in include/unifex/let_value.hpp [222:232]
explicit type(
Predecessor&& pred,
SuccessorFactory2&& func,
Receiver2&& receiver)
: func_((SuccessorFactory2 &&) func),
receiver_((Receiver2 &&) receiver) {
unifex::activate_union_member_with(predOp_, [&] {
return unifex::connect(
(Predecessor &&) pred, predecessor_receiver<operation>{*this});
});
}