(Imported from Trac #442, reported by guest on 2009-01-05)
After a successful cabal update command, the old version of the package could be removed. (It required to rebuild/reinstall all the dependent packages as well. It is reported in #441 ticket.)
I do not think it should be a default behavior, but make it possible would be really nice. :)
(Imported comment by @dcoutts on 2009-01-05)
Currently we never uninstall packages. See #234.
Perhaps the best user interface would be some sort of clean / collect command to uninstall old versions of packages that are no longer needed (like nix). This would involve tracking the packages that the user deliberately installed, see #199. It's a bit tricky since we do not know all libs that are wanted by the user, in particular it's difficult to figure out if the user wants multiple versions of a package installed (unless multiple versions are required by other things they do want installed).
Closing as there's been no activity in years.
We're cleaning up the bug tracker to make it useful again and are thus closing bugs that haven't seen any activity in a long time. Please re-open (or file a new bug) if the problem reappears.