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From: "redi at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug c++/102482] Winit-list-lifetime false positive for temporaries
 with std::initializer_list
Date: Sun, 26 Sep 2021 11:08:00 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D102482

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |diagnostic

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Federico Kircheis from comment #0)
> While the warning is true, the code is completely safe, but the warnings
> seems to imply that foo will access a dangling pointer.

In this case it's safe because the span obejct has the same lifetime as the
initializer_list, but in general that's not true. The warning comes from the
constructor, and is independent of the context in which it's being construc=
ted.

> so I assume the warning is std::initializer_list specific.

Yes. std::initializer_list is a magic language type that the compiler knows=
 all
about. std::vector is just opaque C++ code that the compiler knows nothing
about.=