[GHC] #14759: ListSetOps WARNING causes tests to fail

[GHC]

#14759: ListSetOps WARNING causes tests to fail
-------------------------------------+-------------------------------------
        Reporter:  ezyang            |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.2.2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by alpmestan):

 This very problem was causing a whole bunch of tests to fail when running
 `./validate --slow`:

 {{{
    /run/user/1001/ghctest-tkhsza6q/test
 spaces/./backpack/cabal/T14304/T14304.run                   T14304 [bad
 stderr] (normal)
    /run/user/1001/ghctest-tkhsza6q/test
 spaces/./backpack/cabal/bkpcabal02/bkpcabal02.run           bkpcabal02
 [bad stderr] (normal)
    /run/user/1001/ghctest-tkhsza6q/test
 spaces/./backpack/cabal/bkpcabal03/bkpcabal03.run           bkpcabal03
 [bad stderr] (normal)
    /run/user/1001/ghctest-tkhsza6q/test
 spaces/./backpack/cabal/bkpcabal04/bkpcabal04.run           bkpcabal04
 [bad stderr] (normal)
    /run/user/1001/ghctest-tkhsza6q/test
 spaces/./backpack/cabal/bkpcabal01/bkpcabal01.run           bkpcabal01
 [bad stderr] (normal)
    /run/user/1001/ghctest-tkhsza6q/test
 spaces/./backpack/cabal/bkpcabal05/bkpcabal05.run           bkpcabal05
 [bad stderr] (normal)
    /run/user/1001/ghctest-tkhsza6q/test
 spaces/./backpack/cabal/bkpcabal06/bkpcabal06.run           bkpcabal06
 [bad stderr] (normal)
    /run/user/1001/ghctest-tkhsza6q/test
 spaces/./backpack/cabal/bkpcabal07/bkpcabal07.run           bkpcabal07
 [bad stderr] (normal)
    /run/user/1001/ghctest-tkhsza6q/test   spaces/./cabal/T12733/T12733.run
 T12733 [bad stderr] (normal)
    /run/user/1001/ghctest-tkhsza6q/test   spaces/./cabal/cabal01/t.run
 cabal01 [bad stderr] (normal)
    /run/user/1001/ghctest-tkhsza6q/test
 spaces/./cabal/cabal03/cabal03.run                          cabal03 [bad
 stderr] (normal)
    /run/user/1001/ghctest-tkhsza6q/test
 spaces/./cabal/cabal04/cabal04.run                          cabal04 [bad
 stderr] (normal)
    /run/user/1001/ghctest-tkhsza6q/test
 spaces/./cabal/cabal08/cabal08.run                          cabal08 [bad
 stderr] (normal)
    /run/user/1001/ghctest-tkhsza6q/test
 spaces/./cabal/cabal05/cabal05.run                          cabal05 [bad
 stderr] (normal)
    /run/user/1001/ghctest-tkhsza6q/test
 spaces/./cabal/cabal09/cabal09.run                          cabal09 [bad
 stderr] (normal)
    /run/user/1001/ghctest-tkhsza6q/test
 spaces/./cabal/cabal06/cabal06.run                          cabal06 [bad
 stderr] (normal)
    /run/user/1001/ghctest-tkhsza6q/test   spaces/./driver/T3007/T3007.run
 T3007 [bad stderr] (normal)
    /run/user/1001/ghctest-qrii3s_s/test
 spaces/./patsyn/should_compile/T13350/T13350.run            T13350 [bad
 stderr] (normal)
    /run/user/1001/ghctest-tkhsza6q/test   spaces/./cabal/T12733/T12733.run
 T12733 [bad stderr]
    /run/user/1001/ghctest-tkhsza6q/test   spaces/./driver/T3007/T3007.run
 T3007 [bad stderr] (normal)
 }}}

 I have a patch that fixes those tests, it simply implements Ben's
 suggestion. It's now up on phab as [https://phabricator.haskell.org/D4628
 D4628].

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14759#comment:3>
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