Ivy definition looks something like this:
```
class MyService {
static ngInjectableDef = defineInjectable({
…
});
}
```
Here the argument to `defineInjectable` is well known public contract which needs
to be honored in backward compatible way between versions. The type of the
return value of `defineInjectable` on the other hand is private and can change
shape drastically between versions without effecting backwards compatibility of
libraries publish to NPM. To our users it is effectively an `OpaqueToken`.
By prefixing the type with `ɵ` we are communicating the the outside world that
the value is not public API and is subject to change without backward compatibility.
PR Close#23371
- Remove default injection value from `inject` / `directiveInject` since
it is not possible to set using annotations.
- Module `Injector` is stored on `LView` instead of `LInjector` data
structure because it can change only at `LView` level. (More efficient)
- Add `ngInjectableDef` to `IterableDiffers` so that existing tests can
pass as well as enable `IterableDiffers` to be injectable without
`Injector`
PR Close#23345
This change makes the code cleaner for the user. It does mean
a little bit more work for us since we have to patch the `type` back
into the `DirectiveDef`. However since the patching happens only once
on startup it should not be significant.
PR Close#21374
We used to have a separate `directive` instruction for instantiating
directives. However, such an instruction requires that directives
are created in the correct order, which would require that template
compiler would have knowledge of all dependent directives. This
would break template compilation locality principle.
This change only changes the APIs to expected form but does
not change the semantics. The semantics will need to be corrected
in subsequent commits. The semantic change needed is to
resolve the directive instantiation error at runtime based on
injection dependencies.
PR Close#21374
