Assign to this object the value of the specified rhs object, and return a non-const reference to this object. The allocators of this object and rhs both remain unchanged. The contents of rhs are either move-constructed into or move-assigned to this object. rhs is left in a valid but unspecified state.
Declared in <bslstl_optional.h>
Optional_Base<t_TYPE, t_USES_BSLMA_ALLOC>&
operator=(BloombergLP::bslmf::MovableRef<Optional_Base> rhs);