fix(compiler): only warn for `@Injectable` classes with invalid args.

In v2.x, users had to annotate classes that they intended to use as tokens with `@Injectable`. This is no longer required in v4.x for tokens,
and we now require the constructor parameters of classes annotated
with `@Injectable` to be statically analyzable by ngc.

This commit reduces the error into a warning
if the constructor parameters do not meet this condition.

DEPRECATION:
- Classes annotated with `@Injectable` but whose constructor’s parameter types
  are not statically analyzable by ngc will produce a warning.

Closes #15003

packages/compiler/src/aot/compiler_factory.ts

@@ -67,7 +67,7 @@ export function createAotCompiler(compilerHost: AotCompilerHost, options: AotCom
   const resolver = new CompileMetadataResolver(
       config, new NgModuleResolver(staticReflector), new DirectiveResolver(staticReflector),
       new PipeResolver(staticReflector), summaryResolver, elementSchemaRegistry, normalizer,
-      symbolCache, staticReflector);
+      console, symbolCache, staticReflector);
   // TODO(vicb): do not pass options.i18nFormat here
   const importResolver = {
     getImportAs: (symbol: StaticSymbol) => symbolResolver.getImportAs(symbol),

packages/compiler/src/i18n/extractor.ts

@@ -10,7 +10,7 @@
 /**
  * Extract i18n messages from source code
  */
-import {ViewEncapsulation} from '@angular/core';
+import {ViewEncapsulation, ɵConsole as Console} from '@angular/core';
 
 import {analyzeAndValidateNgModules, extractProgramSymbols} from '../aot/compiler';
 import {StaticAndDynamicReflectionCapabilities} from '../aot/static_reflection_capabilities';
@@ -106,7 +106,7 @@ export class Extractor {
     const resolver = new CompileMetadataResolver(
         config, new NgModuleResolver(staticReflector), new DirectiveResolver(staticReflector),
         new PipeResolver(staticReflector), summaryResolver, elementSchemaRegistry, normalizer,
-        symbolCache, staticReflector);
+        new Console(), symbolCache, staticReflector);
 
     // TODO(vicb): implicit tags & attributes
     const messageBundle = new MessageBundle(htmlParser, [], {}, locale);

packages/compiler/src/metadata_resolver.ts

@@ -6,7 +6,8 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {Attribute, ChangeDetectionStrategy, Component, ComponentFactory, Directive, Host, Inject, Injectable, InjectionToken, ModuleWithProviders, Optional, Provider, Query, RendererType2, SchemaMetadata, Self, SkipSelf, Type, resolveForwardRef, ɵERROR_COMPONENT_TYPE, ɵLIFECYCLE_HOOKS_VALUES, ɵReflectorReader, ɵccf as createComponentFactory, ɵreflector, ɵstringify as stringify} from '@angular/core';
+import {Attribute, ChangeDetectionStrategy, Component, ComponentFactory, Directive, Host, Inject, Injectable, InjectionToken, ModuleWithProviders, Optional, Provider, Query, RendererType2, SchemaMetadata, Self, SkipSelf, Type, resolveForwardRef, ɵConsole as Console, ɵERROR_COMPONENT_TYPE, ɵLIFECYCLE_HOOKS_VALUES, ɵReflectorReader, ɵccf as createComponentFactory, ɵreflector, ɵstringify as stringify} from '@angular/core';
+
 import {StaticSymbol, StaticSymbolCache} from './aot/static_symbol';
 import {ngfactoryFilePath} from './aot/util';
 import {assertArrayOfStrings, assertInterpolationSymbols} from './assertions';
@@ -49,7 +50,7 @@ export class CompileMetadataResolver {
       private _directiveResolver: DirectiveResolver, private _pipeResolver: PipeResolver,
       private _summaryResolver: SummaryResolver<any>,
       private _schemaRegistry: ElementSchemaRegistry,
-      private _directiveNormalizer: DirectiveNormalizer,
+      private _directiveNormalizer: DirectiveNormalizer, private _console: Console,
       @Optional() private _staticSymbolCache: StaticSymbolCache,
       private _reflector: ɵReflectorReader = ɵreflector,
       @Optional() @Inject(ERROR_COLLECTOR_TOKEN) private _errorCollector?: ErrorCollector) {}
@@ -665,7 +666,10 @@ export class CompileMetadataResolver {
   }
 
   getInjectableSummary(type: any): cpl.CompileTypeSummary {
-    return {summaryKind: cpl.CompileSummaryKind.Injectable, type: this._getTypeMetadata(type)};
+    return {
+      summaryKind: cpl.CompileSummaryKind.Injectable,
+      type: this._getTypeMetadata(type, null, false)
+    };
   }
 
   private _getInjectableMetadata(type: Type<any>, dependencies: any[] = null):
@@ -677,11 +681,12 @@ export class CompileMetadataResolver {
     return this._getTypeMetadata(type, dependencies);
   }
 
-  private _getTypeMetadata(type: Type<any>, dependencies: any[] = null): cpl.CompileTypeMetadata {
+  private _getTypeMetadata(type: Type<any>, dependencies: any[] = null, throwOnUnknownDeps = true):
+      cpl.CompileTypeMetadata {
     const identifier = this._getIdentifierMetadata(type);
     return {
       reference: identifier.reference,
-      diDeps: this._getDependenciesMetadata(identifier.reference, dependencies),
+      diDeps: this._getDependenciesMetadata(identifier.reference, dependencies, throwOnUnknownDeps),
       lifecycleHooks:
           ɵLIFECYCLE_HOOKS_VALUES.filter(hook => hasLifecycleHook(hook, identifier.reference)),
     };
@@ -742,8 +747,9 @@ export class CompileMetadataResolver {
     return pipeMeta;
   }
 
-  private _getDependenciesMetadata(typeOrFunc: Type<any>|Function, dependencies: any[]):
-      cpl.CompileDiDependencyMetadata[] {
+  private _getDependenciesMetadata(
+      typeOrFunc: Type<any>|Function, dependencies: any[],
+      throwOnUnknownDeps = true): cpl.CompileDiDependencyMetadata[] {
     let hasUnknownDeps = false;
     const params = dependencies || this._reflector.parameters(typeOrFunc) || [];
 
@@ -797,10 +803,13 @@ export class CompileMetadataResolver {
     if (hasUnknownDeps) {
       const depsTokens =
           dependenciesMetadata.map((dep) => dep ? stringifyType(dep.token) : '?').join(', ');
-      this._reportError(
-          syntaxError(
-              `Can't resolve all parameters for ${stringifyType(typeOrFunc)}: (${depsTokens}).`),
-          typeOrFunc);
+      const message =
+          `Can't resolve all parameters for ${stringifyType(typeOrFunc)}: (${depsTokens}).`;
+      if (throwOnUnknownDeps) {
+        this._reportError(syntaxError(message), typeOrFunc);
+      } else {
+        this._console.warn(`Warning: ${message} This will become an error in Angular v5.x`);
+      }
     }
 
     return dependenciesMetadata;

packages/compiler/test/aot/compiler_spec.ts

@@ -219,6 +219,35 @@ describe('compiler (unbundled Angular)', () => {
          }));
     }
   });
+
+  describe('errors', () => {
+    it('should only warn if not all arguments of an @Injectable class can be resolved',
+       fakeAsync(() => {
+         const FILES: MockData = {
+           app: {
+             'app.ts': `
+                import {Injectable} from '@angular/core';
+
+                @Injectable()
+                export class MyService {
+                  constructor(a: boolean) {}
+                }
+              `
+           }
+         };
+         const host = new MockCompilerHost(['/app/app.ts'], FILES, angularFiles);
+         const aotHost = new MockAotCompilerHost(host);
+         let ok = false;
+         const warnSpy = spyOn(console, 'warn');
+         compile(host, aotHost, expectNoDiagnostics).then(() => ok = true);
+
+         tick();
+
+         expect(ok).toBe(true);
+         expect(warnSpy).toHaveBeenCalledWith(
+             `Warning: Can't resolve all parameters for MyService in /app/app.ts: (?). This will become an error in Angular v5.x`);
+       }));
+  });
 });
 
 describe('compiler (bundled Angular)', () => {

packages/language-service/src/typescript_host.ts

@@ -7,7 +7,7 @@
  */
 
 import {AotSummaryResolver, CompileDirectiveMetadata, CompileMetadataResolver, CompilerConfig, DEFAULT_INTERPOLATION_CONFIG, DirectiveNormalizer, DirectiveResolver, DomElementSchemaRegistry, HtmlParser, InterpolationConfig, NgAnalyzedModules, NgModuleResolver, ParseTreeResult, Parser, PipeResolver, ResourceLoader, StaticReflector, StaticSymbol, StaticSymbolCache, StaticSymbolResolver, SummaryResolver, UrlResolver, analyzeNgModules, componentModuleUrl, createOfflineCompileUrlResolver, extractProgramSymbols} from '@angular/compiler';
-import {Type, ViewEncapsulation} from '@angular/core';
+import {Type, ViewEncapsulation, ɵConsole as Console} from '@angular/core';
 import * as fs from 'fs';
 import * as path from 'path';
 import * as ts from 'typescript';
@@ -115,8 +115,8 @@ export class TypeScriptServiceHost implements LanguageServiceHost {
 
       result = this._resolver = new CompileMetadataResolver(
           config, moduleResolver, directiveResolver, pipeResolver, new SummaryResolver(),
-          elementSchemaRegistry, directiveNormalizer, this._staticSymbolCache, this.reflector,
-          (error, type) => this.collectError(error, type && type.filePath));
+          elementSchemaRegistry, directiveNormalizer, new Console(), this._staticSymbolCache,
+          this.reflector, (error, type) => this.collectError(error, type && type.filePath));
     }
     return result;
   }