This really feels like sanitizer bug, but whatever....
Thanks!
I do not think this is a bug. A team working on sanitizers is exceptionally good.
MemorySanitizer reports all uninitialized memory reads, including, for example, memmove and memcpy of uninitialized memory. This is not necessarily a bug, but this allows the sanitizer to be fast unlike valgrind.
The problem is that all sanitizers exit app on first detected error.
Well, but obviously we are not doing anything bad here. So it must be either a bug in sanitizer or in standard library (or perhaps in compiler).