'switch header/source' doesn't work for switching from CUDA `.cu` to `.cuh` file

[HugoPhibbs]

Environment

• OS and Version: Windows 11
• VS Code Version: 1.99.3
• C/C++ Extension Version: 1.25.3

Bug Summary and Steps to Reproduce

Bug Summary:

When I'm in a .cuh file, 'switch header/source' goes to the corresponding .cu file, but the vice versa isn't true - I can't go from the .cu to .cuh file.

I've recreated the problem with a simple project that looks like so:

demo/
├─ include/
│ ├─ main.cuh
│ └─ second.hpp
└─ src/
├─ main.cu
└─ second.cpp

It switches between 'second (cpp)' header/source fine, but not between main (cuda) header/source

I'm usually running my project on a dev container on a remote host, but I've recreated it locally with windows.

Steps to reproduce:

1. Go to a cuda source .cu file
2. Use 'switch header/source'
3. Nothing happens

Expected behavior:

For it to switch between the CUDA source and header.

Configuration and Logs

-------- Diagnostics - 5/1/2025, 8:46:25 AM
Version: 1.25.3
Current Configuration:
{
    "name": "Win32",
    "includePath": [
        "path/to/demo/**"
    ],
    "defines": [
        "_DEBUG",
        "UNICODE",
        "_UNICODE"
    ],
    "intelliSenseModeIsExplicit": false,
    "cStandardIsExplicit": false,
    "cppStandardIsExplicit": false,
    "mergeConfigurations": false,
    "recursiveIncludes": {},
    "recursiveIncludesReduceIsExplicit": false,
    "recursiveIncludesPriorityIsExplicit": false,
    "recursiveIncludesOrderIsExplicit": false,
    "compilerPath": "C:\\MinGW\\bin\\gcc.exe",
    "compilerPathIsExplicit": true,
    "browse": {
        "limitSymbolsToIncludedHeaders": true
    }
}
Modified Settings:
{
    "C_Cpp.default.compilerPath": "C:\\MinGW\\bin\\gcc.exe"
}
Additional Tracked Settings:
{
    "editorTabSize": 4,
    "editorInsertSpaces": true,
    "editorAutoClosingBrackets": "languageDefined",
    "filesEncoding": "utf8",
    "filesAssociations": {
        "BaseDockerfile": "dockerfile"
    },
    "filesExclude": {
        "**/.git": true,
        "**/.svn": true,
        "**/.hg": true,
        "**/.DS_Store": true,
        "**/Thumbs.db": true
    },
    "filesAutoSaveAfterDelay": true,
    "editorInlayHintsEnabled": true,
    "editorParameterHintsEnabled": true,
    "searchExclude": {
        "**/node_modules": true,
        "**/bower_components": true,
        "**/*.code-search": true
    },
    "workbenchSettingsEditor": "ui"
}
cpptools version (native): 1.25.3.0
Current database path: C:\USERS\HUGOP\APPDATA\LOCAL\MICROSOFT\VSCODE-CPPTOOLS\69AD98F1343FF6AB5994CDF2FD2FED87\.BROWSE.VC.DB
Translation Unit Mappings:
[ C:\Users\hugop\Documents\demo\include\second.hpp - source TU]:
[ C:\Users\hugop\Documents\demo\src\main.cu - source TU]:
    C:\Users\hugop\Documents\demo\include\main.cuh
[ C:\Users\hugop\Documents\demo\src\second.cpp - source TU]:
Translation Unit Configurations:
[ C:\Users\hugop\Documents\demo\include\second.hpp ]
    Process ID: 23072
    Memory Usage: 58 MB
    Include paths:
    Defines:
        _DEBUG
        UNICODE
        _UNICODE
    Standard Version: ms_c++17
    IntelliSense Mode: windows-msvc-x64
[ C:\Users\hugop\Documents\demo\src\main.cu ]
    Process ID: 3808
    Memory Usage: 60 MB
    Include paths:
    Defines:
        _DEBUG
        UNICODE
        _UNICODE
    Standard Version: ms_c++17
    IntelliSense Mode: windows-msvc-x64
[ C:\Users\hugop\Documents\demo\src\second.cpp ]
    Process ID: 13936
    Memory Usage: 59 MB
    Include paths:
    Defines:
        _DEBUG
        UNICODE
        _UNICODE
    Standard Version: ms_c++17
    IntelliSense Mode: windows-msvc-x64
Total Memory Usage: 178 MB

------- Workspace parsing diagnostics -------
Number of files discovered (not excluded): 1
Number of files parsed: 1


### Other Extensions

_No response_

### Additional context

_No response_`

[Colengms]

Hi @HugoPhibbs . Thanks for reporting this. It looks like .cu was missing from the map of source file to header file associations. I have a fix that should make it into our next insiders release.

[sean-mcmanus]

@HugoPhibbs Fixed with https://github.com/microsoft/vscode-cpptools/releases/tag/v1.26.0