Adding helpers to share language specific code

src/Features/CSharp/Portable/SplitOrMergeIfStatements/CSharpSplitIntoConsecutiveIfStatementsCodeRefactoringProvider.cs

@@ -18,16 +18,7 @@ internal sealed class CSharpSplitIntoConsecutiveIfStatementsCodeRefactoringProvi
         protected override int LogicalOrSyntaxKind => (int)SyntaxKind.LogicalOrExpression;
 
         protected override bool IsConditionOfIfStatement(SyntaxNode expression, out SyntaxNode ifStatementNode)
-        {
-            if (expression.Parent is IfStatementSyntax ifStatement && ifStatement.Condition == expression)
-            {
-                ifStatementNode = ifStatement;
-                return true;
-            }
-
-            ifStatementNode = null;
-            return false;
-        }
+            => Helpers.IsConditionOfIfStatement(expression, out ifStatementNode);
 
         protected override bool HasElseClauses(SyntaxNode ifStatementNode)
         {

src/Features/CSharp/Portable/SplitOrMergeIfStatements/CSharpSplitIntoNestedIfStatementsCodeRefactoringProvider.cs

@@ -17,16 +17,7 @@ internal sealed class CSharpSplitIntoNestedIfStatementsCodeRefactoringProvider
         protected override int LogicalAndSyntaxKind => (int)SyntaxKind.LogicalAndExpression;
 
         protected override bool IsConditionOfIfStatement(SyntaxNode expression, out SyntaxNode ifStatementNode)
-        {
-            if (expression.Parent is IfStatementSyntax ifStatement && ifStatement.Condition == expression)
-            {
-                ifStatementNode = ifStatement;
-                return true;
-            }
-
-            ifStatementNode = null;
-            return false;
-        }
+            => Helpers.IsConditionOfIfStatement(expression, out ifStatementNode);
 
         protected override SyntaxNode SplitIfStatement(
             SyntaxNode ifStatementNode, ExpressionSyntax condition1, ExpressionSyntax condition2)

src/Features/CSharp/Portable/SplitOrMergeIfStatements/Helpers.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 Microsoft.CodeAnalysis.CSharp.Syntax;
+
+namespace Microsoft.CodeAnalysis.CSharp.SplitOrMergeIfStatements
+{
+    internal static class Helpers
+    {
+        public static bool IsConditionOfIfStatement(SyntaxNode expression, out SyntaxNode ifStatementNode)
+        {
+            if (expression.Parent is IfStatementSyntax ifStatement && ifStatement.Condition == expression)
+            {
+                ifStatementNode = ifStatement;
+                return true;
+            }
+
+            ifStatementNode = null;
+            return false;
+        }
+    }
+}

src/Features/Core/Portable/SplitOrMergeIfStatements/Consecutive/AbstractMergeConsecutiveIfStatementsCodeRefactoringProvider.cs

@@ -104,7 +104,8 @@ private bool CanBeMergedWithParent(ISyntaxFactsService syntaxFacts, SyntaxNode i
 
         private static SyntaxNode GetPreviousStatement(ISyntaxFactsService syntaxFacts, SyntaxNode statement)
         {
-            if (!syntaxFacts.IsExecutableBlock(statement.Parent))
+            if (!syntaxFacts.IsStatement(statement) ||
+                !syntaxFacts.IsExecutableBlock(statement.Parent))
             {
                 return null;
             }

src/Features/Core/Portable/SplitOrMergeIfStatements/Consecutive/AbstractSplitIntoConsecutiveIfStatementsCodeRefactoringProvider.cs

@@ -65,7 +65,8 @@ await CanBeSeparateStatementsAsync(document, syntaxFacts, currentIfStatement, ca
                 return false;
             }
 
-            if (!syntaxFacts.IsExecutableBlock(ifStatement.Parent))
+            if (!syntaxFacts.IsStatement(ifStatement) ||
+                !syntaxFacts.IsExecutableBlock(ifStatement.Parent))
             {
                 return false;
             }

src/Features/VisualBasic/Portable/SplitOrMergeIfStatements/Helpers.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 Microsoft.CodeAnalysis.VisualBasic.Syntax
+
+Namespace Microsoft.CodeAnalysis.VisualBasic.SplitOrMergeIfStatements
+    Friend Module Helpers
+        Public Function IsConditionOfIfStatement(expression As SyntaxNode, ByRef ifStatementNode As SyntaxNode) As Boolean
+            If TypeOf expression.Parent Is IfStatementSyntax AndAlso
+               DirectCast(expression.Parent, IfStatementSyntax).Condition Is expression AndAlso
+               TypeOf expression.Parent.Parent Is MultiLineIfBlockSyntax Then
+                ifStatementNode = expression.Parent.Parent
+                Return True
+            End If
+
+            If TypeOf expression.Parent Is ElseIfStatementSyntax AndAlso
+               DirectCast(expression.Parent, ElseIfStatementSyntax).Condition Is expression AndAlso
+               TypeOf expression.Parent.Parent Is ElseIfBlockSyntax Then
+                ifStatementNode = expression.Parent.Parent
+                Return True
+            End If
+
+            ifStatementNode = Nothing
+            Return False
+        End Function
+
+        Public Function GetElseClauses(ifStatementNode As SyntaxNode) As SyntaxList(Of SyntaxNode)
+            If TypeOf ifStatementNode Is MultiLineIfBlockSyntax Then
+                Dim ifBlock = DirectCast(ifStatementNode, MultiLineIfBlockSyntax)
+                Return AddIfNotNull(ifBlock.ElseIfBlocks, ifBlock.ElseBlock)
+            ElseIf TypeOf ifStatementNode Is ElseIfBlockSyntax Then
+                Dim elseIfBlock = DirectCast(ifStatementNode, ElseIfBlockSyntax)
+                Dim ifBlock = DirectCast(elseIfBlock.Parent, MultiLineIfBlockSyntax)
+                Dim nextElseIfBlocks = ifBlock.ElseIfBlocks.RemoveRange(0, ifBlock.ElseIfBlocks.IndexOf(elseIfBlock) + 1)
+                Return AddIfNotNull(nextElseIfBlocks, ifBlock.ElseBlock)
+            End If
+            Throw ExceptionUtilities.UnexpectedValue(ifStatementNode)
+        End Function
+
+        Private Function AddIfNotNull(list As SyntaxList(Of SyntaxNode), node As SyntaxNode) As SyntaxList(Of SyntaxNode)
+            Return If(node IsNot Nothing, list.Add(node), list)
+        End Function
+    End Module
+End Namespace

src/Features/VisualBasic/Portable/SplitOrMergeIfStatements/VisualBasicMergeConsecutiveIfStatementsCodeRefactoringProvider.vb

@@ -79,12 +79,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.SplitOrMergeIfStatements
         End Function
 
         Protected Overrides Function HasElseClauses(ifStatementNode As SyntaxNode) As Boolean
-            If TypeOf ifStatementNode Is MultiLineIfBlockSyntax Then
-                Dim ifBlock = DirectCast(ifStatementNode, MultiLineIfBlockSyntax)
-                Return ifBlock.ElseIfBlocks.Count > 0 OrElse ifBlock.ElseBlock IsNot Nothing
-            End If
-
-            Return True
+            Return Helpers.GetElseClauses(ifStatementNode).Count > 0
         End Function
 
         Protected Overrides Function MergeIfStatements(firstIfStatementNode As SyntaxNode,

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

@@ -47,16 +47,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.SplitOrMergeIfStatements
         End Function
 
         Protected Overrides Function GetElseClauses(ifStatementNode As SyntaxNode) As ImmutableArray(Of SyntaxNode)
-            If TypeOf ifStatementNode Is MultiLineIfBlockSyntax Then
-                Dim ifBlock = DirectCast(ifStatementNode, MultiLineIfBlockSyntax)
-                Return ImmutableArray.ToImmutableArray(Of SyntaxNode)(ifBlock.ElseIfBlocks).Add(ifBlock.ElseBlock)
-            ElseIf TypeOf ifStatementNode Is ElseIfBlockSyntax Then
-                Dim elseIfBlock = DirectCast(ifStatementNode, ElseIfBlockSyntax)
-                Dim ifBlock = DirectCast(elseIfBlock.Parent, MultiLineIfBlockSyntax)
-                Dim nextElseIfBlocks = ifBlock.ElseIfBlocks.RemoveRange(0, ifBlock.ElseIfBlocks.IndexOf(elseIfBlock) + 1)
-                Return ImmutableArray.ToImmutableArray(Of SyntaxNode)(nextElseIfBlocks).Add(ifBlock.ElseBlock)
-            End If
-            Throw ExceptionUtilities.UnexpectedValue(ifStatementNode)
+            Return Helpers.GetElseClauses(ifStatementNode).ToImmutableArray()
         End Function
 
         Protected Overrides Function MergeIfStatements(outerIfStatementNode As SyntaxNode,

src/Features/VisualBasic/Portable/SplitOrMergeIfStatements/VisualBasicSplitIntoConsecutiveIfStatementsCodeRefactoringProvider.vb

@@ -16,31 +16,11 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.SplitOrMergeIfStatements
         Protected Overrides ReadOnly Property LogicalOrSyntaxKind As Integer = SyntaxKind.OrElseExpression
 
         Protected Overrides Function IsConditionOfIfStatement(expression As SyntaxNode, ByRef ifStatementNode As SyntaxNode) As Boolean
-            If TypeOf expression.Parent Is IfStatementSyntax AndAlso
-               DirectCast(expression.Parent, IfStatementSyntax).Condition Is expression AndAlso
-               TypeOf expression.Parent.Parent Is MultiLineIfBlockSyntax Then
-                ifStatementNode = expression.Parent.Parent
-                Return True
-            End If
-
-            If TypeOf expression.Parent Is ElseIfStatementSyntax AndAlso
-               DirectCast(expression.Parent, ElseIfStatementSyntax).Condition Is expression AndAlso
-               TypeOf expression.Parent.Parent Is ElseIfBlockSyntax Then
-                ifStatementNode = expression.Parent.Parent
-                Return True
-            End If
-
-            ifStatementNode = Nothing
-            Return False
+            Return Helpers.IsConditionOfIfStatement(expression, ifStatementNode)
         End Function
 
         Protected Overrides Function HasElseClauses(ifStatementNode As SyntaxNode) As Boolean
-            If TypeOf ifStatementNode Is MultiLineIfBlockSyntax Then
-                Dim ifBlock = DirectCast(ifStatementNode, MultiLineIfBlockSyntax)
-                Return ifBlock.ElseIfBlocks.Count > 0 OrElse ifBlock.ElseBlock IsNot Nothing
-            End If
-
-            Return True
+            Return Helpers.GetElseClauses(ifStatementNode).Count > 0
         End Function
 
         Protected Overrides Function SplitIfStatementIntoElseClause(ifStatementNode As SyntaxNode,

src/Features/VisualBasic/Portable/SplitOrMergeIfStatements/VisualbasicSplitIntoNestedIfStatementsCodeRefactoringProvider.vb

@@ -16,22 +16,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.SplitOrMergeIfStatements
         Protected Overrides ReadOnly Property LogicalAndSyntaxKind As Integer = SyntaxKind.AndAlsoExpression
 
         Protected Overrides Function IsConditionOfIfStatement(expression As SyntaxNode, ByRef ifStatementNode As SyntaxNode) As Boolean
-            If TypeOf expression.Parent Is IfStatementSyntax AndAlso
-               DirectCast(expression.Parent, IfStatementSyntax).Condition Is expression AndAlso
-               TypeOf expression.Parent.Parent Is MultiLineIfBlockSyntax Then
-                ifStatementNode = expression.Parent.Parent
-                Return True
-            End If
-
-            If TypeOf expression.Parent Is ElseIfStatementSyntax AndAlso
-               DirectCast(expression.Parent, ElseIfStatementSyntax).Condition Is expression AndAlso
-               TypeOf expression.Parent.Parent Is ElseIfBlockSyntax Then
-                ifStatementNode = expression.Parent.Parent
-                Return True
-            End If
-
-            ifStatementNode = Nothing
-            Return False
+            Return Helpers.IsConditionOfIfStatement(expression, ifStatementNode)
         End Function
 
         Protected Overrides Function SplitIfStatement(ifStatementNode As SyntaxNode,