fatal error: assert.h: No such file or directory on Mac

To resolve this issue, follow these steps:

Confirm Xcode Version:

Verify that you have Xcode version 14.0.1 installed. You can check this by opening Xcode and navigating to “About Xcode” in the Xcode menu.

Check for Xcode Updates:

Open the App Store and check for updates for Xcode. If Xcode 14.1 is available, install it. If not, proceed to the next step.

Update Command Line Tools (CLT):

Update your Command Line Tools (CLT) to ensure compatibility. Run the following command in the terminal:

softwareupdate --all --install --force

If there are no updates or this doesn’t solve the issue, continue to the next step.

Manually Download Command Line Tools:

Download and install the Command Line Tools for Xcode 14.1 manually by visiting this link.

Reinstall Command Line Tools:

If the issue persists, remove and reinstall the Command Line Tools:

sudo rm -rf /Library/Developer/CommandLineTools

sudo xcode-select --install

This will initiate the reinstallation of the Command Line Tools.

Following these steps should help resolve the error, allowing you to proceed with the brew upgrade command successfully.