"Changes of default constructor" build failure(s) — clang 3.2

This code is a defect of the C++ standard:
http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#1344
class foo {
    int a;
    foo(int);
};

foo::foo(int c = 5) : a(c) {

}

No error detected for version 3.2