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