If you had a type checker bug you didn't you manually test that code path at the bare minimum. Type check bugs are the most simplistic bugs to catch. Is it nice sure, but if you can't spot those before you ship I can almost guarantee that you have larger logic bugs that the types won't catch.

What isn't helpful is the the notion that types replace testing. Either manual testing or unit/functional/generative testing. It isn't "safer" at all, it does speed up development by catching the simple bugs so the run edit compile loop is less. If you're saying "my code compiles then it's works", I don't buy it.