Roslyn VB.Net Specify Compiler Version - vb.net

Question

I am trying to compile a VB program using the code below, the code requires VB 15.5 and even when I specify LanguageVersion.Latest or LanguageVersion.VisualBasic15_5, I still get error ERR_ExpectedNamedArgument - Named argument expected. Please use language version 15.5 or greater to use non-trailing named arguments. Some code was removed to simplify example.
Public Function CompileVisualBasicString(StringToBeCompiler As String, SeverityToReport As DiagnosticSeverity, ByRef ResultOfConversion As ConversionResult) As EmitResult
If StringToBeCompiler.IsEmptyNullOrWhitespace Then
ResultOfConversion.FilteredListOfFailures = New List(Of Diagnostic)
ResultOfConversion.Success = True
Return Nothing
End If
Dim syntaxTree As SyntaxTree = VisualBasicSyntaxTree.ParseText(StringToBeCompiler)
Dim assemblyName As String = Path.GetRandomFileName()
Dim PreprocessorSymbols As New Dictionary(Of String, Object) From {
{"NETSTANDARD2_0", Nothing}
}
Dim ParseOptions As VisualBasicParseOptions = New VisualBasicParseOptions(
languageVersion:=LanguageVersion.Latest,
documentationMode:=DocumentationMode.Diagnose,
kind:=SourceCodeKind.Regular,
preprocessorSymbols:=PreprocessorSymbols)
Dim CompilationOptions As VisualBasicCompilationOptions = New VisualBasicCompilationOptions(
outputKind:=OutputKind.DynamicallyLinkedLibrary,
optionExplicit:=False,
optionInfer:=True,
optionStrict:=OptionStrict.Off,
parseOptions:=ParseOptions
)
Dim compilation As VisualBasicCompilation = VisualBasicCompilation.Create(
assemblyName:=assemblyName,
syntaxTrees:={syntaxTree},
references:=References,
options:=CompilationOptions
)
Dim CompileResult As EmitResult
Using ms As MemoryStream = New MemoryStream()
CompileResult = compilation.Emit(ms)
End Using
Return CompileResult
End Function

Answer 1

Thank you George, you solved the problem I needed to include the VisualBasicParseOption to Parse in addition to compile.