Bug fix + add test

src/EditorFeatures/VisualBasicTest/InvertIf/InvertSingleLineIfTests.vb

@@ -530,7 +530,7 @@ End Module")
 
         <WorkItem(529756, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/529756")>
         <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsInvertIf)>
-        Public Async Function TestOnCoditionOfSingleLineIf() As Task
+        Public Async Function TestOnConditionOfSingleLineIf() As Task
             Await TestInRegularAndScriptAsync(
 "Module Program
     Sub Main(args As String())
@@ -616,5 +616,31 @@ End Module
         If Not a Then bMethod() Else aMethod()
 ")
         End Function
+
+        <WorkItem(45177, "https://github.com/dotnet/roslyn/issues/45177")>
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsInvertIf)>
+        Public Async Function TestWithMissingTrueStatementWithinUsing() As Task
+            Await TestInRegularAndScriptAsync(
+"Module Program
+    Sub M(Disposable As IDisposable)
+        Dim x = True
+        Using Disposable
+            [||]If Not x Then End
+        End Using
+
+        Dim y = 0
+    End Sub
+End Module",
+"Module Program
+    Sub M(Disposable As IDisposable)
+        Dim x = True
+        Using Disposable
+            If x Then Else End
+        End Using
+
+        Dim y = 0
+    End Sub
+End Module")
+        End Function
     End Class
 End Namespace

src/Features/VisualBasic/Portable/InvertIf/VisualBasicInvertIfCodeRefactoringProvider.SingleLine.vb

@@ -54,14 +54,16 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.InvertIf
                 ' That way the trailing comments/newlines at the end of the 'if' stay there,
                 ' And the spaces after the true-part stay where they are.
 
-                Dim lastTrue = trueStatements.Last()
-                Dim lastFalse = falseStatements.Last()
+                Dim lastTrue = trueStatements.LastOrDefault()
+                Dim lastFalse = falseStatements.LastOrDefault()
 
-                Dim newLastTrue = lastTrue.WithTrailingTrivia(lastFalse.GetTrailingTrivia())
-                Dim newLastFalse = lastFalse.WithTrailingTrivia(lastTrue.GetTrailingTrivia())
+                If lastTrue IsNot Nothing And lastFalse IsNot Nothing Then
+                    Dim newLastTrue = lastTrue.WithTrailingTrivia(lastFalse.GetTrailingTrivia())
+                    Dim newLastFalse = lastFalse.WithTrailingTrivia(lastTrue.GetTrailingTrivia())
 
-                trueStatements = trueStatements.Replace(lastTrue, newLastTrue)
-                falseStatements = falseStatements.Replace(lastFalse, newLastFalse)
+                    trueStatements = trueStatements.Replace(lastTrue, newLastTrue)
+                    falseStatements = falseStatements.Replace(lastFalse, newLastFalse)
+                End If
             End If
 
             Dim updatedIf = ifNode _