Environment

• OS and Version: Windows 10
• VS Code Version: 1.96.3
• C/C++ Extension Version: 1.22.11

Bug Summary and Steps to Reproduce

Bug Summary:

Create a simple C++ source file (e.g. hello.cpp) that uses some C++20 features, e.g. just #include <span> and define a dummy function that takes a std::span as parameter. Whatever.

Try to compile and run the code.

The error message says:

The contents of <span> are available only with C++20 or later.

Inspecting the command line, it's clear that the compiler flag to activate C++20 is not present.

Starting build...
cmd /c chcp 65001>nul && cl.exe /Zi /EHsc /nologo /FeC:\Users\Giovanni\Demos\CppTests\hello.exe C:\Users\Giovanni\Demos\CppTests\hello.cpp

The C++20 flag is present in both the C/C++ configuration UI and in the c_cpp_properties.json.

Screenshots attached below.

Configuration and Logs

{
    "configurations": [
        {
            "name": "Win32",
            "includePath": [
                "${workspaceFolder}/**"
            ],
            "defines": [
                "_DEBUG",
                "UNICODE",
                "_UNICODE"
            ],
            "windowsSdkVersion": "10.0.18362.0",
            "compilerPath": "cl.exe",
            "cStandard": "c17",
            "cppStandard": "c++20",
            "intelliSenseMode": "windows-msvc-x64"
        }
    ],
    "version": 4
}

Other Extensions

No response

Additional context

No response