[GHC] #7878: Panic when using DerivingGeneric with hs-boot

[GHC]

#7878: Panic when using DerivingGeneric with hs-boot
-------------------------------+--------------------------------------------
    Reporter:  ryant5000       |       Owner:  dreixel           
        Type:  bug             |      Status:  new               
    Priority:  normal          |   Milestone:                    
   Component:  Compiler        |     Version:  7.7               
    Keywords:                  |          Os:  Linux             
Architecture:  x86_64 (amd64)  |     Failure:  Compile-time crash
  Difficulty:  Unknown         |    Testcase:                    
   Blockedby:                  |    Blocking:                    
     Related:                  |  
-------------------------------+--------------------------------------------
Changes (by simonpj):

  * difficulty:  => Unknown


Old description:

> When a module that uses DerivingGeneric has an hs-boot file, a panic like
> the following results:
>
> ghc: panic! (the 'impossible' happened)
>   (GHC version 7.6.3 for x86_64-unknown-linux):
>         tcIfaceGlobal (local): not found:
>     main:A.D1Test{tc apn}
>     [(roo,ghc: panic! (the 'impossible' happened)
>   (GHC version 7.6.3 for x86_64-unknown-linux):
>         ghc: panic! (the 'impossible' happened)
>   (GHC version 7.6.3 for x86_64-unknown-linux):
>         tcIfaceGlobal (local): not found:
>
> The attached files demonstrate the issue.  To reproduce, run 'ghc --make
> C'.  Note that running the same command a second time will not cause the
> error, unless *.hi* files are deleted.

New description:

 When a module that uses `DerivingGeneric` has an hs-boot file, a panic
 like the following results:
 {{{
 ghc: panic! (the 'impossible' happened)
   (GHC version 7.6.3 for x86_64-unknown-linux):
         tcIfaceGlobal (local): not found:
     main:A.D1Test{tc apn}
     [(roo,ghc: panic! (the 'impossible' happened)
   (GHC version 7.6.3 for x86_64-unknown-linux):
         ghc: panic! (the 'impossible' happened)
   (GHC version 7.6.3 for x86_64-unknown-linux):
         tcIfaceGlobal (local): not found:
 }}}
 The attached files demonstrate the issue.  To reproduce, run `ghc --make
 C`.  Note that running the same command a second time will not cause the
 error, unless `*.hi*` files are deleted.

--

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7878#comment:3>
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