ngc with `strictMetadataEmit: true` error on `@inject()` with generic type.

I’m submitting a…

[ ] Regression (a behavior that used to work and stopped working in a new release)
[x] Bug report  
[ ] Performance issue
[ ] Feature request
[ ] Documentation issue or request
[ ] Support request => Please do not submit support request here, instead see https://github.com/angular/angular/blob/master/CONTRIBUTING.md#question
[ ] Other... Please describe:

Current behavior

When you inject a token with @Inject() and generic type, compiling with strictMetadataEmit: true causes the following error:

Metadata collected contains an error that will be reported at runtime: Could not resolve type XXX

I’m using Partial<T> so at first I thought this was related to typescript built-in types but I created myself an export type Optional<T> and still got the same error.

Expected behavior

No error.

Minimal reproduction of the problem with instructions

export interface Setting {
   a: string;
}

export const SETTING = new InjectionToken<Partial<Setting>>('');

export class Foo {
  constructor(@Inject(SETTING) setting: Partial<Setting>){ } 
}

What is the motivation / use case for changing the behavior?

I’m building a lib where user can inject some settings. They’re all optional as missing ones will be filled with default values.

Environment

Angular version: 5.2.0

[alfaproject]

Just got hit by this. ):

[waterplea]

Will @Inject(DOCUMENT) documentRef: Document ever be supported without @dynamic? This seems to be the one opened issue related to this case.