From 69a5d93c9c5870aeb14f489d4bffdc9dec9e1791 Mon Sep 17 00:00:00 2001
From: Jeroen Vermeulen <jtv@users.noreply.github.com>
Date: Sat, 9 Apr 2022 20:25:20 +0200
Subject: [PATCH] Strip `const` and `&` from `value_type`. (#559)

See #558.  MSVC in C++20 or C++23 mode complains without this.
---
 NEWS                   | 1 +
 include/pqxx/types.hxx | 4 ++--
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/NEWS b/NEWS
index 7aa72a273..3da4ecae6 100644
--- a/NEWS
+++ b/NEWS
@@ -6,6 +6,7 @@
  - Disallow nesting of `ignore-deprecated` blocks.
  - Deprecate `exec` functions' `desc` parameter.
  - Fix `placeholders` documentation.  (#557)
+ - Strip `const` and references from `value_type`. (#558)
 7.7.2
  - Fix up damage done by auto-formatting.
 7.7.1
diff --git a/include/pqxx/types.hxx b/include/pqxx/types.hxx
index 5d0df676b..f95b598f8 100644
--- a/include/pqxx/types.hxx
+++ b/include/pqxx/types.hxx
@@ -97,14 +97,14 @@ using strip_t = std::remove_cv_t<std::remove_reference_t<TYPE>>;
  * which we may or may not end up using for this.
  */
 template<std::ranges::range CONTAINER>
-using value_type = decltype(*std::begin(std::declval<CONTAINER>()));
+using value_type = strip_t<decltype(*std::begin(std::declval<CONTAINER>()))>;
 #else  // PQXX_HAVE_CONCEPTS
 /// The type of a container's elements.
 /** At the time of writing there's a similar thing in `std::experimental`,
  * which we may or may not end up using for this.
  */
 template<typename CONTAINER>
-using value_type = decltype(*std::begin(std::declval<CONTAINER>()));
+using value_type = strip_t<decltype(*std::begin(std::declval<CONTAINER>()))>;
 #endif // PQXX_HAVE_CONCEPTS