Fix ExtractMethod in VB elseif blocks

src/Features/VisualBasic/Portable/ExtractMethod/VisualBasicMethodExtractor.VisualBasicCodeGenerator.CallSiteContainerRewriter.vb

@@ -212,6 +212,15 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.ExtractMethod
                                     WithStatements(VisitList(ReplaceStatementsIfNeeded(node.Statements)))
                     End Function
 
+                    Public Overrides Function VisitElseIfBlock(node As ElseIfBlockSyntax) As SyntaxNode
+                        If node IsNot Me.ContainerOfStatementsOrFieldToReplace Then
+                            Return MyBase.VisitElseIfBlock(node)
+                        End If
+
+                        Return node.WithElseIfStatement(ReplaceStatementIfNeeded(node.ElseIfStatement)).
+                                    WithStatements(VisitList(ReplaceStatementsIfNeeded(node.Statements)))
+                    End Function
+
                     Public Overrides Function VisitTryBlock(node As TryBlockSyntax) As SyntaxNode
                         If node IsNot Me.ContainerOfStatementsOrFieldToReplace Then
                             Return MyBase.VisitTryBlock(node)

src/Features/VisualBasicTest/ExtractMethod/ExtractMethodTests.vb

@@ -9,7 +9,7 @@ Imports Microsoft.CodeAnalysis.Editor.UnitTests.CodeActions
 
 Namespace Microsoft.CodeAnalysis.Editor.VisualBasic.UnitTests.CodeRefactorings.ExtractMethod
     <Trait(Traits.Feature, Traits.Features.CodeActionsExtractMethod)>
-    Public Class ExtractMethodTests
+    Public NotInheritable Class ExtractMethodTests
         Inherits AbstractVisualBasicCodeActionTest_NoEditor
 
         Protected Overrides Function CreateCodeRefactoringProvider(workspace As TestWorkspace, parameters As TestParameters) As CodeRefactoringProvider
@@ -1181,5 +1181,79 @@ end class
                 {CodeStyleOptions2.QualifyMethodAccess, CodeStyleOption2.FalseWithSilentEnforcement}
             })
         End Function
+
+        <Fact, WorkItem("https://github.com/dotnet/roslyn/issues/20088")>
+        Public Async Function TestInElseIfBlock1() As Task
+            Await TestInRegularAndScriptAsync(
+"Public Class Class1
+    Private Function Method(arg As Integer?) As Boolean
+        Dim something As Boolean
+        If arg.HasValue Then
+            something = True
+        ElseIf arg.Value < 50 Then
+            [|something = arg.Value > 15|]
+        Else
+            something = False
+        End If
+
+        Return something
+    End Function
+End Class",
+"Public Class Class1
+    Private Function Method(arg As Integer?) As Boolean
+        Dim something As Boolean
+        If arg.HasValue Then
+            something = True
+        ElseIf arg.Value < 50 Then
+            something = {|Rename:NewMethod|}(arg)
+        Else
+            something = False
+        End If
+
+        Return something
+    End Function
+
+    Private Shared Function NewMethod(arg As Integer?) As Boolean
+        Return arg.Value > 15
+    End Function
+End Class")
+        End Function
+
+        <Fact, WorkItem("https://github.com/dotnet/roslyn/issues/20088")>
+        Public Async Function TestInElseIfBlock2() As Task
+            Await TestInRegularAndScriptAsync(
+"Public Class Class1
+    Private Function Method(arg As Integer?) As Boolean
+        Dim something As Boolean
+        If arg.HasValue Then
+            something = True
+        ElseIf arg.Value < 50 Then
+[|            something = arg.Value > 15|]
+        Else
+            something = False
+        End If
+
+        Return something
+    End Function
+End Class",
+"Public Class Class1
+    Private Function Method(arg As Integer?) As Boolean
+        Dim something As Boolean
+        If arg.HasValue Then
+            something = True
+        ElseIf arg.Value < 50 Then
+            something = {|Rename:NewMethod|}(arg)
+        Else
+            something = False
+        End If
+
+        Return something
+    End Function
+
+    Private Shared Function NewMethod(arg As Integer?) As Boolean
+        Return arg.Value > 15
+    End Function
+End Class")
+        End Function
     End Class
 End Namespace