C++ concepts: CopyInsertable
From cppreference.com
                    
                                        
                    
                    
                                                            
                    Specifies that an instance of the type can be copy-constructed in-place by a given allocator.
[edit] Requirements
The type T is CopyInsertable into the container X whose value_type is identical to T if T is MoveInsertable into X, and, given
| A | an allocator type | 
| m | an lvalue of type A | 
| p | the pointer of type T*prepared by the container | 
| v | expression of type (possibly const) T | 
where X::allocator_type is identical to std::allocator_traits<A>::rebind_alloc<T>,
the following expression is well-formed:
std::allocator_traits<A>::construct(m, p, v);
And after evaluation, the value of *p is equivalent to the value of v. The value of v is unchanged.
If X is not allocator-aware, the term is defined as if A were std::allocator<T>, except that no allocator object needs to be created, and user-defined specializations of std::allocator are not instantiated.
[edit] Notes
If A is std::allocator<T>, then this will call placement-new, as by ::new((void*)p) T(v)