Automated g4 rollback of changelist 184594151.

*** Reason for rollback ***

Teams are relying on this throwsArgumentError, so I'll have to do this behind a flag...

*** Original change description ***

feat(Core): Start work on a MissingProviderError, with better error messages.

Added a simple test (passes), and a complex test (skipped, does not pass). In
dev-mode we will start tracking the chain of failed lookups and give a better
error message, i.e. "No provider found for B: A -> B".

Work towards #434.

***

PiperOrigin-RevId: 184617305

_tests/lib/matchers.dart

@@ -1,20 +1,7 @@
 import 'dart:html';
 
-import 'package:angular/src/di/errors.dart';
-import 'package:angular/src/facade/lang.dart';
 import 'package:test/test.dart';
 
-/// Matches a missing provider error thrown at runtime.
-final Matcher throwsMissingProviderError = (() {
-  if (assertionsEnabled()) {
-    return _throwsMissingProviderError;
-  }
-  return throwsArgumentError;
-})();
-
-final _isMissingProviderError = const isInstanceOf<MissingProviderError>();
-final _throwsMissingProviderError = throwsA(_isMissingProviderError);
-
 /// Matches textual content of an element including children.
 Matcher hasTextContent(expected) => new _HasTextContent(expected);
 

_tests/test/di/injector_test.dart

@@ -6,7 +6,6 @@ import 'package:angular/src/di/injector/injector.dart';
 import 'package:test/test.dart';
 import 'package:angular/src/di/reflector.dart' as reflector;
 import 'package:angular_test/angular_test.dart';
-import 'package:_tests/matchers.dart';
 
 import 'injector_test.template.dart' as ng;
 
@@ -44,26 +43,11 @@ void main() {
 
       test('should throw by default', () {
         i = new Injector.empty();
-        expect(
-          () => i.get(ExampleService),
-          throwsMissingProviderError,
-        );
-        expect(
-          () => i.inject(ExampleService),
-          throwsMissingProviderError,
-        );
-        expect(
-          () => i.injectFromSelf(ExampleService),
-          throwsMissingProviderError,
-        );
-        expect(
-          () => i.injectFromAncestry(ExampleService),
-          throwsMissingProviderError,
-        );
-        expect(
-          () => i.injectFromParent(ExampleService),
-          throwsMissingProviderError,
-        );
+        expect(() => i.get(ExampleService), throwsArgumentError);
+        expect(() => i.inject(ExampleService), throwsArgumentError);
+        expect(() => i.injectFromSelf(ExampleService), throwsArgumentError);
+        expect(() => i.injectFromAncestry(ExampleService), throwsArgumentError);
+        expect(() => i.injectFromParent(ExampleService), throwsArgumentError);
       });
 
       test('should use orElse if provided', () {
@@ -80,10 +64,7 @@ void main() {
         i = new Injector.empty(parent);
         expect(i.get(ExampleService), 123);
         expect(i.inject(ExampleService), 123);
-        expect(
-          () => i.injectFromSelf(ExampleService),
-          throwsMissingProviderError,
-        );
+        expect(() => i.injectFromSelf(ExampleService), throwsArgumentError);
         expect(i.injectFromAncestry(ExampleService), 123);
         expect(i.injectFromParent(ExampleService), 123);
       });
@@ -102,14 +83,8 @@ void main() {
         expect(i.get(ExampleService), 123);
         expect(i.inject(ExampleService), 123);
         expect(i.injectFromSelf(ExampleService), 123);
-        expect(
-          () => i.injectFromAncestry(ExampleService),
-          throwsMissingProviderError,
-        );
-        expect(
-          () => i.injectFromParent(ExampleService),
-          throwsMissingProviderError,
-        );
+        expect(() => i.injectFromAncestry(ExampleService), throwsArgumentError);
+        expect(() => i.injectFromParent(ExampleService), throwsArgumentError);
       });
 
       test('should return itself if Injector is passed', () {
@@ -218,10 +193,7 @@ void main() {
 
       test('should thrown when a provider was not found', () {
         i = new Injector.slowReflective([]);
-        expect(
-          () => i.get(#ABC),
-          throwsMissingProviderError,
-        );
+        expect(() => i.get(#ABC), throwsArgumentError);
       });
 
       test('should support resolveAndCreateChild', () {

_tests/test/regression/755_reflective_meta_fail_test.dart

@@ -2,7 +2,6 @@
 @TestOn('browser')
 
 import 'package:test/test.dart';
-import 'package:_tests/matchers.dart';
 import 'package:angular/angular.dart';
 
 import '755_reflective_meta_fail_test.template.dart' as ng_generated;
@@ -16,10 +15,10 @@ void main() {
       const Provider(ServiceInjectingToken, useClass: ServiceInjectingToken),
       // Intentionally omit a binding for "stringToken".
     ]);
-    expect(
-      () => injector.get(ServiceInjectingToken),
-      throwsMissingProviderError,
-    );
+
+    // Used to return an Object representing the secret "notFound" instead of
+    // throwing ArgumentError, which was the expected behavior.
+    expect(() => injector.get(ServiceInjectingToken), throwsArgumentError);
   });
 }
 

angular/lib/src/di/injector/injector.dart

@@ -1,7 +1,5 @@
 import 'package:meta/meta.dart';
 
-import '../errors.dart';
-
 import 'empty.dart';
 import 'hierarchical.dart';
 import 'map.dart';
@@ -19,10 +17,8 @@ typedef T OrElseInject<T>(Injector injector, Object token);
 /// **INTERNAL ONLY**: Sentinel value for determining a missing DI instance.
 const Object throwIfNotFound = const Object();
 
-/// **INTERNAL ONLY**: Throws an error that [token] was not found.
-@alwaysThrows
 Null throwsNotFound(Injector injector, Object token) {
-  throw MissingProviderError.create(injector, token);
+  throw new ArgumentError('No provider found for $token.');
 }
 
 /// Support for imperatively loading dependency injected services at runtime.