Compile error for test suite when building based on nixpkgs

[maralorn]

When updating to reflex 0.8.2.0 in nixpkgs I get a type check error when compiling the test suite:

reflex> test/RequesterT.hs:68:18: error:
reflex>     • Could not deduce: ConstraintsFor TestRequest Read
reflex>         arising from a use of ‘testMatchRequestsWithResponses’
reflex>     • In the first argument of ‘runApp'’, namely
reflex>         ‘testMatchRequestsWithResponses’
reflex>       In a stmt of a 'do' block:
reflex>         os7 <- runApp'
reflex>                  testMatchRequestsWithResponses [Just $ TestRequest_Increment 1]
reflex>       In the expression:
reflex>         do os1 <- runApp' (unwrapApp testOrdering) $ [Just ()]
reflex>            print os1
reflex>            os2 <- runApp' (unwrapApp testSimultaneous)
reflex>                     $ map Just $ [This (), That (), ....]
reflex>            print os2
reflex>            ....
reflex>    |
reflex> 68 |   os7 <- runApp' testMatchRequestsWithResponses [ Just $ TestRequest_Increment 1 ]
reflex>    |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
reflex> 
reflex> test/RequesterT.hs:68:18: error:
reflex>     • No instance for (Show
reflex>                          (TestRequest
reflex>                             (Data.Constraint.Forall.Skolem
reflex>                                (Data.Constraint.Forall.ComposeC Show TestRequest))))
reflex>         arising from a use of ‘testMatchRequestsWithResponses’
reflex>     • In the first argument of ‘runApp'’, namely
reflex>         ‘testMatchRequestsWithResponses’
reflex>       In a stmt of a 'do' block:
reflex>         os7 <- runApp'
reflex>                  testMatchRequestsWithResponses [Just $ TestRequest_Increment 1]
reflex>       In the expression:
reflex>         do os1 <- runApp' (unwrapApp testOrdering) $ [Just ()]
reflex>            print os1
reflex>            os2 <- runApp' (unwrapApp testSimultaneous)
reflex>                     $ map Just $ [This (), That (), ....]
reflex>            print os2
reflex>            ....
reflex>    |
reflex> 68 |   os7 <- runApp' testMatchRequestsWithResponses [ Just $ TestRequest_Increment 1 ]
reflex>    |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

This is without any jailbreaks, with stackage-lts and newest dependencies from hackage.