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
2026-06-24 08:47:59 +00:00 · 2026-06-22 22:20:20 +00:00
parent a7b5ef7f9c 42d2d63235
commit dfd1cf8d87
38 changed files with 213 additions and 246 deletions
--- a/Help/dev/experimental.rst
+++ b/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
--- a/Modules/CMakeDetermineCompilerSupport.cmake
+++ b/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()
--- a/Source/cmCxxModuleUsageEffects.cxx
+++ b/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);
--- a/Source/cmCxxModuleUsageEffects.h
+++ b/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:
--- a/Source/cmExperimental.cxx
+++ b/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.",
--- a/Source/cmGeneratorTarget.cxx
+++ b/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;
  }

--- a/Source/cmGeneratorTarget.h
+++ b/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;
--- a/Source/cmGlobalGenerator.cxx
+++ b/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;
      }
    }
--- a/Source/cmGlobalGenerator.h
+++ b/Source/cmGlobalGenerator.h
@@ -800,7 +800,7 @@ protected:

  virtual bool CheckALLOW_DUPLICATE_CUSTOM_TARGETS() const;

-  bool ApplyCXXStdTargets();
+  bool ApplyCXXStdTarget();
  bool DiscoverSyntheticTargets();

  bool AddHeaderSetVerification();
--- a/Source/cmTarget.cxx
+++ b/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
    }
--- a/Source/cmTarget.h
+++ b/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);
--- a/Tests/RunCMake/CXXModules/CMP0155-NEW.cmake
+++ b/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)

--- a/Tests/RunCMake/CXXModules/CMP0155-OLD.cmake
+++ b/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)

--- a/Tests/RunCMake/CXXModules/ImplicitCXX20.cmake
+++ b/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)
--- a/Tests/RunCMake/CXXModules/Inspect.cmake
+++ b/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}\")
--- a/Tests/RunCMake/CXXModules/NoCXX20.cmake
+++ b/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)
--- a/Tests/RunCMake/CXXModules/NoScanningVariable.cmake
+++ b/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.
--- a/Tests/RunCMake/CXXModulesCompile/depchain-mods-json-file-rebuild-check.cmake
+++ b/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 ()
--- a/Tests/RunCMake/CXXModulesCompile/expect/exp-builddb-imped-all-multi.json
+++ b/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": {
--- a/Tests/RunCMake/CXXModulesCompile/expect/exp-builddb-imped-all.json
+++ b/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": {
--- a/Tests/RunCMake/CXXModulesCompile/expect/exp-builddb-imped-config.json
+++ b/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": {
--- a/Tests/RunCMake/CXXModulesCompile/expect/exp-builddb-imped-cxx-config.json
+++ b/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": {
--- a/Tests/RunCMake/CXXModulesCompile/expect/exp-builddb-imped-cxx-multi.json
+++ b/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": {
--- a/Tests/RunCMake/CXXModulesCompile/expect/exp-builddb-imped-cxx.json
+++ b/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": {
--- a/Tests/RunCMake/CXXModulesCompile/imp-dummy-std/CMakeLists.txt
+++ b/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"
 )
--- a/Tests/RunCMake/CXXModulesCompile/imp-std-exp-no-std-build/CMakeLists.txt
+++ b/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)
--- a/Tests/RunCMake/CXXModulesCompile/imp-std-exp-no-std-build/test/CMakeLists.txt
+++ b/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 ()
--- a/Tests/RunCMake/CXXModulesCompile/imp-std-exp-no-std-install/CMakeLists.txt
+++ b/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)
--- a/Tests/RunCMake/CXXModulesCompile/imp-std-exp-no-std-install/test/CMakeLists.txt
+++ b/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 ()
--- a/Tests/RunCMake/CXXModulesCompile/imp-std-no-std-prop/CMakeLists.txt
+++ b/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)
--- a/Tests/RunCMake/CXXModulesCompile/imp-std-not-in-exp-build/CMakeLists.txt
+++ b/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)
--- a/Tests/RunCMake/CXXModulesCompile/imp-std-not-in-exp-build/test/CMakeLists.txt
+++ b/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 ()
--- a/Tests/RunCMake/CXXModulesCompile/imp-std-not-in-exp-install/CMakeLists.txt
+++ b/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)
--- a/Tests/RunCMake/CXXModulesCompile/imp-std-not-in-exp-install/test/CMakeLists.txt
+++ b/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 ()
--- a/Tests/RunCMake/CXXModulesCompile/imp-std-trans/CMakeLists.txt
+++ b/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")
--- a/Tests/RunCMake/CXXModulesCompile/imp-std/CMakeLists.txt
+++ b/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)
--- a/Tests/RunCMake/cmake_language/Experimental/CxxImportStd-quiet.cmake
+++ b/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"
--- a/Tests/RunCMake/cmake_language/Experimental/CxxImportStd-set.cmake
+++ b/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"