I seem to remember you yourself saying that Nim shouldn't copy bad design just because everyone else does it that way. Obviously all languages have some performance traps, but pointing that out as a response to a concrete example just seems a bit childish.
This might be hard to fix though, as the sequence is generated just to be immediately destroyed again, and the `&` operator returns a new sequence without modifying the original. Of course Nim could potentially see that the original is about to get destroyed and then do some trickery.
