Add an UNUSED_SHOWN_NAMES hint to the analyzer

pkg/analyzer/lib/src/generated/error.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 analyzer.src.generated.error;
 
 import 'dart:collection';
 
 import 'package:analyzer/dart/ast/ast.dart' show AstNode;
 import 'package:analyzer/dart/ast/token.dart';
@@ skipping 2689 matching lines @@
     HintCode.UNNECESSARY_CAST,
     HintCode.UNNECESSARY_NO_SUCH_METHOD,
     HintCode.UNNECESSARY_TYPE_CHECK_FALSE,
     HintCode.UNNECESSARY_TYPE_CHECK_TRUE,
     HintCode.UNUSED_ELEMENT,
     HintCode.UNUSED_FIELD,
     HintCode.UNUSED_IMPORT,
     HintCode.UNUSED_CATCH_CLAUSE,
     HintCode.UNUSED_CATCH_STACK,
     HintCode.UNUSED_LOCAL_VARIABLE,
+    HintCode.UNUSED_SHOWN_NAME,
     HintCode.USE_OF_VOID_RESULT,
     HintCode.FILE_IMPORT_INSIDE_LIB_REFERENCES_FILE_OUTSIDE,
     HintCode.FILE_IMPORT_OUTSIDE_LIB_REFERENCES_FILE_INSIDE,
     HintCode.PACKAGE_IMPORT_CONTAINS_DOT_DOT,
     HtmlErrorCode.PARSE_ERROR,
     HtmlWarningCode.INVALID_URI,
     HtmlWarningCode.URI_DOES_NOT_EXIST,
     StaticTypeWarningCode.EXPECTED_ONE_LIST_TYPE_ARGUMENTS,
     StaticTypeWarningCode.EXPECTED_TWO_MAP_TYPE_ARGUMENTS,
     StaticTypeWarningCode.ILLEGAL_ASYNC_GENERATOR_RETURN_TYPE,
@@ skipping 1052 matching lines @@
       "The stack trace variable '{0}' is not used and can be removed");
 
   /**
    * Unused local variables are local variables which are never read.
    */
   static const HintCode UNUSED_LOCAL_VARIABLE = const HintCode(
       'UNUSED_LOCAL_VARIABLE',
       "The value of the local variable '{0}' is not used");
 
   /**
+   * Unused shown names are names shown on imports which are never used.
+   */
+  static const HintCode UNUSED_SHOWN_NAME =
+      const HintCode('UNUSED_SHOWN_NAME', "The name {0} is shown, but not used.");
+
+  /**
    * Hint for cases where the source expects a method or function to return a
    * non-void result, but the method or function signature returns void.
    *
    * Parameters:
    * 0: the name of the method or function that returns void
    */
   static const HintCode USE_OF_VOID_RESULT = const HintCode(
       'USE_OF_VOID_RESULT',
       "The result of '{0}' is being used, even though it is declared to be 'void'");
 
@@ skipping 1976 matching lines @@
    * Initialize a newly created error code to have the given [name].
    */
   const TodoCode(String name) : super(name, "{0}");
 
   @override
   ErrorSeverity get errorSeverity => ErrorSeverity.INFO;
 
   @override
   ErrorType get type => ErrorType.TODO;
 }