eb22.c

来自「gcc3.2.1源代码」· C语言 代码 · 共 27 行

// Ambiguous conversion, three candidates:
// builtin == (int, int), and the two user-defined operators
// Each one requires a user-defined ICS where another uses builtin conversions,
// so none is the best viable function.

class MyInt
{
public:
        MyInt(int = 0) {}
        operator int() const {return 2;}
};

bool operator==(const MyInt& a, const int& b)
{                                               // ERROR - candidate
        return (int)a == b;
}

bool operator==(const MyInt& a, const MyInt& b)
{                                               // ERROR - candidate
        return (int)a == (int)b;
}

bool f()
{
  return 3 == MyInt();                          // ERROR - ambiguous
}