Clean up reporting HintCode.UNUSED_SHOWN_NAME when a prefixed top-level function is invoked.

pkg/analyzer/test/generated/non_hint_code_test.dart

 // Copyright (c) 2016, 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 analyzer.test.generated.non_hint_code_test;
 
 import 'package:analyzer/src/generated/error.dart';
 import 'package:analyzer/src/generated/source_io.dart';
 
 import '../reflective_tests.dart';
@@ skipping 1078 matching lines @@
         "/lib1.dart",
         r'''
 library lib1;
 class One {}
 topLevelFunction() {}''');
     computeLibrarySourceErrors(source);
     assertNoErrors(source);
     verify([source]);
   }
 
+  void test_unusedImport_prefix_topLevelFunction2() {
+    Source source = addSource(r'''
+library L;
+import 'lib1.dart' hide topLevelFunction;
+import 'lib1.dart' as one show topLevelFunction;
+import 'lib1.dart' as two show topLevelFunction;
+class A {
+  static void x() {
+    One o;
+    one.topLevelFunction();
+    two.topLevelFunction();
+  }
+}''');
+    addNamedSource(
+        "/lib1.dart",
+        r'''
+library lib1;
+class One {}
+topLevelFunction() {}''');
+    computeLibrarySourceErrors(source);
+    assertNoErrors(source);
+    verify([source]);
+  }
+
   void test_useOfVoidResult_implicitReturnValue() {
     Source source = addSource(r'''
 f() {}
 class A {
   n() {
     var a = f();
   }
 }''');
     computeLibrarySourceErrors(source);
     assertNoErrors(source);
@@ skipping 93 matching lines @@
 
   void test_import_valid_outside_lib() {
     cacheSource("/myproj/pubspec.yaml", "");
     cacheSource("/myproj/web/other.dart", "");
     Source source =
         addNamedSource("/myproj/lib2/test.dart", "import '../web/other.dart';");
     computeLibrarySourceErrors(source);
     assertNoErrors(source);
   }
 }