Improve message for import of part.

pkg/compiler/lib/src/warnings.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 dart2js;
 
 const DONT_KNOW_HOW_TO_FIX = "Computer says no!";
 
 /**
  * The messages in this file should meet the following guide lines:
@@ skipping 1108 matching lines @@
           "void x; main() {}",
           "foo(void x) {} main() { foo(null); }",
       ]);
 
   static const MessageKind NULL_NOT_ALLOWED = const MessageKind(
       "`null` can't be used here.");
 
   static const MessageKind BEFORE_TOP_LEVEL = const MessageKind(
       "Part header must come before top-level definitions.");
 
+  static const MessageKind IMPORT_PART_OF = const MessageKind(
+      "The imported library must not have a 'part-of' directive.",
+      howToFix: "Try removing the 'part-of' directive or replacing the "
+                "import of the library with a 'part' directive.",
+      examples: const [const {
+'main.dart': """
+library library;
+
+import 'part.dart';
+
+main() {}
+""",
+
+'part.dart': """
+part of library;
+"""}]);
+
   static const MessageKind LIBRARY_NAME_MISMATCH = const MessageKind(
       "Expected part of library name '#{libraryName}'.",
-      howToFix: "Trying changing the directive to 'part of #{libraryName};'.",
+      howToFix: "Try changing the directive to 'part of #{libraryName};'.",
       examples: const [const {
 'main.dart': """
 library lib.foo;
 
 part 'part.dart';
 
 main() {}
 """,
 
 'part.dart': """
 part of lib.bar;
 """}]);
 
   static const MessageKind MISSING_LIBRARY_NAME = const MessageKind(
       "Library has no name. Part directive expected library name "
       "to be '#{libraryName}'.",
-      howToFix: "Trying adding 'library #{libraryName};' to the library.",
+      howToFix: "Try adding 'library #{libraryName};' to the library.",
       examples: const [const {
 'main.dart': """
 part 'part.dart';
 
 main() {}
 """,
 
 'part.dart': """
 part of lib.foo;
 """}]);
 
   static const MessageKind THIS_IS_THE_PART_OF_TAG = const MessageKind(
       "This is the part of directive.");
 
   static const MessageKind MISSING_PART_OF_TAG = const MessageKind(
       "This file has no part-of tag, but it is being used as a part.");
 
   static const MessageKind DUPLICATED_PART_OF = const MessageKind(
       "Duplicated part-of directive.");
 
-  static const MessageKind ILLEGAL_DIRECTIVE = const MessageKind(
-      "Directive not allowed here.");
-
   static const MessageKind DUPLICATED_LIBRARY_NAME = const MessageKind(
       "Duplicated library name '#{libraryName}'.");
 
   static const MessageKind DUPLICATED_RESOURCE = const MessageKind(
       "The resource '#{resourceUri}' is loaded through both "
       "'#{canonicalUri1}' and '#{canonicalUri2}'.");
 
   static const MessageKind DUPLICATED_LIBRARY_RESOURCE =
       const MessageKind(
           "The library '#{libraryName}' in '#{resourceUri}' is loaded through "
@@ skipping 1245 matching lines @@
   static String convertToString(value) {
     if (value is ErrorToken) {
       // Shouldn't happen.
       return value.assertionMessage;
     } else if (value is Token) {
       value = value.value;
     }
     return '$value';
   }
 }