Agreed. Seems like a pretty risky optimization that fundamentally changed behavior; like it or not the ordering of vectors is often part of the data structure.

Agreed. Seems like a pretty risky optimization that fundamentally changed behavior; like it or not the ordering of vectors is often part of the data structure. Could have just used a prepend to preserve behavior instead pf going down the rabbit hole of re-interpreting the RFC (which is a cop out IMO; it worked before, a change broke it).