VS: Improve error message when CUDA integration is not installed

Fixes: #28142

Modules/CMakeDetermineCompilerId.cmake

@@ -727,7 +727,19 @@ Id flags: ${testflags} ${CMAKE_${lang}_COMPILER_ID_FLAGS_ALWAYS}
     set(id_Link_AdditionalDependencies "")
     if(lang STREQUAL CUDA)
       if(NOT CMAKE_VS_PLATFORM_TOOLSET_CUDA)
-        message(FATAL_ERROR "No CUDA toolset found.")
+        set(maybe_dir "")
+        if(_CMAKE_VS_PLATFORM_TOOLSET_CUDA_INTEGRATION_DIR)
+          string(CONCAT maybe_dir "  "
+            "The folder:\n"
+            "  \"${_CMAKE_VS_PLATFORM_TOOLSET_CUDA_INTEGRATION_DIR}\"\n"
+            "does not contain any \"CUDA *.props\" files.")
+        endif()
+        message(FATAL_ERROR
+          "No CUDA Toolkit integration found in Visual Studio.${maybe_dir}\n"
+          "Install the CUDA Toolkit with its Visual Studio integration component.  "
+          "Make sure the CUDA Toolkit version supports integration with\n"
+          "  ${CMAKE_GENERATOR}\n"
+        )
       endif()
       set(cuda_tools "CUDA ${CMAKE_VS_PLATFORM_TOOLSET_CUDA}")
       set(id_compile "CudaCompile")

Source/cmGlobalVisualStudio10Generator.cxx

@@ -181,6 +181,7 @@ bool cmGlobalVisualStudio10Generator::SetGeneratorToolset(
     if (gl.FindFiles(cmStrCat(bcDir, "/CUDA *.props"))) {
       cudaTools = gl.GetFiles();
     }
+    this->GeneratorToolsetCudaVSIntegrationFolder = std::move(bcDir);
     if (!cudaTools.empty()) {
       std::for_each(cudaTools.begin(), cudaTools.end(), cmCudaToolVersion);
       std::sort(cudaTools.begin(), cudaTools.end(),
@@ -201,7 +202,7 @@ bool cmGlobalVisualStudio10Generator::SetGeneratorToolset(
                  "\n"
                  "cannot detect Visual Studio integration files in path\n"
                  "  ",
-                 bcDir));
+                 this->GeneratorToolsetCudaVSIntegrationFolder));
 
       // Clear the configured tool-set
       this->GeneratorToolsetCuda.clear();
@@ -340,6 +341,9 @@ bool cmGlobalVisualStudio10Generator::SetGeneratorToolset(
   }
   if (char const* cuda = this->GetPlatformToolsetCuda()) {
     mf->AddDefinition("CMAKE_VS_PLATFORM_TOOLSET_CUDA", cuda);
+  } else if (!this->GeneratorToolsetCudaVSIntegrationFolder.empty()) {
+    mf->AddDefinition("_CMAKE_VS_PLATFORM_TOOLSET_CUDA_INTEGRATION_DIR",
+                      this->GeneratorToolsetCudaVSIntegrationFolder);
   }
   if (char const* cudaDir = this->GetPlatformToolsetCudaCustomDir()) {
     mf->AddDefinition("CMAKE_VS_PLATFORM_TOOLSET_CUDA_CUSTOM_DIR", cudaDir);

Source/cmGlobalVisualStudio10Generator.h

@@ -234,6 +234,7 @@ protected:
   std::string GeneratorToolsetCuda;
   std::string GeneratorToolsetCudaCustomDir;
   std::string GeneratorToolsetCudaNvccSubdir;
+  std::string GeneratorToolsetCudaVSIntegrationFolder;
   std::string GeneratorToolsetCudaVSIntegrationSubdir;
   cm::optional<std::string> GeneratorToolsetFortran;
   cm::optional<std::string> DefaultToolsetFortran;