Merge topic 'import-std-refactor'

42d2d63235 c++modules: Copy props from BMI consumers more correctly
6d3e9d8220 c++modules: single import std target

Acked-by: Kitware Robot <kwrobot@kitware.com>
Tested-by: buildbot <buildbot@kitware.com>
Reviewed-by: Ben Boeckel <ben.boeckel@kitware.com>
Merge-request: !12193

Help/dev/experimental.rst

@@ -66,7 +66,7 @@ In order to activate support for ``import std`` in C++23 and newer targets,
 set
 
 * variable ``CMAKE_EXPERIMENTAL_CXX_IMPORT_STD`` to
-* value ``451f2fe2-a8a2-47c3-bc32-94786d8fc91b``.
+* value ``f35a9ac6-8463-4d38-8eec-5d6008153e7d``.
 
 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

Modules/CMakeDetermineCompilerSupport.cmake

@@ -158,7 +158,7 @@ function(cmake_determine_compiler_support lang)
     foreach(_cmake_import_std_version IN ITEMS 23 26)
       if(CMAKE_CXX${_cmake_import_std_version}_COMPILE_FEATURES)
         # Modules JSON covers all versions, otherwise rely on toolchain targets
-        if(CMAKE_CXX_STDLIB_MODULES_JSON OR (TARGET "__CMAKE:CXX${_cmake_import_std_version}"))
+        if(CMAKE_CXX_STDLIB_MODULES_JSON)
           list(APPEND CMAKE_CXX_COMPILER_IMPORT_STD ${_cmake_import_std_version})
         endif()
       endif()

Source/cmCxxModuleUsageEffects.cxx

@@ -12,6 +12,8 @@
 #include "cmGeneratorTarget.h"
 #include "cmListFileCache.h"
 #include "cmMakefile.h"
+#include "cmRange.h"
+#include "cmStringAlgorithms.h"
 #include "cmTarget.h"
 #include "cmValue.h"
 
@@ -96,10 +98,17 @@ FlagFilter GetFlagFilter(cmGeneratorTarget const* gt)
   return filter;
 }
 
+void AppendUsage(std::string& usageHashInput, std::string const& entry)
+{
+  usageHashInput += entry;
+  usageHashInput.push_back('\0');
+}
+
 template <typename Range>
 void AppendUsageEntries(std::string& usageHashInput, Range const& entries)
 {
   std::vector<std::string> entryValues;
+  entryValues.reserve(entries.size());
   for (auto const& entry : entries) {
     entryValues.push_back(entry.Value);
   }
@@ -114,7 +123,8 @@ void AppendUsageEntries(std::string& usageHashInput, Range const& entries)
 }
 }
 
-cmCxxModuleUsageEffects::cmCxxModuleUsageEffects(cmGeneratorTarget const* gt)
+cmCxxModuleUsageEffects::cmCxxModuleUsageEffects(cmGeneratorTarget const* gt,
+                                                 std::string const& config)
 {
   auto const* tgt = gt->Target;
   auto const filter = GetFlagFilter(gt);
@@ -128,11 +138,25 @@ cmCxxModuleUsageEffects::cmCxxModuleUsageEffects(cmGeneratorTarget const* gt)
       tgt->GetImportedCxxModulesCompileOptionsEntries().filter(
         [&](const BT<std::string>& flag) { return !filter(flag.Value); }));
   } else {
-    AppendUsageEntries(usageHashInput, tgt->GetCompileFeaturesEntries());
-    AppendUsageEntries(
+    AppendUsageEntries(usageHashInput,
+                       cmMakeRange(gt->GetCompileOptions(config, "CXX"))
+                         .filter([&](const BT<std::string>& flag) {
+                           return !filter(flag.Value);
+                         }));
+
+    cmValue langStd = gt->GetLanguageStandard("CXX", config);
+    if (!langStd) {
+      langStd = gt->Makefile->GetDefinition("CMAKE_CXX_STANDARD_DEFAULT");
+    }
+    AppendUsage(usageHashInput,
+                cmStrCat("CXX_STANDARD:", langStd ? *langStd : "20"));
+    AppendUsage(
       usageHashInput,
-      tgt->GetCompileOptionsEntries().filter(
-        [&](const BT<std::string>& flag) { return !filter(flag.Value); }));
+      cmStrCat("CXX_EXTENSIONS:", *gt->GetLanguageExtensions("CXX")));
+    AppendUsage(
+      usageHashInput,
+      cmStrCat("CXX_STANDARD_REQUIRED:",
+               gt->GetLanguageStandardRequired("CXX") ? "TRUE" : "FALSE"));
   }
 
   cmCryptoHash hasher(cmCryptoHash::AlgoSHA3_512);

Source/cmCxxModuleUsageEffects.h

@@ -11,7 +11,8 @@ class cmGeneratorTarget;
 class cmCxxModuleUsageEffects
 {
 public:
-  cmCxxModuleUsageEffects(cmGeneratorTarget const* gt);
+  cmCxxModuleUsageEffects(cmGeneratorTarget const* gt,
+                          std::string const& config);
   std::string const& GetHash() const;
 
 private:

Source/cmExperimental.cxx

@@ -31,7 +31,7 @@ cmExperimental::FeatureData const LookupTable[] = {
     cmExperimental::TryCompileCondition::Always },
   // CxxImportStd
   { "CxxImportStd",
-    "451f2fe2-a8a2-47c3-bc32-94786d8fc91b",
+    "f35a9ac6-8463-4d38-8eec-5d6008153e7d",
     "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.",

Source/cmGeneratorTarget.cxx

@@ -5330,8 +5330,6 @@ bool cmGeneratorTarget::IsNullImpliedByLinkLibraries(
 namespace {
 bool CreateCxxStdlibTarget(cmMakefile* makefile, cmLocalGenerator* lg,
                            std::string const& targetName,
-                           std::string const& cxxTargetName,
-                           std::string const& stdLevel,
                            std::vector<std::string> const& configs)
 {
 #ifndef CMAKE_BOOTSTRAP
@@ -5377,20 +5375,17 @@ bool CreateCxxStdlibTarget(cmMakefile* makefile, cmLocalGenerator* lg,
     metadata = std::move(*parseResult.Meta);
   }
 
-  auto const localTargetName = cmStrCat("__cmake_cxx_std_", stdLevel);
-  cmStandardLevelResolver standardResolver(makefile);
   auto* stdlibTgt = makefile->AddLibrary(
-    localTargetName, cmStateEnums::STATIC_LIBRARY, {}, true);
+    "@cmake_cxx_std", cmStateEnums::STATIC_LIBRARY, {}, true);
   cmCxxModuleMetadata::PopulateTarget(*stdlibTgt, *metadata, configs);
-  standardResolver.AddRequiredTargetFeature(stdlibTgt,
-                                            cmStrCat("cxx_std_", stdLevel));
+  cmStandardLevelResolver standardResolver(makefile);
+  standardResolver.AddRequiredTargetFeature(stdlibTgt, "cxx_std_20");
   auto gt = cm::make_unique<cmGeneratorTarget>(stdlibTgt, lg);
   for (auto const& config : configs) {
     gt->ComputeCompileFeatures(config);
   }
 
   lg->AddGeneratorTarget(std::move(gt));
-  makefile->AddAlias(cxxTargetName, localTargetName);
 
 #endif // CMAKE_BOOTSTRAP
 
@@ -5398,11 +5393,8 @@ bool CreateCxxStdlibTarget(cmMakefile* makefile, cmLocalGenerator* lg,
 }
 } // namespace
 
-bool cmGeneratorTarget::ApplyCXXStdTargets()
+bool cmGeneratorTarget::ApplyCXXStdTarget()
 {
-  cmStandardLevelResolver standardResolver(this->Makefile);
-  cmStandardLevel const cxxStd23 =
-    *standardResolver.LanguageStandardLevel("CXX", "23");
   std::vector<std::string> const& configs =
     this->Makefile->GetGeneratorConfigs(cmMakefile::IncludeEmptyConfig);
   auto std_prop = this->GetProperty("CXX_MODULE_STD");
@@ -5466,35 +5458,18 @@ bool cmGeneratorTarget::ApplyCXXStdTargets()
     return true;
   }
 
-  for (auto const& config : configs) {
-    if (this->HaveCxxModuleSupport(config) != Cxx20SupportLevel::Supported) {
-      continue;
-    }
-
-    cm::optional<cmStandardLevel> explicitLevel =
-      this->GetExplicitStandardLevel("CXX", config);
-    if (!explicitLevel || *explicitLevel < cxxStd23) {
-      continue;
-    }
-
-    auto const stdLevel =
-      standardResolver.GetLevelString("CXX", *explicitLevel);
-    auto const cxxTargetName = cmStrCat("__CMAKE::CXX", stdLevel);
-
-    // Create the __CMAKE::CXX## target if it doesn't already exist
-    if (!this->Makefile->FindTargetToUse(cxxTargetName) &&
-        !CreateCxxStdlibTarget(this->Makefile, this->LocalGenerator,
-                               this->GetName(), cxxTargetName, stdLevel,
-                               configs)) {
-      return false;
-    }
-
-    this->Target->AppendProperty(
-      "LINK_LIBRARIES",
-      cmStrCat("$<BUILD_LOCAL_INTERFACE:$<$<CONFIG:", config,
-               ">:", cxxTargetName, ">>"));
+  // Create the single, unreferenceable import std target if it doesn't
+  // already exist. BMI compatibility handles per-consumer standard level
+  // differences by creating synthetic targets as needed.
+  if (!this->Makefile->FindTargetToUse("@cmake_cxx_std") &&
+      !CreateCxxStdlibTarget(this->Makefile, this->LocalGenerator,
+                             this->GetName(), configs)) {
+    return false;
   }
 
+  this->Target->AppendProperty("LINK_LIBRARIES",
+                               "$<BUILD_LOCAL_INTERFACE:@cmake_cxx_std>");
+
   // Check the experimental feature here. A toolchain may have
   // skipped the check in the toolchain preparation logic.
   if (!cmExperimental::HasSupportEnabled(
@@ -5510,21 +5485,26 @@ bool cmGeneratorTarget::ApplyCXXStdTargets()
   return true;
 }
 
-cmCxxModuleUsageEffects const& cmGeneratorTarget::GetCxxModuleUsageEffects()
-  const
+cmCxxModuleUsageEffects const& cmGeneratorTarget::GetCxxModuleUsageEffects(
+  std::string const& config) const
 {
-  if (!this->CxxModuleUsageEffects) {
-    this->CxxModuleUsageEffects.emplace(this);
+
+  auto iter = this->CxxModuleUsageEffects.find(config);
+  if (iter == this->CxxModuleUsageEffects.end()) {
+    auto result = this->CxxModuleUsageEffects.emplace(
+      std::pair<std::string, cmCxxModuleUsageEffects>{
+        config, cmCxxModuleUsageEffects(this, config) });
+    return result.first->second;
   }
 
-  return *this->CxxModuleUsageEffects;
+  return iter->second;
 }
 
 cmGeneratorTarget const* cmGeneratorTarget::GetTargetForCxxModules(
   std::string const& config, cmGeneratorTarget const& bmiConsumer) const
 {
-  auto const& consumingUsage = bmiConsumer.GetCxxModuleUsageEffects();
-  auto const& owningUsage = this->GetCxxModuleUsageEffects();
+  auto const& consumingUsage = bmiConsumer.GetCxxModuleUsageEffects(config);
+  auto const& owningUsage = this->GetCxxModuleUsageEffects(config);
   if (consumingUsage.GetHash() == owningUsage.GetHash()) {
     if (this->IsImported()) {
       return this->GetCxxSyntheticTarget(config, *this);
@@ -5538,7 +5518,8 @@ cmGeneratorTarget const* cmGeneratorTarget::GetTargetForCxxModules(
 cmGeneratorTarget const* cmGeneratorTarget::GetCxxSyntheticTarget(
   std::string const& config, cmGeneratorTarget const& bmiConsumer) const
 {
-  auto const& usageHash = bmiConsumer.GetCxxModuleUsageEffects().GetHash();
+  auto const& usageHash =
+    bmiConsumer.GetCxxModuleUsageEffects(config).GetHash();
   auto cached = this->SynthCxxTargets.find(usageHash);
   if (cached != this->SynthCxxTargets.end()) {
     return cached->second;
@@ -5577,8 +5558,10 @@ cmGeneratorTarget const* cmGeneratorTarget::GetCxxSyntheticTarget(
     }
   }
 
-  // Copy properties which effect consumer compatibility
-  tgt->CopyUsageEffects(bmiConsumer.Target);
+  // Copy properties which effect consumer compatibility.
+  // CopyUsageEffects now uses the consumer's full (own + transitive)
+  // compile features and options.
+  tgt->CopyUsageEffects(&bmiConsumer, config);
 
   // Copy properties which don't effect consumer compatibility
   tgt->CopyCxxModulesEntries(model);
@@ -5599,9 +5582,9 @@ cmGeneratorTarget const* cmGeneratorTarget::GetCxxSyntheticTarget(
   for (auto const& innerConfig : allConfigs) {
     gtp->ComputeCompileFeatures(innerConfig);
   }
-  // See `cmGlobalGenerator::ApplyCXXStdTargets` in
+  // See `cmGlobalGenerator::ApplyCXXStdTarget` in
   // `cmGlobalGenerator::Compute` for non-synthetic target resolutions.
-  if (!gtp->ApplyCXXStdTargets()) {
+  if (!gtp->ApplyCXXStdTarget()) {
     return nullptr;
   }
 

Source/cmGeneratorTarget.h

@@ -1146,8 +1146,9 @@ public:
 
   std::string GetImportedXcFrameworkPath(std::string const& config) const;
 
-  bool ApplyCXXStdTargets();
-  cmCxxModuleUsageEffects const& GetCxxModuleUsageEffects() const;
+  bool ApplyCXXStdTarget();
+  cmCxxModuleUsageEffects const& GetCxxModuleUsageEffects(
+    std::string const& config) const;
   cmGeneratorTarget const* GetTargetForCxxModules(
     std::string const& config, cmGeneratorTarget const& bmiConsumer) const;
   bool DiscoverSyntheticTargets(
@@ -1617,7 +1618,7 @@ private:
     std::map<cmSourceFile const*, ClassifiedFlags> SourceFlags;
   };
   mutable std::map<std::string, cmGeneratorTarget*> SynthCxxTargets;
-  mutable cm::optional<cmCxxModuleUsageEffects> CxxModuleUsageEffects;
+  mutable std::map<std::string, cmCxxModuleUsageEffects> CxxModuleUsageEffects;
   mutable std::map<std::string, InfoByConfig> Configs;
   std::unique_ptr<cmGeneratorFileSets> FileSets;
   bool PchReused = false;

Source/cmGlobalGenerator.cxx

@@ -1677,13 +1677,12 @@ bool cmGlobalGenerator::Compute()
     }
   }
 
-  // We now have all targets set up and std levels constructed. Add
-  // `__CMAKE::CXX*` targets as link dependencies to all targets which need
-  // them.
+  // We now have all targets set up. Add the `@cmake_cxx_std` target as a link
+  // dependency to all targets which need it.
   //
   // Synthetic targets performed this inside of
   // `cmLocalGenerator::DiscoverSyntheticTargets`
-  if (!this->ApplyCXXStdTargets()) {
+  if (!this->ApplyCXXStdTarget()) {
     return false;
   }
 
@@ -2002,12 +2001,12 @@ void cmGlobalGenerator::ComputeTargetOrder(cmGeneratorTarget const* gt,
   entry->second = index++;
 }
 
-bool cmGlobalGenerator::ApplyCXXStdTargets()
+bool cmGlobalGenerator::ApplyCXXStdTarget()
 {
   for (auto const& gen : this->LocalGenerators) {
 
-    // tgt->ApplyCXXStd can create targets itself, so we need iterators which
-    // won't be invalidated by that target creation
+    // tgt->ApplyCXXStdTarget can create a target itself, so we need iterators
+    // which won't be invalidated by that target creation
     auto const& genTgts = gen->GetGeneratorTargets();
     std::vector<cmGeneratorTarget*> existingTgts;
     existingTgts.reserve(genTgts.size());
@@ -2016,7 +2015,7 @@ bool cmGlobalGenerator::ApplyCXXStdTargets()
     }
 
     for (auto const& tgt : existingTgts) {
-      if (!tgt->ApplyCXXStdTargets()) {
+      if (!tgt->ApplyCXXStdTarget()) {
         return false;
       }
     }

Source/cmGlobalGenerator.h

@@ -800,7 +800,7 @@ protected:
 
   virtual bool CheckALLOW_DUPLICATE_CUSTOM_TARGETS() const;
 
-  bool ApplyCXXStdTargets();
+  bool ApplyCXXStdTarget();
   bool DiscoverSyntheticTargets();
 
   bool AddHeaderSetVerification();

Source/cmTarget.cxx

@@ -25,6 +25,7 @@
 #include "cmFileSetMetadata.h"
 #include "cmFindPackageStack.h"
 #include "cmGeneratorExpression.h"
+#include "cmGeneratorTarget.h"
 #include "cmGlobalGenerator.h"
 #include "cmList.h"
 #include "cmListFileCache.h"
@@ -595,6 +596,16 @@ TargetProperty const StaticTargetProperties[] = {
 #undef COMMON_LANGUAGE_PROPERTIES
 #undef IC
 #undef R
+
+cmValue copyProperty(cmTarget const* src, cmTarget* dst,
+                     std::string const& prop)
+{
+  cmValue value = src->GetProperty(prop);
+  // Always set the property; it may have been explicitly unset.
+  dst->SetProperty(prop, value);
+  return value;
+};
+
 }
 
 class cmTargetInternals
@@ -1739,12 +1750,16 @@ cmBTStringRange cmTarget::GetLinkInterfaceDirectExcludeEntries() const
   return cmMakeRange(this->impl->InterfaceLinkLibrariesDirectExclude.Entries);
 }
 
-void cmTarget::CopyUsageEffects(cmTarget const* tgt)
+void cmTarget::CopyUsageEffects(cmGeneratorTarget const* gt,
+                                std::string const& config)
 {
   // Normal targets cannot be the target of a copy.
   assert(!this->IsNormal());
   // Imported targets cannot be the target of a copy.
   assert(!this->IsImported());
+
+  auto const* tgt = gt->Target;
+
   // Only imported or normal targets can be the source of a copy.
   assert(tgt->IsImported() || tgt->IsNormal());
 
@@ -1758,10 +1773,17 @@ void cmTarget::CopyUsageEffects(cmTarget const* tgt)
       cmMakeRange(tgt->impl->ImportedCxxModulesCompileOptions.Entries));
   } else {
     this->impl->CompileFeatures.CopyFromEntries(
-      cmMakeRange(tgt->impl->CompileFeatures.Entries));
+      cmMakeRange(gt->GetCompileFeatures(config)));
     this->impl->CompileOptions.CopyFromEntries(
-      cmMakeRange(tgt->impl->CompileOptions.Entries));
+      cmMakeRange(gt->GetCompileOptions(config, "CXX")));
   }
+
+  cmValue langStd = gt->GetLanguageStandard("CXX", config);
+  if (langStd) {
+    this->SetProperty("CXX_STANDARD", *langStd);
+  }
+  copyProperty(tgt, this, "CXX_EXTENSIONS");
+  copyProperty(tgt, this, "CXX_STANDARD_REQUIRED");
 }
 
 void cmTarget::CopyPolicyStatuses(cmTarget const* tgt)
@@ -1857,9 +1879,6 @@ void cmTarget::CopyCxxModulesProperties(cmTarget const* tgt)
     // -- Language
     // ---- C++
     "CXX_COMPILER_LAUNCHER",
-    "CXX_STANDARD",
-    "CXX_STANDARD_REQUIRED",
-    "CXX_EXTENSIONS",
     "CXX_VISIBILITY_PRESET",
     "CXX_MODULE_STD",
 
@@ -1896,15 +1915,8 @@ void cmTarget::CopyCxxModulesProperties(cmTarget const* tgt)
     "SYSTEM",
   };
 
-  auto copyProperty = [this, tgt](std::string const& prop) -> cmValue {
-    cmValue value = tgt->GetProperty(prop);
-    // Always set the property; it may have been explicitly unset.
-    this->SetProperty(prop, value);
-    return value;
-  };
-
   for (auto const& prop : propertiesToCopy) {
-    copyProperty(prop);
+    copyProperty(tgt, this, prop);
   }
 
   static cm::static_string_view const perConfigPropertiesToCopy[] = {
@@ -1919,12 +1931,13 @@ void cmTarget::CopyCxxModulesProperties(cmTarget const* tgt)
   for (std::string const& configName : configNames) {
     std::string configUpper = cmSystemTools::UpperCase(configName);
     for (auto const& perConfigProp : perConfigPropertiesToCopy) {
-      copyProperty(cmStrCat(perConfigProp, configUpper));
+      copyProperty(tgt, this, cmStrCat(perConfigProp, configUpper));
     }
   }
 
   if (this->GetGlobalGenerator()->IsXcode()) {
-    cmValue xcodeGenerateScheme = copyProperty("XCODE_GENERATE_SCHEME");
+    cmValue xcodeGenerateScheme =
+      copyProperty(tgt, this, "XCODE_GENERATE_SCHEME");
 
     // TODO: Make sure these show up on the imported target in the first place
     // XCODE_ATTRIBUTE_???
@@ -1954,7 +1967,7 @@ void cmTarget::CopyCxxModulesProperties(cmTarget const* tgt)
       };
 
       for (auto const& xcodeProperty : xcodeSchemePropertiesToCopy) {
-        copyProperty(xcodeProperty);
+        copyProperty(tgt, this, xcodeProperty);
       }
 #endif
     }

Source/cmTarget.h

@@ -32,6 +32,7 @@ enum class Visibility;
 class cmCustomCommand;
 class cmFileSet;
 class cmFindPackageStack;
+class cmGeneratorTarget;
 class cmGlobalGenerator;
 class cmInstallTargetGenerator;
 class cmMakefile;
@@ -327,7 +328,8 @@ public:
   cmBTStringRange GetLinkInterfaceDirectEntries() const;
   cmBTStringRange GetLinkInterfaceDirectExcludeEntries() const;
 
-  void CopyUsageEffects(cmTarget const* tgt);
+  void CopyUsageEffects(cmGeneratorTarget const* gt,
+                        std::string const& config);
   void CopyPolicyStatuses(cmTarget const* tgt);
   void CopyCxxModulesEntries(cmTarget const* tgt);
   void CopyCxxModulesProperties(cmTarget const* tgt);

Tests/RunCMake/CXXModules/CMP0155-NEW.cmake

@@ -1,6 +1,3 @@
-# Block making C++ `import std` targets.
-add_library(__CMAKE::CXX23 IMPORTED INTERFACE)
-
 enable_language(CXX)
 unset(CMAKE_CXX_SCANDEP_SOURCE)
 

Tests/RunCMake/CXXModules/CMP0155-OLD.cmake

@@ -1,6 +1,3 @@
-# Block making C++ `import std` targets.
-add_library(__CMAKE::CXX23 IMPORTED INTERFACE)
-
 enable_language(CXX)
 unset(CMAKE_CXX_SCANDEP_SOURCE)
 

Tests/RunCMake/CXXModules/ImplicitCXX20.cmake

@@ -1,9 +1,6 @@
 # Enable scanning by default for targets that explicitly use C++ 20.
 cmake_policy(SET CMP0155 NEW)
 
-# Block making C++ `import std` targets.
-add_library(__CMAKE::CXX23 IMPORTED INTERFACE)
-
 # Force CMAKE_CXX_STANDARD_DEFAULT to be C++ 20.
 set(ENV{CXXFLAGS} "$ENV{CXXFLAGS} ${CMAKE_CXX20_STANDARD_COMPILE_OPTION}")
 enable_language(CXX)

Tests/RunCMake/CXXModules/Inspect.cmake

@@ -15,22 +15,6 @@ if (CMAKE_CXX_FLAGS MATCHES "-std=")
   set(forced_cxx_standard 1)
 endif ()
 
-macro (cxx_check_import_std version)
-  set(have_cxx${version}_import_std 0)
-  if ("${version}" IN_LIST CMAKE_CXX_COMPILER_IMPORT_STD)
-    set(have_cxx${version}_import_std 1)
-  endif ()
-
-  if (TARGET "__CMAKE:CXX${version}" AND NOT have_cxx${version}_import_std)
-    message(FATAL_ERROR
-      "The toolchain's C++${version} target exists, but the user variable does "
-      "not indicate it.")
-  endif ()
-endmacro ()
-
-cxx_check_import_std(23)
-cxx_check_import_std(26)
-
 # Forward information about the C++ compile features.
 string(APPEND info "\
 set(CMAKE_CXX_COMPILE_FEATURES \"${CMAKE_CXX_COMPILE_FEATURES}\")

Tests/RunCMake/CXXModules/NoCXX20.cmake

@@ -1,6 +1,3 @@
-# Block making C++ `import std` targets.
-add_library(__CMAKE::CXX23 IMPORTED INTERFACE)
-
 enable_language(CXX)
 
 add_library(nocxx20)

Tests/RunCMake/CXXModules/NoScanningVariable.cmake

@@ -1,9 +1,6 @@
 # Enable scanning by default for targets that explicitly use C++ 20.
 cmake_policy(SET CMP0155 NEW)
 
-# Block making C++ `import std` targets.
-add_library(__CMAKE::CXX23 IMPORTED INTERFACE)
-
 enable_language(CXX)
 
 # Hide any real scanning rule that may be available.

Tests/RunCMake/CXXModulesCompile/depchain-mods-json-file-rebuild-check.cmake

@@ -2,26 +2,7 @@ file(GLOB synth_dirs
   "${RunCMake_TEST_BINARY_DIR}/CMakeFiles/depchain_with_modules_json_file@synth_*.dir")
 
 list(LENGTH synth_dirs synth_dirs_len)
-if (NOT synth_dirs_len EQUAL 1)
+if (NOT synth_dirs_len EQUAL 0)
   list(APPEND RunCMake_TEST_FAILED
-    "Expected exactly one synthetic target for consuming 'depchain_with_modules_json_file' but found ${synth_dirs_len}: ${synth_dirs}")
-endif ()
-
-list(GET synth_dirs 0 synth_dir)
-
-if (RunCMake_GENERATOR_IS_MULTI_CONFIG)
-  set(dep_modules_json_path "CMakeFiles/depchain_modules_json_file.dir/Debug/CXX.dd")
-  set(modules_json_path "${synth_dir}/Debug/CXXModules.json")
-else ()
-  set(dep_modules_json_path "CMakeFiles/depchain_modules_json_file.dir/CXX.dd")
-  set(modules_json_path "${synth_dir}/CXXModules.json")
-endif ()
-
-
-if ("${modules_json_path}" IS_NEWER_THAN "${RunCMake_TEST_BINARY_DIR}/${dep_modules_json_path}")
-  cmake_path(RELATIVE_PATH modules_json_path
-    BASE_DIRECTORY "${RunCMake_TEST_BINARY_DIR}")
-
-  list(APPEND RunCMake_TEST_FAILED
-    "Object '${dep_modules_json_path}' should have recompiled if '${modules_json_path}' changed.")
+    "Expected no synthetic targets for consuming 'depchain_with_modules_json_file' but found ${synth_dirs_len}: ${synth_dirs}")
 endif ()

Tests/RunCMake/CXXModulesCompile/expect/exp-builddb-imped-all-multi.json

@@ -275,9 +275,9 @@
             "-Dfrom_cmake_cxx_flags",
             "-Dfrom_cmake_cxx_<CONFIG_LOWER>_flags",
             "<CXX20_OPTION>",
-            "-Ddep_interface_option",
             "-Dtarget_interface_option",
             "-Dtarget_public_option",
+            "-Ddep_interface_option",
             "PATH:-Ddepflag=\"CMakeFiles/CXXModules__export_build_database@synth_0.dir<CONFIG_DIR>/.d\"",
             "REGEX:<BMI_ONLY_FLAG>",
             "PATH:<OUTPUT_FLAG>CMakeFiles/CXXModules__export_build_database@synth_0.dir<CONFIG_DIR>/",
@@ -299,9 +299,9 @@
             "-Dfrom_cmake_cxx_flags",
             "-Dfrom_cmake_cxx_<CONFIG_LOWER>_flags",
             "<CXX20_OPTION>",
-            "-Ddep_interface_option",
             "-Dtarget_interface_option",
-            "-Dtarget_public_option"
+            "-Dtarget_public_option",
+            "-Ddep_interface_option"
           ],
           "local-arguments": [
             "-D_MBCS",
@@ -318,9 +318,9 @@
             "-Dfrom_cmake_cxx_flags",
             "-Dfrom_cmake_cxx_<CONFIG_LOWER>_flags",
             "<CXX20_OPTION>",
-            "-Ddep_interface_option",
             "-Dtarget_interface_option",
-            "-Dtarget_public_option"
+            "-Dtarget_public_option",
+            "-Ddep_interface_option"
           ],
           "private": false,
           "provides": {
@@ -354,9 +354,9 @@
             "-Dfrom_cmake_cxx_flags",
             "-Dfrom_cmake_cxx_<CONFIG_OTHER_LOWER>_flags",
             "<CXX20_OPTION>",
-            "-Ddep_interface_option",
             "-Dtarget_interface_option",
             "-Dtarget_public_option",
+            "-Ddep_interface_option",
             "PATH:-Ddepflag=\"CMakeFiles/CXXModules__export_build_database@synth_0.dir<CONFIG_OTHER_DIR>/.d\"",
             "REGEX:<BMI_ONLY_FLAG>",
             "PATH:<OUTPUT_FLAG>CMakeFiles/CXXModules__export_build_database@synth_0.dir<CONFIG_OTHER_DIR>/",
@@ -378,9 +378,9 @@
             "-Dfrom_cmake_cxx_flags",
             "-Dfrom_cmake_cxx_<CONFIG_OTHER_LOWER>_flags",
             "<CXX20_OPTION>",
-            "-Ddep_interface_option",
             "-Dtarget_interface_option",
-            "-Dtarget_public_option"
+            "-Dtarget_public_option",
+            "-Ddep_interface_option"
           ],
           "local-arguments": [
             "-D_MBCS",
@@ -397,9 +397,9 @@
             "-Dfrom_cmake_cxx_flags",
             "-Dfrom_cmake_cxx_<CONFIG_OTHER_LOWER>_flags",
             "<CXX20_OPTION>",
-            "-Ddep_interface_option",
             "-Dtarget_interface_option",
-            "-Dtarget_public_option"
+            "-Dtarget_public_option",
+            "-Ddep_interface_option"
           ],
           "private": false,
           "provides": {
@@ -436,8 +436,8 @@
             "-Dfrom_compile_options",
             "-Dtarget_private_option",
             "-Dtarget_public_option",
-            "-Ddep_interface_option",
             "-Dtarget_interface_option",
+            "-Ddep_interface_option",
             "PATH:-Ddepflag=\"CMakeFiles/CXXModules__export_build_database@synth_1.dir<CONFIG_DIR>/.d\"",
             "REGEX:<BMI_ONLY_FLAG>",
             "PATH:<OUTPUT_FLAG>CMakeFiles/CXXModules__export_build_database@synth_1.dir<CONFIG_DIR>/",
@@ -462,8 +462,8 @@
             "-Dfrom_compile_options",
             "-Dtarget_private_option",
             "-Dtarget_public_option",
-            "-Ddep_interface_option",
-            "-Dtarget_interface_option"
+            "-Dtarget_interface_option",
+            "-Ddep_interface_option"
           ],
           "local-arguments": [
             "-D_MBCS",
@@ -483,8 +483,8 @@
             "-Dfrom_compile_options",
             "-Dtarget_private_option",
             "-Dtarget_public_option",
-            "-Ddep_interface_option",
-            "-Dtarget_interface_option"
+            "-Dtarget_interface_option",
+            "-Ddep_interface_option"
           ],
           "private": false,
           "provides": {
@@ -521,8 +521,8 @@
             "-Dfrom_compile_options",
             "-Dtarget_private_option",
             "-Dtarget_public_option",
-            "-Ddep_interface_option",
             "-Dtarget_interface_option",
+            "-Ddep_interface_option",
             "PATH:-Ddepflag=\"CMakeFiles/CXXModules__export_build_database@synth_1.dir<CONFIG_OTHER_DIR>/.d\"",
             "REGEX:<BMI_ONLY_FLAG>",
             "PATH:<OUTPUT_FLAG>CMakeFiles/CXXModules__export_build_database@synth_1.dir<CONFIG_OTHER_DIR>/",
@@ -547,8 +547,8 @@
             "-Dfrom_compile_options",
             "-Dtarget_private_option",
             "-Dtarget_public_option",
-            "-Ddep_interface_option",
-            "-Dtarget_interface_option"
+            "-Dtarget_interface_option",
+            "-Ddep_interface_option"
           ],
           "local-arguments": [
             "-D_MBCS",
@@ -568,8 +568,8 @@
             "-Dfrom_compile_options",
             "-Dtarget_private_option",
             "-Dtarget_public_option",
-            "-Ddep_interface_option",
-            "-Dtarget_interface_option"
+            "-Dtarget_interface_option",
+            "-Ddep_interface_option"
           ],
           "private": false,
           "provides": {

Tests/RunCMake/CXXModulesCompile/expect/exp-builddb-imped-all.json

@@ -149,9 +149,9 @@
             "-Dfrom_cmake_cxx_flags",
             "-Dfrom_cmake_cxx_<CONFIG_LOWER>_flags",
             "<CXX20_OPTION>",
-            "-Ddep_interface_option",
             "-Dtarget_interface_option",
             "-Dtarget_public_option",
+            "-Ddep_interface_option",
             "PATH:-Ddepflag=\"CMakeFiles/CXXModules__export_build_database@synth_0.dir<CONFIG_DIR>/.d\"",
             "REGEX:<BMI_ONLY_FLAG>",
             "PATH:<OUTPUT_FLAG>CMakeFiles/CXXModules__export_build_database@synth_0.dir<CONFIG_DIR>/",
@@ -173,9 +173,9 @@
             "-Dfrom_cmake_cxx_flags",
             "-Dfrom_cmake_cxx_<CONFIG_LOWER>_flags",
             "<CXX20_OPTION>",
-            "-Ddep_interface_option",
             "-Dtarget_interface_option",
-            "-Dtarget_public_option"
+            "-Dtarget_public_option",
+            "-Ddep_interface_option"
           ],
           "local-arguments": [
             "-D_MBCS",
@@ -192,9 +192,9 @@
             "-Dfrom_cmake_cxx_flags",
             "-Dfrom_cmake_cxx_<CONFIG_LOWER>_flags",
             "<CXX20_OPTION>",
-            "-Ddep_interface_option",
             "-Dtarget_interface_option",
-            "-Dtarget_public_option"
+            "-Dtarget_public_option",
+            "-Ddep_interface_option"
           ],
           "private": false,
           "provides": {
@@ -231,8 +231,8 @@
             "-Dfrom_compile_options",
             "-Dtarget_private_option",
             "-Dtarget_public_option",
-            "-Ddep_interface_option",
             "-Dtarget_interface_option",
+            "-Ddep_interface_option",
             "PATH:-Ddepflag=\"CMakeFiles/CXXModules__export_build_database@synth_1.dir<CONFIG_DIR>/.d\"",
             "REGEX:<BMI_ONLY_FLAG>",
             "PATH:<OUTPUT_FLAG>CMakeFiles/CXXModules__export_build_database@synth_1.dir<CONFIG_DIR>/",
@@ -257,8 +257,8 @@
             "-Dfrom_compile_options",
             "-Dtarget_private_option",
             "-Dtarget_public_option",
-            "-Ddep_interface_option",
-            "-Dtarget_interface_option"
+            "-Dtarget_interface_option",
+            "-Ddep_interface_option"
           ],
           "local-arguments": [
             "-D_MBCS",
@@ -278,8 +278,8 @@
             "-Dfrom_compile_options",
             "-Dtarget_private_option",
             "-Dtarget_public_option",
-            "-Ddep_interface_option",
-            "-Dtarget_interface_option"
+            "-Dtarget_interface_option",
+            "-Ddep_interface_option"
           ],
           "private": false,
           "provides": {

Tests/RunCMake/CXXModulesCompile/expect/exp-builddb-imped-config.json

@@ -149,9 +149,9 @@
             "-Dfrom_cmake_cxx_flags",
             "-Dfrom_cmake_cxx_<CONFIG_LOWER>_flags",
             "<CXX20_OPTION>",
-            "-Ddep_interface_option",
             "-Dtarget_interface_option",
             "-Dtarget_public_option",
+            "-Ddep_interface_option",
             "PATH:-Ddepflag=\"CMakeFiles/CXXModules__export_build_database@synth_0.dir<CONFIG_DIR>/.d\"",
             "REGEX:<BMI_ONLY_FLAG>",
             "PATH:<OUTPUT_FLAG>CMakeFiles/CXXModules__export_build_database@synth_0.dir<CONFIG_DIR>/",
@@ -173,9 +173,9 @@
             "-Dfrom_cmake_cxx_flags",
             "-Dfrom_cmake_cxx_<CONFIG_LOWER>_flags",
             "<CXX20_OPTION>",
-            "-Ddep_interface_option",
             "-Dtarget_interface_option",
-            "-Dtarget_public_option"
+            "-Dtarget_public_option",
+            "-Ddep_interface_option"
           ],
           "local-arguments": [
             "-D_MBCS",
@@ -192,9 +192,9 @@
             "-Dfrom_cmake_cxx_flags",
             "-Dfrom_cmake_cxx_<CONFIG_LOWER>_flags",
             "<CXX20_OPTION>",
-            "-Ddep_interface_option",
             "-Dtarget_interface_option",
-            "-Dtarget_public_option"
+            "-Dtarget_public_option",
+            "-Ddep_interface_option"
           ],
           "private": false,
           "provides": {
@@ -231,8 +231,8 @@
             "-Dfrom_compile_options",
             "-Dtarget_private_option",
             "-Dtarget_public_option",
-            "-Ddep_interface_option",
             "-Dtarget_interface_option",
+            "-Ddep_interface_option",
             "PATH:-Ddepflag=\"CMakeFiles/CXXModules__export_build_database@synth_1.dir<CONFIG_DIR>/.d\"",
             "REGEX:<BMI_ONLY_FLAG>",
             "PATH:<OUTPUT_FLAG>CMakeFiles/CXXModules__export_build_database@synth_1.dir<CONFIG_DIR>/",
@@ -257,8 +257,8 @@
             "-Dfrom_compile_options",
             "-Dtarget_private_option",
             "-Dtarget_public_option",
-            "-Ddep_interface_option",
-            "-Dtarget_interface_option"
+            "-Dtarget_interface_option",
+            "-Ddep_interface_option"
           ],
           "local-arguments": [
             "-D_MBCS",
@@ -278,8 +278,8 @@
             "-Dfrom_compile_options",
             "-Dtarget_private_option",
             "-Dtarget_public_option",
-            "-Ddep_interface_option",
-            "-Dtarget_interface_option"
+            "-Dtarget_interface_option",
+            "-Ddep_interface_option"
           ],
           "private": false,
           "provides": {

Tests/RunCMake/CXXModulesCompile/expect/exp-builddb-imped-cxx-config.json

@@ -149,9 +149,9 @@
             "-Dfrom_cmake_cxx_flags",
             "-Dfrom_cmake_cxx_<CONFIG_LOWER>_flags",
             "<CXX20_OPTION>",
-            "-Ddep_interface_option",
             "-Dtarget_interface_option",
             "-Dtarget_public_option",
+            "-Ddep_interface_option",
             "PATH:-Ddepflag=\"CMakeFiles/CXXModules__export_build_database@synth_0.dir<CONFIG_DIR>/.d\"",
             "REGEX:<BMI_ONLY_FLAG>",
             "PATH:<OUTPUT_FLAG>CMakeFiles/CXXModules__export_build_database@synth_0.dir<CONFIG_DIR>/",
@@ -173,9 +173,9 @@
             "-Dfrom_cmake_cxx_flags",
             "-Dfrom_cmake_cxx_<CONFIG_LOWER>_flags",
             "<CXX20_OPTION>",
-            "-Ddep_interface_option",
             "-Dtarget_interface_option",
-            "-Dtarget_public_option"
+            "-Dtarget_public_option",
+            "-Ddep_interface_option"
           ],
           "local-arguments": [
             "-D_MBCS",
@@ -192,9 +192,9 @@
             "-Dfrom_cmake_cxx_flags",
             "-Dfrom_cmake_cxx_<CONFIG_LOWER>_flags",
             "<CXX20_OPTION>",
-            "-Ddep_interface_option",
             "-Dtarget_interface_option",
-            "-Dtarget_public_option"
+            "-Dtarget_public_option",
+            "-Ddep_interface_option"
           ],
           "private": false,
           "provides": {
@@ -231,8 +231,8 @@
             "-Dfrom_compile_options",
             "-Dtarget_private_option",
             "-Dtarget_public_option",
-            "-Ddep_interface_option",
             "-Dtarget_interface_option",
+            "-Ddep_interface_option",
             "PATH:-Ddepflag=\"CMakeFiles/CXXModules__export_build_database@synth_1.dir<CONFIG_DIR>/.d\"",
             "REGEX:<BMI_ONLY_FLAG>",
             "PATH:<OUTPUT_FLAG>CMakeFiles/CXXModules__export_build_database@synth_1.dir<CONFIG_DIR>/",
@@ -257,8 +257,8 @@
             "-Dfrom_compile_options",
             "-Dtarget_private_option",
             "-Dtarget_public_option",
-            "-Ddep_interface_option",
-            "-Dtarget_interface_option"
+            "-Dtarget_interface_option",
+            "-Ddep_interface_option"
           ],
           "local-arguments": [
             "-D_MBCS",
@@ -278,8 +278,8 @@
             "-Dfrom_compile_options",
             "-Dtarget_private_option",
             "-Dtarget_public_option",
-            "-Ddep_interface_option",
-            "-Dtarget_interface_option"
+            "-Dtarget_interface_option",
+            "-Ddep_interface_option"
           ],
           "private": false,
           "provides": {

Tests/RunCMake/CXXModulesCompile/expect/exp-builddb-imped-cxx-multi.json

@@ -275,9 +275,9 @@
             "-Dfrom_cmake_cxx_flags",
             "-Dfrom_cmake_cxx_<CONFIG_LOWER>_flags",
             "<CXX20_OPTION>",
-            "-Ddep_interface_option",
             "-Dtarget_interface_option",
             "-Dtarget_public_option",
+            "-Ddep_interface_option",
             "PATH:-Ddepflag=\"CMakeFiles/CXXModules__export_build_database@synth_0.dir<CONFIG_DIR>/.d\"",
             "REGEX:<BMI_ONLY_FLAG>",
             "PATH:<OUTPUT_FLAG>CMakeFiles/CXXModules__export_build_database@synth_0.dir<CONFIG_DIR>/",
@@ -299,9 +299,9 @@
             "-Dfrom_cmake_cxx_flags",
             "-Dfrom_cmake_cxx_<CONFIG_LOWER>_flags",
             "<CXX20_OPTION>",
-            "-Ddep_interface_option",
             "-Dtarget_interface_option",
-            "-Dtarget_public_option"
+            "-Dtarget_public_option",
+            "-Ddep_interface_option"
           ],
           "local-arguments": [
             "-D_MBCS",
@@ -318,9 +318,9 @@
             "-Dfrom_cmake_cxx_flags",
             "-Dfrom_cmake_cxx_<CONFIG_LOWER>_flags",
             "<CXX20_OPTION>",
-            "-Ddep_interface_option",
             "-Dtarget_interface_option",
-            "-Dtarget_public_option"
+            "-Dtarget_public_option",
+            "-Ddep_interface_option"
           ],
           "private": false,
           "provides": {
@@ -354,9 +354,9 @@
             "-Dfrom_cmake_cxx_flags",
             "-Dfrom_cmake_cxx_<CONFIG_OTHER_LOWER>_flags",
             "<CXX20_OPTION>",
-            "-Ddep_interface_option",
             "-Dtarget_interface_option",
             "-Dtarget_public_option",
+            "-Ddep_interface_option",
             "PATH:-Ddepflag=\"CMakeFiles/CXXModules__export_build_database@synth_0.dir<CONFIG_OTHER_DIR>/.d\"",
             "REGEX:<BMI_ONLY_FLAG>",
             "PATH:<OUTPUT_FLAG>CMakeFiles/CXXModules__export_build_database@synth_0.dir<CONFIG_OTHER_DIR>/",
@@ -378,9 +378,9 @@
             "-Dfrom_cmake_cxx_flags",
             "-Dfrom_cmake_cxx_<CONFIG_OTHER_LOWER>_flags",
             "<CXX20_OPTION>",
-            "-Ddep_interface_option",
             "-Dtarget_interface_option",
-            "-Dtarget_public_option"
+            "-Dtarget_public_option",
+            "-Ddep_interface_option"
           ],
           "local-arguments": [
             "-D_MBCS",
@@ -397,9 +397,9 @@
             "-Dfrom_cmake_cxx_flags",
             "-Dfrom_cmake_cxx_<CONFIG_OTHER_LOWER>_flags",
             "<CXX20_OPTION>",
-            "-Ddep_interface_option",
             "-Dtarget_interface_option",
-            "-Dtarget_public_option"
+            "-Dtarget_public_option",
+            "-Ddep_interface_option"
           ],
           "private": false,
           "provides": {
@@ -436,8 +436,8 @@
             "-Dfrom_compile_options",
             "-Dtarget_private_option",
             "-Dtarget_public_option",
-            "-Ddep_interface_option",
             "-Dtarget_interface_option",
+            "-Ddep_interface_option",
             "PATH:-Ddepflag=\"CMakeFiles/CXXModules__export_build_database@synth_1.dir<CONFIG_DIR>/.d\"",
             "REGEX:<BMI_ONLY_FLAG>",
             "PATH:<OUTPUT_FLAG>CMakeFiles/CXXModules__export_build_database@synth_1.dir<CONFIG_DIR>/",
@@ -462,8 +462,8 @@
             "-Dfrom_compile_options",
             "-Dtarget_private_option",
             "-Dtarget_public_option",
-            "-Ddep_interface_option",
-            "-Dtarget_interface_option"
+            "-Dtarget_interface_option",
+            "-Ddep_interface_option"
           ],
           "local-arguments": [
             "-D_MBCS",
@@ -483,8 +483,8 @@
             "-Dfrom_compile_options",
             "-Dtarget_private_option",
             "-Dtarget_public_option",
-            "-Ddep_interface_option",
-            "-Dtarget_interface_option"
+            "-Dtarget_interface_option",
+            "-Ddep_interface_option"
           ],
           "private": false,
           "provides": {
@@ -521,8 +521,8 @@
             "-Dfrom_compile_options",
             "-Dtarget_private_option",
             "-Dtarget_public_option",
-            "-Ddep_interface_option",
             "-Dtarget_interface_option",
+            "-Ddep_interface_option",
             "PATH:-Ddepflag=\"CMakeFiles/CXXModules__export_build_database@synth_1.dir<CONFIG_OTHER_DIR>/.d\"",
             "REGEX:<BMI_ONLY_FLAG>",
             "PATH:<OUTPUT_FLAG>CMakeFiles/CXXModules__export_build_database@synth_1.dir<CONFIG_OTHER_DIR>/",
@@ -547,8 +547,8 @@
             "-Dfrom_compile_options",
             "-Dtarget_private_option",
             "-Dtarget_public_option",
-            "-Ddep_interface_option",
-            "-Dtarget_interface_option"
+            "-Dtarget_interface_option",
+            "-Ddep_interface_option"
           ],
           "local-arguments": [
             "-D_MBCS",
@@ -568,8 +568,8 @@
             "-Dfrom_compile_options",
             "-Dtarget_private_option",
             "-Dtarget_public_option",
-            "-Ddep_interface_option",
-            "-Dtarget_interface_option"
+            "-Dtarget_interface_option",
+            "-Ddep_interface_option"
           ],
           "private": false,
           "provides": {

Tests/RunCMake/CXXModulesCompile/expect/exp-builddb-imped-cxx.json

@@ -149,9 +149,9 @@
             "-Dfrom_cmake_cxx_flags",
             "-Dfrom_cmake_cxx_<CONFIG_LOWER>_flags",
             "<CXX20_OPTION>",
-            "-Ddep_interface_option",
             "-Dtarget_interface_option",
             "-Dtarget_public_option",
+            "-Ddep_interface_option",
             "PATH:-Ddepflag=\"CMakeFiles/CXXModules__export_build_database@synth_0.dir<CONFIG_DIR>/.d\"",
             "REGEX:<BMI_ONLY_FLAG>",
             "PATH:<OUTPUT_FLAG>CMakeFiles/CXXModules__export_build_database@synth_0.dir<CONFIG_DIR>/",
@@ -173,9 +173,9 @@
             "-Dfrom_cmake_cxx_flags",
             "-Dfrom_cmake_cxx_<CONFIG_LOWER>_flags",
             "<CXX20_OPTION>",
-            "-Ddep_interface_option",
             "-Dtarget_interface_option",
-            "-Dtarget_public_option"
+            "-Dtarget_public_option",
+            "-Ddep_interface_option"
           ],
           "local-arguments": [
             "-D_MBCS",
@@ -192,9 +192,9 @@
             "-Dfrom_cmake_cxx_flags",
             "-Dfrom_cmake_cxx_<CONFIG_LOWER>_flags",
             "<CXX20_OPTION>",
-            "-Ddep_interface_option",
             "-Dtarget_interface_option",
-            "-Dtarget_public_option"
+            "-Dtarget_public_option",
+            "-Ddep_interface_option"
           ],
           "private": false,
           "provides": {
@@ -231,8 +231,8 @@
             "-Dfrom_compile_options",
             "-Dtarget_private_option",
             "-Dtarget_public_option",
-            "-Ddep_interface_option",
             "-Dtarget_interface_option",
+            "-Ddep_interface_option",
             "PATH:-Ddepflag=\"CMakeFiles/CXXModules__export_build_database@synth_1.dir<CONFIG_DIR>/.d\"",
             "REGEX:<BMI_ONLY_FLAG>",
             "PATH:<OUTPUT_FLAG>CMakeFiles/CXXModules__export_build_database@synth_1.dir<CONFIG_DIR>/",
@@ -257,8 +257,8 @@
             "-Dfrom_compile_options",
             "-Dtarget_private_option",
             "-Dtarget_public_option",
-            "-Ddep_interface_option",
-            "-Dtarget_interface_option"
+            "-Dtarget_interface_option",
+            "-Ddep_interface_option"
           ],
           "local-arguments": [
             "-D_MBCS",
@@ -278,8 +278,8 @@
             "-Dfrom_compile_options",
             "-Dtarget_private_option",
             "-Dtarget_public_option",
-            "-Ddep_interface_option",
-            "-Dtarget_interface_option"
+            "-Dtarget_interface_option",
+            "-Ddep_interface_option"
           ],
           "private": false,
           "provides": {

Tests/RunCMake/CXXModulesCompile/imp-dummy-std/CMakeLists.txt

@@ -1,5 +1,5 @@
 set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "451f2fe2-a8a2-47c3-bc32-94786d8fc91b")
+  "f35a9ac6-8463-4d38-8eec-5d6008153e7d")
 set(CMAKE_CXX_STDLIB_MODULES_JSON
   "${CMAKE_CURRENT_LIST_DIR}/../dummy-std/manifest/dummy-std.modules.json"
 )

Tests/RunCMake/CXXModulesCompile/imp-std-exp-no-std-build/CMakeLists.txt

@@ -1,5 +1,5 @@
 set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "451f2fe2-a8a2-47c3-bc32-94786d8fc91b")
+  "f35a9ac6-8463-4d38-8eec-5d6008153e7d")
 
 cmake_minimum_required(VERSION 3.29)
 project(cxx_modules_import_std_export_no_std CXX)

Tests/RunCMake/CXXModulesCompile/imp-std-exp-no-std-build/test/CMakeLists.txt

@@ -39,7 +39,7 @@ list(FILTER usage_dependent_targets EXCLUDE REGEX "CXXModules::")
 # Strip quotes.
 string(REPLACE "\"" "" usage_dependent_targets "${usage_dependent_targets}")
 
-if ("__CMAKE::CXX23" IN_LIST usage_dependent_targets)
+if ("@cmake_cxx_std" IN_LIST usage_dependent_targets)
   message(SEND_ERROR
-    "The main export requires the '__CMAKE::CXX23' target")
+    "The main export requires the '@cmake_cxx_std' target")
 endif ()

Tests/RunCMake/CXXModulesCompile/imp-std-exp-no-std-install/CMakeLists.txt

@@ -1,5 +1,5 @@
 set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "451f2fe2-a8a2-47c3-bc32-94786d8fc91b")
+  "f35a9ac6-8463-4d38-8eec-5d6008153e7d")
 
 cmake_minimum_required(VERSION 3.29)
 project(cxx_modules_import_std_export_no_std CXX)

Tests/RunCMake/CXXModulesCompile/imp-std-exp-no-std-install/test/CMakeLists.txt

@@ -39,7 +39,7 @@ list(FILTER usage_dependent_targets EXCLUDE REGEX "CXXModules::")
 # Strip quotes.
 string(REPLACE "\"" "" usage_dependent_targets "${usage_dependent_targets}")
 
-if ("__CMAKE::CXX23" IN_LIST usage_dependent_targets)
+if ("@cmake_cxx_std" IN_LIST usage_dependent_targets)
   message(SEND_ERROR
-    "The main export requires the '__CMAKE::CXX23' target")
+    "The main export requires the '@cmake_cxx_std' target")
 endif ()

Tests/RunCMake/CXXModulesCompile/imp-std-no-std-prop/CMakeLists.txt

@@ -1,5 +1,5 @@
 set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "451f2fe2-a8a2-47c3-bc32-94786d8fc91b")
+  "f35a9ac6-8463-4d38-8eec-5d6008153e7d")
 
 cmake_minimum_required(VERSION 3.29)
 project(cxx_modules_import_std_no_std_property CXX)

Tests/RunCMake/CXXModulesCompile/imp-std-not-in-exp-build/CMakeLists.txt

@@ -1,5 +1,5 @@
 set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "451f2fe2-a8a2-47c3-bc32-94786d8fc91b")
+  "f35a9ac6-8463-4d38-8eec-5d6008153e7d")
 
 cmake_minimum_required(VERSION 3.29)
 project(cxx_modules_import_std_not_in_export CXX)

Tests/RunCMake/CXXModulesCompile/imp-std-not-in-exp-build/test/CMakeLists.txt

@@ -39,7 +39,7 @@ list(FILTER usage_dependent_targets EXCLUDE REGEX "CXXModules::")
 # Strip quotes.
 string(REPLACE "\"" "" usage_dependent_targets "${usage_dependent_targets}")
 
-if ("__CMAKE::CXX23" IN_LIST usage_dependent_targets)
+if ("@cmake_cxx_std" IN_LIST usage_dependent_targets)
   message(SEND_ERROR
-    "The main export requires the '__CMAKE::CXX23' target")
+    "The main export requires the '@cmake_cxx_std' target")
 endif ()

Tests/RunCMake/CXXModulesCompile/imp-std-not-in-exp-install/CMakeLists.txt

@@ -1,5 +1,5 @@
 set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "451f2fe2-a8a2-47c3-bc32-94786d8fc91b")
+  "f35a9ac6-8463-4d38-8eec-5d6008153e7d")
 
 cmake_minimum_required(VERSION 3.29)
 project(cxx_modules_import_std_not_in_export CXX)

Tests/RunCMake/CXXModulesCompile/imp-std-not-in-exp-install/test/CMakeLists.txt

@@ -39,7 +39,7 @@ list(FILTER usage_dependent_targets EXCLUDE REGEX "CXXModules::")
 # Strip quotes.
 string(REPLACE "\"" "" usage_dependent_targets "${usage_dependent_targets}")
 
-if ("__CMAKE::CXX23" IN_LIST usage_dependent_targets)
+if ("@cmake_cxx_std" IN_LIST usage_dependent_targets)
   message(SEND_ERROR
-    "The main export requires the '__CMAKE::CXX23' target")
+    "The main export requires the '@cmake_cxx_std' target")
 endif ()

Tests/RunCMake/CXXModulesCompile/imp-std-trans/CMakeLists.txt

@@ -1,14 +1,8 @@
 set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "451f2fe2-a8a2-47c3-bc32-94786d8fc91b")
+  "f35a9ac6-8463-4d38-8eec-5d6008153e7d")
 
 cmake_minimum_required(VERSION 3.29)
 
-if (EXPORT_NO_STD)
-  # Block making C++ `import std` targets.
-  add_library(__CMAKE::CXX23 IMPORTED INTERFACE)
-  add_library(__CMAKE::CXX26 IMPORTED INTERFACE)
-endif ()
-
 project(cxx_modules_import_std_transitive CXX)
 
 include("${CMAKE_SOURCE_DIR}/../cxx-modules-rules.cmake")

Tests/RunCMake/CXXModulesCompile/imp-std/CMakeLists.txt

@@ -1,5 +1,5 @@
 set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "451f2fe2-a8a2-47c3-bc32-94786d8fc91b")
+  "f35a9ac6-8463-4d38-8eec-5d6008153e7d")
 
 cmake_minimum_required(VERSION 3.29)
 project(cxx_modules_import_std CXX)

Tests/RunCMake/cmake_language/Experimental/CxxImportStd-quiet.cmake

@@ -13,7 +13,7 @@ if (NOT feature_present STREQUAL "FALSE")
 endif ()
 
 set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "451f2fe2-a8a2-47c3-bc32-94786d8fc91b")
+  "f35a9ac6-8463-4d38-8eec-5d6008153e7d")
 
 cmake_language(GET_EXPERIMENTAL_FEATURE_ENABLED
   "CxxImportStd"

Tests/RunCMake/cmake_language/Experimental/CxxImportStd-set.cmake

@@ -1,5 +1,5 @@
 set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD
-  "451f2fe2-a8a2-47c3-bc32-94786d8fc91b")
+  "f35a9ac6-8463-4d38-8eec-5d6008153e7d")
 
 cmake_language(GET_EXPERIMENTAL_FEATURE_ENABLED
   "CxxImportStd"