IntelliSense Issues with C++ Modules hints

[xBLACKICEx]

Environment

• OS and Version: Win11 24H2 21600.2448
• VS Code Version: 1.95.2
• C/C++ Extension Version: v1.23.1 (pre-release)

Bug Summary and Steps to Reproduce

Bug Summary:

with C++ modules:
IntelliSense fails to fetch function parameter names.

Inline hints for parameter names are not displayed.

Type deduction is overly verbose for certain templates (e.g., std::basic_string instead of std::string).

---

Expected behavior:

Configuration and Logs

{
    "configurations": [
        {
            "name": "Win32",
            "includePath": [
                "${workspaceFolder}/**"
            ],
            "cStandard": "c23",
            "cppStandard": "c++23",
            "intelliSenseMode": "windows-msvc-x64",
            "compilerPath": "cl.exe",
            "compilerArgs": [
                "/ifcSearchDir",
                "${workspaceFolder}/ifc"
            ]
        }
    ],
    "version": 4
}

log: no log found at output (C/C++ Task was not displayed)

Other Extensions

No response

Additional context

No response

[sean-mcmanus]

@xBLACKICEx This is a duplicate of https://developercommunity.visualstudio.com/t/C:-Pop-up-tip-shows-incorrect-signatur/10405046 -- which they closed as Lower Priority -- but it seems like a relatively major issue to me for users using modules.

[bobbrow]

@sean-mcmanus I agree with you on this. Can you open a new ticket? I didn't recall seeing this issue and it looked like Russell had triaged it before I saw it.