update specs for swap()#42
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Please, do not just apply this change. I just want to discuss this, as I am not sure myself what your goals are. When you only hide this overload of `std::swap` in cases where `T` is not swappable the effect will be that the generic version of `std::swap` will become a viable candidate, and this generic `swap` does not require the `T` to be swappable. So instead, maybe you just want a hard error? If so, you can apply this commit. The note is taken from the specification of `swap` for `std::array`: http://eel.is/c++draft/array#members-5 The constraints for the member `swap` can be left as they are: there is no interaction with other overloads.
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cc @CaseyCarter |
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When you only hide this overload of
std::swapin cases whereTis not swappable the effect will be that the generic version ofstd::swapwill become a viable candidate, and this generic swap does not require theTto be swappable.
The default implementation of std::swap is viable only if static_vector<T, N> is both move constructible and move assignable, which presumably will only be the case when T is both move constructible and move assignable. I can't be bothered to care about move constructible, move assignable, yet non-swappable types which I've only ever observed in the libc++ test suite. (std::ranges::swap, for example, never sees deleted swap overloads found via ADL. If your type is move constructible and move assignable, it's going to get swapped.)
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Please, do not just apply this change. I just want to discuss this, as I am not sure myself what your goals are.
When you only hide this overload of
std::swapin cases whereTis not swappable the effect will be that the generic version ofstd::swapwill become a viable candidate, and this genericswapdoes not require theTto be swappable. So instead, maybe you just want a hard error? If so, you can apply this commit. The note is taken from the specification ofswapforstd::array: http://eel.is/c++draft/array#members-5The constraints for the member
swapcan be left as they are: there is no interaction with other overloads.