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From: "redi at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/56568] std::initializer_list return value contents lost prematurely
Date: Thu, 03 Sep 2015 21:49:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56568

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |INVALID

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to fuzzyTew from comment #1)
> Here's an example I ran into using a plain int:
> http://coliru.stacked-crooked.com/a/1dfad4e209339aa1

That's undefined behaviour. You create a temporary array with one element, then
return an initializer_list which is bound to that local array, which goes out
of scope.

Your example and the original testcase are equivalent to:

const int& f() {
  long i = 0;
  return i;
}

which creates a temporary and binds a reference to it, resulting in a dangling
reference.

std::initializer_list is not a container, don't try to do clever things with
it, you will get burnt.