Implement correct scoping rules for variables.

pkg/analyzer_experimental/lib/src/services/formatter_impl.dart

 // Copyright (c) 2013, 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 formatter_impl;
 
 import 'dart:math';
 
 import 'package:analyzer_experimental/analyzer.dart';
 import 'package:analyzer_experimental/src/generated/parser.dart';
@@ skipping 1276 matching lines @@
     //Handle EOLs before newlines
     if (isAtEOL(comment)) {
       emitComment(comment, previousToken);
       comment = comment.next;
       currentToken = comment != null ? comment : token;
     }
 
     var lines = max(min, countNewlinesBetween(previousToken, currentToken));
     writer.newlines(lines);
 
-    var previousToken = currentToken.previous;
+    var newPreviousToken = currentToken.previous;
 
     while (comment != null) {
 
-      emitComment(comment, previousToken);
+      emitComment(comment, newPreviousToken);
 
       var nextToken = comment.next != null ? comment.next : token;
       var newlines = calculateNewlinesBetweenComments(comment, nextToken);
       if (newlines > 0) {
         writer.newlines(newlines);
         lines += newlines;
       } else if (!isEOF(token)) {
         space();
       }
 
-      previousToken = comment;
+      newPreviousToken = comment;
       comment = comment.next;
     }
 
-    previousToken = token;

[karlklose, 2013/09/26 07:05:43]

@pquitslund: This looks like a bug.

[ngeoffray, 2013/09/26 07:48:38]

Why did you have to fix it? Isn't it OK to shadow a field?

[pquitslund, 2013/09/30 16:12:48]

Hmmm, I agree this doesn't look right.  I have another proposed fix though. 
Let's just remove the variable declaration for 'previousToken'.  I don't think I
intended to be shadowing here but I do think I want the side-effect of updating
the cached previous.  (Although, that may benefit from a rethink too.)

[pquitslund, 2013/09/30 17:23:34]

And here's that fix: https://codereview.chromium.org/25304002/

+    newPreviousToken = token;
     return lines;
   }
 
 
   ensureTrailingNewline() {
     if (writer.lastToken is! NewlineToken) {
       writer.newline();
     }
   }
   
@@ skipping 80 matching lines @@
     var lastLine =
         lineInfo.getLocation(lastOffset).lineNumber;
     var currentLine =
         lineInfo.getLocation(currentOffset).lineNumber;
     return currentLine - lastLine;
   }
 
   String toString() => writer.toString();
 
 }