https://buildd.debian.org/status/package.php?p=haskell-syb-with-class&suite=sid

...
hlibrary.setup: Encountered missing or private dependencies:
template-haskell >=2.4 && <2.17

 at /usr/share/perl5/Debian/Debhelper/Buildsystem/Haskell/Recipes.pm line 107.
	Debian::Debhelper::Buildsystem::Haskell::Recipes::run_quiet("debian/hlibrary.setup", "configure", "--ghc", "-v2", "--package-db=/var/lib/ghc/package.conf.d", "--prefix=/usr", "--libdir=/usr/lib/haskell-packages/ghc/lib", "--libexecdir=/usr/lib", ...) called at /usr/share/perl5/Debian/Debhelper/Buildsystem/Haskell/Recipes.pm line 131
	Debian::Debhelper::Buildsystem::Haskell::Recipes::run("debian/hlibrary.setup", "configure", "--ghc", "-v2", "--package-db=/var/lib/ghc/package.conf.d", "--prefix=/usr", "--libdir=/usr/lib/haskell-packages/ghc/lib", "--libexecdir=/usr/lib", ...) called at /usr/share/perl5/Debian/Debhelper/Buildsystem/Haskell/Recipes.pm line 620
	Debian::Debhelper::Buildsystem::Haskell::Recipes::configure_recipe() called at -e line 1
make: *** [/usr/share/cdbs/1/class/hlibrary.mk:153: build-ghc-stamp] Error 25

We believe that the bug you reported is fixed in the latest version of
haskell-syb-with-class, which is due to be installed in the Debian FTP archive.

A summary of the changes between this version and the previous one is
attached.

Thank you for reporting the bug, which will now be closed.  If you
have further comments please address them to 1013792@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.

Debian distribution maintenance software
pp.
Ilias Tsitsimpis <iliastsi@debian.org> (supplier of updated haskell-syb-with-class package)

(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmaster@ftp-master.debian.org)
Format: 1.8
Date: Sun, 03 Jul 2022 13:56:36 +0300
Source: haskell-syb-with-class
Architecture: source
Version: 0.6.1.14-1
Distribution: unstable
Urgency: medium
Maintainer: Debian Haskell Group <pkg-haskell-maintainers@lists.alioth.debian.org>
Changed-By: Ilias Tsitsimpis <iliastsi@debian.org>
Closes: 1013792
Changes:
 haskell-syb-with-class (0.6.1.14-1) unstable; urgency=medium
 .
   * New upstream release (Closes: #1013792)
   * Declare compliance with Debian policy 4.6.1
Checksums-Sha1:
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 9a982650c50eb64c492d0ef6bc29971f1adf2c17 3528 haskell-syb-with-class_0.6.1.14-1.debian.tar.xz
 feb6bdfb51021280651c62dbcd5d48246ec92be9 8474 haskell-syb-with-class_0.6.1.14-1_amd64.buildinfo
Checksums-Sha256:
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Files:
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