#include <map>

int main()
{
	// Comparison lambda (see https://e...content-available-to-author-only...e.com/w/cpp/container/map/map).
    auto comp = [](int a, int b) { return b < a; };

	// This compiles.
    std::map<int, int> m1 {{5, 6}, {3, 4}, {1, 2}};

    // This also compiles.
    std::map<int, int, decltype(comp)> m2(comp);

	// This doesn't compile (error: expected ‘}’ at end of input).
    std::map<int, int, decltype(comp)> m3(comp) {{5, 6}, {3, 4}, {1, 2}};

    return 0;
}