This currently fails to compile:

void foo() nothrow @safe @nogc
{
    int[5] a = [ 1, 2, 3, 4, 5 ];
    _d_assert_fail!("==")(a, [ 1, 2, 3, 4, 5 ]); // fails: non-nogc
}

// void _d_assert_fail!("==")(ref const(int[5]) a, scope const(int[]) b)
void _d_assert_fail(string comp, A, B)(auto ref const scope A a, auto ref const scope B b)
{}

The problem is that the array literal is needlessly allocated by the GC, although _d_assert_fail is not going to escape any reference to its data, and a stack allocation would do just fine, making this work for -betterC as well as eliminating one hurdle towards compiling the Phobos unittests with -checkaction=context.