if (since == null && replacement == null)
problem = new DeprecatedAPIProblem(site, name);
else if (since != null && replacement == null)
problem = new DeprecatedAPIWithSinceProblem(site, name, since);
else if (since == null && replacement != null)
problem = new DeprecatedAPIWithReplacementProblem(site, name, replacement);
else if (since != null && replacement != null)