Experimental: Remove import std experimental gate

Fixes: #28014
2026-10-03 04:03:23 +03:00 · 2026-09-25 11:03:02 -04:00
1 parent b65a094a31
commit 4874f044bd
@@ -59,24 +59,6 @@ When activated, this experimental feature provides the following:
 .. _CPS: https://cps-org.github.io/cps/
 .. |CPS| replace:: Common Package Specification

-C++ ``import std`` support
-==========================
-
-In order to activate support for ``import std`` in C++23 and newer targets,
-set
-
-* variable ``CMAKE_EXPERIMENTAL_CXX_IMPORT_STD`` to
-* value ``25d6f6aa-be65-4692-b44e-87b23e96d4e1``.
-
-This UUID may change in future versions of CMake.  Be sure to use the value
-documented here by the source tree of the version of CMake with which you are
-experimenting.  It must be set before the ``CXX`` toolchain is discovered by
-CMake, usually as part of a ``project()`` call.
-
-When activated, this experimental feature provides the following:
-
-* Targets may use ``import std;`` in any scanned C++ source file.
-
 Build database support
 ======================

@@ -86,6 +86,8 @@ modules includes:
 ``import std`` Support
 ======================

+.. versionadded:: 4.5
+
 Support for ``import std`` is limited to the following toolchain and standard
 library combinations:

@@ -108,12 +110,6 @@ for ``IMPORTED`` targets.
 ``import std`` is available for all language standards which support C++ module
 scanning (ie, C++20 and newer).

-.. note::
-
-   This support is provided only when experimental support for
-   ``import std`` has been enabled by the
-   ``CMAKE_EXPERIMENTAL_CXX_IMPORT_STD`` gate.
-
 Generator Support
 =================

@@ -506,9 +502,6 @@ The set of sources which need to be scanned may be modified using the
 :command:`target_sources`, :command:`target_compile_features`, and
 :command:`set_property` commands.

-Additionally, targets may use the :prop_tgt:`CXX_MODULE_STD` target property
-to indicate that ``import std`` is desired within the target's sources.
-
 Generate
 ^^^^^^^^

@@ -233,7 +233,6 @@ Properties on Targets
   /prop_tgt/CXX_MODULE_SET
   /prop_tgt/CXX_MODULE_SET_NAME
   /prop_tgt/CXX_MODULE_SETS
-   /prop_tgt/CXX_MODULE_STD
   /prop_tgt/CXX_SCAN_FOR_MODULES
   /prop_tgt/CXX_STANDARD
   /prop_tgt/CXX_STANDARD_REQUIRED
@@ -475,7 +475,6 @@ Variables that Control the Build
   /variable/CMAKE_CUDA_RESOLVE_DEVICE_SYMBOLS
   /variable/CMAKE_CUDA_RUNTIME_LIBRARY
   /variable/CMAKE_CUDA_SEPARABLE_COMPILATION
-   /variable/CMAKE_CXX_MODULE_STD
   /variable/CMAKE_CXX_SCAN_FOR_MODULES
   /variable/CMAKE_DEBUG_POSTFIX
   /variable/CMAKE_DEBUGGER_WORKING_DIRECTORY
@@ -644,7 +643,6 @@ Variables for Languages
   /variable/CMAKE_CUDA_STANDARD_REQUIRED
   /variable/CMAKE_CUDA_TOOLKIT_INCLUDE_DIRECTORIES
   /variable/CMAKE_CXX_COMPILE_FEATURES
-   /variable/CMAKE_CXX_COMPILER_IMPORT_STD
   /variable/CMAKE_CXX_EXTENSIONS
   /variable/CMAKE_CXX_STANDARD
   /variable/CMAKE_CXX_STANDARD_REQUIRED
@@ -1,46 +0,0 @@
-CXX_MODULE_STD
--------------
-
-.. versionchanged:: 4.5
-
-   ``CXX_MODULE_STD`` no longer has any effect. ``import std;`` is handled
-   automatically on all sources with :prop_tgt:`CXX_SCAN_FOR_MODULES` enabled.
-
-.. versionadded:: 3.30
-
-``CXX_MODULE_STD`` is a boolean specifying whether the target may use
-``import std;`` its C++ sources or not.
-
-.. note::
-
-   This setting is meaningful only when experimental support for ``import
-   std;`` has been enabled by the ``CMAKE_EXPERIMENTAL_CXX_IMPORT_STD`` gate.
-
-When this property is explicitly set to ``ON``, CMake will add a dependency to
-a target which provides the C++ standard library's modules for the C++
-standard applied to the target. This target is only applicable within the
-current build and will not appear in the exported interfaces of the targets.
-When consumed, these targets will be reapplied as necessary.
-
-.. note::
-
-   Similar to the introduction of :prop_tgt:`CXX_SCAN_FOR_MODULES`, this
-   property defaults to **not** adding ``import std`` support to targets using
-   ``cxx_std_23`` without an explicit request in order to preserve existing
-   behavior for projects using C++23 without ``import std``. A future policy
-   to change the default behavior is expected once the feature sees wider
-   usage.
-
-This property's value is not relevant for targets which disable scanning (see
-:prop_tgt:`CXX_SCAN_FOR_MODULES`). Additionally, this property only applies to
-targets utilizing C++23 (``cxx_std_23``) or newer.
-
-The property supports
-:manual:`generator expressions <cmake-generator-expressions(7)>`, however
-expressions that depend upon the configuration, the consuming target, or the
-linker language are not allowed. Whether a target uses ``import std`` should
-not depend upon such things as it is a static property of the target's source
-code.
-
-Targets which are exported with C++ module sources will have this property's
-resolved value exported.
@@ -0,0 +1,10 @@
+import-std
+----------
+
+* The experimental gate for ``import std`` has been dropped. ``import std`` is
+  available for all C++20 and later code with :prop_tgt:`CXX_SCAN_FOR_MODULES`
+  enabled.
+
+* Variable :variable:`CMAKE_CXX_STDLIB_MODULES_JSON` sets a specific module
+  metadata file which CMake will use for constructing ``import std`` instead
+  of relying on automatic detection via the current C++ compiler.
@@ -1,20 +0,0 @@
-CMAKE_CXX_COMPILER_IMPORT_STD
-----------------------------
-
-.. versionchanged:: 4.5
-
-   Reporting of supported C++ standard levels has been removed as toolchains
-   no longer control generation of standard library targets.
-   ``CMAKE_CXX_COMPILER_IMPORT_STD`` is left undefined.
-
-.. versionadded:: 3.30
-
-A list of C++ standard levels for which ``import std`` support exists for the
-current C++ toolchain.  Support for C++\<NN\> may be detected using a
-``<NN> IN_LIST CMAKE_CXX_COMPILER_IMPORT_STD`` predicate with the
-:command:`if` command.
-
-.. note::
-
-   This variable is meaningful only when experimental support for ``import
-   std;`` has been enabled by the ``CMAKE_EXPERIMENTAL_CXX_IMPORT_STD`` gate.
@@ -1,20 +0,0 @@
-CMAKE_CXX_MODULE_STD
--------------------
-
-.. versionchanged:: 4.5
-
-   ``CMAKE_CXX_MODULE_STD`` no longer has any effect. ``import std;`` is handled
-   automatically on all sources with :prop_tgt:`CXX_SCAN_FOR_MODULES` enabled.
-
-.. versionadded:: 3.30
-
-Whether to add utility targets as dependencies to targets with at least
-``cxx_std_23`` or not.
-
-.. note::
-
-   This setting is meaningful only when experimental support for ``import
-   std;`` has been enabled by the ``CMAKE_EXPERIMENTAL_CXX_IMPORT_STD`` gate.
-
-This variable is used to initialize the :prop_tgt:`CXX_MODULE_STD` property on
-all targets.  See that target property for additional information.
@@ -1,7 +1,7 @@
 CMAKE_CXX_STDLIB_MODULES_JSON
 -----------------------------

-.. versionadded:: 4.2
+.. versionadded:: 4.5

 This variable may be used to set the path to a metadata file for CMake to
 understand how the ``import std`` target for the active CXX compiler should be
@@ -220,17 +220,6 @@ function(cmake_cxx_find_modules_json)
    return ()
  endif ()

-  # Check the experimental flag. Check it here to avoid triggering warnings in
-  # situations that don't support the feature anyways.
-  set(_cmake_supported_import_std_experimental "")
-  cmake_language(GET_EXPERIMENTAL_FEATURE_ENABLED
-    "CxxImportStd"
-    _cmake_supported_import_std_experimental)
-  if (NOT _cmake_supported_import_std_experimental)
-    set(CMAKE_CXX_COMPILER_IMPORT_STD_ERROR_MESSAGE "Experimental `import std` support not enabled when detecting toolchain; it must be set before `CXX` is enabled (usually a `project()` call)" PARENT_SCOPE)
-    return ()
-  endif ()
-
  _cmake_cxx_find_modules_json()
  set(CMAKE_CXX_COMPILER_IMPORT_STD_ERROR_MESSAGE "${CMAKE_CXX_COMPILER_IMPORT_STD_ERROR_MESSAGE}" PARENT_SCOPE)
  set(CMAKE_CXX_STDLIB_MODULES_JSON "${CMAKE_CXX_STDLIB_MODULES_JSON}" PARENT_SCOPE)
@@ -29,14 +29,6 @@ cmExperimental::FeatureData const LookupTable[] = {
    "only for experimentation and feedback to CMake developers.",
    {},
    cmExperimental::TryCompileCondition::Always },
-  // CxxImportStd
-  { "CxxImportStd",
-    "25d6f6aa-be65-4692-b44e-87b23e96d4e1",
-    "CMAKE_EXPERIMENTAL_CXX_IMPORT_STD",
-    "CMake's support for `import std;` in C++23 and newer is experimental. It "
-    "is meant only for experimentation and feedback to CMake developers.",
-    {},
-    cmExperimental::TryCompileCondition::Always },
  // MappedPackageInfo
  { "MappedPackageInfo",
    "ababa1b5-7099-495f-a9cd-e22d38f274f2",
@@ -18,7 +18,6 @@ public:
  enum class Feature
  {
    ExportPackageDependencies,
-    CxxImportStd,
    MappedPackageInfo,
    ExportBuildDatabase,
    GenerateSbom,
@@ -5446,11 +5446,6 @@ bool CreateCxxStdlibTarget(cmMakefile* makefile, cmLocalGenerator* lg,

 bool cmGeneratorTarget::ApplyCXXStdTarget()
 {
-  if (!cmExperimental::HasSupportEnabled(
-        *this->Makefile, cmExperimental::Feature::CxxImportStd)) {
-    return true;
-  }
-
  std::vector<std::string> const& configs =
    this->Makefile->GetGeneratorConfigs(cmMakefile::IncludeEmptyConfig);

@@ -1,5 +1,57 @@
 include("${CMAKE_CURRENT_LIST_DIR}/check-json.cmake")

+# The `import std` support targets are generated by CMake and their build
+# database contents vary by toolchain (flags, depfile paths, module names,
+# translation unit ordering, etc.).  Ignore everything related to them so
+# that the same expectations can be shared across platforms.
+function (filter_import_std_sets json_in json_out)
+  set(json "${json_in}")
+
+  # Drop `@cmake_cxx_std@` sets.
+  string(JSON sets_len LENGTH "${json}" "sets")
+  if (sets_len GREATER 0)
+    math(EXPR last "${sets_len} - 1")
+    set(std_indices "")
+    foreach (idx RANGE "${last}")
+      string(JSON name GET "${json}" "sets" "${idx}" "name")
+      if (name MATCHES "^@cmake_cxx_std@")
+        list(APPEND std_indices "${idx}")
+      endif ()
+    endforeach ()
+    list(REVERSE std_indices)
+    foreach (idx IN LISTS std_indices)
+      string(JSON json REMOVE "${json}" "sets" "${idx}")
+    endforeach ()
+  endif ()
+
+  # Drop references to those sets from every `visible-sets` array.
+  string(JSON sets_len LENGTH "${json}" "sets")
+  if (sets_len GREATER 0)
+    math(EXPR last "${sets_len} - 1")
+    foreach (idx RANGE "${last}")
+      string(JSON vis_len LENGTH "${json}" "sets" "${idx}" "visible-sets")
+      if (vis_len GREATER 0)
+        math(EXPR vis_last "${vis_len} - 1")
+        set(vis_indices "")
+        foreach (vis_idx RANGE "${vis_last}")
+          string(JSON vis_name GET
+            "${json}" "sets" "${idx}" "visible-sets" "${vis_idx}")
+          if (vis_name MATCHES "^@cmake_cxx_std@")
+            list(APPEND vis_indices "${vis_idx}")
+          endif ()
+        endforeach ()
+        list(REVERSE vis_indices)
+        foreach (vis_idx IN LISTS vis_indices)
+          string(JSON json REMOVE
+            "${json}" "sets" "${idx}" "visible-sets" "${vis_idx}")
+        endforeach ()
+      endif ()
+    endforeach ()
+  endif ()
+
+  set("${json_out}" "${json}" PARENT_SCOPE)
+endfunction ()
+
 function (check_build_database expect_basename fname component)
  if (component STREQUAL "NO_EXIST")
    if (EXISTS "${RunCMake_TEST_BINARY_DIR}/${fname}")
@@ -70,6 +122,8 @@ function (check_build_database expect_basename fname component)
  file(READ "${RunCMake_TEST_BINARY_DIR}/${fname}" actual)
  file(READ "${expected_file}" expect)

+  filter_import_std_sets("${actual}" actual)
+
  set(RunCMake_TEST_FAILED_before "${RunCMake_TEST_FAILED}")
  set(RunCMake_TEST_FAILED "")

@@ -1,9 +0,0 @@
-CMake Warning \(experimental\) at .*/Modules/Compiler/CMakeCommonCompilerMacros\.cmake:[0-9]* \(cmake_language\):
-  CMake's support for `import std;` in C\+\+23 and newer is experimental\.  It
-  is meant only for experimentation and feedback to CMake developers\.
-Call Stack \(most recent call first\):
-  .*/Modules/CMakeDetermineCompilerSupport\.cmake:[0-9]* \(cmake_cxx_find_modules_json\)
-  .*/Modules/CMakeTestCXXCompiler\.cmake:[0-9]* \(CMAKE_DETERMINE_COMPILER_SUPPORT\)
-  CMakeLists\.txt:[0-9]* \(project\)
-This warning is for project developers\.  Use -Wno-author or -Wno-experimental
-to suppress it\.
@@ -1,5 +1,3 @@
-set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "25d6f6aa-be65-4692-b44e-87b23e96d4e1")
 set(CMAKE_CXX_STDLIB_MODULES_JSON
  "${CMAKE_CURRENT_LIST_DIR}/../dummy-std/manifest/dummy-std.modules.json"
 )
@@ -1,9 +0,0 @@
-CMake Warning \(experimental\) at .*/Modules/Compiler/CMakeCommonCompilerMacros\.cmake:[0-9]* \(cmake_language\):
-  CMake's support for `import std;` in C\+\+23 and newer is experimental\.  It
-  is meant only for experimentation and feedback to CMake developers\.
-Call Stack \(most recent call first\):
-  .*/Modules/CMakeDetermineCompilerSupport\.cmake:[0-9]* \(cmake_cxx_find_modules_json\)
-  .*/Modules/CMakeTestCXXCompiler\.cmake:[0-9]* \(CMAKE_DETERMINE_COMPILER_SUPPORT\)
-  CMakeLists\.txt:[0-9]* \(project\)
-This warning is for project developers\.  Use -Wno-author or -Wno-experimental
-to suppress it\.
@@ -1,6 +1,3 @@
-set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "25d6f6aa-be65-4692-b44e-87b23e96d4e1")
-
 cmake_minimum_required(VERSION 3.29)
 project(cxx_modules_import_std_export_no_std CXX)

@@ -1,9 +0,0 @@
-CMake Warning \(experimental\) at .*/Modules/Compiler/CMakeCommonCompilerMacros\.cmake:[0-9]* \(cmake_language\):
-  CMake's support for `import std;` in C\+\+23 and newer is experimental\.  It
-  is meant only for experimentation and feedback to CMake developers\.
-Call Stack \(most recent call first\):
-  .*/Modules/CMakeDetermineCompilerSupport\.cmake:[0-9]* \(cmake_cxx_find_modules_json\)
-  .*/Modules/CMakeTestCXXCompiler\.cmake:[0-9]* \(CMAKE_DETERMINE_COMPILER_SUPPORT\)
-  CMakeLists\.txt:[0-9]* \(project\)
-This warning is for project developers\.  Use -Wno-author or -Wno-experimental
-to suppress it\.
@@ -1,6 +1,3 @@
-set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "25d6f6aa-be65-4692-b44e-87b23e96d4e1")
-
 cmake_minimum_required(VERSION 3.29)
 project(cxx_modules_import_std_export_no_std CXX)

@@ -1,9 +0,0 @@
-CMake Warning \(experimental\) at .*/Modules/Compiler/CMakeCommonCompilerMacros\.cmake:[0-9]* \(cmake_language\):
-  CMake's support for `import std;` in C\+\+23 and newer is experimental\.  It
-  is meant only for experimentation and feedback to CMake developers\.
-Call Stack \(most recent call first\):
-  .*/Modules/CMakeDetermineCompilerSupport\.cmake:[0-9]* \(cmake_cxx_find_modules_json\)
-  .*/Modules/CMakeTestCXXCompiler\.cmake:[0-9]* \(CMAKE_DETERMINE_COMPILER_SUPPORT\)
-  CMakeLists\.txt:[0-9]* \(project\)
-This warning is for project developers\.  Use -Wno-author or -Wno-experimental
-to suppress it\.
@@ -1,6 +1,3 @@
-set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "25d6f6aa-be65-4692-b44e-87b23e96d4e1")
-
 cmake_minimum_required(VERSION 3.29)
 project(cxx_modules_import_std_no_json CXX)

@@ -1,9 +0,0 @@
-CMake Warning \(experimental\) at .*/Modules/Compiler/CMakeCommonCompilerMacros\.cmake:[0-9]* \(cmake_language\):
-  CMake's support for `import std;` in C\+\+23 and newer is experimental\.  It
-  is meant only for experimentation and feedback to CMake developers\.
-Call Stack \(most recent call first\):
-  .*/Modules/CMakeDetermineCompilerSupport\.cmake:[0-9]* \(cmake_cxx_find_modules_json\)
-  .*/Modules/CMakeTestCXXCompiler\.cmake:[0-9]* \(CMAKE_DETERMINE_COMPILER_SUPPORT\)
-  CMakeLists\.txt:[0-9]* \(project\)
-This warning is for project developers\.  Use -Wno-author or -Wno-experimental
-to suppress it\.
@@ -1,6 +1,3 @@
-set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "25d6f6aa-be65-4692-b44e-87b23e96d4e1")
-
 cmake_minimum_required(VERSION 3.29)
 project(cxx_modules_import_std_not_in_export CXX)

@@ -1,9 +0,0 @@
-CMake Warning \(experimental\) at .*/Modules/Compiler/CMakeCommonCompilerMacros\.cmake:[0-9]* \(cmake_language\):
-  CMake's support for `import std;` in C\+\+23 and newer is experimental\.  It
-  is meant only for experimentation and feedback to CMake developers\.
-Call Stack \(most recent call first\):
-  .*/Modules/CMakeDetermineCompilerSupport\.cmake:[0-9]* \(cmake_cxx_find_modules_json\)
-  .*/Modules/CMakeTestCXXCompiler\.cmake:[0-9]* \(CMAKE_DETERMINE_COMPILER_SUPPORT\)
-  CMakeLists\.txt:[0-9]* \(project\)
-This warning is for project developers\.  Use -Wno-author or -Wno-experimental
-to suppress it\.
@@ -1,6 +1,3 @@
-set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "25d6f6aa-be65-4692-b44e-87b23e96d4e1")
-
 cmake_minimum_required(VERSION 3.29)
 project(cxx_modules_import_std_not_in_export CXX)

@@ -1,9 +0,0 @@
-CMake Warning \(experimental\) at .*/Modules/Compiler/CMakeCommonCompilerMacros\.cmake:[0-9]* \(cmake_language\):
-  CMake's support for `import std;` in C\+\+23 and newer is experimental\.  It
-  is meant only for experimentation and feedback to CMake developers\.
-Call Stack \(most recent call first\):
-  .*/Modules/CMakeDetermineCompilerSupport\.cmake:[0-9]* \(cmake_cxx_find_modules_json\)
-  .*/Modules/CMakeTestCXXCompiler\.cmake:[0-9]* \(CMAKE_DETERMINE_COMPILER_SUPPORT\)
-  CMakeLists\.txt:[0-9]* \(project\)
-This warning is for project developers\.  Use -Wno-author or -Wno-experimental
-to suppress it\.
@@ -1,6 +1,3 @@
-set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "25d6f6aa-be65-4692-b44e-87b23e96d4e1")
-
 cmake_minimum_required(VERSION 3.29)
 project(cxx_modules_import_std_shared CXX)

@@ -1,6 +1,3 @@
-set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "25d6f6aa-be65-4692-b44e-87b23e96d4e1")
-
 cmake_minimum_required(VERSION 3.29)
 project(cxx_modules_library CXX)

@@ -1,9 +0,0 @@
-CMake Warning \(experimental\) at .*/Modules/Compiler/CMakeCommonCompilerMacros\.cmake:[0-9]* \(cmake_language\):
-  CMake's support for `import std;` in C\+\+23 and newer is experimental\.  It
-  is meant only for experimentation and feedback to CMake developers\.
-Call Stack \(most recent call first\):
-  .*/Modules/CMakeDetermineCompilerSupport\.cmake:[0-9]* \(cmake_cxx_find_modules_json\)
-  .*/Modules/CMakeTestCXXCompiler\.cmake:[0-9]* \(CMAKE_DETERMINE_COMPILER_SUPPORT\)
-  CMakeLists\.txt:[0-9]* \(project\)
-This warning is for project developers\.  Use -Wno-author or -Wno-experimental
-to suppress it\.
@@ -1,9 +0,0 @@
-CMake Warning \(experimental\) at .*/Modules/Compiler/CMakeCommonCompilerMacros\.cmake:[0-9]* \(cmake_language\):
-  CMake's support for `import std;` in C\+\+23 and newer is experimental\.  It
-  is meant only for experimentation and feedback to CMake developers\.
-Call Stack \(most recent call first\):
-  .*/Modules/CMakeDetermineCompilerSupport\.cmake:[0-9]* \(cmake_cxx_find_modules_json\)
-  .*/Modules/CMakeTestCXXCompiler\.cmake:[0-9]* \(CMAKE_DETERMINE_COMPILER_SUPPORT\)
-  CMakeLists\.txt:[0-9]* \(project\)
-This warning is for project developers\.  Use -Wno-author or -Wno-experimental
-to suppress it\.
@@ -1,9 +0,0 @@
-CMake Warning \(experimental\) at .*/Modules/Compiler/CMakeCommonCompilerMacros\.cmake:[0-9]* \(cmake_language\):
-  CMake's support for `import std;` in C\+\+23 and newer is experimental\.  It
-  is meant only for experimentation and feedback to CMake developers\.
-Call Stack \(most recent call first\):
-  .*/Modules/CMakeDetermineCompilerSupport\.cmake:[0-9]* \(cmake_cxx_find_modules_json\)
-  .*/Modules/CMakeTestCXXCompiler\.cmake:[0-9]* \(CMAKE_DETERMINE_COMPILER_SUPPORT\)
-  CMakeLists\.txt:[0-9]* \(project\)
-This warning is for project developers\.  Use -Wno-author or -Wno-experimental
-to suppress it\.
@@ -1,9 +0,0 @@
-CMake Warning \(experimental\) at .*/Modules/Compiler/CMakeCommonCompilerMacros\.cmake:[0-9]* \(cmake_language\):
-  CMake's support for `import std;` in C\+\+23 and newer is experimental\.  It
-  is meant only for experimentation and feedback to CMake developers\.
-Call Stack \(most recent call first\):
-  .*/Modules/CMakeDetermineCompilerSupport\.cmake:[0-9]* \(cmake_cxx_find_modules_json\)
-  .*/Modules/CMakeTestCXXCompiler\.cmake:[0-9]* \(CMAKE_DETERMINE_COMPILER_SUPPORT\)
-  CMakeLists\.txt:[0-9]* \(project\)
-This warning is for project developers\.  Use -Wno-author or -Wno-experimental
-to suppress it\.
@@ -1,9 +0,0 @@
-CMake Warning \(experimental\) at .*/Modules/Compiler/CMakeCommonCompilerMacros\.cmake:[0-9]* \(cmake_language\):
-  CMake's support for `import std;` in C\+\+23 and newer is experimental\.  It
-  is meant only for experimentation and feedback to CMake developers\.
-Call Stack \(most recent call first\):
-  .*/Modules/CMakeDetermineCompilerSupport\.cmake:[0-9]* \(cmake_cxx_find_modules_json\)
-  .*/Modules/CMakeTestCXXCompiler\.cmake:[0-9]* \(CMAKE_DETERMINE_COMPILER_SUPPORT\)
-  CMakeLists\.txt:[0-9]* \(project\)
-This warning is for project developers\.  Use -Wno-author or -Wno-experimental
-to suppress it\.
@@ -1,6 +1,3 @@
-set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "25d6f6aa-be65-4692-b44e-87b23e96d4e1")
-
 cmake_minimum_required(VERSION 3.29)

 project(cxx_modules_import_std_transitive CXX)
@@ -1,6 +1,3 @@
-set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "25d6f6aa-be65-4692-b44e-87b23e96d4e1")
-
 cmake_minimum_required(VERSION 3.29)
 project(cxx_modules_import_std CXX)

@@ -28,17 +28,17 @@ foreach (consumer IN LISTS expected_consumers)

  file(READ "${depend_info_file}" depend_info_json)

-  # Extract linked-target-dirs array length and first element
+  # Extract linked-target-dirs.
  string(JSON linked_dirs_len LENGTH "${depend_info_json}" "linked-target-dirs")
  string(JSON linked_dirs GET "${depend_info_json}" "linked-target-dirs")

  if (consumer STREQUAL "consumer20")
-    set(expected_linked_tgt_regex "^importable\.dir$")
+    set(expected_linked_tgt_regex "^importable\\.dir$")
    set(expected_linked_tgt_desc "owning target dir for 'importable'")
    set(expected_linked_tgt_has_bmi 0)
  elseif (consumer STREQUAL "consumer23" OR
          consumer STREQUAL "consumer23flag")
-    set(expected_linked_tgt_regex "^importable@synth_[A-Za-z0-9_]+\.dir$")
+    set(expected_linked_tgt_regex "^importable@synth_[A-Za-z0-9_]+\\.dir$")
    set(expected_linked_tgt_desc "shared synthetic target dir for 'importable'")
    set(expected_linked_tgt_has_bmi 1)
  else ()
@@ -53,35 +53,40 @@ foreach (consumer IN LISTS expected_consumers)
    continue()
  endif ()

-  # For this test, expect exactly one linked target dir per consumer
-  if (NOT linked_dirs_len EQUAL 1)
+  set(importable_dirs "")
+  set(linked_dir "")
+  set(linked_tgt_name "")
+  foreach (idx RANGE "${linked_dirs_len}")
+    if (idx EQUAL linked_dirs_len)
+      break ()
+    endif ()
+    string(JSON candidate GET "${depend_info_json}" "linked-target-dirs" "${idx}")
+    if (RunCMake_GENERATOR_IS_MULTI_CONFIG)
+      cmake_path(GET candidate PARENT_PATH candidate_root)
+    else ()
+      set(candidate_root "${candidate}")
+    endif ()
+    cmake_path(GET candidate_root FILENAME candidate_name)
+    if (candidate_name MATCHES "^importable(@synth_[A-Za-z0-9_]+)?\\.dir$")
+      list(APPEND importable_dirs "${candidate}")
+      set(linked_dir "${candidate}")
+      set(linked_tgt_name "${candidate_name}")
+    endif ()
+  endforeach ()
+
+  list(LENGTH importable_dirs importable_dirs_len)
+  if (NOT importable_dirs_len EQUAL 1)
    list(APPEND RunCMake_TEST_FAILED
-      "Expected 1 linked-target-dir for '${consumer}' but found ${linked_dirs_len}: ${linked_dirs}")
-    continue()
+      "Expected exactly one 'importable' linked-target-dir for '${consumer}' but found ${importable_dirs_len}: ${linked_dirs}")
+    continue ()
  endif ()

-  string(JSON linked_dir GET "${depend_info_json}" "linked-target-dirs" 0)
-
-  if (RunCMake_GENERATOR_IS_MULTI_CONFIG)
-    cmake_path(GET linked_dir PARENT_PATH linked_tgt_root)
-  else ()
-    set(linked_tgt_root "${linked_dir}")
-  endif ()
-
-  cmake_path(GET linked_tgt_root FILENAME linked_tgt_name)
-
  if (NOT linked_tgt_name MATCHES "${expected_linked_tgt_regex}")
    list(APPEND RunCMake_TEST_FAILED
      "Consumer '${consumer}' should link to ${expected_linked_tgt_desc} but found ${linked_dir}")
    continue()
  endif ()

-  if (RunCMake_GENERATOR_IS_MULTI_CONFIG)
-    set(linked_output_dir "${linked_dir}/${config_dir}")
-  else ()
-    set(linked_output_dir "${linked_dir}")
-  endif ()
-
  # Verify the linked target dir exists and contains a BMI
  if (NOT EXISTS "${linked_dir}")
    list(APPEND RunCMake_TEST_FAILED
@@ -1,12 +0,0 @@
-CMake Warning \(experimental\) at [^
-]*/Modules/Compiler/CMakeCommonCompilerMacros\.cmake:[0-9]* \(cmake_language\):
-  CMake's support for `import std;` in C\+\+23 and newer is experimental\.  It
-  is meant only for experimentation and feedback to CMake developers\.
-Call Stack \(most recent call first\):
-  [^
-]*/Modules/CMakeDetermineCompilerSupport\.cmake:[0-9]* \(cmake_cxx_find_modules_json\)
-  [^
-]*/Modules/CMakeTestCXXCompiler\.cmake:[0-9]* \(CMAKE_DETERMINE_COMPILER_SUPPORT\)
-  CMakeLists\.txt:[0-9]* \(project\)
-This warning is for project developers\.  Use -Wno-author or -Wno-experimental
-to suppress it\.
@@ -1,6 +1,3 @@
-set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "25d6f6aa-be65-4692-b44e-87b23e96d4e1")
-
 cmake_minimum_required(VERSION 3.29)
 project(codemodel_v2_import_std CXX)

@@ -1,25 +0,0 @@
-cmake_diagnostic(SET CMD_EXPERIMENTAL IGNORE)
-
-set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "01234567-0123-0123-0123-0123456789ab")
-
-cmake_language(GET_EXPERIMENTAL_FEATURE_ENABLED
-  "CxxImportStd"
-  feature_present)
-
-if (NOT feature_present STREQUAL "FALSE")
-  message(FATAL_ERROR
-    "Expected the `CxxImportStd` feature to be disabled.")
-endif ()
-
-set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "25d6f6aa-be65-4692-b44e-87b23e96d4e1")
-
-cmake_language(GET_EXPERIMENTAL_FEATURE_ENABLED
-  "CxxImportStd"
-  feature_present)
-
-if (NOT feature_present STREQUAL "TRUE")
-  message(FATAL_ERROR
-    "Expected the `CxxImportStd` feature to be enabled.")
-endif ()
@@ -1,7 +0,0 @@
-^CMake Warning \(experimental\) at Experimental/CxxImportStd-set\.cmake:4 \(cmake_language\):
-  CMake's support for `import std;` in C\+\+23 and newer is experimental\.  It
-  is meant only for experimentation and feedback to CMake developers\.
-Call Stack \(most recent call first\):
-  CMakeLists\.txt:[0-9]+ \(include\)
-This warning is for project developers\.  Use -Wno-author or -Wno-experimental
-to suppress it\.$
@@ -1,11 +0,0 @@
-set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "25d6f6aa-be65-4692-b44e-87b23e96d4e1")
-
-cmake_language(GET_EXPERIMENTAL_FEATURE_ENABLED
-  "CxxImportStd"
-  feature_present)
-
-if (NOT feature_present STREQUAL "TRUE")
-  message(FATAL_ERROR
-    "Expected the `CxxImportStd` feature to be enabled.")
-endif ()
@@ -1,8 +0,0 @@
-cmake_language(GET_EXPERIMENTAL_FEATURE_ENABLED
-  "CxxImportStd"
-  feature_present)
-
-if (NOT feature_present STREQUAL "FALSE")
-  message(FATAL_ERROR
-    "Expected the `CxxImportStd` feature to be disabled.")
-endif ()
@@ -1,27 +0,0 @@
-^CMake Warning \(experimental\) at Experimental/CxxImportStd-wrong\.cmake:4 \(cmake_language\):
-  CMAKE_EXPERIMENTAL_CXX_IMPORT_STD is set to incorrect value
-
-    01234567-0123-0123-0123-0123456789ab
-
-  See 'Help/dev/experimental\.rst' in the source tree of this version of CMake
-  for documentation of the experimental feature and the corresponding
-  activation value\.  This project's code may require changes to work with
-  this CMake's version of the feature\.
-Call Stack \(most recent call first\):
-  CMakeLists\.txt:[0-9]+ \(include\)
-This warning is for project developers\.  Use -Wno-author or -Wno-experimental
-to suppress it\.
-+
-CMake Warning \(experimental\) at Experimental/CxxImportStd-wrong\.cmake:19 \(cmake_language\):
-  CMAKE_EXPERIMENTAL_CXX_IMPORT_STD is set to incorrect value
-
-    76543210-3210-3210-3210-ba9876543210
-
-  See 'Help/dev/experimental\.rst' in the source tree of this version of CMake
-  for documentation of the experimental feature and the corresponding
-  activation value\.  This project's code may require changes to work with
-  this CMake's version of the feature\.
-Call Stack \(most recent call first\):
-  CMakeLists\.txt:[0-9]+ \(include\)
-This warning is for project developers\.  Use -Wno-author or -Wno-experimental
-to suppress it\.$
@@ -1,21 +0,0 @@
-set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "01234567-0123-0123-0123-0123456789ab")
-
-cmake_language(GET_EXPERIMENTAL_FEATURE_ENABLED
-  "CxxImportStd"
-  feature_present)
-
-if (NOT feature_present STREQUAL "FALSE")
-  message(FATAL_ERROR
-    "Expected the `CxxImportStd` feature to be disabled.")
-endif ()
-
-# Test if/when warning is repeated.
-cmake_language(GET_EXPERIMENTAL_FEATURE_ENABLED
-  "CxxImportStd"
-  feature_present)
-set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "76543210-3210-3210-3210-ba9876543210")
-cmake_language(GET_EXPERIMENTAL_FEATURE_ENABLED
-  "CxxImportStd"
-  feature_present)
@@ -158,10 +158,6 @@ run_cmake_command(
    -P ${RunCMake_SOURCE_DIR}/get_message_log_level.cmake
  )

-run_cmake(Experimental/CxxImportStd-set)
-run_cmake(Experimental/CxxImportStd-unset)
-run_cmake(Experimental/CxxImportStd-wrong)
-run_cmake(Experimental/CxxImportStd-quiet)
 run_cmake(Experimental/ExportPackageDependencies-set)
 run_cmake(Experimental/ExportPackageDependencies-unset)
 run_cmake(Experimental/ExportPackageDependencies-wrong)