export const SomeInjectionToken = new InjectionToken<AAA>('HostEnvironment');

export const enum AAA {  S = 1,  D = 3 };

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent {
  constructor(
    @Optional() @Inject(SomeInjectionToken) p: AAA
  ) {
    console.log(p);
  }
  title = 'injectEnumBug';
}

ReferenceError: AAA is not defined
    at push../src/app/app.component.ts.AppComponent.ctorParameters (main.js:108)
    at ReflectionCapabilities._ownParameters (vendor.js:45378)
    at ReflectionCapabilities.parameters (vendor.js:45403)
    at reflectDependencies (vendor.js:45561)
    at directiveMetadata (vendor.js:60983)
    at Function.get (vendor.js:60886)
    at getComponentDef (vendor.js:36704)
    at verifyDeclarationsHaveDefinitions (vendor.js:60557)
    at Array.forEach ()
    at verifySemanticsOfNgModuleDef (vendor.js:60529)

Angular CLI: 10.0.6
Node: 10.15.2
OS: win32 x64

Angular: 10.0.10
... animations, common, compiler, compiler-cli, core, forms
... platform-browser, platform-browser-dynamic, router
Ivy Workspace: Yes

Package                           Version
-----------------------------------------------------------
@angular-devkit/architect         0.1000.6
@angular-devkit/build-angular     0.1000.6
@angular-devkit/build-optimizer   0.1000.6
@angular-devkit/build-webpack     0.1000.6
@angular-devkit/core              10.0.6
@angular-devkit/schematics        10.0.6
@angular/cli                      10.0.6
@ngtools/webpack                  10.0.6
@schematics/angular               10.0.6
@schematics/update                0.1000.6
rxjs                              6.5.5
typescript                        3.9.7
webpack                           4.43.0