Why can’t I replace std::map with std::unordered_map

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I guess that because std::unordered_map needs to rehash, and therefore copy elements, the types need to be complete, whereas a map, only ever working with pointers to elements, will not exhibit that problem.

The solution here is to have an unordered map to a pointer:

std::unordered_map<uint32_t, std::shared_ptr<Test> >.

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