[GHC] #6031: Cannot derive instances for empty datatypes defined in other modules

[GHC]

#6031: Cannot derive instances for empty datatypes defined in other modules
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 Reporter:  dreixel           |          Owner:                  
     Type:  bug               |         Status:  new             
 Priority:  normal            |      Component:  Compiler        
  Version:  7.5               |       Keywords:                  
       Os:  Unknown/Multiple  |   Architecture:  Unknown/Multiple
  Failure:  None/Unknown      |       Testcase:                  
Blockedby:                    |       Blocking:                  
  Related:                    |  
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Comment(by simonpj@…):

 commit bf6f7085c62370081d4fe421202ec31c9e51bcb4
 {{{
 Author: Simon Peyton Jones <simonpj at microsoft.com>
 Date:   Sun Apr 22 16:24:07 2012 +0100

     Empty data types should not be "trimmed" by TidyPgm

     That in turn means that you can derive Show etc in other modules,
     fixing Trac #6031

  compiler/main/TidyPgm.lhs |   26 +++++++++++++++++---------
  1 files changed, 17 insertions(+), 9 deletions(-)
 }}}

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Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/6031#comment:1>
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