Intellisense Can't Find Preprocessor Definition from "defines" Field of "c_cpp_properties.json"

[abhra0897]

Type: LanguageService

Describe the bug

• OS and Version: Ubuntu 20.04 LTS
• VS Code Version: 1.45.1
• C/C++ Extension Version: 0.28.1
• Other extensions you installed (and if the issue persists after disabling them): Cortex-Debug (Yes)
• Does this issue involve using SSH remote to run the extension on a remote machine?: No
• Bug Description: Intellisense can't find preprocessor macro definitions that are passed to the defines field in the c_cpp_properties.json file. This bug occurs regardless of the project size or the number of projects opened in the workspace.

Steps to reproduce

1. Create a folder and open vscode into that folder.
2. Create a new file and name it main.c.
3. Write the following C code into that file and save it.

#if defined (FOO)
  #define BAR 10
#endif
int main()
{
    int var_bar = BAR;
    return 0;
}

4. Create a new file and name it c_cpp_properties.json.
5. Write the following JSON code into that file and save it.

{
    "configurations": [
      {
        "name": "Linux",
        "intelliSenseMode": "gcc-x64",
        "defines": [
          "FOO"
        ],
        "includePath": []
      }
    ],
    "version": 1
}

6. See: intellisense can't find that FOO is defined and showing red error line under BAR in the int var_bar = BAR; line.

Expected behavior
The defines field in the c_cpp_properties.json file contains a list of preprocessor definitions for the IntelliSense engine to use while parsing files. So, as FOO is written in defines, IntelliSense should NOT show error in int var_bar = BAR;.

Logs

-------- Diagnostics - 27/5/2020, 4:11:08 am
Version: 0.28.1
Current Configuration:
{
    "name": "Linux",
    "includePath": [
        "${workspaceFolder}/**"
    ],
    "defines": [],
    "compilerPath": "/usr/bin/clang",
    "cStandard": "c11",
    "cppStandard": "c++14",
    "intelliSenseMode": "clang-x64",
    "compilerArgs": [],
    "browse": {
        "path": [
            "${workspaceFolder}/**"
        ],
        "limitSymbolsToIncludedHeaders": true
    }
}
Translation Unit Mappings:
[ /home/rik/Works/C_CPP/intellisense_bug_repro/main.c ]:
    /home/rik/Works/C_CPP/intellisense_bug_repro/main.c
Translation Unit Configurations:
[ /home/rik/Works/C_CPP/intellisense_bug_repro/main.c ]:
    Process ID: 21119
    Memory Usage: 16 MB
    Compiler Path: /usr/bin/clang
    Includes:
        /usr/local/include
        /usr/lib/llvm-10/lib/clang/10.0.0/include
        /usr/include/x86_64-linux-gnu
        /usr/include
    Standard Version: c11
    IntelliSense Mode: clang-x64
    Other Flags:
        --clang
        --clang_version=100000
Total Memory Usage: 16 MB

File exclude: **/.git
File exclude: **/.svn
File exclude: **/.hg
File exclude: **/CVS
File exclude: **/.DS_Store
File exclude: **/.vscode
Search exclude: **/node_modules
Search exclude: **/bower_components
Search exclude: **/*.code-search
Search exclude: **/.vscode
Populate include completion cache.
Discovering files...
  Processing folder (recursive): /usr/local/include/
  Processing folder (recursive): /usr/lib/llvm-10/lib/clang/10.0.0/include/
  Processing folder (recursive): /usr/include/
Error squiggle count: 1
Update IntelliSense time (sec): 0.253
  Processing folder (recursive): /home/rik/Works/C_CPP/intellisense_bug_repro/
  Discovering files: 20467 file(s) processed
  0 file(s) removed from database
Done discovering files.
Parsing remaining files...
  Parsing: 1 files(s) processed
Done parsing remaining files.

Screenshots

[Colengms]

Hi @abhra0897 . I'm not able to (easily) repro this issue. With (almost) exactly what you've provided, this works for me. Are you sure your c_cpp_properties.json is in the correct location? It should be in the workspace, in a .vscode directory. If you do not yet have a c_cpp_properties.json, you can use the C/C++: Edit Configurations (JSON) command to create it.

One thing that I noticed is that your c_cpp_properties.json contains a version number of "1". Version 1 is no longer recognized. When I try to save a c_cpp_properties.json with a version of 1, I get an error message, and a version of 4 is immediately written in its place.

Could you try repro'ing with a newly created c_cpp_properties.json file, perhaps in a new empty folder, and confirm that it uses version 4 and not 1? If you still repro, could you provide the exactly contents of that repro? (perhaps attach the 2 text files involved to this issue, and note the directory structure).

[abhra0897]

Are you sure your c_cpp_properties.json is in the correct location? It should be in the workspace, in a .vscode directory.

@Colengms Yes, I've just figured it out and was about to explain and close this issue. It's solved now. Thanks for your reply.