Defined in Call signatures Return value void Examples struct Error final std string what fn expected<int Error> ex 42 Observe for side effects only ex | fn inspect int v noexcept REQUIRE v 42 | fn discard is observed by and the value is discarded by no warning for discarded result of 42 inspect discard inspect Discard the value explicitly This is useful when only side effects are desired and the final value is not needed Use through the fn discard nielbloid Unconditionally discards the value