Fix warnings and hints.

sdk/lib/_internal/compiler/implementation/scanner/token.dart

 // Copyright (c) 2011, 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.
 
 part of scanner;
 
 const int EOF_TOKEN = 0;
 
 const int KEYWORD_TOKEN = $k;
 const int IDENTIFIER_TOKEN = $a;
@@ skipping 81 matching lines @@
   /**
    * The character offset of the start of this token within the source text.
    */
   final int charOffset;
 
   /**
    * The next token in the token stream.
    */
   Token next;
 
-  Token(PrecedenceInfo this.info, int this.charOffset);
+  Token(this.info, this.charOffset);
 
   get value => info.value;
 
   /**
    * Returns the string value for keywords and symbols. For instance 'class' for
    * the [CLASS] keyword token and '*' for a [Token] based on [STAR_INFO]. For
    * other tokens, such identifiers, strings, numbers, etc, [stringValue]
    * returns [:null:].
    *
    * [stringValue] should only be used for testing keywords and symbols.
@@ skipping 432 matching lines @@
 
 const PrecedenceInfo HEXADECIMAL_INFO =
   const PrecedenceInfo(const SourceString('hexadecimal'), 0, HEXADECIMAL_TOKEN);
 
 const PrecedenceInfo COMMENT_INFO =
   const PrecedenceInfo(const SourceString('comment'), 0, COMMENT_TOKEN);
 
 // For reporting lexical errors.
 const PrecedenceInfo ERROR_INFO =
   const PrecedenceInfo(const SourceString('?'), 0, UNKNOWN_TOKEN);