueClause(SyntaxNode node)
             => ((EqualsValueClauseSyntax)node)?.Value;
 
         public bool IsExecutableBlock(SyntaxNode node)
-            => node.IsKind(SyntaxKind.Block);
+            => node.IsKind(SyntaxKind.Block, SyntaxKind.SwitchSection);
 
         public SyntaxList<SyntaxNode> GetExecutableBlockStatements(SyntaxNode node)
-            => ((BlockSyntax)node).Statements;
+        {
+            switch (node)
+            {
+                case BlockSyntax block:
+                    return block.Statements;
+                case SwitchSectionSyntax switchSection:
+                    return switchSection.Statements;
+                default:
+                    throw ExceptionUtilities.UnexpectedValue(node);
+            }
+        }
 
         public SyntaxNode FindInnermostCommonExecutableBlock(IEnumerable<SyntaxNode> nodes)
             => nodes.FindInnermostCommonBlock();
 
+        public bool IsStatementContainer(SyntaxNode node)
+            => IsExecutableBlock(node) || node.IsEmbeddedStatementOwner();
+
+        public IReadOnlyList<SyntaxNode> GetStatementContainerStatements(SyntaxNode node) => IsExecutableBlock(node)
+                ? GetExecutableBlockStatements(node)
+                : (IReadOnlyList<SyntaxNode>)ImmutableArray.Create<SyntaxNode>(node.GetEmbeddedStatement());
+
         public bool IsCastExpression(SyntaxNode node)
             => node is CastExpressionSyntax;
 

src/Workspaces/Core/Portable/LanguageServices/SyntaxFactsService/ISyntaxFactsService.cs

@@ -290,6 +290,9 @@ internal interface ISyntaxFactsService : ILanguageService
         SyntaxList<SyntaxNode> GetExecutableBlockStatements(SyntaxNode node);
         SyntaxNode FindInnermostCommonExecutableBlock(IEnumerable<SyntaxNode> nodes);
 
+        bool IsStatementContainer(SyntaxNode node);
+        IReadOnlyList<SyntaxNode> GetStatementContainerStatements(SyntaxNode node);
+
         bool AreEquivalent(SyntaxToken token1, SyntaxToken token2);
         bool AreEquivalent(SyntaxNode node1, SyntaxNode node2);
 

src/Workspaces/Core/Portable/Utilities/IReadOnlyListExtensions.cs

@@ -20,6 +20,19 @@ public static T Last<T>(this IReadOnlyList<T> list)
             return list[list.Count - 1];
         }
 
+        public static int IndexOf<T>(this IReadOnlyList<T> list, T item)
+        {
+            for (int i = 0; i < list.Count; ++i)
+            {
+                if (list[i].Equals(item))
+                {
+                    return i;
+                }
+            }
+
+            return -1;
+        }
+
         private class ReadOnlyList<T> : IReadOnlyList<T>
         {
             private readonly IList<T> _list;

src/Workspaces/VisualBasic/Portable/LanguageServices/VisualBasicSyntaxFactsService.vb

@@ -1824,6 +1824,14 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
             Return nodes.FindInnermostCommonExecutableBlock()
         End Function
 
+        Public Function IsStatementContainer(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsStatementContainer
+            Return IsExecutableBlock(node)
+        End Function
+
+        Public Function GetStatementContainerStatements(node As SyntaxNode) As IReadOnlyList(Of SyntaxNode) Implements ISyntaxFactsService.GetStatementContainerStatements
+            Return GetExecutableBlockStatements(node)
+        End Function
+
         Private Function ISyntaxFactsService_GetLeadingBlankLines(node As SyntaxNode) As ImmutableArray(Of SyntaxTrivia) Implements ISyntaxFactsService.GetLeadingBlankLines
             Return MyBase.GetLeadingBlankLines(node)
         End Function