Implement correct scoping rules for variables.

sdk/lib/_internal/compiler/implementation/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 = "";
 
 /**
  * The messages in this file should meet the following guide lines:
@@ skipping 791 matching lines @@
   // This is used as an exception.
   static const MessageKind INVALID_SOURCE_FILE_LOCATION = const MessageKind('''
 Invalid offset (#{offset}) in source map.
 File: #{fileName}
 Length: #{length}''');
 
   static const MessageKind TOP_LEVEL_VARIABLE_DECLARED_STATIC =
       const MessageKind(
           "Error: Top-level variable cannot be declared static.");
 
-  static const MessageKind REFERENCE_IN_INITIALIZATION = const MessageKind(
-       "Error: Variable '#{variableName}' is referenced during its "
-       "initialization.",
-       howToFix: "If you are trying to reference a shadowed variable, rename"
+  static const MessageKind ACCESS_BEFORE_INITIALIZATION = const MessageKind(
+      "Error: Variable '#{variableName}' is referenced before its "
+      "initialization.",
+      howToFix: "If you are trying to reference a shadowed variable, rename"
          " one of the variables.",
-       examples: const ["""
+      examples: const ["""
 foo(t) {
   var t = t;
   return t;
 }
 
 main() => foo(1);
 """]);
 
   static const MessageKind CONST_WITHOUT_INITIALIZER = const MessageKind(
       "Error: A constant variable must be initialized.",
@@ skipping 485 matching lines @@
 
 class CompileTimeConstantError extends Diagnostic {
   CompileTimeConstantError(MessageKind kind, Map arguments, bool terse)
     : super(kind, arguments, terse);
 }
 
 class CompilationError extends Diagnostic {
   CompilationError(MessageKind kind, Map arguments, bool terse)
     : super(kind, arguments, terse);
 }