[GHC] #11077: ghc panic: ieName failed pattern match (-fwarn-missing-exported-sigs) (was: ghc panic: ieName failed pattern match)

[GHC]

#11077: ghc panic: ieName failed pattern match (-fwarn-missing-exported-sigs)
-------------------------------------+-------------------------------------
        Reporter:  woehr             |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.10.2
      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:                    |
-------------------------------------+-------------------------------------
Changes (by thomie):

 * cc: gridaphobe (added)


Comment:

 Thanks! Reproducible with HEAD. It seems `-fwarn-missing-exported-sigs`
 (#2526) has something to do with it.

 {{{
 $ cat T11077.hs
 module T11077 (module X, foo) where
 import Data.List as X
 foo = undefined

 $ ghc -c T11077.hs -fwarn-missing-exported-sigs
 ghc: panic! (the 'impossible' happened)
   (GHC version 7.11.20151104 for x86_64-unknown-linux):
         ieName failed pattern match!
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11077#comment:4>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler