[GHC] #4100: ghci should use UserInterrupt exception from base, not private Interrupted exception

[GHC]

#4100: ghci should use UserInterrupt exception from base, not private Interrupted
exception
---------------------------------+------------------------------------------
    Reporter:  duncan            |       Owner:              
        Type:  bug               |      Status:  new         
    Priority:  normal            |   Component:  Compiler    
     Version:  6.12.2            |    Keywords:              
          Os:  Unknown/Multiple  |    Testcase:              
Architecture:  Unknown/Multiple  |     Failure:  None/Unknown
---------------------------------+------------------------------------------
 In response to the user pressing control-C, ghci uses an exception
 `Interrupted :: GhcException` from the module `Panic`.

 Testsuites designed to be used in ghci (like QuickCheck) need to
 distinguish this interrupted exception from other exceptions which
 indicate an actual failing test.

 Since this exception is only defined in the ghc package, this means that
 packages such as QuickCheck are forced to depend on the ghc package. This
 causes no end of problems.

 The solution is for ghci to use the (newer) exception from
 `Control.Exception`, `UserInterrupt :: AsyncException`. Then packages such
 as QC do not need to depend on the ghc package and everyone will be happy.

 The QC developers indicate they're happy to switch it. They just need to
 know which version it will be fixed in, so they can write the appropriate
 CPP magic to do the right thing based on the ghc version.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/4100>
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