The idea of having the language force the programmer to check for all cases of an algebraic type had not been invented at the time. It's hard to blame them for the problem. I mean, yeah, they should have arrived at that solution, but it took a few more years of language research to hit upon it.

Go appeared 2009…

Haskell appeared much earlier.

Yes, exactly that's the point. But the parent wrote:

> The idea of having the language force the programmer to check for all cases of an algebraic type had not been invented at the time.