What if `... more lines ...` depends on `x == 5`? Then you'd want the compiler to catch the assertion error, rather than whatever obscure error is thrown later

What if `... more lines ...` depends on `x == 5`? Then you'd want the compiler to catch the assertion error, rather than whatever obscure error is thrown later on. And if it breaks production, you are breaking production without the assertion; runtime assertions aren't ideal but they're better than nothing. If you don't rely on `x == 5` in the else branch it's a bad idea, and too many of these spurious assertions will create a habit of just removing assertions whenever they fail.