C/C++ IntelliSense red underlines stopped working after clicking lightbulb

[Asmitha27662]

VS Code Version: 1.124.2
OS: Windows 11 (x64)
C/C++ Extension Version: (1.32.2)

Problem:
Red underlines for errors stopped appearing in .c files
after I accidentally clicked something on the lightbulb menu.
The lightbulb still appears for some mistakes but red
underlines do not appear at all.

What I tried:

• Reset IntelliSense Database
• Reset IntelliSense configuration
• Deleted workspaceStorage cache
• Disabled and re-enabled C/C++ extension
• Checked c_cpp_properties.json (compiler path is correct)
• Checked errorSquiggles setting (set to Enabled)
• Checked intelliSenseEngine (set to Default)
• Developer: Reload Window
• The { } icon shows at bottom left

Expected behavior:
Red underlines should appear under syntax errors in .c files

Current behavior:
No red underlines appear even for obvious errors like:
int x = "hello";

[bobbrow]

VS Code has a few levels of settings (global and workspace). Did you check the settings.json file in your .vscode folder for the value of the errorSquiggles setting? My guess is that you might have been looking at the global (User) setting value since that's what VS Code shows you by default, but your workspace setting is overriding that.

You can also check by running the "C/C++: Log Diagnostics" command and we will print out what we think the effective setting value is.

For example:

Modified Settings:
{
    "C_Cpp.errorSquiggles": "disabled",
}