Element.noSuchMethod breaks analysis server checks

[eukreign]

I'm using the standard dart:html APIs to build Custom Elements and this means I have a lot of classes extending HtmlElement/Element.

The problem is that if you extend Element it has an implementation for noSuchMethod() way up the inheritance path (in JSObject). It appears that the Dart analysis service throws its hands up when it finds a class with noSuchMethod().

Here is an example:

https://dartpad.dartlang.org/5f0b6acae7fb19c37c29dbb653948ee7

The expectation is that both FooConcrete and FooConcrete2 should exhibit the same error regarding a missing getter implementation. But because FooConcrete2 extends Element which has noSuchMethod() no error is produced.

[bwilkerson]

This is actually working as intended. Section 10.4 of the specification reads:

It is a static warning if an abstract member m is declared or inherited in a concrete class C unless:
• m overrides a concrete member, or
• C has a noSuchMethod() method distinct from the one declared in class Object.

Because FooConcrete2 has an implementation of noSuchMethod() that is not the one declared in class Object, no error is expected.

While it would be useful for you to get an error here, it was felt that if you're explicitly handling missing methods via noSuchMethod then you probably don't want the error.

[eukreign]

The problem is not at all with Dart or the analysis server. I'm sorry if the wording in my issue was misleading.

The problem is that Element has a noSuchMethod() implementation and this limits the developer ergonomics of building Custom Elements.

The solution is for Element to not have noSuchMethod(), that is the goal of this github issue.

Is there another issue tracker I should use for dart:html?

[bwilkerson]

Nope, I just misunderstood.

[alan-knight]

It's not dart:html that has that method, it's dart:js. I believe the use of that is Dartium-specific, so an alternative would be for the analyzer to use the dart2js version of the library. @jacob314

[jacob314]

The Analyzer should be using the dart2js version of dart:html which does not use noSuchMethod. The use of NoSuchMethod in Dartium is an implementation detail.