--- meson.build	2025-11-21 13:42:58.000000000 +0800
+++ meson.build	2026-07-11 18:10:44.000000000 +0800
@@ -3,7 +3,7 @@
   'ashuffle',
   ['c', 'cpp'],
   version: 'v3.14.10',
-  default_options: ['cpp_std=c++17', 'warning_level=2']
+  default_options: ['cpp_std=c++20', 'warning_level=2']
 )
 
 add_global_arguments(
@@ -110,7 +110,7 @@
 
   absl_opts = cmake.subproject_options()
   absl_opts.add_cmake_defines({
-    'CMAKE_CXX_STANDARD': '17',
+    'CMAKE_CXX_STANDARD': '20',
     # See above.
     'CMAKE_PROJECT_absl_INCLUDE': absl_project_inc,
     # Absl's CMAKE build feels like it is MinGW for some reason when building
@@ -132,7 +131,7 @@
 else
   cpp = meson.get_compiler('cpp')
 
-  # note that the system's absl needs to be compiled for C++17 standard
+  # note that the system's absl needs to be compiled for C++17 or C++20 standard
   # or final link will fail.
   foreach lib : absl_libs
     dep = dependency(lib)
@@ -145,7 +145,7 @@
 if not get_option('unsupported_use_system_yamlcpp')
   yaml_cpp_opts = cmake.subproject_options()
   yaml_cpp_opts.add_cmake_defines({
-    'CMAKE_CXX_STANDARD': '17',
+    'CMAKE_CXX_STANDARD': '20',
     'YAML_BUILD_SHARED_LIBS': 'OFF',
     # Use new linker policy to avoid warnings.
     'CMAKE_POLICY_DEFAULT_CMP0156': 'NEW',
@@ -219,7 +218,7 @@
     googletest_opts = cmake.subproject_options()
     googletest_opts.add_cmake_defines({
       'BUILD_GMOCK': 'ON',
-      'CMAKE_CXX_STANDARD': '17',
+      'CMAKE_CXX_STANDARD': '20',
       'INSTALL_GTEST': 'OFF',
       # Use new linker policy to avoid warnings.
       'CMAKE_POLICY_DEFAULT_CMP0156': 'NEW',