fix(ivy): error when using forwardRef in Injectable's useClass (#30532)

Fixes Ivy throwing an error when something is passed in as a `forwardRef` into `@Injectable`'s `useClass` option. The error was being thrown, because we were trying to get the provider factory off of the wrapper function, rather than the value itself.

This PR resolves FW-1335.

PR Close #30532

packages/core/src/di/forward_ref.ts

@@ -57,11 +57,11 @@ export function forwardRef(forwardRefFn: ForwardRefFn): Type<any> {
  * @publicApi
  */
 export function resolveForwardRef<T>(type: T): T {
-  const fn: any = type;
+  return isForwardRef(type) ? type() : type;
-  if (typeof fn === 'function' && fn.hasOwnProperty(__forward_ref__) &&
-      fn.__forward_ref__ === forwardRef) {
-    return fn();
-  } else {
-    return type;
 }
+
+/** Checks whether a function is wrapped by a `forwardRef`. */
+export function isForwardRef(fn: any): fn is() => any {
+  return typeof fn === 'function' && fn.hasOwnProperty(__forward_ref__) &&
+      fn.__forward_ref__ === forwardRef;
 }

packages/core/src/di/jit/environment.ts

@@ -7,6 +7,7 @@
  */
 
 import {Type} from '../../interface/type';
+import {isForwardRef, resolveForwardRef} from '../forward_ref';
 import {ɵɵinject} from '../injector_compatibility';
 import {getInjectableDef, getInjectorDef, ɵɵdefineInjectable, ɵɵdefineInjector} from '../interface/defs';
 
@@ -26,6 +27,14 @@ export const angularCoreDiEnv: {[name: string]: Function} = {
 
 function getFactoryOf<T>(type: Type<any>): ((type?: Type<T>) => T)|null {
   const typeAny = type as any;
+
+  if (isForwardRef(type)) {
+    return (() => {
+      const factory = getFactoryOf<T>(resolveForwardRef(typeAny));
+      return factory ? factory() : null;
+    }) as any;
+  }
+
   const def = getInjectableDef<T>(typeAny) || getInjectorDef<T>(typeAny);
   if (!def || def.factory === undefined) {
     return null;

packages/core/src/render3/di.ts

@@ -6,6 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
+import {isForwardRef, resolveForwardRef} from '../di/forward_ref';
 import {InjectionToken} from '../di/injection_token';
 import {Injector} from '../di/injector';
 import {injectRootLimpMode, setInjectImplementation} from '../di/injector_compatibility';
@@ -633,6 +634,14 @@ export class NodeInjector implements Injector {
  */
 export function ɵɵgetFactoryOf<T>(type: Type<any>): FactoryFn<T>|null {
   const typeAny = type as any;
+
+  if (isForwardRef(type)) {
+    return (() => {
+      const factory = ɵɵgetFactoryOf<T>(resolveForwardRef(typeAny));
+      return factory ? factory() : null;
+    }) as any;
+  }
+
   const def = getComponentDef<T>(typeAny) || getDirectiveDef<T>(typeAny) ||
       getPipeDef<T>(typeAny) || getInjectableDef<T>(typeAny) || getInjectorDef<T>(typeAny);
   if (!def || def.factory === undefined) {

packages/core/test/acceptance/providers_spec.ts

@@ -9,6 +9,7 @@
 import {Component, Directive, Inject, Injectable, InjectionToken, Injector, NgModule, Optional, forwardRef} from '@angular/core';
 import {TestBed, async, inject} from '@angular/core/testing';
 import {By} from '@angular/platform-browser';
+import {expect} from '@angular/platform-browser/testing/src/matchers';
 import {onlyInIvy} from '@angular/private/testing';
 
 describe('providers', () => {
@@ -319,6 +320,54 @@ describe('providers', () => {
       expect(fixture.componentInstance.myService.dep.value).toBe('one');
     });
 
+    it('should support forward refs in useClass when impl version is also provided', () => {
+
+      @Injectable({providedIn: 'root', useClass: forwardRef(() => SomeProviderImpl)})
+      abstract class SomeProvider {
+      }
+
+      @Injectable()
+      class SomeProviderImpl extends SomeProvider {
+      }
+
+      @Component({selector: 'my-app', template: ''})
+      class App {
+        constructor(public foo: SomeProvider) {}
+      }
+
+      TestBed.configureTestingModule(
+          {declarations: [App], providers: [{provide: SomeProvider, useClass: SomeProviderImpl}]});
+      const fixture = TestBed.createComponent(App);
+      fixture.detectChanges();
+
+      expect(fixture.componentInstance.foo).toBeAnInstanceOf(SomeProviderImpl);
+    });
+
+
+    onlyInIvy('VE bug (see FW-1454)')
+        .it('should support forward refs in useClass when token is provided', () => {
+
+          @Injectable({providedIn: 'root', useClass: forwardRef(() => SomeProviderImpl)})
+          abstract class SomeProvider {
+          }
+
+          @Injectable()
+          class SomeProviderImpl extends SomeProvider {
+          }
+
+          @Component({selector: 'my-app', template: ''})
+          class App {
+            constructor(public foo: SomeProvider) {}
+          }
+
+          TestBed.configureTestingModule(
+              {declarations: [App], providers: [{provide: SomeProvider, useClass: SomeProvider}]});
+          const fixture = TestBed.createComponent(App);
+          fixture.detectChanges();
+
+          expect(fixture.componentInstance.foo).toBeAnInstanceOf(SomeProviderImpl);
+        });
+
   });
 
   describe('flags', () => {

packages/core/test/bundling/injection/bundle.golden_symbols.json

@@ -155,6 +155,9 @@
   {
     "name": "isFactoryProvider"
   },
+  {
+    "name": "isForwardRef"
+  },
   {
     "name": "isTypeProvider"
   },

packages/core/test/bundling/todo/bundle.golden_symbols.json

@@ -1043,6 +1043,9 @@
   {
     "name": "isFactory"
   },
+  {
+    "name": "isForwardRef"
+  },
   {
     "name": "isJsObject"
   },