Jump to macro definition failed when expanding macros with length around 2400.

[smwikipedia]

Type: LanguageService

Describe the bug

• OS and Version:
  Windows 10 Version 1709

• VS Code Version:
  Version: 1.38.1 (user setup)
  Commit: b37e54c98e1a74ba89e03073e5a3761284e3ffb0
  Date: 2019-09-11T13:35:15.005Z
  Electron: 4.2.10
  Chrome: 69.0.3497.128
  Node.js: 10.11.0
  V8: 6.9.427.31-electron.0
  OS: Windows_NT x64 10.0.16299

• C/C++ Extension Version:
  0.25.1

• Other extensions you installed (and if the issue persists after disabling them):

• A clear and concise description of what the bug is.
  Open this repo in VS Code:
  https://github.com/smwikipedia/macroExpansion

There are 2 files in that repo:

• a.h: defines a bunch of macros
• a.c: use the macros defined in a.h

In a.c file, line 7 to line 33 are some macros. See below:

Jump to definition for ztest_test_suite on line 7 in a.c. It will jump to struct unit_test in a.h at line 1. This is incorrect. See below:

So this issue seems to be related to the length of the macro expansion result. So I tried deleting single arbitrary line from a.c between line 8 and line 32.
Repeat jump to definition for ztest_test_suite on line 7 in a.c again. It will jump to #define ztest_test_suite(suite, ...) at line 31 in a.h. This is the correct result. See below:

The final macro expansion length is about 2400. It doesn't exceed the 20000 token length limitation. However, even if I changed to "editor.maxTokenizationLineLength": 50000 in the settings.json. The issue still remains.

[sean-mcmanus]

Thanks for reporting this. The bug also repros in VS, so I've filed a bug at https://developercommunity.visualstudio.com/content/problem/752497/cc-intellisense-based-go-to-definition-fails-for-m.html . You could upvote that if you have a Microsoft account.

[smwikipedia]

Thanks. So Visual Studio and Visual Studio Code share some implementations?

[smwikipedia]

I have upvoted that VS bug report. I see this issue was removed from the 0.26.1 milestone. Kind of disappointing. Could you reveal if it will be covered in any future milestones? Thanks. @sean-mcmanus

[sean-mcmanus]

Yeah, our low level parsing and IntelliSense code is shared. We plan to share more later.

It was removed from 0.26.1 because we don't know when the fix will get in -- it depends on when the VC++ team decides to fix. I was able to fix it for your specific repro via changing a hard-coded array size, but I don't think that is the correct fix.

[Colengms]

@sean-mcmanus Did this make it into 1.2.1 ?

[sean-mcmanus]

No. It's for 1.3.0-insiders.

[sean-mcmanus]

Fixed with https://github.com/microsoft/vscode-cpptools/releases/tag/1.3.0-insiders .

[smwikipedia]

Glad it is claimed to be fixed.

[michelleangela]

Fix is released in the 1.3.0 release version https://github.com/microsoft/vscode-cpptools/releases/tag/1.3.0