treewide: Bump C++ standard version to C++23

Compilers in nixpkgs have caught up and major distros
should also have recent enough compilers. It would be
nice to have newer features like more full featured
ranges and deducing this.

doc/manual/source/installation/prerequisites-source.md

@@ -10,7 +10,7 @@
   - Bash Shell. The `./configure` script relies on bashisms, so Bash is
     required.
 
-  - A version of GCC or Clang that supports C++20.
+  - A version of GCC or Clang that supports C++23.
 
   - `pkg-config` to locate dependencies. If your distribution does not
     provide it, you can get it from

nix-meson-build-support/export/meson.build

@@ -14,7 +14,7 @@ extra_pkg_config_variables = get_variable('extra_pkg_config_variables', {})
 
 extra_cflags = []
 if not meson.project_name().endswith('-c')
-  extra_cflags += [ '-std=c++2a' ]
+  extra_cflags += [ '-std=c++23' ]
 endif
 
 import('pkgconfig').generate(
@@ -34,7 +34,7 @@ meson.override_dependency(
   declare_dependency(
     include_directories : include_dirs,
     link_with : this_library,
-    compile_args : [ '-std=c++2a' ],
+    compile_args : [ '-std=c++23' ],
     dependencies : deps_public_subproject + deps_public,
     variables : extra_pkg_config_variables,
   ),

src/libcmd/meson.build

@@ -3,7 +3,7 @@ project(
   'cpp',
   version : files('.version'),
   default_options : [
-    'cpp_std=c++2a',
+    'cpp_std=c++23',
     # TODO(Qyriad): increase the warning level
     'warning_level=1',
     'errorlogs=true', # Please print logs for tests that fail

src/libexpr-c/meson.build

@@ -3,7 +3,7 @@ project(
   'cpp',
   version : files('.version'),
   default_options : [
-    'cpp_std=c++2a',
+    'cpp_std=c++23',
     # TODO(Qyriad): increase the warning level
     'warning_level=1',
     'errorlogs=true', # Please print logs for tests that fail

src/libexpr-test-support/meson.build

@@ -3,7 +3,7 @@ project(
   'cpp',
   version : files('.version'),
   default_options : [
-    'cpp_std=c++2a',
+    'cpp_std=c++23',
     # TODO(Qyriad): increase the warning level
     'warning_level=1',
     'errorlogs=true', # Please print logs for tests that fail

src/libexpr-test-support/tests/value/context.cc

@@ -1,3 +1,4 @@
+#include <exception> // Needed by rapidcheck on Darwin
 #include <rapidcheck.h>
 
 #include "nix/store/tests/path.hh"

src/libexpr-tests/derived-path.cc

@@ -1,5 +1,6 @@
 #include <nlohmann/json.hpp>
 #include <gtest/gtest.h>
+#include <exception> // Needed by rapidcheck on Darwin
 #include <rapidcheck/gtest.h>
 
 #include "nix/store/tests/derived-path.hh"

src/libexpr-tests/meson.build

@@ -3,7 +3,7 @@ project(
   'cpp',
   version : files('.version'),
   default_options : [
-    'cpp_std=c++2a',
+    'cpp_std=c++23',
     # TODO(Qyriad): increase the warning level
     'warning_level=1',
     'errorlogs=true', # Please print logs for tests that fail

src/libexpr/meson.build

@@ -3,7 +3,7 @@ project(
   'cpp',
   version : files('.version'),
   default_options : [
-    'cpp_std=c++2a',
+    'cpp_std=c++23',
     # TODO(Qyriad): increase the warning level
     'warning_level=1',
     'errorlogs=true', # Please print logs for tests that fail

src/libfetchers-c/meson.build

@@ -3,7 +3,7 @@ project(
   'cpp',
   version : files('.version'),
   default_options : [
-    'cpp_std=c++2a',
+    'cpp_std=c++23',
     # TODO(Qyriad): increase the warning level
     'warning_level=1',
     'errorlogs=true', # Please print logs for tests that fail

src/libfetchers-tests/meson.build

@@ -3,7 +3,7 @@ project(
   'cpp',
   version : files('.version'),
   default_options : [
-    'cpp_std=c++2a',
+    'cpp_std=c++23',
     # TODO(Qyriad): increase the warning level
     'warning_level=1',
     'errorlogs=true', # Please print logs for tests that fail

src/libfetchers/meson.build

@@ -3,7 +3,7 @@ project(
   'cpp',
   version : files('.version'),
   default_options : [
-    'cpp_std=c++2a',
+    'cpp_std=c++23',
     # TODO(Qyriad): increase the warning level
     'warning_level=1',
     'errorlogs=true', # Please print logs for tests that fail

src/libflake-c/meson.build

@@ -3,7 +3,7 @@ project(
   'cpp',
   version : files('.version'),
   default_options : [
-    'cpp_std=c++2a',
+    'cpp_std=c++23',
     # TODO(Qyriad): increase the warning level
     'warning_level=1',
     'errorlogs=true', # Please print logs for tests that fail

src/libflake-tests/meson.build

@@ -3,7 +3,7 @@ project(
   'cpp',
   version : files('.version'),
   default_options : [
-    'cpp_std=c++2a',
+    'cpp_std=c++23',
     # TODO(Qyriad): increase the warning level
     'warning_level=1',
     'errorlogs=true', # Please print logs for tests that fail

src/libflake/meson.build

@@ -3,7 +3,7 @@ project(
   'cpp',
   version : files('.version'),
   default_options : [
-    'cpp_std=c++2a',
+    'cpp_std=c++23',
     # TODO(Qyriad): increase the warning level
     'warning_level=1',
     'errorlogs=true', # Please print logs for tests that fail

src/libmain-c/meson.build

@@ -3,7 +3,7 @@ project(
   'cpp',
   version : files('.version'),
   default_options : [
-    'cpp_std=c++2a',
+    'cpp_std=c++23',
     # TODO(Qyriad): increase the warning level
     'warning_level=1',
     'errorlogs=true', # Please print logs for tests that fail

src/libmain/meson.build

@@ -3,7 +3,7 @@ project(
   'cpp',
   version : files('.version'),
   default_options : [
-    'cpp_std=c++2a',
+    'cpp_std=c++23',
     # TODO(Qyriad): increase the warning level
     'warning_level=1',
     'errorlogs=true', # Please print logs for tests that fail

src/libstore-c/meson.build

@@ -3,7 +3,7 @@ project(
   'cpp',
   version : files('.version'),
   default_options : [
-    'cpp_std=c++2a',
+    'cpp_std=c++23',
     # TODO(Qyriad): increase the warning level
     'warning_level=1',
     'errorlogs=true', # Please print logs for tests that fail

src/libstore-test-support/derived-path.cc

@@ -1,5 +1,6 @@
 #include <regex>
 
+#include <exception> // Needed by rapidcheck on Darwin
 #include <rapidcheck.h>
 
 #include "nix/store/tests/derived-path.hh"

src/libstore-test-support/include/nix/store/tests/outputs-spec.hh

@@ -1,6 +1,7 @@
 #pragma once
 ///@file
 
+#include <exception> // Needed by rapidcheck on Darwin
 #include <rapidcheck/gen/Arbitrary.h>
 
 #include "nix/store/outputs-spec.hh"

src/libstore-test-support/meson.build

@@ -3,7 +3,7 @@ project(
   'cpp',
   version : files('.version'),
   default_options : [
-    'cpp_std=c++2a',
+    'cpp_std=c++23',
     # TODO(Qyriad): increase the warning level
     'warning_level=1',
     'errorlogs=true', # Please print logs for tests that fail

src/libstore-test-support/path.cc

@@ -1,6 +1,7 @@
-#include <rapidcheck/gen/Arbitrary.h>
+#include <exception> // Needed by rapidcheck on Darwin
 #include <regex>
 
+#include <rapidcheck/gen/Arbitrary.h>
 #include <rapidcheck.h>
 
 #include "nix/store/path-regex.hh"

src/libstore-tests/meson.build

@@ -3,7 +3,7 @@ project(
   'cpp',
   version : files('.version'),
   default_options : [
-    'cpp_std=c++2a',
+    'cpp_std=c++23',
     # TODO(Qyriad): increase the warning level
     'warning_level=1',
     'errorlogs=true', # Please print logs for tests that fail

src/libstore/meson.build

@@ -3,7 +3,7 @@ project(
   'cpp',
   version : files('.version'),
   default_options : [
-    'cpp_std=c++2a',
+    'cpp_std=c++23',
     # TODO(Qyriad): increase the warning level
     'warning_level=1',
     'errorlogs=true', # Please print logs for tests that fail

src/libutil-c/meson.build

@@ -3,7 +3,7 @@ project(
   'cpp',
   version : files('.version'),
   default_options : [
-    'cpp_std=c++2a',
+    'cpp_std=c++23',
     # TODO(Qyriad): increase the warning level
     'warning_level=1',
     'errorlogs=true', # Please print logs for tests that fail

src/libutil-test-support/hash.cc

@@ -1,5 +1,6 @@
 #include <regex>
 
+#include <exception> // Needed by rapidcheck on Darwin
 #include <rapidcheck.h>
 
 #include "nix/util/hash.hh"

src/libutil-test-support/meson.build

@@ -3,7 +3,7 @@ project(
   'cpp',
   version : files('.version'),
   default_options : [
-    'cpp_std=c++2a',
+    'cpp_std=c++23',
     # TODO(Qyriad): increase the warning level
     'warning_level=1',
     'errorlogs=true', # Please print logs for tests that fail

src/libutil-tests/meson.build

@@ -3,7 +3,7 @@ project(
   'cpp',
   version : files('.version'),
   default_options : [
-    'cpp_std=c++2a',
+    'cpp_std=c++23',
     # TODO(Qyriad): increase the warning level
     'warning_level=1',
     'errorlogs=true', # Please print logs for tests that fail

src/libutil/meson.build

@@ -3,7 +3,7 @@ project(
   'cpp',
   version : files('.version'),
   default_options : [
-    'cpp_std=c++2a',
+    'cpp_std=c++23',
     # TODO(Qyriad): increase the warning level
     'warning_level=1',
     'errorlogs=true', # Please print logs for tests that fail

src/nix/meson.build

@@ -3,7 +3,7 @@ project(
   'cpp',
   version : files('.version'),
   default_options : [
-    'cpp_std=c++2a',
+    'cpp_std=c++23',
     # TODO(Qyriad): increase the warning level
     'warning_level=1',
     'errorlogs=true', # Please print logs for tests that fail

tests/functional/meson.build

@@ -2,7 +2,7 @@ project(
   'nix-functional-tests',
   version : files('.version'),
   default_options : [
-    'cpp_std=c++2a',
+    'cpp_std=c++23',
     # TODO(Qyriad): increase the warning level
     'warning_level=1',
     'errorlogs=true', # Please print logs for tests that fail