Why does clang++ destroy only one foo object?

I have the following example code:

#include <iostream>
using namespace std;

struct foo {
    foo()  { cout << "foo constructed.\n"; }
    ~foo() { cout << "foo destroyed.\n"; }
};

struct bar {
    bar(foo t=foo{}) { }
};

int main(int argc, char **argv) {
    bar X[2]{};
    return 0;
}

When I compile it with clang++ -std=c++11 test.cc, the program produces the following output:

foo constructed.
foo constructed.
foo destroyed.

but I expected an additional "foo destroyed." between the two "foo constructed." lines. Why is only one foo destroyed? This happens with clang 3.5.1 as well as 3.6.0.

Thanks for all the people who tested it! This seems to be a bug in clang. I'd appreciate if someone reports it to llvm.org. My few bugs reports there were, let say, not really helpful, so I am not looking to repeat that experience.