https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91777
Bug ID: 91777
Summary: No warning for iterator going out of scope
Product: gcc
Version: 9.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: Hi-Angel at yandex dot ru
Target Milestone: ---
The testcase below would've worked if instead of `return {l,…` was used `return
{move(l),…`. But it wasn't, and due to lack of borrow-semantics in C++ language
such mistakes are easy to make. In these circumstances programmers has to rely
on compiler warnings, so it would be amazing if GCC warn about iterators still
referencing the out-of-scope container.
# Steps to reproduce (in terms of terminal commands)
$ cat test.cpp
#include <cstdio>
#include <list>
using namespace std;
pair<list<int>, list<int>::const_iterator> foo() {
list<int> l = {1,2,3};
return {l, l.begin()};
}
int main() {
pair p = foo();
printf("%i\n", *p.second);
}
$ g++ test.cpp -o a -O3 -Wall -Wextra -Wsign-conversion -std=c++17
-fsanitize=address,undefined
## Expected
A warning about the second element in `return {l, l.begin()}` become invalid
once `l` goes out of scope.
## Actual
No output.
