I too feel like containers are the main area where it is painful. The sort of built-in generics we have in Go are useful in most circumstances, but it'd be nice to have custom containers which could take any type, instead of having to specify them separately. Errors is the other area where it feels like they could help (though the article points out possible problems with this).
That said your third approach (make custom concrete types as required) has not been a huge problem for me in practice, and is probably the best choice for now.
That said your third approach (make custom concrete types as required) has not been a huge problem for me in practice, and is probably the best choice for now.