[GHC] #11077: ghc panic: ieName failed pattern match

[GHC]

#11077: ghc panic: ieName failed pattern match
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           Reporter:  woehr          |             Owner:
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  7.10.2
           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:
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 My custom prelude module is producing the following panic in ghc:
 {{{
 <no location info>:
     ghc: panic! (the 'impossible' happened)
   (GHC version 7.10.2 for x86_64-unknown-linux):
         ieName failed pattern match!

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

 The module is as follows:
 {{{#!hs
 module Prelude
 ( module X
 , tshow
 ) where

 import BasePrelude as X
 import Data.Text as X (Text, pack, unpack)

 tshow :: Show a => a -> Text
 tshow = pack . show
 }}}

 In my cabal file I depend on base-noprelude and base-prelude and use the
 above as my custom Prelude module. The panic is triggered by ```tshow```.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11077>
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