c++ pointer assignment doesn't work in MSVC 2015

The following code:

    void reverse(char* string)
    {
        char* first = string;
        char* last = string + strlen(string);
        while (first < last)
        {
            --last; 
            char temp = *first;
            *first = *last;
            *last = temp;
            ++first;
        }
    }

breaks at the line: *first = *last in MSVC 2015. Can you explain why? What would be the correct way of performing the assignment?