[masklinn]

> They could've avoided nils entirely with that for example. Or have less annoying error handling.

TBF neither generics nor sum types were necessary for either, these could have been builtins or language-level features.

To start with it's not like Go has been shy about those for things they didn't want to formalise (yet), but even in languages where they're library-ish features it's common for them to have language-level support.