std::move_only_function::operator=
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                    < cpp | utility | functional | move only function
                    
                                                            
                    |   move_only_function& operator=( move_only_function&& other );  | 
(1) | (since C++23) | 
|   move_only_function& operator=( const move_only_function& ) = delete;  | 
(2) | (since C++23) | 
|   move_only_function& operator=( std::nullptr_t ) noexcept;  | 
(3) | (since C++23) | 
|   template< class F >  move_only_function& operator=( F&& f );  | 
(4) | (since C++23) | 
Assigns a new target to std::move_only_function or destroys its target.
1) Moves the target of 
other to *this or destroys the target of *this (if any) if other is empty, by auto(std::move(other)).swap(*this). other is in a valid state with an unspecified value after move assignment.3) Destroys the current target if it exists. *this is empty after the call.
4) Sets the target of *this to the callable 
f, or destroys the current target if f is a null function pointer, a null pointer to member function, or an empty std::move_only_function, as if by executing move_only_function(std::forward<F>(f)).swap(*this);. This overload participates in overload resolution only if the constructor of move_only_function from F participates in overload resolution. The program is ill-formed or has undefined behavior if the selected constructor call is ill-formed or has undefined behavior.Parameters
| other | - |   another std::move_only_function object to move the target of
 | 
| f | - | a callable object to initialize the new target with | 
Return value
*this
Notes
It is intentional not to require the move assignment operator to be noexcept to leave room for an allocator-aware move_only_function in future.
move_only_function can be assigned from std::in_place_type<Fn> given it can be constructed from that argument.
See also
|   assigns a new target  (public member function of std::function<R(Args...)>)  |