useFactory in @Injectable doesn't work using object's shorthand method definition

🐞 bug report

Affected Package

The issue is caused by package @angular/core

Is this a regression?

Yes, the previous version in which this bug was not present was: I don't know

Description

useFactory doesn’t work when I use it like this:

@Injectable({
  providedIn: 'root',
  useFactory() {
    console.log('this useFactory should be called, but... nope :`(')

    return {}
  },
})
class TestService {
  constructor() {
    console.log('this constructor should not be called!!! but it's');
  }
}

Using an arrow function, an anonymous function or an exported function work (see repro). But using an arrow function angular language service complains… it works at runtime and building, but it’s annoying

🔬 Minimal Reproduction

this repro uses 9.1.1, but it doesn’t work with latest (10.0.12) either

https://ng-run.com/edit/zwh0lwIk3NYX9tKWSUMt

🔥 Exception or Error

🌍 Your Environment

Angular Version:

Angular CLI: 10.0.7
Node: 14.6.0
OS: linux x64

Angular: 10.0.12
... animations, common, compiler, compiler-cli, core, forms
... localize, platform-browser, platform-browser-dynamic, router
Ivy Workspace: Yes

Package                           Version
-----------------------------------------------------------
@angular-devkit/architect         0.1000.4
@angular-devkit/build-angular     0.1000.7
@angular-devkit/build-optimizer   0.1000.7
@angular-devkit/build-webpack     0.1000.7
@angular-devkit/core              10.0.4
@angular-devkit/schematics        10.0.7
@angular/cdk                      10.1.3
@angular/cli                      10.0.7
@ngtools/webpack                  10.0.7
@schematics/angular               10.0.7
@schematics/update                0.1000.7
rxjs                              6.6.2
typescript                        3.9.7
webpack                           4.43.0

Anything else relevant?

[djleonskennedy]

Useless functionality, can be removed

[tonivj5]

No problem, thanks for confirm! 😄