C++14 and later supports size-aware deletion of heap objects, when the compiler is able to determine at compile time what the exact size of a particular object
is. For this purpose, there are specific variants of "operator delete" that take an additional size_t argument. If such a variant is called, the size is passed through to the underlying allocator, which can optionally utilize this size for for more efficient deallocation.
A recent change in libc++'s implementation of std::string has introduced a potential mismatch between the actual size allocated on the heap for the contained string, and the size that is passed to "operator delete" when the string is eventually destroyed.
