[libcxx-commits] [PATCH] D81133: Use allocator_traits to consistently allocate/deallocate/construct/destroy objects in std::any

[Marshall Clow via Phabricator via libcxx-commits]

mclow.lists marked an inline comment as done.
mclow.lists added inline comments.


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Comment at: libcxx/include/any:382
     static void __destroy(any & __this) {
-        _Tp & __value = *static_cast<_Tp *>(static_cast<void*>(&__this.__s.__buf));
-        __value.~_Tp();
+        typedef allocator<_Tp> _Alloc;
+        typedef allocator_traits<_Alloc> _ATraits;
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EricWF wrote:
> Is it the case that the allocator which allocated this memory is always equal to a default constructed allocator? If not, this is UB.
Remember that we're not talking about an arbitrary allocator, but `std::allocator`
(It can be a user specialization, but it's still `std::allocator`)

See http://eel.is/c++draft/allocator.globals.   They're always equal. 



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https://reviews.llvm.org/D81133