brew can't find vim formulae for Mojave

Question

After upgrading my Macbook to OSX 10.14.2 I am unable to install vim. I did do an upgrade of XCode and

xcode-select --install

after the upgrade to Mojave.

There is a system vim v.8.0 that is provided by Apple, but this does not readily work with the python v.2.7.15 that YouCompleteMe is using.

So the following:

brew install vim --with-override-system-vi

fails with

Error: No available formula with the name "vim"

There is a Homebrew formula for vim so a missing formulae is not the problem. Also my brew installation is clean:

brew update && brew upgrade
brew cleanup -s

were ran with no errors. Also

brew doctor

indicated no problems and running:

git fsck

came up clean.

Git remote:

git remote -v
origin  https://github.com/Homebrew/brew (fetch)
origin  https://github.com/Homebrew/brew (push)

Answer 1

I found a solution for my particular problem

rm -rf /usr/local/Homebrew/Library/Taps/homebrew/homebrew-core; brew update

Discovered it in an issue discussion on Github, No formulae at all were found in taps #2387 posted by MikeMcquaid

Also, I found it necessary to

brew unlink python@2

in order for YCM to work (that formulae left on my system from Yosemite environment)