Header file with duplicate name but unique directory not identified by intellisense

[BeckBusch]

Bug Summary

I am using VSCode to work on source files from a large Visual Studio solution with many projects. Each project has its its own directory with various source files, and a subfolder for resource headers.

Solution/
├─ ProjectA/
│ ├─ Resources/
│ │ ├─ common.h
│ ├─ SourceA.cpp
├─ ProjectB/
│ ├─ Resources/
│ │ ├─ common.h
│ ├─ SourceB.cpp

ProjectA/Resources/common.h will only ever be referenced by source files within the ProjectA directory.
The issue with this is each of these resource headers has the same filename, so the intellisense database will only process the first one it finds. This is usually the first project folder alphabetically.
When running intellisense, on the above example, references to ProjectA/Resources/common.h by ProjectA/SourceA.cpp are resolved.
References to ProjectB/Resources/common.h by ProjectB/SourceB.cpp are not resolved and result in red squiggles with "identifier XYZ is undefined"

However when I click on the identifier in Source.B and select "go to definition" the extension correctly opens ProjectB/Resources/common.h and jumps to the selected identifier.

Configuration and Logs

This behavior is found in the default configurations. I have not been able to find a change to the configuration that alters this behavior.

Debug log diagnostics do not display anything unusual or useful.

Environment

• OS and Version: Win 11 25H2
• VS Code Version: 1.125.1 (issue identified on earlier versions)
• C/C++ Extension Version: 1.33.0 (issue identified on earlier versions)

[sean-mcmanus]

@BeckBusch This is happening because of the recursive includes feature which is on by default (the ** in "includePath": [ "${workspaceFolder}/**" ]). That feature will turn the include path into effectively [ "ProjectA/Resources", "ProjectB/Resources" ], so the 1st include path gets used by both folder since they try to resolve one after the other.

One alternative is to create a multi-root workspace with each project as the root:

Another alternative would be to generate a compile_commands.json based on your workspace/project files, such as via the msbuild extractor tool at https://github.com/microsoft/msbuild-extractor-sample , and then setting the c_cpp_properties.json compileCommands property to that file. You could also possibly get Copilot to create the compile_commands.json or a script to create one.