Yarn add/remove are really slow after adding a "file:" dependency?

My folder structure is:

foo/
  bar/
    package.json
  package.json

package.json has:

  "workspaces": [
    "bar"
  ]

Eslint's import/no-extraneous-dependencies wants me to add foo to foo/bar/package.json. I added the dependency:

"foo": "file:..",

However, now all the Yarn commands are really slow. E.g. taking 10min to install a package that would normally take 15s. Is there something wrong with my setup?