anchor.diff:                namedArgumentValues);
           }
         } else if (constructor.name == "" &&
  -          identical(definingClass, typeProvider.symbolType) &&
  +          definingClass == typeProvider.symbolType &&
             argumentCount == 1) {
           if (!checkSymbolArguments(
               arguments, argumentValues, namedArgumentValues)) {
  
positive.code:               valueFromEnvironment,
                new DartObjectImpl(typeProvider.boolType, BoolState.FALSE_STATE),
                namedArgumentValues);
          } else if (identical(definingClass, typeProvider.intType)) {
            DartObject valueFromEnvironment;
            valueFromEnvironment =
                _declaredVariables.getInt(typeProvider, variableName);
  
negative.code:               valueFromEnvironment,
                new DartObjectImpl(typeProvider.nullType, NullState.NULL_STATE),
                namedArgumentValues);
          } else if (definingClass == typeProvider.stringType) {
            DartObject valueFromEnvironment;
            valueFromEnvironment =
                _declaredVariables.getString(typeProvider, variableName);
  