Adding C# tests, fixing a bug

src/EditorFeatures/CSharpTest/SplitIntoNestedIfStatements/SplitIntoNestedIfStatementsTests.cs

@@ -519,7 +519,7 @@ void M(bool a, bool b)
         }
 
         [Fact]
-        public async Task SplitWithStatementNoBlock()
+        public async Task SplitWithStatementWithoutBlock()
         {
             await TestInRegularAndScriptAsync(
 @"class C
@@ -628,7 +628,7 @@ void M(bool a, bool b)
         }
 
         [Fact]
-        public async Task SplitWithElseStatementNoBlock()
+        public async Task SplitWithElseStatementWithoutBlock()
         {
             await TestInRegularAndScriptAsync(
 @"class C

src/Features/Core/Portable/SplitIntoNestedIfStatements/AbstractMergeNestedIfStatementsCodeRefactoringProvider.cs

@@ -74,7 +74,7 @@ private async Task<Document> FixAsync(Document document, TextSpan span, ISyntaxF
         private static bool IsFirstStatementOfIfStatement(
             ISyntaxFactsService syntaxFacts, SyntaxNode statement, out TIfStatementSyntax ifStatement)
         {
-            if (syntaxFacts.IsStatementContainer(statement.Parent) &&
+            if ((statement.Parent is TIfStatementSyntax || syntaxFacts.IsPureBlock(statement.Parent)) &&
                 syntaxFacts.GetStatementContainerStatements(statement.Parent).FirstOrDefault() == statement)
             {
                 do
@@ -87,7 +87,7 @@ private async Task<Document> FixAsync(Document document, TextSpan span, ISyntaxF
 
                     statement = statement.Parent;
                 }
-                while (syntaxFacts.IsStatementContainer(statement.Parent) &&
+                while ((statement.Parent is TIfStatementSyntax || syntaxFacts.IsPureBlock(statement.Parent)) &&
                        syntaxFacts.GetStatementContainerStatements(statement.Parent).TrySingleOrDefault() == statement);
             }
 

src/Test/Utilities/Portable/Traits/Traits.cs

@@ -99,6 +99,7 @@ public static class Features
             public const string CodeActionsMakeFieldReadonly = "CodeActions.MakeFieldReadonly";
             public const string CodeActionsMakeMethodAsynchronous = "CodeActions.MakeMethodAsynchronous";
             public const string CodeActionsMakeMethodSynchronous = "CodeActions.MakeMethodSynchronous";
+            public const string CodeActionsMergeNestedIfStatements = "CodeActions.MergeNestedIfStatements";
             public const string CodeActionsMoveDeclarationNearReference = "CodeActions.MoveDeclarationNearReference";
             public const string CodeActionsMoveToTopOfFile = "CodeActions.MoveToTopOfFile";
             public const string CodeActionsMoveType = "CodeActions.MoveType";

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

@@ -1897,6 +1897,9 @@ public SyntaxNode GetTypeOfVariableDeclarator(SyntaxNode node)
         public SyntaxNode GetValueOfEqualsValueClause(SyntaxNode node)
             => ((EqualsValueClauseSyntax)node)?.Value;
 
+        public bool IsPureBlock(SyntaxNode node)
+            => node.IsKind(SyntaxKind.Block);
+
         public bool IsExecutableBlock(SyntaxNode node)
             => node.IsKind(SyntaxKind.Block, SyntaxKind.SwitchSection);
 

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

@@ -288,6 +288,7 @@ internal interface ISyntaxFactsService : ILanguageService
         bool IsTopLevelNodeWithMembers(SyntaxNode node);
         bool HasIncompleteParentMember(SyntaxNode node);
 
+        bool IsPureBlock(SyntaxNode node);
         bool IsExecutableBlock(SyntaxNode node);
         SyntaxList<SyntaxNode> GetExecutableBlockStatements(SyntaxNode node);
         SyntaxNode FindInnermostCommonExecutableBlock(IEnumerable<SyntaxNode> nodes);

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

@@ -1816,6 +1816,11 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
             Return DirectCast(node, EqualsValueSyntax).Value
         End Function
 
+        Public Function IsPureBlock(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsPureBlock
+            ' VB has no equivalent of curly braces.
+            Return False
+        End Function
+
         Public Function IsExecutableBlock(node As SyntaxNode) As Boolean Implements ISyntaxFactsService.IsExecutableBlock
             Return node.IsExecutableBlock()
         End Function