Isn't that not necessarily out of the ordinary though? What if there's a cosmic ray that change's the value to something not expected by the exhaustive switch? Or more likely, what if an update to a dynamic library adds another value to that enum (or whatever)? What some languages do is add an implicit default case. It's what Java does, at least: https://openjdk.org/jeps/361

> What if there's a cosmic ray that change's the value to something not expected by the exhaustive switch?

I could forgive that.

The TypeScript case is more like "what if instead of checking the types we just actually don't check the types?".