fn test_array_cast() {
    mut keys := ['']
    unsafe {
        vp := voidptr(&keys)
        mut p := &[]string(vp)
        (*p)[0] = 'hi'
        assert *p == ['hi']
    }
    assert keys[0] == 'hi'
}

fn test_int() {
    mut arr := [2.3, 3]
    unsafe {
        vp := voidptr(&arr)
        p := &[]f64(vp)
        assert *p == arr
    }
}

fn test_ref_array_cast_to_elem_ptr_uses_array_data() {
    mut buf := []u8{len: 4}
    p := unsafe { &u8(&buf) }
    unsafe {
        p[0] = `A`
        p[1] = `B`
    }
    assert buf[0] == `A`
    assert buf[1] == `B`
}

struct Header {
mut:
    first  u8
    second u8
}

fn test_ref_array_cast_to_struct_ptr_uses_array_data() {
    mut buf := []u8{len: int(sizeof(Header))}
    header := unsafe { &Header(&buf) }
    unsafe {
        header.first = `x`
        header.second = `y`
    }
    assert buf[0] == `x`
    assert buf[1] == `y`
}

fn test_ref_array_cast_to_array_header_keeps_header_address() {
    mut arr := [1, 2]
    header := unsafe { &array(&arr) }
    assert unsafe { header.len } == 2
}