This change retracts support for metadata version 2.
The collector used to produce version 2 metadata was incomplete
and can cause the AOT compiler to fail to resolve symbols or
produce other spurious errors.
All libraries compiled and published with 2.3.0 ngc will need
to be recompiled and updated with this change.
## Inheritance Semantics:
Decorators:
1) list the decorators of the class and its parents in the ancestor first order
2) only use the last decorator of each kind (e.g. @Component / ...)
Constructor parameters:
If a class inherits from a parent class and does not declare
a constructor, it inherits the parent class constructor,
and with it the parameter metadata of that parent class.
Lifecycle hooks:
Follow the normal class inheritance model,
i.e. lifecycle hooks of parent classes will be called
even if the method is not overwritten in the child class.
## Example
E.g. the following is a valid use of inheritance and it will
also inherit all metadata:
```
@Directive({selector: 'someDir'})
class ParentDirective {
constructor(someDep: SomeDep) {}
ngOnInit() {}
}
class ChildDirective extends ParentDirective {}
```
Closes#11606Closes#12892
- `NgHost` to `CompilerHost`
- `AotCompilerHost.resolveFileToImport` to `AotCompilerHost.fileNameToModuleName`
- `AotCompilerHoset.resolveImportToFile` to `AotCompilerHost.moduleNameToFileName`
