//# publish
module 0x42.B {
    struct T has drop {g: u64}

    public new(g: u64): Self.T {
    label b0:
        return T{g: move(g)};
    }

    public t(this: &mut Self.T) {
        let g: &mut u64;
    label b0:
        g = &mut copy(this).T::g;
        *copy(g) = 2;
        assert(*move(g) == 2, 42);
        _ = move(this);
        return;
    }
}

//# publish
module 0x42.A {
    import 0x42.B;
    struct T has drop {f: B.T}

    public new(f: B.T): Self.T {
    label b0:
        return T{f: move(f)};
    }

    public t(this: &mut Self.T) {
        let f: &mut B.T;
    label b0:
        f = &mut copy(this).T::f;
        // safe to modify reference through nested calls
        B.t(move(f));
        _ = move(this);
        return;
    }
}

//# run
import 0x42.A;
import 0x42.B;

main() {
    let b: B.T;
    let x: A.T;
    let x_ref: &mut A.T;
label b0:
    b = B.new(0);
    x = A.new(move(b));
    x_ref = &mut x;
    A.t(move(x_ref));
    return;
}