public SyntaxTree AddSource(GeneratedSourceText sourceText)
{
var compilation = DeclaringCompilation as CSharpCompilation ?? throw new NotSupportedException("Non C# compilation is not supported");
var syntax = CSharpSyntaxTree.ParseText(sourceText.SourceText, new CSharpParseOptions(compilation.LanguageVersion), cancellationToken: Parent._context.OnOperationCanceled);
DeclaringCompilation = DeclaringCompilation.AddSyntaxTrees(syntax);
GeneratedSourceTexts.Add(sourceText);
return(syntax);
}