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From: "arthur.j.odwyer at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libstdc++/70472]
 is_copy_constructible<vector<unique_ptr<int>>>::value is true
Date: Mon, 24 Jul 2023 18:21:03 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D70472

Arthur O'Dwyer <arthur.j.odwyer at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |arthur.j.odwyer at gmail d=
ot com

--- Comment #14 from Arthur O'Dwyer <arthur.j.odwyer at gmail dot com> ---
> The problem is that std::vector does have a copy constructor, so the trai=
t value is true, but instantiating that constructor produces an error when =
the value_type is not copyable.

Worse, the value_type can be incomplete, as in

struct Node {
  std::vector<Node> children_;
};

Askar: see
https://quuxplusone.github.io/blog/2020/02/05/vector-is-copyable-except-whe=
n-its-not/
I suggest closing this bug report as Not A Bug. It certainly shouldn't be
tagged `wrong-code`.=