[Pkg-haskell-maintainers] Bug#788781: carettah: FTBFS with ghc 7.8(?): Render.hs:26:36: Not in scope: type constructor or class `G.Markup'

[Chris West (Faux)]

Package: carettah
Version: 0.3.0-1
Severity: serious
Justification: fails to build from source (but built successfully in the past)

Dear Maintainer,

The package fails to build in sid, which currently has ghc 7.8:

Building carettah-0.3.0...
Preprocessing executable '_carettah_main_' for carettah-0.3.0...
[1 of 6] Compiling FormatPangoMarkup ( FormatPangoMarkup.hs, dist-ghc/build/_carettah_main_/_carettah_main_-tmp/FormatPangoMarkup.o )
[2 of 6] Compiling Paths_carettah   ( dist-ghc/build/autogen/Paths_carettah.hs, dist-ghc/build/_carettah_main_/_carettah_main_-tmp/Paths_carettah.o )
[3 of 6] Compiling WrapPaths        ( WrapPaths.hs, dist-ghc/build/_carettah_main_/_carettah_main_-tmp/WrapPaths.o )
[4 of 6] Compiling Config           ( Config.hs, dist-ghc/build/_carettah_main_/_carettah_main_-tmp/Config.o )
[5 of 6] Compiling Render           ( Render.hs, dist-ghc/build/_carettah_main_/_carettah_main_-tmp/Render.o )

Render.hs:26:36: Not in scope: type constructor or class `G.Markup'
/usr/share/cdbs/1/class/hlibrary.mk:146: recipe for target 'build-ghc-stamp' failed

Full build logs can be seen on the Reproducible Builds builder:
https://reproducible.debian.net/rb-pkg/unstable/amd64/carettah.html

-- System Information:
Debian Release: stretch/sid
  APT prefers unstable
  APT policy: (500, 'unstable'), (1, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 3.19.0-20-generic (SMP w/8 CPU cores)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)