Bug#1013787: haskell-operational FTBFS: error: Ambiguous occurrence ‘singleton’

[Adrian Bunk]

Source: haskell-operational
Version: 0.2.3.5-5
Severity: serious
Tags: ftbfs bookworm sid

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

...
[1 of 1] Compiling Main             ( doc/examples/TicTacToe.hs, dist-ghc/build/operational-TicTacToe/operational-TicTacToe-tmp/Main.o )

src/Control/Monad/Operational.hs:26:1: warning: [-Wunused-imports]
    The import of ‘Control.Applicative’ is redundant
      except perhaps to import instances from ‘Control.Applicative’
    To import instances alone, use: import Control.Applicative()
   |
26 | import Control.Applicative
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^

src/Control/Monad/Operational.hs:26:1: warning: [-Wunused-imports]
    The import of ‘Control.Applicative’ is redundant
      except perhaps to import instances from ‘Control.Applicative’
    To import instances alone, use: import Control.Applicative()
   |
26 | import Control.Applicative
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^

doc/examples/TicTacToe.hs:46:13: error:
    Ambiguous occurrence ‘singleton’
    It could refer to
       either ‘Control.Monad.Operational.singleton’,
              imported from ‘Control.Monad.Operational’ at doc/examples/TicTacToe.hs:19:1-32
           or ‘Data.List.singleton’,
              imported from ‘Data.List’ at doc/examples/TicTacToe.hs:23:1-16
              (and originally defined in ‘base-4.15.1.0:Data.OldList’)
   |
46 | readBoard = singleton ReadBoard
   |             ^^^^^^^^^

doc/examples/TicTacToe.hs:47:13: error:
    Ambiguous occurrence ‘singleton’
    It could refer to
       either ‘Control.Monad.Operational.singleton’,
              imported from ‘Control.Monad.Operational’ at doc/examples/TicTacToe.hs:19:1-32
           or ‘Data.List.singleton’,
              imported from ‘Data.List’ at doc/examples/TicTacToe.hs:23:1-16
              (and originally defined in ‘base-4.15.1.0:Data.OldList’)
   |
47 | playMove  = singleton . PlayMove
   |             ^^^^^^^^^
 at /usr/share/perl5/Debian/Debhelper/Buildsystem/Haskell/Recipes.pm line 107.
	Debian::Debhelper::Buildsystem::Haskell::Recipes::run_quiet("debian/hlibrary.setup", "build", "--builddir=dist-ghc") called at /usr/share/perl5/Debian/Debhelper/Buildsystem/Haskell/Recipes.pm line 131
	Debian::Debhelper::Buildsystem::Haskell::Recipes::run("debian/hlibrary.setup", "build", "--builddir=dist-ghc") called at /usr/share/perl5/Debian/Debhelper/Buildsystem/Haskell/Recipes.pm line 640
	Debian::Debhelper::Buildsystem::Haskell::Recipes::build_recipe() called at -e line 1
make: *** [/usr/share/cdbs/1/class/hlibrary.mk:153: build-ghc-stamp] Error 25