anchor.diff:  const _violation = '_violation';
   const violationRef = Reference(_violation);
   
  -violationTypeRef(String standardPackage) =>
  +Reference violationTypeRef(String standardPackage) =>
       Reference(_violationType, validationErrorImport(standardPackage));
   
   createViolationFactory(String standardPackage) {
  
positive.code:          ].map((expression) => expression.statement));
      });
  }
  
  
negative.code:         b.requiredParameters
              ..add(Parameter((b) => b..type = refer('String')..name = msgFormat))
              ..add(Parameter((b) => b..type = refer('String')..name = typeName))
              ..add(fieldPathParam);
          b.optionalParameters.add(actualValueParam);
          var path = 'path';
          var type = violationTypeRef(standardPackage);
          b..returns = type
           ..body = Block.of(<Expression>[
               type.newInstance([]).assignVar(result),
               resultRef.property('msgFormat').assign(refer(msgFormat)),
               resultRef.property('typeName').assign(refer(typeName)),
  