This came up in D100595.
Differential Revision: https://reviews.llvm.org/D100728
_LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__f) == &__c,
"list::splice(iterator, list, iterator, iterator) called with second iterator not"
" referring to list argument");
+ _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__l) == &__c,
+ "list::splice(iterator, list, iterator, iterator) called with third iterator not"
+ " referring to list argument");
if (this == &__c)
{
for (const_iterator __i = __f; __i != __l; ++__i)