Dumper fails badly for std::string with custom allocator

#include <string>

namespace ns {

template<class T>
struct alloc
{
public:
    typedef size_t size_type;
    typedef T* pointer;
    typedef const T* const_pointer;
    typedef T value_type;
    typedef T& reference;
    typedef const T& const_reference;
    typedef ptrdiff_t difference_type;

    inline bool operator==(const alloc<T>&) const { return true; }
    inline bool operator!=(const alloc<T>&) const { return false; }

    pointer allocate(size_t n) { return (pointer)allocator.allocate(n*sizeof(T)); }
    void deallocate(pointer p, size_t n) { allocator.deallocate(p, n); }
    std::allocator<T> allocator;
};

using allocat = alloc<char>;

class string : public std::basic_string<char, std::char_traits<char>, allocat>
{
    using base = std::basic_string<char, std::char_traits<char>, allocat>;
    using base::basic_string;
};
}

int main()
{
    std::string str1("test");
    ns::string str2("test");
    return 0; // Break here
}