Intellisense is giving unrelated results for definitions

[TheJCAB]

Bug type: Language Service

Describe the bug

• OS and Version: Windows 10 Pro 21H2
• VS Code Version: 1.63.2
• C/C++ Extension Version: 1.8.0 preview (but I've seen this in the last week or two, on some earlier version)
• Other extensions you installed (and if the issue persists after disabling them): Several, and I don't have the time right now to go fishing for this, but I can demo and allow control of my machine for investigation if needed.
• If using SSH remote, specify OS of remote machine: No
• A clear and concise description of what the bug is, including information about the workspace (i.e. is the workspace a single project or multiple projects, size of the project, etc).

All versions of "go to definition" (mouse float tooltip, go to definiton, peek definition, peek type definition...) are giving me patently nonsensical results for some definitions. Usually (maybe always, I need to pay more attention over time), what I get is the definition of some macro from sal.h, not always the same one.

Two things of note:
1- This happens both in our smaller project (we use CMake-tools for building) and in the Windows codebase (I work at MS) which doesn't use CMake.
2- The mouse float tooltip will show completely different definitions depending on which character of the identifier I float over. Usually, they are all different SAL macros. The one I'm looking at actually gives me the correct definition in the tooltip if I float over the last couple of characters of the identifier. But go to or peek definition always inevitably takes me only to the definitions shown if I float over the first couple of characters.

That last one is probably a good clue to what's going on here.

Steps to reproduce

1. Only for some identifiers in my source code, use any of go to definition, peek definition or float the mouse over it.
2. Observe the wrong definition.

Expected behavior

Correct definitions shown and traveled to.

Code sample and logs

• Code sample
  none

• Configurations in c_cpp_properties.json
  none

• Logs from running C/C++: Log Diagnostics from the VS Code command palette

-------- Diagnostics - 1/20/2022, 10:15:56 AM
Version: 1.8.0
Current Configuration:
{
    "name": "Win32",
    "includePath": [
        "${workspaceFolder}/**",
        "${vcpkgRoot}/x64-windows/include",
        "${vcpkgRoot}/x86-windows/include"
    ],
    "defines": [
        "_DEBUG",
        "UNICODE",
        "_UNICODE"
    ],
    "windowsSdkVersion": "10.0.22000.0",
    "compilerPath": "C:/Program Files/Microsoft Visual Studio/2022/Preview/VC/Tools/MSVC/14.31.30818/bin/Hostx64/x64/cl.exe",
    "cStandard": "c17",
    "cppStandard": "c++17",
    "intelliSenseMode": "windows-msvc-x64",
    "compilerArgs": [],
    "intelliSenseModeIsExplicit": false,
    "cStandardIsExplicit": false,
    "cppStandardIsExplicit": false,
    "mergeConfigurations": false,
    "compilerPathIsExplicit": false,
    "configurationProvider": "ms-vscode.cmake-tools",
    "browse": {
        "path": [
            "${workspaceFolder}/**",
            "${vcpkgRoot}/x64-windows/include",
            "${vcpkgRoot}/x86-windows/include"
        ],
        "limitSymbolsToIncludedHeaders": true
    }
}
Custom browse configuration: 
{
    "browsePath": [
... censored ...
    ],
    "compilerPath": "c:/program files/microsoft visual studio/2022/preview/vc/tools/msvc/14.31.30818/bin/hostx64/x64/cl.exe",
    "compilerArgs": []
}
Custom configurations:
[ X:\... censored ....cpp ]
{
    "defines": [
        "DBG",
        "NOMINMAX",
... censored ...
        "UNICODE",
        "_NO_CRT_STDIO_INLINE",
        "_SCL_SECURE_NO_WARNINGS",
        "_SILENCE_CXX17_UNCAUGHT_EXCEPTION_DEPRECATION_WARNING",
        "_UNICODE"
    ],
    "standard": "c++17",
    "includePath": [
... censored ...
    ],
    "compilerPath": "c:/program files/microsoft visual studio/2022/preview/vc/tools/msvc/14.31.30818/bin/hostx64/x64/cl.exe",
    "compilerArgs": [
        "-MTd",
        "/EHs-c-",
        "/Odi",
        "/Brepro",
        "/Z7",
        "/d2Zi+",
        "/Zl",
        "/Zp8",
        "/GF",
        "/ZH:SHA_256",
        "-permissive-",
        "/FC",
        "/bigobj",
        "/W4",
        "/WX",
        "/GR-",
        "/Gw",
        "/Gy",
        "/wd4324",
        "/wd4499",
        "/Qspectre",
        "/await",
        "/GS",
        "/guard:cf",
        "-std:c++17"
... censored ...
    ]
}
Translation Unit Mappings:
[ X:\... censored ....cpp ]:
    X:\... censored ....cpp
    C:\Program Files\Microsoft Visual Studio\2022\Preview\VC\Tools\MSVC\14.31.30818\include\sal.h *
Translation Unit Configurations:
[ X:\... censored ....cpp ]:
    Process ID: 38908
    Memory Usage: 197 MB
    Compiler Path: c:/program files/microsoft visual studio/2022/preview/vc/tools/msvc/14.31.30818/bin/hostx64/x64/cl.exe
    Includes:
... censored ...
        C:\PROGRAM FILES\MICROSOFT VISUAL STUDIO\2022\PREVIEW\VC\TOOLS\MSVC\14.31.30818\INCLUDE
        C:\PROGRAM FILES\MICROSOFT VISUAL STUDIO\2022\PREVIEW\VC\TOOLS\MSVC\14.31.30818\ATLMFC\INCLUDE
        C:\PROGRAM FILES (X86)\WINDOWS KITS\10\INCLUDE\10.0.22000.0\UM
        C:\PROGRAM FILES (X86)\WINDOWS KITS\10\INCLUDE\10.0.22000.0\UCRT
        C:\PROGRAM FILES (X86)\WINDOWS KITS\10\INCLUDE\10.0.22000.0\SHARED
        C:\PROGRAM FILES (X86)\WINDOWS KITS\10\INCLUDE\10.0.22000.0\WINRT
        C:\PROGRAM FILES (X86)\WINDOWS KITS\10\INCLUDE\10.0.22000.0\CPPWINRT
    Defines:
        DBG
        NOMINMAX
... censored ...
        UNICODE
        _NO_CRT_STDIO_INLINE
        _SCL_SECURE_NO_WARNINGS
        _SILENCE_CXX17_UNCAUGHT_EXCEPTION_DEPRECATION_WARNING
        _UNICODE
    Standard Version: ms_c++17
    IntelliSense Mode: windows-msvc-x64
    Other Flags:
        --pack_alignment
        8
        --no_ms_permissive
        --no_rtti
        --ms_await
Total Memory Usage: 197 MB

------- Workspace parsing diagnostics -------
Number of files discovered (not excluded): 6402
Number of files parsed: 512

• Logs from the language server logging

loggingLevel: Debug
loggingLevel has changed to: Debug
cpptools/didChangeCppProperties
$/setTraceNotification
cpptools/fileChanged: C:\Users\jcab\AppData\Roaming\Code\User\settings.json
Checking for syntax errors: C:\Program Files\Microsoft Visual Studio\2022\Preview\VC\Tools\MSVC\14.31.30818\include\sal.h
Queueing IntelliSense update for files in translation unit of: X:\... censored ....cpp
cpptools/fileChanged: C:\Users\jcab\AppData\Roaming\Code\User\settings.json
Checking for syntax errors: C:\Program Files\Microsoft Visual Studio\2022\Preview\VC\Tools\MSVC\14.31.30818\include\sal.h
Queueing IntelliSense update for files in translation unit of: X:\... censored ....cpp
cpptools/finishUpdateSquiggles
Error squiggle count: 16
Error squiggle count: 0
Update IntelliSense time (sec): 0.613
loggingLevel has changed to: Error
cpptools/didChangeSettings
IntelliSense Engine = Default.
Enhanced Colorization is enabled.
Error squiggles are enabled if all header dependencies are resolved.
Autocomplete is enabled.
loggingLevel has changed to: Debug
cpptools/didChangeCppProperties
$/setTraceNotification
cpptools/getCodeActions: X:\... censored ....cpp (id: 100)
cpptools/textEditorSelectionChange
cpptools/getDocumentSymbols: X:\... censored ....cpp (id: 101)
cpptools/textEditorSelectionChange
cpptools/activeDocumentChange: X:\... censored ....cpp
cpptools/getDocumentSymbols
cpptools/getFoldingRanges: X:\... censored ....cpp (id: 102)
cpptools/getCodeActions: X:\... censored ....cpp (id: 103)
idle loop: reparsing the active document
Checking for syntax errors: X:\... censored ....cpp
Queueing IntelliSense update for files in translation unit of: X:\... censored ....cpp
cpptools/finishUpdateSquiggles
Error squiggle count: 16
Error squiggle count: 0
Update IntelliSense time (sec): 0.318
cpptools/getFoldingRanges: X:\... censored ....cpp (id: 104)
cpptools/getCodeActions: X:\... censored ....cpp (id: 105)
textDocument/hover: X:\... censored ....cpp (id: 106)
textDocument/hover: X:\... censored ....cpp (id: 107)
textDocument/hover: X:\... censored ....cpp (id: 108)
textDocument/hover: X:\... censored ....cpp (id: 109)
textDocument/hover: X:\... censored ....cpp (id: 110)
textDocument/hover: X:\... censored ....cpp (id: 111)
Request canceled: 111
textDocument/hover: X:\... censored ....cpp (id: 112)
textDocument/hover: X:\... censored ....cpp (id: 113)
textDocument/hover: X:\... censored ....cpp (id: 114)
cpptools/textEditorSelectionChange
cpptools/textEditorSelectionChange
cpptools/activeDocumentChange: X:\... censored ....cpp
cpptools/getCodeActions: X:\... censored ....cpp (id: 115)
textDocument/definition: X:\... censored ....cpp (id: 116)
cpptools/getCodeActions: C:\Program Files\Microsoft Visual Studio\2022\Preview\VC\Tools\MSVC\14.31.30818\include\sal.h (id: 117)
cpptools/getFoldingRanges: C:\Program Files\Microsoft Visual Studio\2022\Preview\VC\Tools\MSVC\14.31.30818\include\sal.h (id: 118)
cpptools/getCodeActions: C:\Program Files\Microsoft Visual Studio\2022\Preview\VC\Tools\MSVC\14.31.30818\include\sal.h (id: 119)
textDocument/hover: X:\... censored ....cpp (id: 120)
textDocument/definition: X:\... censored ....cpp (id: 121)
cpptools/getCodeActions: C:\Program Files\Microsoft Visual Studio\2022\Preview\VC\Tools\MSVC\14.31.30818\include\sal.h (id: 122)
cpptools/textEditorSelectionChange
cpptools/getDocumentSymbols: C:\Program Files\Microsoft Visual Studio\2022\Preview\VC\Tools\MSVC\14.31.30818\include\sal.h (id: 123)
cpptools/textEditorSelectionChange
cpptools/getDocumentSymbols
cpptools/activeDocumentChange: C:\Program Files\Microsoft Visual Studio\2022\Preview\VC\Tools\MSVC\14.31.30818\include\sal.h
cpptools/getFoldingRanges: C:\Program Files\Microsoft Visual Studio\2022\Preview\VC\Tools\MSVC\14.31.30818\include\sal.h (id: 124)
cpptools/getCodeActions: C:\Program Files\Microsoft Visual Studio\2022\Preview\VC\Tools\MSVC\14.31.30818\include\sal.h (id: 125)
idle loop: reparsing the active document
Checking for syntax errors: C:\Program Files\Microsoft Visual Studio\2022\Preview\VC\Tools\MSVC\14.31.30818\include\sal.h
Queueing IntelliSense update for files in translation unit of: X:\... censored ....cpp
cpptools/finishUpdateSquiggles
Error squiggle count: 16
Error squiggle count: 0
Update IntelliSense time (sec): 0.325
cpptools/getFoldingRanges: C:\Program Files\Microsoft Visual Studio\2022\Preview\VC\Tools\MSVC\14.31.30818\include\sal.h (id: 126)

That's a few mouse floats on different parts of the identifier (giving different definitions), and then a peek definition and then a go to definition.

Screenshots

I can add screen snips if needed, but they wouldn't add any new information.

Additional context

None

[sean-mcmanus]

Can you confirm that it's a regression via switching to the non-Prerelease 1.7.1?

Also, there is a known potential IntelliSense regression that only repros with a recent STL, so if you could check if it still repros with a non-preview build of the VC tools that could help. It's also FYI it's not recommended to ship/test production code using the Preview builds of the VC tools.

I'll see if someone else on our team can follow up more...

[TheJCAB]

@sean-mcmanus I can't seem to be able to switch back to 1.7.1. None of the options ("Switch to Release Version" or "Install Another Version...") results in a non-release version. It always ends up in Pre-release 1.8.0, for some reason.

Regarding the VC tools... this is just my local setup. We don't release or test out of my machine 😁. I do find it useful to locally stay at the bleeding edge to watch out for changes before they happen in our official builds. Regardless, that's not particularly relevant to this issue, right?

I'm not going to try switching to a release VS at this time. It's too disruptive. VSCode's CMake tools don't currently allow me to choose which installed toolset of Visual Studio it'll configure for building, when using CMake presets (completely different issue, nothing to do with C/C++ tools), so in order to ensure I'm testing he right thing I'd need to uninstall what I have and I'm not about to do that. I hope you understand.

One clarification: in the description I originally mentioned that this is happening also in the Windows codebase, which doesn't use CMake, and instead uses a separate proprietary extension. for its build system. Well... I actually had that extension disabled, so reproing in that repo was essentially reproing on a folder with plain C++ code (no CMake). It's still a good datapoint that this is happening in two different repos (one CMake and the other not) in my machine.

[TheJCAB]

Ok, I managed to find a way for 1.7.1 to stay up long enough to test, and it works fine in that version. The extension then always auto-updates to the preview 1.8.0. So this seems to be an issue with 1.8.0.

[sean-mcmanus]

You need to also set extensions.autoUpdate to false (I think that requirement will go away once the non-Release 1.8.2 or so is released),

There is some IntelliSense bug (I believe a regression) that only repros with a new STL (I'm not sure of the complete details). We could potentially cherry pick the fix into 1.8.1 to rule that out.

Our team has the Preview and non-Preview builds of VC installed and we can switch between which one gets used by Ninja/CMake depending on which Developer Command Prompt we use.

This sounds like it could be an important regression we should investigate.

[TheJCAB]

"switch between which one gets used by Ninja/CMake depending on which Developer Command Prompt we use" - You mean launch VSCode from a developer command prompt? We don't normally do that, and I never thought of doing that. In fact, my VSCode instances are ususally auto-launched for me after a Windows Update reboot and remain open until the next Windows Update. It's... fun how it remembers which ones I had open. GUI tools are... GUI. Not exactly natural to manage them from a command prompt. But we digress... 😊 this is a CMake tools and personal workflow issue, if at all.

"set extensions.autoUpdate to false" - but that halts updates of all extensions. Is this an issue within the C/C++ tools extension?

I'll be happy to try any potential fixes you throw my way.

Thanx!

[sean-mcmanus]

I was referring to building from the Developer Command Prompt. If you're building from VS Code using the CMake Tools extension you can choose which VC toolset you're using from the dropdown UI in the status bar.

extensions.autoUpdate to false would be needed if you're using VS Code Insiders and you don't explicitly set C_Cpp.updateChannel to "Default"...otherwise, make sure C_Cpp.updateChannel is set to "Default". However, 1.8.0 changes our update mechanism to VS Code's Insider mechanism so there could be some bug somewhere. @Colengms you may want to review this report.

[sean-mcmanus]

We believe this is fixed with https://github.com/microsoft/vscode-cpptools/releases/tag/1.8.1 (let us know if you're still hitting it).