fix(language-service): do not report errors for `OpaqueToken` (#19427)

`OpaqueToken` was removed from angular but the language-service
should not report errors when it is used for older versions of
angular.

packages/compiler/src/aot/static_reflector.ts

@@ -44,6 +44,7 @@ export class StaticReflector implements CompileReflector {
   private methodCache = new Map<StaticSymbol, {[key: string]: boolean}>();
   private conversionMap = new Map<StaticSymbol, (context: StaticSymbol, args: any[]) => any>();
   private injectionToken: StaticSymbol;
+  private opaqueToken: StaticSymbol;
   private ROUTES: StaticSymbol;
   private ANALYZE_FOR_ENTRY_COMPONENTS: StaticSymbol;
   private annotationForParentClassWithSummaryKind =
@@ -270,6 +271,7 @@ export class StaticReflector implements CompileReflector {
 
   private initializeConversionMap(): void {
     this.injectionToken = this.findDeclaration(ANGULAR_CORE, 'InjectionToken');
+    this.opaqueToken = this.findDeclaration(ANGULAR_CORE, 'OpaqueToken');
     this.ROUTES = this.tryFindDeclaration(ANGULAR_ROUTER, 'ROUTES');
     this.ANALYZE_FOR_ENTRY_COMPONENTS =
         this.findDeclaration(ANGULAR_CORE, 'ANALYZE_FOR_ENTRY_COMPONENTS');
@@ -561,9 +563,12 @@ export class StaticReflector implements CompileReflector {
                 staticSymbol = simplifyInContext(
                     context, expression['expression'], depth + 1, /* references */ 0);
                 if (staticSymbol instanceof StaticSymbol) {
-                  if (staticSymbol === self.injectionToken) {
+                  if (staticSymbol === self.injectionToken || staticSymbol === self.opaqueToken) {
                     // if somebody calls new InjectionToken, don't create an InjectionToken,
                     // but rather return the symbol to which the InjectionToken is assigned to.
+
+                    // OpaqueToken is supported too as it is required by the language service to
+                    // support v4 and prior versions of Angular.
                     return context;
                   }
                   const argExpressions: any[] = expression['arguments'] || [];

packages/language-service/test/diagnostics_spec.ts

@@ -314,6 +314,28 @@ describe('diagnostics', () => {
       expect(diagnostic).toEqual([]);
     });
 
+    it('should not report errors for using the now removed OpaqueToken (support for v4)', () => {
+      const app_component = `
+        import { Component, Inject, OpaqueToken } from '@angular/core';
+        import { NgForm } from '@angular/common';
+
+        export const token = new OpaqueToken();
+
+        @Component({
+          selector: 'example-app',
+          template: '...'
+        })
+        export class AppComponent {
+          constructor (@Inject(token) value: string) {}
+          onSubmit(form: NgForm) {}
+        }
+      `;
+      const fileName = '/app/app.component.ts';
+      mockHost.override(fileName, app_component);
+      const diagnostics = ngService.getDiagnostics(fileName);
+      expect(diagnostics).toEqual([]);
+    });
+
     function addCode(code: string, cb: (fileName: string, content?: string) => void) {
       const fileName = '/app/app.component.ts';
       const originalContent = mockHost.getFileContent(fileName);