From 17b614303f2176398ba3bbcec3c237628447bde5 Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rwgk@google.com>
Date: Thu, 3 Aug 2023 13:36:29 -0700
Subject: [PATCH] clang 17 compatibility fixes (#4767)

* Copy clang 17 compatibility fixes from PR #4762 to a separate PR.

* Add gcc:13 C++20

* Add silkeh/clang:16-bullseye C++20
---
 .github/workflows/ci.yml   |  4 ++++
 include/pybind11/cast.h    | 10 +++++++++-
 include/pybind11/pytypes.h | 10 +++++++++-
 3 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 48f7c5e93..46e88132c 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -302,6 +302,9 @@ jobs:
           - clang: 15
             std: 20
             container_suffix: "-bullseye"
+          - clang: 16
+            std: 20
+            container_suffix: "-bullseye"
 
     name: "🐍 3 • Clang ${{ matrix.clang }} • C++${{ matrix.std }} • x64"
     container: "silkeh/clang:${{ matrix.clang }}${{ matrix.container_suffix }}"
@@ -465,6 +468,7 @@ jobs:
           - { gcc: 10, std: 17 }
           - { gcc: 11, std: 20 }
           - { gcc: 12, std: 20 }
+          - { gcc: 13, std: 20 }
 
     name: "🐍 3 • GCC ${{ matrix.gcc }} • C++${{ matrix.std }}• x64"
     container: "gcc:${{ matrix.gcc }}"
diff --git a/include/pybind11/cast.h b/include/pybind11/cast.h
index db3934118..b3c8ebe17 100644
--- a/include/pybind11/cast.h
+++ b/include/pybind11/cast.h
@@ -1377,7 +1377,15 @@ inline namespace literals {
 /** \rst
     String literal version of `arg`
  \endrst */
-constexpr arg operator"" _a(const char *name, size_t) { return arg(name); }
+constexpr arg
+#if !defined(__clang__) && defined(__GNUC__) && __GNUC__ < 5
+operator"" _a // gcc 4.8.5 insists on having a space (hard error).
+#else
+operator""_a // clang 17 generates a deprecation warning if there is a space.
+#endif
+    (const char *name, size_t) {
+    return arg(name);
+}
 } // namespace literals
 
 PYBIND11_NAMESPACE_BEGIN(detail)
diff --git a/include/pybind11/pytypes.h b/include/pybind11/pytypes.h
index 64aad6347..580a4658e 100644
--- a/include/pybind11/pytypes.h
+++ b/include/pybind11/pytypes.h
@@ -1612,7 +1612,15 @@ inline namespace literals {
 /** \rst
     String literal version of `str`
  \endrst */
-inline str operator"" _s(const char *s, size_t size) { return {s, size}; }
+inline str
+#if !defined(__clang__) && defined(__GNUC__) && __GNUC__ < 5
+operator"" _s // gcc 4.8.5 insists on having a space (hard error).
+#else
+operator""_s // clang 17 generates a deprecation warning if there is a space.
+#endif
+    (const char *s, size_t size) {
+    return {s, size};
+}
 } // namespace literals
 
 /// \addtogroup pytypes