On Sep 12, 2014, at 8:26 AM, Andreas Rossberg wrote:
>>
>
> Thanks Mark, this was exactly my concern as well. In general, it is
> bogus to assume that the parameter lists of a base and a derived
> constructor bear any relation. And even if they happen to do so today,
> they might no longer tomorrow, which your example demonstrates quite
> well. So just silently forwarding an argument list nilly-willy is
> broken.
>
> I think it's fine to have a default "new super" call, but only with an
> empty argument list. That would also be more in line with what other
> languages do.
>
Other languages that do that are predominately statically-typed OO languages
with static overloading. In that situation, the most generic choice is
non-parameters as some overload has to be chosen for the implicit call site.
But for JS, which does have a static overload selection requirement, we have
other alternatives and the no-argument choice seems highly error prone.
Consider Mark's example again. If developers are saying they would prefer to
write:
```js
class ColoredPoint extends Point {
constructor(x, y, color) {
this.color = color;
}
}
```
Then some will do it (regardless of the actual semantics) and they will
silently get an instance without x or y properties. That is pretty clearly not
their intent.
I think this is a much bigger error hazard then the v2 refactoring issue that
Mark is concerned about.
Allen
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