SYNOPSIS
dh_haskell_provides [debhelper options] [-Xpackage] [--exclude=package] [file ...]DESCRIPTION
dh_haskell_provides is a debhelper program that calculates the correct virtual package to provide, so that dependencies can guarantee ABI stability.For a package with an idea of package-version-longhashstring, it generates a virtual package of the form libghc-package-dev-version-longh for the -dev package and libghc-package-prof-version-longh for the prof package respectively.
This script writes the debian/$package.substvars file, including in it the haskell:Provides. So, to use this package, include in the Provides: field in debian/control ${haskell:Provides}.