Parser Error Numbers

Is there any way to attach error numbers to parser and semantic analysis errors? I am trying to get something like this to work:

[Test]
public void Missing_conditional_in_if_statement_creates_expression_expected_error()
{
    string text = "if( ";
    FormulaParseData results = Parse(text, g => g.IfExpression);
    var errors = results.Errors.ToList();
    Assert.AreEqual(1, errors.Count);
    Assert.AreEqual(Errors.ExpressionExpected, errors[0].Number);
}

 Without this I am left with trying to match errors on their text contents.