feat(core): support metadata reflection for native class types

[trotyl]

closes #21731

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/angular/angular/blob/master/CONTRIBUTING.md#commit
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

[ ] Bugfix
[x] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[ ] Documentation content changes
[ ] angular.io application / infrastructure changes
[ ] Other... Please describe:

What is the current behavior?

Issue Number: #21731

What is the new behavior?

Using class inheritance in native class (targeting es2015) is now supported.

Does this PR introduce a breaking change?

[ ] Yes
[x] No

Other information

[trotyl]

Timeout in unrelated spec, should be a flake.

[vicb]

http://test/OCL:186493712:BASE:186493872:1519241655230:6e59754

[vicb]

closing as rebased in 22356

[vicb]

Could you please double check this logic ?

This change seems to trigger the following error:

class Base {
  constructor(t: Type) {...}
}

class Extend extends Base {
 // no ctor
}

// -> Can't resolve all parameters for BasicSearchResultChildComp: (?)

[trotyl]

Will have a look

[trotyl]

This looks weird, I can even confirm the OP's plunker works under 6.0.0-beta.5. Could you provide a little more information about:

• Whether the code compiled to es5 or es2015+?
• Does Base annotated with @Injectable()?
• Is Type a class rather than a interface or type?

[vicb]

What I can share for now:

---- controller.ts
// no annotation
export class Controller implements OnInit {
  @Input() result: ...;

  constructor(
      private readonly a: AType,
      private readonly g: GType) {}
// ...
}

---- comp.ts
@Component({
  selector: '...',
  templateUrl: ...,
})
export class Comp extends Controller {
}

[vicb]

I'll investigate more tomorrow

[trotyl]

It could be the lacking of class decorator in base class caused this problem, but I guess that's by design?

[devoto13]

I would rather call it a workaround. And IIRC it was working in some older versions without a decorator on an abstract base class.

[trotyl]

That's due to lacking of inheritance support in some very old versions, the current behavior is the natural result of combining inheritance semantics and TypeScript metadata emitting rules.

If there's no way to fix (except changing the design), I think it can be called by design (but could be a design failure).

Also, this change only make the behavior consistent between compiled classes (functions) and native classes, previously the natives class doesn't follow inheritance semantics (cannot inherit parent parameters), so some errors are now revealed, not introduced (just better error message).

[vicb]

@trotyl @devoto13 thanks for your help - the issue was on our side !
I'll probably reapply the change soon.

[vicb]

@trotyl Could you please add a test case for the error described in my previous comment.
I guess I'll have to revert this commit tomorrow (we did revert that change internally because it breaks some code)
Thanks.

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