https://github.com/bitcoin/bitcoin/blob/68f3c7eb080e461cfeac37f8db7034fe507241d0/src/prevector.h#L152-L158

I'm opening an issue as its fix is too tiny to become a pull request.

Can be solved by renaming the struct to
```c
     struct indirect_contents { 
         size_type capacity; 
         char* indirect; 
     }; 
```
const_iterator(iterator x) : ptr(&(*x)) {}
        const T& operator*() const { return *ptr; }
        const T* operator->() const { return ptr; }
        const T& operator[](size_type pos) const { return ptr[pos]; }
        const_iterator& operator++() { ptr++; return *this; }
        const_iterator& operator--() { ptr--; return *this; }
        const_iterator operator++(int) { const_iterator copy(*this); ++(*this); return copy; }
        const_iterator operator--(int) { const_iterator copy(*this); --(*this); return copy; }
        difference_type friend operator-(const_iterator a, const_iterator b) { return (&(*a) - &(*b)); }
        const_iterator operator+(size_type n) { return const_iterator(ptr + n); }
        const_iterator& operator+=(size_type n) { ptr += n; return *this; }
        const_iterator operator-(size_type n) { return const_iterator(ptr - n); }
        const_iterator& operator-=(size_type n) { ptr -= n; return *this; }
        bool operator==(const_iterator x) const { return ptr == x.ptr; }
        bool operator!=(const_iterator x) const { return ptr != x.ptr; }
        bool operator>=(const_iterator x) const { return ptr >= x.ptr; }
        bool operator<=(const_iterator x) const { return ptr <= x.ptr; }
        bool operator>(const_iterator x) const { return ptr > x.ptr; }
        bool operator<(const_iterator x) const { return ptr < x.ptr; }
    };
    class const_reverse_iterator {
        const T* ptr;
    public:
        typedef Diff difference_type;
        typedef const T value_type;
        typedef const T* pointer;
        typedef const T& reference;
        typedef std::bidirectional_iterator_tag iterator_category;
        const_reverse_iterator(const T* ptr_) : ptr(ptr_) {}