Show import chains for unsupported dart:* library imports.

tests/compiler/dart2js/missing_file_test.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 // Test that the compiler can handle imports when package root has not been set.
 
 library dart2js.test.missing_file;
 
 import 'dart:async';
 import 'package:async_helper/async_helper.dart';
 import "package:compiler/src/diagnostics/messages.dart";
 import 'package:expect/expect.dart';
 import 'memory_compiler.dart';
 
 const MEMORY_SOURCE_FILES = const {
   'main.dart': '''
+import 'foo.dart';
+main() {}
+''',
 
-import 'foo.dart';
+'bar.dart': '''
+import 'dart:foo';
+main() {}
+''',
 
+'baz.dart': '''
+import 'dart:io';
 main() {}
 ''',
 };
 
-Future runTest(Uri main, MessageKind expectedMessageKind) async {
-  print("\n\n\n");
+Future runTest(Uri main,
+               {MessageKind error,
+                MessageKind info}) async {
+  print("----\nentry-point: $main\n");
 
   DiagnosticCollector diagnostics = new DiagnosticCollector();
   OutputCollector output = new OutputCollector();
   await runCompiler(
+      entryPoint: main,
       memorySourceFiles: MEMORY_SOURCE_FILES,
       diagnosticHandler: diagnostics,
       outputProvider: output);
 
   Expect.isFalse(output.hasExtraOutput);
-  Expect.equals(1, diagnostics.errors.length);
-  Expect.equals(expectedMessageKind, diagnostics.errors.first.message.kind);
+  Expect.equals(error != null ? 1 : 0, diagnostics.errors.length);
+  if (error != null) {
+    Expect.equals(error, diagnostics.errors.first.message.kind);
+  }
+  Expect.equals(info != null ? 1 : 0, diagnostics.infos.length);
+  if (info != null) {
+    Expect.equals(info, diagnostics.infos.first.message.kind);
+  }
+  Expect.equals(0, diagnostics.warnings.length);
+  Expect.equals(0, diagnostics.hints.length);
 }
 
 void main() {
   asyncTest(() async {
     await runTest(
-        Uri.parse('memory:main.dart'), MessageKind.READ_SCRIPT_ERROR);
+        Uri.parse('memory:main.dart'),
+        error: MessageKind.READ_SCRIPT_ERROR);
+
     await runTest(
-        Uri.parse('memory:foo.dart'), MessageKind.READ_SCRIPT_ERROR);
+        Uri.parse('memory:foo.dart'),
+        error: MessageKind.READ_SELF_ERROR);
+
     await runTest(
-        Uri.parse('dart:foo'), MessageKind.READ_SCRIPT_ERROR);
+        Uri.parse('dart:foo'),
+        error: MessageKind.LIBRARY_NOT_FOUND);
+
+    await runTest(
+        Uri.parse('dart:io'),
+        error: MessageKind.LIBRARY_NOT_SUPPORTED,
+        info: MessageKind.DISALLOWED_LIBRARY_IMPORT);
+
+    await runTest(
+        Uri.parse('memory:bar.dart'),
+        error: MessageKind.LIBRARY_NOT_FOUND);
+
+    await runTest(
+        Uri.parse('memory:baz.dart'),
+        error: MessageKind.LIBRARY_NOT_SUPPORTED,
+        info: MessageKind.DISALLOWED_LIBRARY_IMPORT);
   });
 }