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From: "ppalka at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug c++/104996] [10/11/12 Regression] Overload resolution over
 rvalue/const lvalue array reference parameters for an init. list argument
 incorrectly picks the const lvalue ref. overload
Date: Mon, 21 Mar 2022 13:27:00 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D104996

--- Comment #3 from Patrick Palka <ppalka at gcc dot gnu.org> ---
For the record, the full rejects-valid testcase is:

// #g.1: rvalue reference function parameter
constexpr bool g(int&&)       { return true; }

// #g.2: const lvalue reference function parameter
constexpr bool g(int const&)  { return false; }

static_assert(g(0), ""); // OK: all compilers agree

// #f.1: rvalue ref overload
template<int size>
constexpr bool f(int (&&)[size])      { return true; }

// #f.2: lvalue ref overload
template<int size>
constexpr bool f(int const (&)[size]) { return false; }

template<typename T>
using type =3D T;

static_assert(f(type<int[3]>{1, 2, 3})); // OK: all compilers agree.

static_assert(f({1, 2, 3}), ""); // Clang: OK    (picks #f.1)
                                 // MSVC:  OK    (picks #f.1)
                                 // GCC:   Error (picks #f.2)=