Updated the interal runtime's ClassInfo type to match the one in object.di . Runtime now compiles and runminitest is back to normal except for typeinfo10.d .

module union1;

union U
{
    float f;
    int i;
}

void main()
{
    float f = 2;
    U u = U(f);
    assert(u.i == *cast(int*)&f);
}