Report hint on unmatched show and hide combinators.

pkg/compiler/lib/src/diagnostics/messages.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.
 
 
 /**
  * The messages in this file should meet the following guide lines:
  *
  * 1. The message should be a complete sentence starting with an uppercase
  * letter, and ending with a period.
@@ skipping 166 matching lines @@
   DUPLICATE_INITIALIZER,
   DUPLICATE_LABEL,
   DUPLICATE_SUPER_INITIALIZER,
   DUPLICATE_TYPE_VARIABLE_NAME,
   DUPLICATED_LIBRARY_NAME,
   DUPLICATED_LIBRARY_RESOURCE,
   DUPLICATED_PART_OF,
   DUPLICATED_RESOURCE,
   EMPTY_CATCH_DECLARATION,
   EMPTY_ENUM_DECLARATION,
+  EMPTY_HIDE,
   EQUAL_MAP_ENTRY_KEY,
+  EMPTY_SHOW,
   EXISTING_DEFINITION,
   EXISTING_LABEL,
   EXPECTED_IDENTIFIER_NOT_RESERVED_WORD,
   EXPONENT_MISSING,
   EXPORT_BEFORE_PARTS,
   EXTERNAL_WITH_BODY,
   EXTRA_CATCH_DECLARATION,
   EXTRA_FORMALS,
   EXTRANEOUS_MODIFIER,
   EXTRANEOUS_MODIFIER_REPLACE,
@@ skipping 617 matching lines @@
 import 'conflictsWithDartAsWell.dart';
 
 main() {
   print("Hail Caesar ${Duration.x}");
 }
 """}]),
 
       MessageKind.DUPLICATE_EXPORT:
         const MessageTemplate(MessageKind.DUPLICATE_EXPORT,
           "Duplicate export of '#{name}'.",
-          howToFix: "Trying adding 'hide #{name}' to one of the exports.",
+          howToFix: "Try adding 'hide #{name}' to one of the exports.",
           examples: const [const {
 'main.dart': """
 export 'decl1.dart';
 export 'decl2.dart';
 
 main() {}""",
 'decl1.dart': "class Class {}",
 'decl2.dart': "class Class {}"}]),
 
       MessageKind.DUPLICATE_EXPORT_CONT:
         const MessageTemplate(MessageKind.DUPLICATE_EXPORT_CONT,
           "This is another export of '#{name}'."),
 
       MessageKind.DUPLICATE_EXPORT_DECL:
         const MessageTemplate(MessageKind.DUPLICATE_EXPORT_DECL,
           "The exported '#{name}' from export #{uriString} is defined here."),
 
+      MessageKind.EMPTY_HIDE:
+        const MessageTemplate(MessageKind.EMPTY_HIDE,
+            "Library '#{uri}' doesn't export a '#{name}' declaration.",
+      howToFix: "Try removing '#{name}' the 'hide' clause.",
+      examples: const [
+        const {
+            'main.dart': """
+import 'dart:core' hide Foo;
+
+main() {}"""},
+        const {
+'main.dart': """
+export 'dart:core' hide Foo;
+
+main() {}"""},
+]),
+
+      MessageKind.EMPTY_SHOW:
+        const MessageTemplate(MessageKind.EMPTY_SHOW,
+            "Library '#{uri}' doesn't export a '#{name}' declaration.",
+      howToFix: "Try removing '#{name}' from the 'show' clause.",
+      examples: const [
+        const {
+            'main.dart': """
+import 'dart:core' show Foo;
+
+main() {}"""},
+        const {
+'main.dart': """
+export 'dart:core' show Foo;
+
+main() {}"""},
+]),
+
       MessageKind.NOT_A_TYPE:
         const MessageTemplate(MessageKind.NOT_A_TYPE,
           "'#{node}' is not a type."),
 
       MessageKind.NOT_A_PREFIX:
         const MessageTemplate(MessageKind.NOT_A_PREFIX,
           "'#{node}' is not a prefix."),
 
       MessageKind.PREFIX_AS_EXPRESSION:
         const MessageTemplate(MessageKind.PREFIX_AS_EXPRESSION,
@@ skipping 2550 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';
   }
 }