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From: "ppalka at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug c++/102283] Inconsistent/wrong overload resolution when using
 an initializer list and a defaulted template parameter
Date: Tue, 12 Oct 2021 13:47:08 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D102283

--- Comment #7 from Patrick Palka <ppalka at gcc dot gnu.org> ---
(In reply to Fedor Chelnokov from comment #0 in PR102691)
> This code is valid:
> ```
> struct Foo {};
> struct Bar {};
>=20
> constexpr int Baz(const Foo&) { return 0; }
> constexpr int Baz(Bar&&) { return 1; }
>=20
> int main()
> {
>   static_assert( Baz({}) =3D=3D 1 );
> }
> ```
> Here Baz(Bar&&) must be preferred according to [over.ics.rank]/(3.2), as
> Clang does.

But according to [over.ics.list]/8, isn't the conversion from {} to an
aggregate type a user-defined conversion sequence and not a standard conver=
sion
sequence?  And according to [over.ics.rank]/3.3, two such user-defined
conversion sequences to different types are incomparable.=