H := Rectangle {
    x: {foo: "42"};
//    ^error{Cannot convert \{ foo: string,\} to length}
    y: [ 45, 45, 45, 45 ];
//    ^error{Cannot convert \[float32\] to length}
    color: [ { a: 45, b: 55, }, {a: 44, b: 54},];
//        ^error{Cannot convert \[\{ a: float32,b: float32,\}\] to color}

}