[GHC] #13991: I was building/testing a haskell project using stack ..suddenly I see the following output. Also attached the project

[GHC]

#13991: I was building/testing a haskell project using stack ..suddenly I see the
following output. Also attached the project
-------------------------------------+-------------------------------------
           Reporter:  chandrakoduru  |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.0.1
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 putting-haskell-to-test-0.0.1.0: build (lib + test)
 Preprocessing library putting-haskell-to-test-0.0.1.0...
 Preprocessing test suite 'HUnitTest' for putting-haskell-to-
 test-0.0.1.0...
 [1 of 1] Compiling Main             ( test/HUnitTest/Spec.hs, .stack-
 work/dist/x86_64-linux/Cabal-1.24.2.0/build/HUnitTest/HUnitTest-tmp/Main.o
 )
 ghc: panic! (the 'impossible' happened)
   (GHC version 8.0.2 for x86_64-unknown-linux):
         initTc: unsolved constraints
   WC {wc_insol =
         [W] @?=_a1lM :: t_a1lL[tau:1] (CHoleCan: @?=)
         [W] testCase_a1m2 :: t_a1m1[tau:1] (CHoleCan: testCase)
         [W] simpleMathFunction_a1mb :: t_a1ma[tau:1] (CHoleCan:
 simpleMathFunction)
         [W] @?=_a1xp :: t_a1xo[tau:1] (CHoleCan: @?=)
         [W] testCase_a1xB :: t_a1xA[tau:1] (CHoleCan: testCase)
         [W] simpleMathFunction_a1xK :: t_a1xJ[tau:1] (CHoleCan:
 simpleMathFunction)}

 Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug

 Progress: 1/2
 --  While building package putting-haskell-to-test-0.0.1.0 using:
       /home/local/ANT/chandrak/.stack/setup-exe-cache/x86_64-linux/Cabal-
 simple_mPHDZzAJ_1.24.2.0_ghc-8.0.2 --builddir=.stack-
 work/dist/x86_64-linux/Cabal-1.24.2.0 build lib:putting-haskell-to-test
 test:HUnitTest --ghc-options " -ddump-hi -ddump-to-file"
     Process exited with code: ExitFailure 1

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13991>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler