Following code is legal, according to spec, but not compile.

f(0) works fine

g(0) is the same thing, but not compile.

more discussion:
http://stackoverflow.com/questions/11684954/can-function-default-template-parameter-be-put-before-non-default-ones

-----------------------------------
#include <iostream>
#include <array>
#include <vector>

using namespace std;

struct X {};

template <class T = X, typename U>
void f(const U& m) {}

template <class T = X, typename U>
void g(const U& m) { auto ff = [] () {}; }

int main()
{
	f(0);
	g(0);
	return 0;
}