swc/crates/swc_ecma_parser/tests/tsc/derivedClassOverridesProtectedMembers4.ts

var x: { foo: string; }
var y: { foo: string; bar: string; }

class Base {
    protected a: typeof x;
}

class Derived1 extends Base {
    public a: typeof x;
}

class Derived2 extends Derived1 {
    protected a: typeof x; // Error, parent was public
}