[GHC] #13612: ghc.exe: panic! (the 'impossible' happened)

[GHC]

#13612: ghc.exe: panic! (the 'impossible' happened)
-------------------------------------+-------------------------------------
           Reporter:  hmemcpy        |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.0.2
           Keywords:                 |  Operating System:  Windows
       Architecture:  x86_64         |   Type of failure:  Compile-time
  (amd64)                            |  crash or panic
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
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 Full output:
 {{{
 ghc.exe: panic! (the 'impossible' happened)
   (GHC version 8.0.2 for x86_64-unknown-mingw32):
         initTc: unsolved constraints
   WC {wc_insol = [W] n_a1qA :: t_a1qz[tau:1] (CHoleCan: n)}

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

 This failed on a trivial (albeit incorrect) "Hello world" code, while
 trying to execute it with stack: **stack Main.hs**

 The code file is attached.

 Note that this error happens when it incorrectly specifies the non-
 existing value **n** (instead of **name**) in the last expression.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13612>
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