It will just return the smallest function that passes your tests.
It works by enumerating ALL possible functions and running them. Obviously, that naive approach is exponential, so, the entire point is whether we can apply some clever tricks (based on optimal evaluators) to make this search "slightly less intractable".
So, to answer your question directly: if you asked it to design a prime number generator, if it found anything at all, it would probably be a simple, slow trial-and-error algorithm, or something in these lines.
It works by enumerating ALL possible functions and running them. Obviously, that naive approach is exponential, so, the entire point is whether we can apply some clever tricks (based on optimal evaluators) to make this search "slightly less intractable".
So, to answer your question directly: if you asked it to design a prime number generator, if it found anything at all, it would probably be a simple, slow trial-and-error algorithm, or something in these lines.