why is ++ overloaded but not -- for c++ bool

Question

I am trying to figure out why I can ++b a bool but not --b it

#include <stdio.h>

int main(void)
{
    bool b = false;
    ++b;
    --b; // error C2428: '--' : not allowed on operand of type 'bool'

    printf("%s %d", b ? "true" : "false", b);

    getchar();
    return 0;
}