Before shrink to fit, you could easily have produced this with a few references and a "use std::swap unconditionally". The std::swap thing is only one pitfall,

Before shrink to fit, you could easily have produced this with a few references and a "use std::swap unconditionally". The std::swap thing is only one pitfall, the reliance on "our memcpy will do the right thing with any overlap" is a bit risky (and doesn't hold with LD_PRELOAD, but I think it may have been switched to using the LLVM based librt project anyway, that is I'm not sure these calls are supposed to become naked memcpy).