How to conditionally invoke a generic method with constraints? [duplicate]

Answer 1

You can use a helper class and dynamic type to skip compile-time checks:

sealed class CountDuplicatesFastCaller
{
    public int Call(IList list) where T : IComparable
    {
        return CountDuplicatesFast(list);
    }
}

public static int CountDuplicates(IList list)
{
    if (typeof (IComparable).IsAssignableFrom(typeof (T)))
    {
        return ((dynamic) new CountDuplicatesFastCaller()).Call(list);
    }
    else
    {
        /* use the slow algorithm */
    }
}

This should be faster than pure reflection because of DLR caching mechanisms.