https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86127
--- Comment #10 from Jonathan Wakely <redi at gcc dot gnu.org> --- As I said in comment 6, I've already removed the copies that forward_list does on destruction. As I said in comment 3, there are no copies in the default constructor, they're in the initializer-list constructors. The standard says the initializer-list constructors look like: vector(initializer_list<T>, const Allocator& = Allocator()); That default argument needs to get copied into the vector's allocator member somehow. It could be avoided by defining: vector(initializer_list<T>); vector(initializer_list<T>, const Allocator&); But doing so just to avoid making copies of a cheap-to-copy object is not a good justification, and would make it impossible to explicitly instantiate the container with a non-default constructible allocator type. Node-based containers such as forward_list and map neede to convert the allocator from the value_type to the node type. That can either happen once on construction, or every time elements are inserted or erased. Doing it on construction is the obvious choice, and that's where you see the "template copy constructor" lines for forward_list and map. The standard allows those copies, and they should be cheap. There is no bug here.
