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; 
     }; 
```
swap(other);
        return *this;
    }
    size_type size() const {
        return is_direct() ? _size : _size - N - 1;
    }
    bool empty() const {
        return size() == 0;
    }
    iterator begin() { return iterator(item_ptr(0)); }
    const_iterator begin() const { return const_iterator(item_ptr(0)); }
    iterator end() { return iterator(item_ptr(size())); }
    const_iterator end() const { return const_iterator(item_ptr(size())); }
    reverse_iterator rbegin() { return reverse_iterator(item_ptr(size() - 1)); }
    const_reverse_iterator rbegin() const { return const_reverse_iterator(item_ptr(size() - 1)); }
    reverse_iterator rend() { return reverse_iterator(item_ptr(-1)); }
    const_reverse_iterator rend() const { return const_reverse_iterator(item_ptr(-1)); }
    size_t capacity() const {
        if (is_direct()) {
            return N;
        } else {
            return _union.capacity;
        }
    }
    T& operator[](size_type pos) {