Why doesn't explicit bool() conversion happen in contextual conversion

Question

If the following test-programm

#include 

class A {
public:
    A() {}
    explicit operator bool() const {
        std::cout << __PRE         


        

Answer 1

what are the rules giving the conversion to non-const-int precedence over converting to const-bool?

Using const member function of a non-const object, requires conversion of a non-const object into const-object. That is why operator int() has a better match over operator bool() const.

To make it a bit clearer, if you would remove int operators, what really happens with the first bool context (first if) is this :

if ( const_cast(a).operator bool() ) {

Instead, what happens is this :

if ( a.operator int() )