From bf0b457461f2892b480eb7b1790e75ff76fe2fc9 Mon Sep 17 00:00:00 2001
From: Ben Boeckel <ben.boeckel@kitware.com>
Date: Sat, 24 Feb 2024 17:30:41 -0500
Subject: [PATCH] Tests/CXXModules: add test case for `import std` support

---
 Tests/RunCMake/CXXModules/RunCMakeTest.cmake         |  6 ++++++
 .../CXXModules/examples/import-std/CMakeLists.txt    | 12 ++++++++++++
 .../RunCMake/CXXModules/examples/import-std/main.cxx | 10 ++++++++++
 3 files changed, 28 insertions(+)
 create mode 100644 Tests/RunCMake/CXXModules/examples/import-std/CMakeLists.txt
 create mode 100644 Tests/RunCMake/CXXModules/examples/import-std/main.cxx

diff --git a/Tests/RunCMake/CXXModules/RunCMakeTest.cmake b/Tests/RunCMake/CXXModules/RunCMakeTest.cmake
index 14829a1643..75e062e663 100644
--- a/Tests/RunCMake/CXXModules/RunCMakeTest.cmake
+++ b/Tests/RunCMake/CXXModules/RunCMakeTest.cmake
@@ -175,6 +175,7 @@ endfunction ()
 # - `partitions`: module partitions are supported
 # - `internal_partitions`: internal module partitions are supported
 # - `bmionly`: the compiler supports BMI-only builds
+# - `import_std23`: the compiler supports `import std` for C++23
 #
 # Generator-based:
 # - `compile_commands`: the generator supports `compile_commands.json`
@@ -221,6 +222,11 @@ if ("named" IN_LIST CMake_TEST_MODULE_COMPILATION)
   run_cxx_module_test(same-src-name)
   run_cxx_module_test(scan_properties)
   run_cxx_module_test(target-objects)
+
+  if ("cxx_std_23" IN_LIST CMAKE_CXX_COMPILE_FEATURES AND
+      "import_std23" IN_LIST CMake_TEST_MODULE_COMPILATION)
+    run_cxx_module_test(import-std)
+  endif ()
 endif ()
 
 # Tests which require compile commands support.
diff --git a/Tests/RunCMake/CXXModules/examples/import-std/CMakeLists.txt b/Tests/RunCMake/CXXModules/examples/import-std/CMakeLists.txt
new file mode 100644
index 0000000000..4e894c7066
--- /dev/null
+++ b/Tests/RunCMake/CXXModules/examples/import-std/CMakeLists.txt
@@ -0,0 +1,12 @@
+cmake_minimum_required(VERSION 3.29)
+project(cxx_modules_import_std CXX)
+
+include("${CMAKE_SOURCE_DIR}/../cxx-modules-rules.cmake")
+
+set(CMAKE_CXX_MODULE_STD 1)
+
+add_executable(main
+  main.cxx)
+target_compile_features(main PRIVATE cxx_std_23)
+
+add_test(NAME main COMMAND main)
diff --git a/Tests/RunCMake/CXXModules/examples/import-std/main.cxx b/Tests/RunCMake/CXXModules/examples/import-std/main.cxx
new file mode 100644
index 0000000000..6dafd014c0
--- /dev/null
+++ b/Tests/RunCMake/CXXModules/examples/import-std/main.cxx
@@ -0,0 +1,10 @@
+import std;
+
+int main(int argc, char* argv[])
+{
+  if (argc > 0 && argv[0]) {
+    std::string argv0 = argv[0];
+    std::cout << "program: " << argv0 << std::endl;
+  }
+  return 0;
+}