## 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
BREAKING CHANGE:
- all `…Metadata` classes have been removed. Use the corresponding decorator
as constructor or for `instanceof` checks instead.
- Example:
* Before: `new ComponentMetadata(…)`
* After: `new Component(…)`
- Note: `new Component(…)` worked before as well.
BREAKING CHANGE: previously deprecated @Component.directives and @Component.pipes support was removed.
All the components and pipes now must be declarated via an NgModule. NgModule is the basic
compilation block passed into the Angular compiler via Compiler#compileModuleSync or #compileModuleAsync.
Because of this change, the Compiler#compileComponentAsync and #compileComponentSync were removed as well -
any code doing compilation should compile module instead using the apis mentioned above.
Lastly, since modules are the basic compilation unit, the ngUpgrade module was modified to always require
an NgModule to be passed into the UpgradeAdapter's constructor - previously this was optional.
The methods on `ViewResolverMock` have been merged into `DirectiveResolver`.
BREAKING CHANGE:
- ES5 users can no longer use the `View(…)` function to provide `ViewMetadata`.
This mirrors the removal of the `@View` decorator a while ago.
Tobias Bosch
Victor Berchet
Igor Minar
Julie Ralph
ScottSWu
Alex Eagle
ScottSWu