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From: "redi at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug libstdc++/102181] std::advance and
 std::views::iota<std::int64_t> don't work
Date: Thu, 02 Sep 2021 21:44:54 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D102181

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
You need to use std::ranges::advance here, because iota_view is "special".

The reason std::advance doesn't work is that the type of v.begin() does not
meet the Cpp17InputIterator requirements, because its difference_type is
__int128, which is not a signed integer type when using -std=3Dc++17 (but i=
t is
when using -std=3Dgnu++20). Failing to meet the Cpp17InputIterator requirem=
ents
means that std::iterator_traits<decltype(b)>::iterator_category defaults to
output_iterator_tag. And you can't advance an output iterator.=