private static void MatchesImpl(IChecker <string, ICheck <string> > checker, string regExp, bool negated)
{
checker.BeginCheck(negated)
.Expecting(regExp, "matches", "does not match")
.FailsIfNull()
.FailsIf(sut => new Regex(regExp).IsMatch(sut) == false, "The {0} does not match the {1}.")
.Negates("The {0} matches {1}, whereas it must not.")
.EndCheck();
}