20 General utilities library [utilities]

20.6 Optional objects [optional]

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

Table 44: optional​::​operator=(const optional<U>&) effects [tab:optional.assign.copy.templ]
*this contains a value
*this does not contain a value
rhs contains a value
assigns *rhs to the contained value
initializes the contained value as if direct-non-list-initializing an object of type T with *rhs
rhs does not contain a value
destroys the contained value by calling val->T​::​~T()
no effect