Fix for explicit dart:core import.

pkg/analyzer/test/generated/static_warning_code_test.dart

 // Copyright (c) 2014, 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.
 
 library engine.static_warning_code_test;
 
 import 'package:analyzer/src/generated/error.dart';
 import 'package:analyzer/src/generated/source_io.dart';
 import 'package:unittest/unittest.dart';
 
@@ skipping 3353 matching lines @@
     computeLibrarySourceErrors(source);
     assertErrors(source, [StaticWarningCode.UNDEFINED_IDENTIFIER]);
   }
 
   void test_undefinedIdentifier_function() {
     Source source = addSource("int a() => b;");
     computeLibrarySourceErrors(source);
     assertErrors(source, [StaticWarningCode.UNDEFINED_IDENTIFIER]);
   }
 
+  void test_undefinedIdentifier_importCore_withShow() {
+    Source source = addSource(r'''
+import 'dart:core' show List;
+main() {
+  List;
+  String;
+}''');
+    computeLibrarySourceErrors(source);
+    assertErrors(source, [StaticWarningCode.UNDEFINED_IDENTIFIER]);
+  }
+
   void test_undefinedIdentifier_initializer() {
     Source source = addSource("var a = b;");
     computeLibrarySourceErrors(source);
     assertErrors(source, [StaticWarningCode.UNDEFINED_IDENTIFIER]);
   }
 
   void test_undefinedIdentifier_methodInvocation() {
     Source source = addSource("f() { C.m(); }");
     computeLibrarySourceErrors(source);
     assertErrors(source, [StaticWarningCode.UNDEFINED_IDENTIFIER]);
@@ skipping 117 matching lines @@
 
   void test_voidReturnForGetter() {
     Source source = addSource(r'''
 class S {
   void get value {}
 }''');
     computeLibrarySourceErrors(source);
     assertErrors(source, [StaticWarningCode.VOID_RETURN_FOR_GETTER]);
   }
 }