"return this" from inherited method not working as expected

I'm writing classes where the methods return "this" to allow for method chaining.

When the method is inherited then "return this" doesn't seem to be working as expected:

```
class A {
one() { return this; } // "this" should return the instance of "B" when inherited
}

class B extends A {
two() {}
}

const b = new B();

b.one(); // ok
b.two(); // ok
b.one().two(); // Cannot call `b.one().two` because property `two` is missing in `A`
```

On flow/try:

https://flow.org/try/#0MYGwhgzhAECC0G8BQ1oHsB2BTAFASkWgCcsAXAVyI2lIAsBLCAbmgF9oB6D6AIjsZ7QItNORAATYmUrU6WaPQwRSYDMHloAZrwBCggO60s1RUaL1SWcUlZIkoSDB3QsAD0sZxMeMlSl9aPiItrb2mMrQAEbQALzQ2PrQOvhMdpEAdJi4eCxc6ADWSBn+gTmc3GiFGVn46SUp5dAAwqoYaKTQwGAgINAABtXYtSV9UVhd5BDyAA5EaNNYRKQAnv0jCjAAtowQigDmCtR9sH12QA

Any suggestions appreciated, thanks.