IntelliSense picks up wrong include path and shows false-positive error squiggles

[kokostek]

IntelliSense picks up wrong include path and shows false-positive error squiggles

[v-frankwang]

@gcampbell-msft @kokostek The user's problem is that cmake uses the vs2022 generator, but IntelliSense in vscode searches for header files in the vs2017 include directory. I reproduced the issue raised by the user and here are the steps to reproduce this issue

Repro steps:

 1. Create a folder named test and open it with vscode.
 2. Create a CMakeLists.txt file and add the following code：
      cmake_minimum_required(VERSION 3.12)
      project(VSCodeCMakeTest)
     add_executable(main main.cpp)
     target_compile_features(main PUBLIC cxx_std_20)
 4. Create a main.cpp file and add the following code：
      #include <cstdio>
      #include <ranges>

      int main(int argc, const char* argv[])
      {
           return 0;
      }
 6. Create a CMakePreset,json file and add the following code：
     {
        "version": 3,
        "configurePresets": [
          {
            "name": "win-x64-debug",
            "description": "Target Windows with the Visual Studio development environment.",
            "generator": "Visual Studio 17 2022",
            "binaryDir": "${sourceDir}/build/${presetName}",
            "installDir": "${sourceDir}/build/${presetName}",
            "cacheVariables": {
            "CMAKE_C_COMPILER": "cl.exe",
            "CMAKE_CXX_COMPILER": "cl.exe",
            "CMAKE_BUILD_TYPE": "Debug",
            "CMAKE_CONFIGURATION_TYPES": "Debug"
         },
            "condition": {
            "type": "equals",
            "lhs": "${hostSystemName}",
            "rhs": "Windows"
          },
            "architecture": {
            "value": "x64",
            "strategy": "set"
    }
  }
]

}
8. Run command:"CMake:Configure"
9. Select "configurePresets":"win-x64-debug"

Actual result:

[kokostek]

@jophippe Thanks for the update! Yes, seems like it is fixed now with pre-release cpptools. Though I had to delete cache and reconfigure to make error squiggles go away.

[v-frankwang]

@gcampbell-msft I think the user this problem is because, #include this header file is introduced in c++20 standard, but visual studio2017 doesn't support C++20 standard, so that's why this problem is occurring, even if you add target_compile_features in CMakeLists file ( main PUBLIC cxx_std_20) in the CMakeLists file, it should not make the compiler to support C++20, I don't know if I understand correctly, can you give me some suggestions?

[kokostek]

@v-frankwang, not quite. I have vs2022 installed, and cmake uses vs2022 generator and configure/build runs successfully. The problem is that the IntelliSense in vscode searches for headers in vs2017 include dir for some unknown reason, and shows false-positive error squiggles.

[jophippe]

@kokostek Looks like this is most likely a bug in cpptools: microsoft/vscode-cpptools#12293
It should be fixed in cpptools version 1.21.0, which is available in pre-release. You can switch to the pre-release version on the cpptools extension page. Please let us know if that fixes your issue.
Thanks!