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From: "hewillk at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libstdc++/108362] New: views::istream is SFINAE-unfriendly
Date: Tue, 10 Jan 2023 15:24:06 +0000
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X-Bugzilla-Component: libstdc++
X-Bugzilla-Version: 13.0
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D108362

            Bug ID: 108362
           Summary: views::istream is SFINAE-unfriendly
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hewillk at gmail dot com
  Target Milestone: ---

Similar issue with https://github.com/microsoft/STL/pull/3335.

#include <ranges>
#include <iostream>

template<class T>
concept can_istream_view =3D requires {
  std::views::istream<T>(std::cin);
};

struct S { };
static_assert(!can_istream_view<S>);

https://godbolt.org/z/b3W1KsPWd=