Implement LWG-3778 vector<bool> missing exception specifications
#3332
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CaseyCarter
reviewed
Jan 9, 2023
| @@ -2931,7 +2926,8 @@ public: | |||
| this->_Swap_proxy_and_iterators(_Right); | |||
| } | |||
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| _CONSTEXPR20 vector& operator=(vector&& _Right) noexcept(is_nothrow_move_assignable_v<_Mybase>) { | |||
| _CONSTEXPR20 vector& operator=(vector&& _Right) noexcept( | |||
| _Choose_pocma_v<_Alvbase> != _Pocma_values::_No_propagate_allocators) { | |||
| if (this == _STD addressof(_Right)) { | |||
| return *this; | |||
| } | |||
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For other reviewers: vector<bool>::swap is already unconditionally noexcept with a strengthened comment in our implementation. We were previously strengthening from nothing to unconditional, after LWG-3778 we're strengthening from conditional to unconditional because we still aren't interested in throwing on precondition violation. (No change requested.)
CaseyCarter
approved these changes
Jan 9, 2023
StephanTLavavej
approved these changes
Jan 11, 2023
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I'm mirroring this to the MSVC-internal repo - please notify me if any further changes are pushed. |
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Thanks for implementing this LWG issue resolution in everyone's favorite partial specialization! 😻 👻 ✅ |
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Fixes #3226.
Notes:
vector<bool, _Alloc>need to default-construct an_Allocinstead of_Alvbasein order to implement the required exception specification. I think this is not related to allocator propagation and thus possibly not covered by LWG-3267.P1004R2_constexpr_vector_booldue to this. Not sure whether such change is right now..._Vb_valfrom an allocator is alwaysnoexcept, so I changed the superfluous conditionalnoexceptto unconditional one.vector<bool, _Alloc>from(vector&&, const _Identity_t<_Alloc>&)is notnoexceptin the current working draft, so I added// strengthened.vector<bool, _Alloc>detect the properties of_Alvbase, which is consistent with other containers that need allocator rebinding.vector<bool>missing exception specifications #3226 (comment)), which would be able to resolve the divergence between standard requirements and actual implementations._Vb_valis not even move-assignable - the explicitly declared move constructor make the move assignment operator not declared, and the copy assignment operator implicitly deleted.