Store actual Reference(s) for additional exports.

pkg/front_end/test/fasta/ambiguous_export_test.dart

-// Copyright (c) 2017, 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.md file.
-
-import 'package:async_helper/async_helper.dart' show asyncTest;
-
-import 'package:expect/expect.dart' show Expect;
-
-import 'package:front_end/src/fasta/builder/builder.dart'
-    show InvalidTypeBuilder;
-
-import 'package:front_end/src/fasta/compiler_context.dart' show CompilerContext;
-
-import 'package:front_end/src/fasta/dill/dill_library_builder.dart'
-    show DillLibraryBuilder;
-
-import 'package:front_end/src/fasta/dill/dill_target.dart' show DillTarget;
-
-import 'package:kernel/ast.dart'
-    show Field, Library, Name, Program, StringLiteral;
-
-main() async {
-  await asyncTest(() async {
-    Library library = new Library(Uri.parse("org.dartlang.fasta:library"));
-    Field field = new Field(new Name("_exports#", library),
-        initializer:
-            new StringLiteral("[[null,\"main\",\"Problem with main\"]]"));
-    library.addMember(field);
-    Program program = new Program(libraries: <Library>[library]);
-    await CompilerContext.runWithDefaultOptions((CompilerContext c) async {
-      DillTarget target =
-          new DillTarget(c.options.ticker, null, c.options.target);
-      target.loader.appendLibraries(program);
-      DillLibraryBuilder builder = target.loader.read(library.importUri, -1);
-      await target.loader.buildOutline(builder);
-      builder.finalizeExports();
-      var mainExport = builder.exportScope.local["main"];
-      Expect.isTrue(mainExport is InvalidTypeBuilder);
-    });
-  });
-}