Downcasting generic maths types

Question

Assuming that I have a generic class/method with a generic number constraint (using the new preview generic math feature):

public void DoAThing<TValue>(TValue value) where TValue : struct, INumber<TValue>
{
   ...
}

Is there a way to downcast this further to one of the other interfaces? For example, one of these sorts of things:

    if (typeof(IFloatingPoint<TValue>).IsAssignableFrom(typeof(TValue)))
    {
        // do some floating-point-only logic without a specific value
    }
    if (value is IFloatingPoint<TValue> fpnum)
    {
        // do some floating-point-only logic on fpnum
    }

Currently, the compiler objects to this, saying that TValue must be convertible to IFloatingPoint<TValue> to use it as a parameter... which is exactly what I'm trying to test.