fixes #209, remove tree mutation from CodeChecker

lib/src/testing.dart

 // Copyright (c) 2015, 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 dev_compiler.src.testing;
 
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/file_system/memory_file_system.dart';
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/engine.dart' show AnalysisContext;
@@ skipping 223 matching lines @@
 
   visitNode(AstNode node) {
     var token = node.beginToken;
     var comment = token.precedingComments;
     // Use error marker found in an immediately preceding comment,
     // and attach it to the outermost expression that starts at that token.
     if (comment != null) {
       while (comment.next != null) {
         comment = comment.next;
       }
-      if (comment.end == token.offset &&
-          _realParent(node).beginToken != token) {
+      if (comment.end == token.offset && node.parent.beginToken != token) {
         var commentText = '$comment';
         var start = commentText.lastIndexOf('/*');
         var end = commentText.lastIndexOf('*/');
         if (start != -1 && end != -1) {
           expect(start, lessThan(end));
           var errors = commentText.substring(start + 2, end).split(',');
           var expectations = errors.map(_ErrorExpectation.parse);
           expectedErrors[node] = expectations.where((x) => x != null).toList();
         }
       }
     }
     return super.visitNode(node);
   }
-
-  /// Get the node's parent, ignoring fake conversion nodes.
-  AstNode _realParent(AstNode node) {
-    var p = node.parent;
-    while (p is Conversion) p = p.parent;

[Jennifer Messerly, 2015/06/08 23:51:37]

after renamed Conversion -> CoercionInfo, I noticed this code is now dead

-    return p;
-  }
 }
 
 /// Describes an expected message that should be produced by the checker.
 class _ErrorExpectation {
   final Level level;
   final Type type;
   _ErrorExpectation(this.level, this.type);
 
   static _ErrorExpectation _parse(String descriptor) {
     var tokens = descriptor.split(':');
@@ skipping 20 matching lines @@
     expect(tokens[1], "should", reason: 'invalid error descriptor');
     expect(tokens[2], "be", reason: 'invalid error descriptor');
     if (tokens[0] == "pass") return null;
     // TODO(leafp) For now, we just use whatever the current expectation is,
     // eventually we could do more automated reporting here.
     return _parse(tokens[0]);
   }
 
   String toString() => '$level $type';
 }