Don't perform incremental resolution if curly brackets are not balanced.

pkg/analyzer/lib/src/generated/incremental_resolution_validator.dart

 // Copyright (c) 2014, 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 engine.incremental_resolution_validator;
 
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/element.dart';
 
 
@@ skipping 763 matching lines @@
     WithClause other = this.other;
     _visitList(node.mixinTypes, other.mixinTypes);
   }
 
   @override
   visitYieldStatement(YieldStatement node) {
     YieldStatement other = this.other;
     _visitNode(node.expression, other.expression);
   }
 
+  void _assertNode(AstNode a, AstNode b) {
+    _expectEquals(a.offset, b.offset);
+    _expectEquals(a.length, b.length);
+  }
+
   void _expectEquals(actual, expected) {
     if (actual != expected) {
       String message = '';
       message += 'Expected: $expected\n';
       message += '  Actual: $actual\n';
       _fail(message);
     }
   }
 
   void _expectIsNull(obj) {
@@ skipping 62 matching lines @@
     _verifyElement(node.element, other.element);
     _visitAnnotatedNode(node, other);
   }
 
   _visitDirective(Directive node, Directive other) {
     _verifyElement(node.element, other.element);
     _visitAnnotatedNode(node, other);
   }
 
   void _visitExpression(Expression a, Expression b) {
+//    print('[${a.offset}] |$a| vs. [${b.offset}] |$b|');
     _verifyType(a.staticType, b.staticType);
     _verifyType(a.propagatedType, b.propagatedType);
     _verifyElement(a.staticParameterElement, b.staticParameterElement);
     _verifyElement(a.propagatedParameterElement, b.propagatedParameterElement);
+    _assertNode(a, b);
   }
 
   void _visitList(NodeList nodeList, NodeList otherList) {
     int length = nodeList.length;
     _expectLength(otherList, length);
     for (int i = 0; i < length; i++) {
       _visitNode(nodeList[i], otherList[i]);
     }
   }
 
   void _visitNode(AstNode node, AstNode other) {
     if (node == null) {
       _expectIsNull(other);
     } else {
       this.other = other;
-      _expectEquals(node.offset, other.offset);
-      _expectEquals(node.length, other.length);
+      _assertNode(node, other);
       node.accept(this);
     }
   }
 
   void _visitNormalFormalParameter(NormalFormalParameter node,
       NormalFormalParameter other) {
     _verifyElement(node.element, other.element);
     _visitNode(node.documentationComment, other.documentationComment);
     _visitList(node.metadata, other.metadata);
     _visitNode(node.identifier, other.identifier);
@@ skipping 38 matching lines @@
    *     package:project/my_lib.dart      -> my_lib.dart
    */
   static String _getShortElementLocationUri(String uri) {
     int index = uri.lastIndexOf('/');
     if (index == -1) {
       return uri;
     }
     return uri.substring(index + 1);
   }
 }