fix(compiler): don't throw when Symbol is used as DI token

Closes #13314

modules/@angular/compiler/src/compile_metadata.ts

@@ -81,6 +81,7 @@ function _sanitizeIdentifier(name: string): string {
 }
 
 let _anonymousTypeIndex = 0;
+const symbols = new Map<Symbol, string>();
 
 export function identifierName(compileIdentifier: CompileIdentifierMetadata): string {
   if (!compileIdentifier || !compileIdentifier.reference) {
@@ -90,6 +91,14 @@ export function identifierName(compileIdentifier: CompileIdentifierMetadata): st
   if (ref instanceof StaticSymbol) {
     return ref.name;
   }
+  if (typeof ref === 'symbol') {
+    if (symbols.has(ref)) {
+      return symbols.get(ref);
+    }
+    const symbolStr = ref.toString().replace(/\(|\)/g, '_');
+    symbols.set(ref, symbolStr);
+    return symbolStr;
+  }
   if (ref['__anonymousType']) {
     return ref['__anonymousType'];
   }

modules/@angular/compiler/test/integration_spec.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {Component, Directive, Input} from '@angular/core';
+import {Component, Directive, Inject, Input} from '@angular/core';
 import {ComponentFixture, TestBed, async} from '@angular/core/testing';
 import {By} from '@angular/platform-browser/src/dom/debug/by';
 import {expect} from '@angular/platform-browser/testing/matchers';
@@ -38,6 +38,23 @@ export function main() {
          }));
     });
 
+    it('should not throw when Symbol is used as DI token', async(() => {
+         const SOME_SYMBOL = Symbol('SomeSymbol');
+
+         @Component({selector: 'symbol', template: ''})
+         class CmpWithSymbol {
+           constructor(@Inject(SOME_SYMBOL) public symbol: string) {}
+         }
+
+         TestBed.configureTestingModule({
+           declarations: [CmpWithSymbol],
+           providers: [{provide: SOME_SYMBOL, useValue: 'value'}]
+         });
+
+         const fixture = TestBed.createComponent(CmpWithSymbol);
+         fixture.detectChanges();
+         expect(fixture.componentInstance.symbol).toEqual('value');
+       }));
   });
 }