Type parameters. As in meta programming?
Discussion
golang's "generics" are really just a logical extension of duck typing... if it can be inferred, then it is permitted if the type parameter specifies it
although i don't know yet what the ~ means in them yet, didn't read that in the docs yet but i've seen it in an "x" package
In D we have full blown metaprogramming. I don't use it all too heavily except in a few projects like serializers etc.
But it is great. I can write code that writes code.