From: Patrick Palka <ppalka@redhat.com>
Date: Fri, 21 May 2021 04:05:18 +0000 (-0400)
Subject: libstdc++: Implement LWG 3490 change to drop_while_view::begin()
X-Git-Tag: releases/gcc-11.3.0~770
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0dd0905e2f59c1e8fc1597355f47afb53630cfc9;p=thirdparty%2Fgcc.git

libstdc++: Implement LWG 3490 change to drop_while_view::begin()

libstdc++-v3/ChangeLog:

	PR libstdc++/100606
	* include/std/ranges (drop_while_view::begin): Assert the
	precondition added by LWG 3490.

(cherry picked from commit 11784fe27d879a10dc8a79212c37f50d4f7146f3)
---

diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges
index 3ef352949dff..4e01ef57401a 100644
--- a/libstdc++-v3/include/std/ranges
+++ b/libstdc++-v3/include/std/ranges
@@ -2389,6 +2389,7 @@ namespace views::__adaptor
 	if (_M_cached_begin._M_has_value())
 	  return _M_cached_begin._M_get(_M_base);
 
+	__glibcxx_assert(_M_pred.has_value());
 	auto __it = __detail::find_if_not(ranges::begin(_M_base),
 					  ranges::end(_M_base),
 					  std::cref(*_M_pred));