There is another standard library related scenario: hash tables. The std unordered containers will store the hash of each key unless your hash function is noexc

There is another standard library related scenario: hash tables. The std unordered containers will store the hash of each key unless your hash function is noexcept. Analogous to how vector needs noexcept move for fast reserve and resize, unordered containers need noexcept hash to avoid extra memory usage. See https://gcc.gnu.org/onlinedocs/libstdc++/manual/unordered_associative.html https://gcc.gnu.org/onlinedocs/libstdc++/manual/unordered_as...