Testing nested initializer-lists without initializer-list constructors.

no-init-list.cpp

/* Compiles and works with recent GCC and Clang in C++11 mode.
 *   $ g++ --version
 *   g++ (GCC) 4.8.2 20131219 (prerelease)
 *
 *   $ clang++ --version
 *   clang version 3.4 (tags/RELEASE_34/final)
 */

#include <vector>
#include <iostream>

struct Vec3 {
	Vec3(int x, int y, int z): x(x), y(y), z(z) {}

	int x;
	int y;
	int z;
};

struct Mat3 {
	Mat3(Vec3 a, Vec3 b, Vec3 c): a(a), b(b), c(c) {}

	Vec3 a;
	Vec3 b;
	Vec3 c;
};

static std::ostream &operator<<(std::ostream &ss, const Vec3 &v) {
	return (ss << "(" << v.x << " " << v.y << " " << v.z << ")");
}

static std::ostream &operator<<(std::ostream &ss, const Mat3 &m) {
	return (ss << m.a << "\n" << m.b << "\n" << m.c << "\n");
}

static void test_vec3() {
	std::vector<Vec3> vs{
		{ 1,2,3 },
		{ 2,3,4 },
		{ 3,4,5 },
	};

	std::cout << "std::vector<Vec3>:\n";
	for (const auto &v : vs) {
		std::cout << v << "\n";
	}
}

static void test_mat3() {
	std::vector<Mat3> ms{
		{
			{ 1, 0, 0 },
			{ 0, 1, 0 },
			{ 0, 0, 1 },
		},
		{
			{ 1, 2, 3 },
			{ 4, 5, 6 },
			{ 7, 8, 9 },
		},
	};

	std::cout << "std::vector<Mat3>:\n";
	for (const auto &m : ms) {
		std::cout << m;
	}
}

int main() {
	test_vec3();
	test_mat3();
	return 0;
}

Ah... I just tested on VC2013... VC bug? Obscure POD rules?