20 General utilities library [utilities]

20.6 Optional objects [optional]

20.6.3 Class template optional [optional.optional] Assignment [optional.assign]

Table 43: optional​::​operator=(optional&&) effects [tab:optional.assign.move]
*this contains a value
*this does not contain a value
rhs contains a value
assigns std​::​move(*rhs) to the contained value
initializes the contained value as if direct-non-list-initializing an object of type T with std​::​move(*rhs)
rhs does not contain a value
destroys the contained value by calling val->T​::​~T()
no effect