feat(core): Add type information to injector.get() (#13785)

- Introduce `InjectionToken<T>` which is a parameterized and type-safe
  version of `OpaqueToken`.

DEPRECATION:
- `OpaqueToken` is now deprecated, use `InjectionToken<T>` instead.
- `Injector.get(token: any, notFoundValue?: any): any` is now deprecated
  use the same method which is now overloaded as
  `Injector.get<T>(token: Type<T>|InjectionToken<T>, notFoundValue?: T): T;`.

Migration
- Replace `OpaqueToken` with `InjectionToken<?>` and parameterize it.
- Migrate your code to only use `Type<?>` or `InjectionToken<?>` as
  injection tokens. Using other tokens will not be supported in the
  future.

BREAKING CHANGE:
- Because `injector.get()` is now parameterize it is possible that code
  which used to work no longer type checks. Example would be if one
  injects `Foo` but configures it as `{provide: Foo, useClass: MockFoo}`.
  The injection instance will be that of `MockFoo` but the type will be
  `Foo` instead of `any` as in the past. This means that it was possible
  to call a method on `MockFoo` in the past which now will fail type
  check. See this example:

```
class Foo {}
class MockFoo extends Foo {
  setupMock();
}

var PROVIDERS = [
  {provide: Foo, useClass: MockFoo}
];

...

function myTest(injector: Injector) {
  var foo = injector.get(Foo);
  // This line used to work since `foo` used to be `any` before this
  // change, it will now be `Foo`, and `Foo` does not have `setUpMock()`.
  // The fix is to downcast: `injector.get(Foo) as MockFoo`.
  foo.setUpMock();
}
```

PR Close #13785

modules/@angular/compiler/src/aot/static_reflector.ts

@@ -17,7 +17,8 @@ const ANGULAR_IMPORT_LOCATIONS = {
   coreDecorators: '@angular/core/src/metadata',
   diDecorators: '@angular/core/src/di/metadata',
   diMetadata: '@angular/core/src/di/metadata',
-  diOpaqueToken: '@angular/core/src/di/opaque_token',
+  diInjectionToken: '@angular/core/src/di/injection_token',
+  diOpaqueToken: '@angular/core/src/di/injection_token',
   animationMetadata: '@angular/core/src/animation/metadata',
   provider: '@angular/core/src/di/provider'
 };
@@ -34,6 +35,7 @@ export class StaticReflector implements ReflectorReader {
   private parameterCache = new Map<StaticSymbol, any[]>();
   private methodCache = new Map<StaticSymbol, {[key: string]: boolean}>();
   private conversionMap = new Map<StaticSymbol, (context: StaticSymbol, args: any[]) => any>();
+  private injectionToken: StaticSymbol;
   private opaqueToken: StaticSymbol;
 
   constructor(
@@ -229,9 +231,10 @@ export class StaticReflector implements ReflectorReader {
   }
 
   private initializeConversionMap(): void {
-    const {coreDecorators, diDecorators, diMetadata, diOpaqueToken, animationMetadata, provider} =
-        ANGULAR_IMPORT_LOCATIONS;
-    this.opaqueToken = this.findDeclaration(diOpaqueToken, 'OpaqueToken');
+    const {coreDecorators, diDecorators,      diMetadata, diInjectionToken,
+           diOpaqueToken,  animationMetadata, provider} = ANGULAR_IMPORT_LOCATIONS;
+    this.injectionToken = this.findDeclaration(diInjectionToken, 'InjectionToken');
+    this.opaqueToken = this.findDeclaration(diInjectionToken, 'OpaqueToken');
 
     this._registerDecoratorOrConstructor(this.findDeclaration(diDecorators, 'Host'), Host);
     this._registerDecoratorOrConstructor(
@@ -382,7 +385,8 @@ export class StaticReflector implements ReflectorReader {
         }
         if (expression instanceof StaticSymbol) {
           // Stop simplification at builtin symbols
-          if (expression === self.opaqueToken || self.conversionMap.has(expression)) {
+          if (expression === self.injectionToken || expression === self.opaqueToken ||
+              self.conversionMap.has(expression)) {
             return expression;
           } else {
             const staticSymbol = expression;
@@ -506,9 +510,9 @@ export class StaticReflector implements ReflectorReader {
                 // Determine if the function is a built-in conversion
                 staticSymbol = simplifyInContext(context, expression['expression'], depth + 1);
                 if (staticSymbol instanceof StaticSymbol) {
-                  if (staticSymbol === self.opaqueToken) {
-                    // if somebody calls new OpaqueToken, don't create an OpaqueToken,
-                    // but rather return the symbol to which the OpaqueToken is assigned to.
+                  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.
                     return context;
                   }
                   const argExpressions: any[] = expression['arguments'] || [];
@@ -674,4 +678,4 @@ function positionalError(message: string, fileName: string, line: number, column
   (result as any).line = line;
   (result as any).column = column;
   return result;
-}
+}

modules/@angular/compiler/src/jit/compiler_factory.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {COMPILER_OPTIONS, Compiler, CompilerFactory, CompilerOptions, Inject, OpaqueToken, Optional, PLATFORM_INITIALIZER, PlatformRef, Provider, ReflectiveInjector, TRANSLATIONS, TRANSLATIONS_FORMAT, Type, ViewEncapsulation, createPlatformFactory, isDevMode, platformCore} from '@angular/core';
+import {COMPILER_OPTIONS, Compiler, CompilerFactory, CompilerOptions, Inject, InjectionToken, Optional, PLATFORM_INITIALIZER, PlatformRef, Provider, ReflectiveInjector, TRANSLATIONS, TRANSLATIONS_FORMAT, Type, ViewEncapsulation, createPlatformFactory, isDevMode, platformCore} from '@angular/core';
 
 import {AnimationParser} from '../animation/animation_parser';
 import {CompilerConfig} from '../config';
@@ -40,7 +40,7 @@ const _NO_RESOURCE_LOADER: ResourceLoader = {
           `No ResourceLoader implementation has been provided. Can't read the url "${url}"`);}
 };
 
-const baseHtmlParser = new OpaqueToken('HtmlParser');
+const baseHtmlParser = new InjectionToken('HtmlParser');
 
 /**
  * A set of providers that provide `JitCompiler` and its dependencies to use for

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

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {AnimationAnimateMetadata, AnimationEntryMetadata, AnimationGroupMetadata, AnimationKeyframesSequenceMetadata, AnimationMetadata, AnimationStateDeclarationMetadata, AnimationStateMetadata, AnimationStateTransitionMetadata, AnimationStyleMetadata, AnimationWithStepsMetadata, Attribute, ChangeDetectionStrategy, Component, ComponentFactory, Directive, Host, Inject, Injectable, ModuleWithProviders, OpaqueToken, Optional, Provider, Query, SchemaMetadata, Self, SkipSelf, Type, resolveForwardRef} from '@angular/core';
+import {AnimationAnimateMetadata, AnimationEntryMetadata, AnimationGroupMetadata, AnimationKeyframesSequenceMetadata, AnimationMetadata, AnimationStateDeclarationMetadata, AnimationStateMetadata, AnimationStateTransitionMetadata, AnimationStyleMetadata, AnimationWithStepsMetadata, Attribute, ChangeDetectionStrategy, Component, ComponentFactory, Directive, Host, Inject, Injectable, InjectionToken, ModuleWithProviders, Optional, Provider, Query, SchemaMetadata, Self, SkipSelf, Type, resolveForwardRef} from '@angular/core';
 
 import {StaticSymbol, StaticSymbolCache} from './aot/static_symbol';
 import {ngfactoryFilePath} from './aot/util';
@@ -27,7 +27,7 @@ import {getUrlScheme} from './url_resolver';
 import {MODULE_SUFFIX, SyntaxError, ValueTransformer, visitValue} from './util';
 
 export type ErrorCollector = (error: any, type?: any) => void;
-export const ERROR_COLLECTOR_TOKEN = new OpaqueToken('ErrorCollector');
+export const ERROR_COLLECTOR_TOKEN = new InjectionToken('ErrorCollector');
 
 // Design notes:
 // - don't lazily create metadata:

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

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {Inject, OpaqueToken, Optional, SchemaMetadata} from '@angular/core';
+import {Inject, InjectionToken, Optional, SchemaMetadata} from '@angular/core';
 import {CompileDirectiveMetadata, CompileDirectiveSummary, CompilePipeSummary, CompileTemplateSummary, CompileTokenMetadata, CompileTypeMetadata, identifierName} from '../compile_metadata';
 import {Parser} from '../expression_parser/parser';
 import {isPresent} from '../facade/lang';
@@ -67,7 +67,7 @@ const TEXT_CSS_SELECTOR = CssSelector.parse('*')[0];
  *
  * This is currently an internal-only feature and not meant for general use.
  */
-export const TEMPLATE_TRANSFORMS = new OpaqueToken('TemplateTransforms');
+export const TEMPLATE_TRANSFORMS = new InjectionToken('TemplateTransforms');
 
 export class TemplateParseError extends ParseError {
   constructor(message: string, span: ParseSourceSpan, level: ParseErrorLevel) {

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

@@ -6,12 +6,13 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {Inject, PACKAGE_ROOT_URL} from '@angular/core';
+import {Inject, InjectionToken, PACKAGE_ROOT_URL} from '@angular/core';
 
 import {isBlank, isPresent} from './facade/lang';
 import {CompilerInjectable} from './injectable';
 
 
+
 /**
  * Create a {@link UrlResolver} with no package prefix.
  */