From c1f613a296c6b3318d93ceb122007df590011e6c Mon Sep 17 00:00:00 2001
From: Steve Downey <sdowney@gmail.com>
Date: Tue, 11 Nov 2025 07:44:14 -0500
Subject: [PATCH 1/2] P3913R1 Optimize for std::optional in range adaptors

Fixes #8481
Fixes NB PL-011 (C++26 CD)
Also fixes https://github.com/cplusplus/nbballot/issues/783
---
 source/ranges.tex | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/source/ranges.tex b/source/ranges.tex
index c93b855ec9..b28f0bb4fa 100644
--- a/source/ranges.tex
+++ b/source/ranges.tex
@@ -5898,6 +5898,10 @@
 except that the evaluations of \tcode{E} and \tcode{F}
 are indeterminately sequenced.
 
+\item
+Otherwise, if \tcode{T} is a specialization of
+\tcode{optional} and \tcode{T} models \libconcept{view}, then
+\tcode{(static_cast<D>(F) == D() ? ((void)E, T()) : \exposidnc{decay-copy}(E))}.
 \item
 Otherwise, if \tcode{T} models
 \libconcept{random_access_range} and \libconcept{sized_range}
@@ -6380,7 +6384,10 @@
 then \tcode{((void)F, \exposidnc{decay-copy}(E))},
 except that the evaluations of \tcode{E} and \tcode{F}
 are indeterminately sequenced.
-
+\item
+Otherwise, if \tcode{T} is a specialization of \tcode{optional}
+and \tcode{T} models \libconcept{view}, then
+\tcode{(static_cast<D>(F) == D() ? \exposidnc{decay-copy}(E) : ((void)E, T()))}.
 \item
 Otherwise, if \tcode{T} models
 \libconcept{random_access_range} and \libconcept{sized_range}
@@ -9909,6 +9916,9 @@
   If the type of \tcode{E} is
   a (possibly cv-qualified) specialization of \tcode{reverse_view},
   then \tcode{E.base()}.
+\item
+  Otherwise, if \tcode{E} is specialization of \tcode{optional} and \tcode{E}
+  models \libconcept{view}, then \tcode{\exposidnc{decay-copy}(E)}.
 \item
   Otherwise, if the type of \tcode{E} is \cv{} \tcode{subrange<reverse_iterator<I>, reverse_iterator<I>, K>}
   for some iterator type \tcode{I} and
@@ -10061,6 +10071,9 @@
 if \tcode{U} denotes \tcode{empty_view<X>}
 for some type \tcode{X}, then \tcode{auto(views::empty<const X>)}.
 \item
+Otherwise, if \tcode{U} denotes \tcode{optional<X\&>}
+for some type \tcode{X}, then \tcode{optional<const X\&>(E)}.
+\item
 Otherwise,
 if \tcode{U} denotes \tcode{span<X, Extent>}
 for some type \tcode{X} and some extent \tcode{Extent},

From 0b4cae3d2e6a4ad326261f842ae324d83f1c71e5 Mon Sep 17 00:00:00 2001
From: Steve Downey <sdowney@gmail.com>
Date: Sun, 16 Nov 2025 16:39:08 -0500
Subject: [PATCH 2/2] Add linebreaks around items

Add linebreaks around newly added items in the itemize blocks.
---
 source/ranges.tex | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/source/ranges.tex b/source/ranges.tex
index b28f0bb4fa..ee17326a40 100644
--- a/source/ranges.tex
+++ b/source/ranges.tex
@@ -5902,6 +5902,7 @@
 Otherwise, if \tcode{T} is a specialization of
 \tcode{optional} and \tcode{T} models \libconcept{view}, then
 \tcode{(static_cast<D>(F) == D() ? ((void)E, T()) : \exposidnc{decay-copy}(E))}.
+
 \item
 Otherwise, if \tcode{T} models
 \libconcept{random_access_range} and \libconcept{sized_range}
@@ -6384,10 +6385,12 @@
 then \tcode{((void)F, \exposidnc{decay-copy}(E))},
 except that the evaluations of \tcode{E} and \tcode{F}
 are indeterminately sequenced.
+
 \item
 Otherwise, if \tcode{T} is a specialization of \tcode{optional}
 and \tcode{T} models \libconcept{view}, then
 \tcode{(static_cast<D>(F) == D() ? \exposidnc{decay-copy}(E) : ((void)E, T()))}.
+
 \item
 Otherwise, if \tcode{T} models
 \libconcept{random_access_range} and \libconcept{sized_range}
@@ -9916,9 +9919,11 @@
   If the type of \tcode{E} is
   a (possibly cv-qualified) specialization of \tcode{reverse_view},
   then \tcode{E.base()}.
+
 \item
   Otherwise, if \tcode{E} is specialization of \tcode{optional} and \tcode{E}
   models \libconcept{view}, then \tcode{\exposidnc{decay-copy}(E)}.
+
 \item
   Otherwise, if the type of \tcode{E} is \cv{} \tcode{subrange<reverse_iterator<I>, reverse_iterator<I>, K>}
   for some iterator type \tcode{I} and
@@ -10070,9 +10075,11 @@
 Otherwise,
 if \tcode{U} denotes \tcode{empty_view<X>}
 for some type \tcode{X}, then \tcode{auto(views::empty<const X>)}.
+
 \item
 Otherwise, if \tcode{U} denotes \tcode{optional<X\&>}
 for some type \tcode{X}, then \tcode{optional<const X\&>(E)}.
+
 \item
 Otherwise,
 if \tcode{U} denotes \tcode{span<X, Extent>}