[GHC] #7241: GHC-7.6.1 panics on template haskell code

[GHC]

#7241: GHC-7.6.1 panics on template haskell code
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        Reporter:  akamaus             |            Owner:  Yuras
            Type:  bug                 |           Status:  new
        Priority:  normal              |        Milestone:  7.8.3
       Component:  Template Haskell    |          Version:  7.6.1
      Resolution:                      |         Keywords:
Operating System:  Unknown/Multiple    |     Architecture:
 Type of failure:  Compile-time crash  |  Unknown/Multiple
       Test Case:                      |       Difficulty:  Unknown
        Blocking:                      |       Blocked By:
                                       |  Related Tickets:
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Changes (by Yuras):

 * owner:  simonpj => Yuras


Comment:

 So, the comment added in
 changeset:d8d798b1b33ab0593ed03f193360b8725ba2c2ba is not fully correct.
 `findLocalDupsRdrEnv` doesn't catch this particular case because duplicate
 `Name`s are totally identical, including `SrcSpan`.

 I'll prepare a patch to emit error in case of duplicate GRE. The test case
 from #8932 will produce two errors, but I think it is ok. Definitely
 better then obscure panic.

 Please let me know if I'm going in wrong direction.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7241#comment:6>
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