MSVC_VERSION is incorrect when cmake configure project with tool kit clang-cl

[L-Sun]

Brief Issue Summary

When I configure my project, the cmake variable ${MSVC_VERSION} output incorrectly.
Here is my CMakeLists.txt

cmake_minimum_required(VERSION 3.15)

project(MyProject)

add_executable(main main.cpp)
if(MSVC)
    message("MSVC_VERSION: ${MSVC_VERSION}")
endif(MSVC)

Expected:

1. run command CMake: Delete Cache and Reconfigure
2. and Output panel will show:

...
[cmake] MSVC_VERSION: 1924
[cmake]  
[cmake] -- Configuring done
[cmake] -- Generating done

Apparent Behavior:

1. run command CMake: Delete Cache and Reconfigure
2. and Output panel show the following message

...
[cmake] MSVC_VERSION: 1911
[cmake]  
[cmake] -- Configuring done
[cmake] -- Generating done

Other Notes/Information

When I add 'VCToolsInstallDir' to MSVC_ENVIRONMENT_VARIABLES array in \.vscode\extensions\ms-vscode.cmake-tools-1.3.0\dist\main.js(or src/kit.ts) of extension.
and reconfigure my project. It works as expected. The cmake variable ${MSVC_VERSION} is correct.

Platform and Versions

• Operating System: Windows
• CMake Version: 3.16.4
• VSCode Version: 1.42.0
• CMake Tools Extension Version: 1.3.0
• Compiler/Toolchain: clang-cl (11.0.0) + VS2019 (v16.4.4)
• visualStudioArchitecture: amd64

[tklajnscek]

+1
Just hit the same issue where Clang can't find the MSVC toolkit correctly.
Traced it down to this after many hours.

Is there any specific reason the VCToolsInstallDir is omitted from MSVC_ENVIRONMENT_VARIABLES ? Seems like someone generated this a while ago and it never got updated.

Clang uses VCToolsInstallDir to find the location of the toolkit.

See https://clang.llvm.org/doxygen/MSVC_8cpp_source.html -> findVCToolChainViaEnvironment()

[tklajnscek]

Oh, just to be clear - in my case this doesn't simply mess up the MSVC_VERSION.
It completely fails to compile anything because the include/lib paths are set to non-existing locations.

[andreeis]

This fix is included in the 1.9.0 CMake Tools release. Please upgrade your extension in VSCode and let us know if you encounter any other issues.