Daily bit(e) of C++ | Heterogeneous lookup in unordered containers
Daily bit(e) of C++ #409, C++20 heterogeneous lookup for unordered containers: std::unordered_(multi)set, std::unordered_(multi)map.
While heterogeneous lookup in ordered containers has been available since C++14, we only got heterogeneous lookup for unordered containers in C++20.
To enable heterogeneous lookup, the container must be instantiated with a hasher and an equality comparator that support all types we want to use for lookup.
