line 352 is not related to string. try to print its type like print(type(self.type2test)) that's list type. e.g. list.
list('abcdefghcij') is ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'c', 'i', 'j']

By watching CI, it is causing dead-lock. it didn't finish during 4 hours.

Now, two list method index, remove works normally by fixing _mut_iter_equal_skeleton method.

Nice catch! The changed codes seem totally fine to me. Please check unexpected success in test_list, test_deque tests 😊

@qingshi163 could you review this PR?

As I remember, the guard or borrower is to optimize the compare by check if the class is not the heap type, so we can reuse the compare function in each loop. Also to use rich_compare_bool we cannot reuse the PyTypeRef for the compared object but this will be no more the issue if we can fetch the PyType atomicly in the future.

Yes, the correctness is more important than performance, but if you can solve the problem without drawback the performance could be amazing. if not please advise the issue or the failing point of the current implement, so we could see why this is not going to work.

@youknowone

Thanks