Created attachment 398935 [details]
Patch

std::iterator is now deprecated in C++17, and defining these five typedefs in iterator class becomes the recommended way.

    using iterator_category = Category;
    using value_type = T;
    using difference_type = Distance;
    using pointer = Pointer;
    using reference = Reference;

https://www.fluentcpp.com/2018/05/08/std-iterator-deprecated/

It seems that we need to do the opposite thing :), or we should create std::iterator like thing in WTF and replace the current use of std::iterator with that.

OK.

There are 14 places we are using std::iterator.