[GHC] #10279: panic on haskell-src-exts

[GHC]

#10279: panic on haskell-src-exts
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        Reporter:  throwaway123      |                   Owner:  ezyang
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:
       Component:  Compiler          |                 Version:  7.10.1
      Resolution:                    |                Keywords:
Operating System:  Linux             |            Architecture:  x86_64
 Type of failure:  Compile-time      |  (amd64)
  crash                              |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:                    |  Differential Revisions:
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Comment (by ezyang):

 OK, did some reading of haskell-src-exts-qq and it's the same problem as
 https://github.com/ekmett/lens/issues/496 and #9745:

 {{{
 -- | The generic functions in 'Language.Haskell.TH.Quote' don't use global
 -- names for syntax constructors. This has the unfortunate effect of
 breaking
 -- quotation when the haskell-src-exts syntax module is imported
 qualified.
 -- The solution is to set the flavour of all names to 'NameG'.
 qualify :: Name -> Name
 -- Need special cases for constructors used in string literals. Assume
 nearly
 -- all else is a datatype defined in Syntax module of haskell-src-exts.
 qualify n | ":" <- nameBase n = '(:)
           | "[]" <- nameBase n = '[]
           | "(,)" <- nameBase n = '(,)
           | "Nothing" <- nameBase n = 'Nothing
           | "Just" <- nameBase n = 'Just
           | "SrcLoc" <- nameBase n = 'Hs.SrcLoc
           | "Boxed" <- nameBase n = 'Hs.Boxed
           | otherwise = Name (mkOccName (nameBase n)) flavour
     where pkg = "haskell-src-exts-" ++ VERSION_haskell_src_exts
           flavour = NameG VarName (mkPkgName pkg)
                     (mkModName "Language.Haskell.Exts.Syntax")
 }}}

 This is not going to work with package keys.

 It seems pretty clear to me that we should improve the error message in
 this case, though it's not altogether clear where it should live (probably
 the TH code?)

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10279#comment:6>
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