private async Task <Solution> UseCorrectType(Document document, TypeSyntax syntax, CancellationToken cancellationToken)
{
var root = await document.GetSyntaxRootAsync(cancellationToken).ConfigureAwait(false);
var semanticModel = await document.GetSemanticModelAsync(cancellationToken).ConfigureAwait(false);
var argumentList = syntax.Ancestors().OfType <TypeDeclarationSyntax>().First();
var symbol = semanticModel.GetDeclaredSymbol(argumentList, cancellationToken);
var identifier = SyntaxFactory.ParseName(symbol.ToString()).WithAdditionalAnnotations(Simplifier.Annotation);
root = root.ReplaceNode(syntax, identifier);
document = document.WithSyntaxRoot(root);
return(document.Project.Solution);
}