This allows std::is_nothrow_swappable{,_with} to work properly.
This only touches user-facing classes, with the following exceptions:
map,set: only doc changes (with a drive-by missing semicolon fix), detail::tree which they derive from already forwards noexcept for swap.
flat_set: only doc changes for flat_set and a change for detail::flat_tree, which it derives from to get swap.
static_vector: while this adds the forwarding, member static_vector::swap is currently never noexcept, although it could be for noexcept-swappable and noexcept-move-constructible elements.
small_vector: there is no free swap, and member swap is never noexcept, although it could be for noexcept-swappable and noexcept-move-constructible elements. Swapping small_vectors of exact same type goes through std::swap, which seems to get noexcept right, and small_vectors of different sizes use swap for boost::container::vector, which fails to detect when such swap could be noexcept. This patch doesn't touch small_vector.
scoped_allocator: neither member nor free swap are noexcept, although they should be, and all other constructions/assignments/comparisons too, as they only forward these operations to underlying allocators, which are required to not throw exceptions for them. Only static_vector's static_storage_allocator might throw for these and it shouldn't appear in scoped_allocator. Unsure of the scope of changes needed or whether it is even worth it, this patch doesn't touch scoped_allocator.
I am unsure on the last three points, feel free to correct and cherry-pick as needed.
igaztanaga
commented
3 years ago
This allows
std::is_nothrow_swappable{,_with}to work properly. This only touches user-facing classes, with the following exceptions:map,set: only doc changes (with a drive-by missing semicolon fix),detail::treewhich they derive from already forwardsnoexceptforswap.flat_set: only doc changes forflat_setand a change fordetail::flat_tree, which it derives from to getswap.static_vector: while this adds the forwarding, memberstatic_vector::swapis currently nevernoexcept, although it could be for noexcept-swappable and noexcept-move-constructible elements.small_vector: there is no free swap, and member swap is nevernoexcept, although it could be for noexcept-swappable and noexcept-move-constructible elements. Swappingsmall_vectors of exact same type goes throughstd::swap, which seems to getnoexceptright, andsmall_vectors of different sizes useswapforboost::container::vector, which fails to detect when such swap could benoexcept. This patch doesn't touchsmall_vector.scoped_allocator: neither member nor freeswaparenoexcept, although they should be, and all other constructions/assignments/comparisons too, as they only forward these operations to underlying allocators, which are required to not throw exceptions for them. Onlystatic_vector'sstatic_storage_allocatormight throw for these and it shouldn't appear inscoped_allocator. Unsure of the scope of changes needed or whether it is even worth it, this patch doesn't touchscoped_allocator.I am unsure on the last three points, feel free to correct and cherry-pick as needed.