This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21 Core Issues List revision 112e. See http://www.open-std.org/jtc1/sc22/wg21/ for the official list.
An ambiguity can occur with a requires-clause that ends in an operator-function-id:
template<typename T> requires T::operator int const // part of operator-type-id or return type? unsigned f(); template<typename T> requires T::operator int [[attr]] // appertains to type int or to declaration of g? void g();
Such cases are always ill-formed, because they involve an atomic constraint of non-bool type.