How could you possibly quantify "too long" when you can perform arbitrary computation at compile-time? How do you know the library you're using doesn't need you to compute and embed the first N primes in the final output?

At least if your type checker weren't Turing complete, you know it will finish at some point.

But if you got a deadline, everything over it is bad.

Sure, but "not fast enough for me because X" and simply "wrong/incorrect" are completely different claims.