https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86127
--- Comment #8 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Scott Constable from comment #7) > (In reply to Jonathan Wakely from comment #1) > > The allocator requirements say that move construction must be equivalent to > > copy construction, and allocators should be cheap to copy anyway. I don't > > consider this a bug. > > To be nitpicky, it looks like this equivalence requirement was introduced > recently in the C++20 draft. I'm compiling using C++14. It's a defect report, so applies to previous standards. https://wg21.link/lwg2593 Applying that change selectively would be madness. > I agree that allocators should be cheap to copy, but as a general principle > I think that all objects should be copied only when necessary. This is the > behavior I have observed in STL containers in libc++, as shown in my example > above. It just makes sense to me that when an STL container is moved, its > allocator should be moved, and no copying should be performed. And that's exactly what libstdc++ does. Your test fails to distinguish between copies/moves performed during move construction and other operations.
