Single `#include` inside of array causes VSCode to report the "expected an expression" error

[HYBRID-BEING]

Environment

• OS and Version: Windows 11 24H2 (Build 26100.4349)
• VS Code Version: 1.101.2
• C/C++ Extension Version: 1.26.3

Bug Summary and Steps to Reproduce

Bug Summary:

I'm currently working on a project that combines an X macro with an #include statement to populate an array from a generated file, like this:

// main.c
#include <stdio.h>

#define X(n) n
int array[] = {
#include "file.txt"
    // 0
};  // "expected an expression"
#undef X

int main() {
    for (int i = 0; i < 3; i++)
    {
        printf("%i\n", array[i]);  // Output is "123", as expected.
    }
    return 0;
}

// file.txt
X(1),
X(2),
X(3),

It feels hackish, but it compiles and runs. However, VSCode doesn't seem to like the fact that array has nothing but #include "file.txt" inside. Uncommenting 0 makes the error go away, although, this obviously makes array to have 4 items instead of intended 3.

Steps to reproduce:

1. Create main.c and file.txt and insert code above;
2. Open main.c in VSCode;
3. Notice error on line 7.

Expected behavior:

VSCode should understand that #include "file.txt" with expanded macros provide an expected expression.

Configuration and Logs

-------- Diagnostics - 6/30/2025, 1:54:07 AM
Version: 1.26.3
Current Configuration:
{
    "name": "Win32",
    "includePath": [
        "${workspaceFolder}/**"
    ],
    "defines": [
        "_DEBUG",
        "UNICODE",
        "_UNICODE"
    ],
    "windowsSdkVersion": "10.0.26100.0",
    "compilerPath": "cl.exe",
    "cStandard": "c17",
    "cppStandard": "c++17",
    "intelliSenseMode": "windows-msvc-x64",
    "compilerPathInCppPropertiesJson": "cl.exe",
    "intelliSenseModeIsExplicit": false,
    "cStandardIsExplicit": false,
    "cppStandardIsExplicit": false,
    "mergeConfigurations": false,
    "recursiveIncludes": {},
    "recursiveIncludesReduceIsExplicit": false,
    "recursiveIncludesPriorityIsExplicit": false,
    "recursiveIncludesOrderIsExplicit": false,
    "compilerPathIsExplicit": false,
    "browse": {
        "limitSymbolsToIncludedHeaders": true
    }
}
Modified Settings:
{
    "C_Cpp.autocompleteAddParentheses": true,
    "C_Cpp.formatting": "clangFormat",
    "C_Cpp.clang_format_fallbackStyle": "{ BasedOnStyle: Google, IndentWidth: 4, AlignAfterOpenBracket: BlockIndent, BinPackArguments: false, PenaltyBreakAssignment: 64 }",
    "C_Cpp.codeAnalysis.clangTidy.enabled": true
}
Additional Tracked Settings:
{
    "editorTabSize": 4,
    "editorInsertSpaces": true,
    "editorAutoClosingBrackets": "languageDefined",
    "filesEncoding": "utf8",
    "filesAssociations": {},
    "filesExclude": {
        "**/.git": true,
        "**/.svn": true,
        "**/.hg": true,
        "**/.DS_Store": true,
        "**/Thumbs.db": true
    },
    "filesAutoSaveAfterDelay": false,
    "editorInlayHintsEnabled": true,
    "editorParameterHintsEnabled": true,
    "searchExclude": {
        "**/node_modules": true,
        "**/bower_components": true,
        "**/*.code-search": true
    },
    "workbenchSettingsEditor": "ui"
}
cpptools version (native): 1.26.3.0
Current database path: C:\USERS\OPERATOR\APPDATA\LOCAL\TEMP\{4514E1A3-0F0D-4E39-A2F4-4D7081E65254}\.BROWSE.VC.DB
Translation Unit Mappings:
[ C:\Users\operator\Desktop\repos\test\main.c - source TU]:
    C:\Users\operator\Desktop\repos\test\file.txt
Translation Unit Configurations:
[ C:\Users\operator\Desktop\repos\test\main.c ]
    Process ID: 11608
    Memory Usage: 63 MB
    Compiler Path: C:\Program Files (x86)\Microsoft Visual Studio\2022\BuildTools\VC\Tools\MSVC\14.43.34808\bin\Hostx64\x64\cl.exe
    Include paths:
        include: C:\Program Files (x86)\Microsoft Visual Studio\2022\BuildTools\VC\Tools\MSVC\14.43.34808\include
        include: C:\Program Files (x86)\Microsoft Visual Studio\2022\BuildTools\VC\Auxiliary\VS\include
        include: C:\Program Files (x86)\Windows Kits\10\Include\10.0.26100.0\ucrt
        include: C:\Program Files (x86)\Windows Kits\10\Include\10.0.26100.0\um
        include: C:\Program Files (x86)\Windows Kits\10\Include\10.0.26100.0\shared
        include: C:\Program Files (x86)\Windows Kits\10\Include\10.0.26100.0\winrt
        include: C:\Program Files (x86)\Windows Kits\10\Include\10.0.26100.0\cppwinrt
        include: C:\Program Files (x86)\Windows Kits\NETFXSDK\4.7.2\Include\um
        system include: C:\Program Files (x86)\Windows Kits\10\Include\10.0.26100.0\um
        system include: C:\Program Files (x86)\Windows Kits\10\Include\10.0.26100.0\ucrt
        system include: C:\Program Files (x86)\Windows Kits\10\Include\10.0.26100.0\shared
        system include: C:\Program Files (x86)\Windows Kits\10\Include\10.0.26100.0\winrt
        system include: C:\Program Files (x86)\Windows Kits\10\Include\10.0.26100.0\cppwinrt
    Defines:
        _DEBUG
        UNICODE
        _UNICODE
    Standard Version: ms_c17
    IntelliSense Mode: windows-msvc-x64
    Other Flags:
        --using_directory
        C:\Program Files (x86)\Microsoft Visual Studio\2022\BuildTools\VC\Tools\MSVC\14.43.34808\lib\x86
        --using_directory
        C:\Program Files (x86)\Microsoft Visual Studio\2022\BuildTools\VC\Tools\MSVC\14.43.34808\lib\x86\store\references
        --using_directory
        C:\Program Files (x86)\Windows Kits\10\UnionMetadata\10.0.26100.0
        --using_directory
        C:\Program Files (x86)\Windows Kits\10\References\10.0.26100.0
        --using_directory
        C:\Windows\Microsoft.NET\Framework\v4.0.30319
Total Memory Usage: 63 MB

------- Workspace parsing diagnostics -------
Number of files discovered (not excluded): 5082
Number of files parsed: 238

Other Extensions

No response

Additional context

No response

[sean-mcmanus]

@HYBRID-BEING FYI, the bug only repros with .c files and not .cpp. I've filed a bug on our shared VS parser at https://developercommunity.visualstudio.com/t/C-IntelliSense-gives-an-invalid-error-wh/10930443 .

[HYBRID-BEING]

Actually, the example can be simplified to just:

// main.c
int array[] = {
#include "file.txt"
    // 0
};  // "expected an expression"

int main() {
    for (int i = 0; i < 3; i++)
    {
        printf("%i\n", array[i]);  // Output is "123", as expected.
    }
    return 0;
}

// file.txt
1,2,3,

It looks like the bug isn't related to #define.