[GHC] #2412: Interaction between type synonyms and .hs-boot causes panic "tcIfaceGlobal (local): not found"

[GHC]

#2412: Interaction between type synonyms and .hs-boot causes panic "tcIfaceGlobal
(local): not found"
-------------------------------+--------------------------------------------
    Reporter:  batterseapower  |        Owner:         
        Type:  bug             |       Status:  new    
    Priority:  normal          |    Milestone:         
   Component:  Compiler        |      Version:  6.9    
    Severity:  normal          |   Resolution:         
    Keywords:                  |     Testcase:         
Architecture:  Unknown         |           Os:  Unknown
-------------------------------+--------------------------------------------
Comment (by batterseapower):

 Actually, I've just confirmed that the synonym Main.Spqr is irrelevant:
 you can replace the use of it in Main.Baz with Foo.Bar itself and get the
 same behaviour.

 A workaround for this bug is to use a newtype rather than a type synonym
 in Foo.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2412#comment:1>
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