[TheDong]

My guess is that originally, the post didn't have "// body omitted" below.

The actual implementation requires having the `S` type to refer to, and the point of this post is to explain why the `S` type has to be named. By writing it as they did, the "// body omitted" one _could_ have had the same body, even without an 'S' type to refer to.

I bet the "// body omitted" bit of the post got refactored, and the reason for making the first one different from the stdlib impl got lost.