[Bug libstdc++/98473] std::vector::insert(pos, first, last) doesn't compile for T which has a deleted assignment operator

[redi at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98473

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Borislav Stanimirov from comment #2)
> (In reply to Jonathan Wakely from comment #1)
> 
> > To meet the requirements of the standard we would need to insert them at the
> > end and then use std::rotate to reposition them.
> 
> Or, to save move assignments, first "make a hole" and then copy-construct
> b's in place (some destructors of moved-out objects) will have to be called.

If any of those copy constructions throws then you have a vector with holes in
it, breaking the invariant. Making that exception safe makes the code more
complicated (and slower) which is why inserting them at the end and rotating is
a better choice.