This was missed in commit d90a61d671 (VS: Make C++ module BMIs public by default for shared libraries, 2023-06-08, v3.27.0-rc4~12^2).
@@ -1,4 +1,4 @@
-set(CMake_TEST_MODULE_COMPILATION "named,partitions,internal_partitions" CACHE STRING "")
+set(CMake_TEST_MODULE_COMPILATION "named,partitions,internal_partitions,shared" CACHE STRING "")
include("${CMAKE_CURRENT_LIST_DIR}/configure_windows_msvc_cxx_modules_common.cmake")
include("${CMAKE_CURRENT_LIST_DIR}/configure_windows_vs_common.cmake")