SlackBuildsOrg/haskell/haskell-half

This package supplies half-precision floating point values with
1 bit of sign, 5 bits of exponent, 11 bits of mantissa trailing a
leading 1 bit with proper underflow. These arise commonly in GPU
applications.

After uninstalling, run this command to unregister the package from
the ghc package database:   ghc-pkg recache