anchor.diff:      'method13': new Impact(implicitCasts: ['int'], parameterChecks: ['String']),
     };
   
  +  Map<String, Impact> expectedImpactMapNnbdOn = <String, Impact>{
  +    'method1': const Impact(),
  +    'method2': new Impact(implicitCasts: ['int*']),
  +    'method3': new Impact(parameterChecks: ['int*']),
  +    'method4': new Impact(asCasts: ['int*']),
  +    'method5': const Impact(),
  +    'method6': const Impact(),
  +    'method7': const Impact(),
  +    'method8': const Impact(),
  +    'method9': new Impact(implicitCasts: ['int*']),
  +    'method10': const Impact(),
  +    'method11': const Impact(),
  +    'method12': const Impact(),
  +    'method13':
  +        new Impact(implicitCasts: ['int*'], parameterChecks: ['String*']),
  +  };
  +
  +  Map<String, Impact> expectedImpactMap =
  +      isDart2jsNnbd ? expectedImpactMapNnbdOn : expectedImpactMapNnbdOff;
     retainDataForTesting = true;
     CompilationResult result =
         await runCompiler(memorySourceFiles: {'main.dart': source});
     Expect.isTrue(result.isSuccess);
     Compiler compiler = result.compiler;
  +  var options = compiler.options;
  +
  +  String printType(DartType type) {
  +    return type.toStructuredText(
  +        printLegacyStars: true, useLegacySubtyping: options.useLegacySubtyping);
  +  }
   
     KClosedWorld closedWorld = compiler.frontendClosedWorldForTesting;
     ElementEnvironment elementEnvironment = closedWorld.elementEnvironment;
  
positive.code: import 'package:compiler/src/compiler.dart';
  import 'package:compiler/src/common_elements.dart';
  import 'package:compiler/src/elements/entities.dart';
  import 'package:compiler/src/world.dart';
  import 'package:compiler/src/universe/use.dart';
  import 'package:compiler/src/universe/world_impact.dart';
  
negative.code: }
  ''';
  
    Map<String, Impact> expectedImpactMapNnbdOff = <String, Impact>{
      'method1': const Impact(),
      'method2': new Impact(implicitCasts: ['int']),
      'method3': new Impact(parameterChecks: ['int']),
  