// { dg-do compile { target c++11 } } // From N2235 // 4.5.3 constant expressions // p 4 struct A { constexpr A(int i) : val(i) { } constexpr operator int() const { return val; } constexpr operator long() const { return -1; } private: int val; }; template struct X { static const int i = I; }; constexpr A a = 42; X x; // OK: unique conversion to int int ar[X::i]; // also OK int ary[a]; // { dg-error "could not convert" } ambiguous conversion // { dg-error "9:size of array .ary. has non-integral" "" { target c++11 } .-1 }