Joost Koehoorn

This is due to an architectural change in Ivy. In the previous compiler (ViewEngine), the check for unknown elements would occur during parsing of the template. In Ivy, templates are...

Btw, it should certainly be possible to adjust the type checker to handle this differently, independent of `fullTemplateTypeCheck`. It would actually be a better design if it were that way.

I can explain that :-) If `fullTemplateTypeCheck` is disabled, any `ng-template` (or structural directive template) in an Angular template are not type checked for compatibility reasons (the `fullTemplateTypeCheck` was introduced...

Does using a relative path instead of an absolute path resolve the issue? I wouldn't be surprised if the absolute path specifies that only the `src` directory in the root...

@grantwhiting Nope, this one hasn't been figured out yet. I don't see this being modeled using the currently available type checking tools, as `ngSwitchCase` expressions have to be combined with...

@ofirrifo Please see https://github.com/angular/angular/issues/35139#issuecomment-581850479 for how this can be caught the nice way. The error occurs in a part of the compiler where dealing with such errors is a bit...

Relabelling as core as this looks like a rendering issue at runtime.

Yep, definitely incorrect. The template checker should be using `null` given that is how it currently behaves at runtime. @thw0rted Please capture your concern in #34385 as that is about...

We have decided not to land the fix, as it brings us further away from ES2020 optional chaining semantics, which would require the opposite breaking change in the future. No...

Thank you for the excellent bug report, this is indeed an issue.