[GHC] #1678: runIO does not catch userErrors, just causes code generation to fail silently

[GHC]

#1678: runIO does not catch userErrors, just causes code generation to fail
silently
-------------------------------+--------------------------------------------
  Reporter:  greenrd           |          Owner:                
      Type:  bug               |         Status:  new           
  Priority:  normal            |      Milestone:                
 Component:  Template Haskell  |        Version:  6.7           
  Severity:  normal            |       Keywords:                
Difficulty:  Unknown           |             Os:  Linux         
  Testcase:                    |   Architecture:  x86_64 (amd64)
-------------------------------+--------------------------------------------
If a userError is thrown inside a runIO computation inside a splice, no
 indication of the error is given - instead, the compiler just fails to
 generate a valid .hi file, leaving the user none the wiser as to what has
 gone wrong.

 (Actually, maybe this is a more general problem than just runIO - I also
 noticed that use of "undefined" in a splice can cause an "impossible"
 error in GHC.)

 This is with a checkout from today from darcs.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1678>
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