anchor.diff:  import 'package:meta/meta.dart';
  +import 'package:angular/src/compiler/compile_metadata.dart';
  +import 'package:angular/src/compiler/identifiers.dart'
  +    show DomHelpers, Identifiers;
   import 'package:angular/src/compiler/ir/model.dart' as ir;
  +import 'package:angular/src/compiler/output/output_ast.dart' as o;
  +import 'package:angular/src/compiler/template_ast.dart'
  +    show
  +        BoundDirectivePropertyAst,
  +        BoundElementPropertyAst,
  +        BoundExpression,
  +        DirectiveAst,
  +        PropertyBindingType;
   import 'package:angular/src/core/change_detection/constants.dart'
       show ChangeDetectionStrategy;
   import 'package:angular/src/core/linker/view_type.dart';
  
positive.code: import 'package:angular/src/core/security.dart';
  import 'package:angular_compiler/cli.dart';
  
  import '../compile_metadata.dart';
  import '../identifiers.dart' show DomHelpers, Identifiers;
  import '../output/output_ast.dart' as o;
  import '../template_ast.dart'
      show
          BoundDirectivePropertyAst,
          BoundElementPropertyAst,
          BoundExpression,
          DirectiveAst,
          PropertyBindingType;
  import 'bound_value_converter.dart';
  import 'compile_element.dart' show CompileElement, CompileNode;
  import 'compile_method.dart' show CompileMethod;
  
negative.code:     // Expression for current value of expression when value is re-read.
      var currValExpr = _createCurrValueExpr(bindingIndex);
  
      var updateStmts = <o.Statement>[
        _toUpdateStatement(boundProp, converter, appViewInstance, renderNode,
            isHtmlElement, currValExpr)
      ];
  
      final fieldType = _fieldType(boundProp);
      final checkExpression = converter.convertToExpression(
          boundProp.value, boundProp.sourceSpan, fieldType);
      _bind(
  