Недопустимый доступ к памяти из-за окончательной формы библиотеки поддержки директив

Я экспериментирую с библиотекой поддержки директив.

Этот код работает отлично, и valgrind не показывает проблем с памятью

#include <gsl>
#include <iostream>

int main() {
const int length = 10;
int *arr = new int [length];
auto _ = gsl::finally([arr] { delete[] arr; });

for (int i = 0; i<length; i++){
arr[i] = i;
}
for (int i = 0; i<length; i++){
std::cout << arr[i] << " ";
}

}

Если назначение finally заявление к auto _ удаляется, valgrind показывает следующие недопустимые операции чтения / записи. Почему мне нужно присвоить оператор finally значению, которое впоследствии больше не требуется?

Я использую gsl-lite, версия 0.28.0.

Сломанный код:

#include <gsl>
#include <iostream>

int main() {
const int length = 10;
int *arr = new int [length];
gsl::finally([arr] { delete[] arr; });

for (int i = 0; i<length; i++){
arr[i] = i;
}
for (int i = 0; i<length; i++){
std::cout << arr[i] << " ";
}

}

Выход Valgrind:

==15802== Memcheck, a memory error detector
==15802== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==15802== Using Valgrind-3.13.0 and LibVEX; rerun with -h for copyright info
==15802== Command: ./a.out
==15802==
==15802== Invalid write of size 8
==15802==    at 0x400E1A: main (in /data/home/gwe/projekte/clean_code/gsl/a.out)
==15802==  Address 0x4c3e040 is 0 bytes inside a block of size 40 free'd
==15802==    at 0x4A0862D: operator delete[](void*) (vg_replace_malloc.c:621)
==15802==    by 0x400E04: main (in /data/home/gwe/projekte/clean_code/gsl/a.out)
==15802==  Block was alloc'd at
==15802==    at 0x4A07898: operator new[](unsigned long) (vg_replace_malloc.c:423)
==15802==    by 0x400DF4: main (in /data/home/gwe/projekte/clean_code/gsl/a.out)
==15802==
==15802== Invalid write of size 8
==15802==    at 0x400E24: main (in /data/home/gwe/projekte/clean_code/gsl/a.out)
==15802==  Address 0x4c3e050 is 16 bytes inside a block of size 40 free'd
==15802==    at 0x4A0862D: operator delete[](void*) (vg_replace_malloc.c:621)
==15802==    by 0x400E04: main (in /data/home/gwe/projekte/clean_code/gsl/a.out)
==15802==  Block was alloc'd at
==15802==    at 0x4A07898: operator new[](unsigned long) (vg_replace_malloc.c:423)
==15802==    by 0x400DF4: main (in /data/home/gwe/projekte/clean_code/gsl/a.out)
==15802==
==15802== Invalid write of size 4
==15802==    at 0x400E2B: main (in /data/home/gwe/projekte/clean_code/gsl/a.out)
==15802==  Address 0x4c3e060 is 32 bytes inside a block of size 40 free'd
==15802==    at 0x4A0862D: operator delete[](void*) (vg_replace_malloc.c:621)
==15802==    by 0x400E04: main (in /data/home/gwe/projekte/clean_code/gsl/a.out)
==15802==  Block was alloc'd at
==15802==    at 0x4A07898: operator new[](unsigned long) (vg_replace_malloc.c:423)
==15802==    by 0x400DF4: main (in /data/home/gwe/projekte/clean_code/gsl/a.out)
==15802==
==15802== Invalid write of size 4
==15802==    at 0x400E34: main (in /data/home/gwe/projekte/clean_code/gsl/a.out)
==15802==  Address 0x4c3e064 is 36 bytes inside a block of size 40 free'd
==15802==    at 0x4A0862D: operator delete[](void*) (vg_replace_malloc.c:621)
==15802==    by 0x400E04: main (in /data/home/gwe/projekte/clean_code/gsl/a.out)
==15802==  Block was alloc'd at
==15802==    at 0x4A07898: operator new[](unsigned long) (vg_replace_malloc.c:423)
==15802==    by 0x400DF4: main (in /data/home/gwe/projekte/clean_code/gsl/a.out)
==15802==
==15802== Invalid read of size 4
==15802==    at 0x400E45: main (in /data/home/gwe/projekte/clean_code/gsl/a.out)
==15802==  Address 0x4c3e040 is 0 bytes inside a block of size 40 free'd
==15802==    at 0x4A0862D: operator delete[](void*) (vg_replace_malloc.c:621)
==15802==    by 0x400E04: main (in /data/home/gwe/projekte/clean_code/gsl/a.out)
==15802==  Block was alloc'd at
==15802==    at 0x4A07898: operator new[](unsigned long) (vg_replace_malloc.c:423)
==15802==    by 0x400DF4: main (in /data/home/gwe/projekte/clean_code/gsl/a.out)
==15802==
0 1 2 3 4 5 6 7 8 9 ==15802==
==15802== HEAP SUMMARY:
==15802==     in use at exit: 0 bytes in 0 blocks
==15802==   total heap usage: 1 allocs, 1 frees, 40 bytes allocated
==15802==
==15802== All heap blocks were freed -- no leaks are possible
==15802==
==15802== For counts of detected and suppressed errors, rerun with: -v
==15802== ERROR SUMMARY: 16 errors from 5 contexts (suppressed: 4 from 4)