
If there’s an old installation of e.g. `apple-gcc42` from when it was part of `homebrew/core` then the tab will say it was from the `homebrew/core` tap and then we’ll complain at the user (see #1459 for an example). Instead, we only want to complain when the user actually types in `homebrew/core/apple-gcc42` into a `brew` command. Closes #1459.