If Go 2 is bringing us generics, then couldn't that `builtin` package provide real type signatures for the builtin functions instead of fake ones? Instead of

  func delete(m map[Type]Type1, key Type)

it could have

  func Delete(type Type, Type1 somecontract) (m map[Type]Type1, key Type)

in there, and a program compiled with Go 2 would have an implied instance of

  func delete = builtin.Delete(T, U)

in its global namespace for every map with a `delete` used somewhere in the code.