[GHC] #8932: Panic with TemplateHaskell and duplicate indentifiers

[GHC]

#8932: Panic with TemplateHaskell and duplicate indentifiers
-----------------------------------+---------------------------------------
       Reporter:  jstolarek        |             Owner:
           Type:  bug              |            Status:  new
       Priority:  normal           |         Milestone:
      Component:  Template         |           Version:  7.8.1-rc2
  Haskell                          |  Operating System:  Unknown/Multiple
       Keywords:                   |   Type of failure:  Compile-time crash
   Architecture:                   |         Test Case:
  Unknown/Multiple                 |          Blocking:
     Difficulty:  Unknown          |
     Blocked By:                   |
Related Tickets:                   |
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 This code causes GHC panic under 7.8.1-RC2:

 {{{
 {-# LANGUAGE TemplateHaskell #-}

 module TXXXX where

 $([d|
   foo :: a -> a
   foo x = x
  |])

 foo :: a
 foo = undefined
 }}}

 {{{
 [killy at xerxes : /dane/projekty/sandbox/haskell] ghc -fforce-recomp
 TXXXX.hs
 [1 of 1] Compiling TXXXX            ( TXXXX.hs, TXXXX.o )
 Loading package ghc-prim ... linking ... done.
 Loading package integer-gmp ... linking ... done.
 Loading package base ... linking ... done.
 Loading package array-0.5.0.0 ... linking ... done.
 Loading package deepseq-1.3.0.2 ... linking ... done.
 Loading package containers-0.5.4.0 ... linking ... done.
 Loading package pretty-1.1.1.1 ... linking ... done.
 Loading package template-haskell ... linking ... done.
 ghc: panic! (the 'impossible' happened)
   (GHC version 7.8.0.20140226 for x86_64-unknown-linux):
         lookupExactOcc
     foo_a2kL{v}
     [main:TXXXX.foo{v a2kL} defined at TXXXX.hs:11:1,
      main:TXXXX.foo{v a2kL} defined at TXXXX.hs:5:3]
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8932>
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