libghc-type-errors-dev 0.2.0.0-2 (amd64 binary) in ubuntu focal

 This is a collection of tools for writing better, more ergonomic type
 errors for Haskell libraries. Some of the more interesting features
 are the ability to observe stuckedness and phantomness, as well as
 perform substitutions over types.
 .
 This package provides a library for the Haskell programming language.
 See http://www.haskell.org/ for more information on Haskell.