The following program fails to compile (it compiles fine under 4.1.2)
#include <iostream>
class MyClass {
double x;
public:
MyClass(double X) : x(X) {}
MyClass(int I) : x(I) {}
friend bool operator&&(int i, const MyClass& Z);
};
inline bool operator&&(int i, const MyClass& Z) {
return int(Z.x) == i;
}
int main() {
int k =3;
MyClass X(3.1);
std::cout << (k && X) << std::endl;
}
giving
/usr/lib/gcc/i686-pc-linux-gnu/4.2.0-alpha20070131/include/g++-v4/ostream: In
destructor 'std::basic_ostream<_CharT, _Traits>::sentry::~sentry() [with _CharT
= char, _Traits = std::char_traits<char>]':
/usr/lib/gcc/i686-pc-linux-gnu/4.2.0-alpha20070131/include/g++-v4/bits/ostream.tcc:70:
instantiated from 'std::basic_ostream<_CharT, _Traits>&
std::basic_ostream<_CharT, _Traits>::_M_insert(_ValueT) [with _ValueT = bool,
_CharT = char, _Traits = std::char_traits<char>]'
/usr/lib/gcc/i686-pc-linux-gnu/4.2.0-alpha20070131/include/g++-v4/ostream:201:
instantiated from 'std::basic_ostream<_CharT, _Traits>&
std::basic_ostream<_CharT, _Traits>::operator<<(bool) [with _CharT = char,
_Traits = std::char_traits<char>]'
g++-4.2_bug.C:19: instantiated from here
/usr/lib/gcc/i686-pc-linux-gnu/4.2.0-alpha20070131/include/g++-v4/ostream:455:
error: ISO C++ says that these are ambiguous, even though the worst conversion
for the first is better than the worst conversion for the second:
/usr/lib/gcc/i686-pc-linux-gnu/4.2.0-alpha20070131/include/g++-v4/ostream:455:
note: candidate 1: operator&&(bool, bool) <built-in>
g++-4.2_bug.C:12: note: candidate 2: bool operator&&(int, const MyClass&)
--
Summary: ostream ambiguous operator&&
Product: gcc
Version: 4.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: jarausch at skynet dot be
GCC host triplet: gcc-4.2.0-alpha20070131
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31031
