BTW I just also noticed the following error in libcxx/include/list line 1603:
list<_Tp, _Alloc>::pop_back()
{
_LIBCPP_ASSERT(!empty(), "list::pop_front() called with empty list");
pop_front should read pop_back
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Shriramana Sharma ஶ்ரீரமணஶர்மா श्रीरमणशर्मा