As described by Richard in https://groups.google.com/a/isocpp.org/d/msg/std-discussion/S1kmj0wF5-g/fb6agEYoL2IJ
we should allow:
template<typename S>
struct A {
template<typename T> static auto default_lambda() {
return [](const T&) { return 42; };
}
template<class U = decltype(default_lambda<S>())>
U func(U u = default_lambda<S>()) { return u; }
};
int run2 = A<double>{}.func()(3.14);
int run3 = A<char>{}.func()('a');
This patch allows the code using the same trickery that was used to allow the code in non-member functions at namespace scope.
Please see http://llvm-reviews.chandlerc.com/D1844 for richard's approval.
llvm-svn: 192166
Faisal Vali