"Xcode must be fully installed before you can continue"
Recently, I ran into a hiccup on Expo when I was trying to open up an iOS device. And if you found this, maybe you have too.
"Xcode must be fully installed before you can continue".
The problem was I did have it installed.
The simple fix, run the following command:
sudo xcode-select -s /Applications/Xcode.app/Contents/Developer
Thanks to this thread, I was able to get over it.