[GHC] #3454: ghci freezes on failed pattern match in recursive list comprehension

[GHC]

#3454: ghci freezes on failed pattern match in recursive list comprehension
-----------------------------+----------------------------------------------
Reporter:  Syzygies          |          Owner:                  
    Type:  bug               |         Status:  new             
Priority:  normal            |      Component:  Compiler        
 Version:  6.10.4            |       Severity:  normal          
Keywords:                    |       Testcase:                  
      Os:  Unknown/Multiple  |   Architecture:  Unknown/Multiple
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 The following freezes ghci (top shows no resources consumed):

 {{{
 Prelude> let xs = [1..5] : [ xt | (_:xt) <- xs ] in take 7 xs
 [[1,2,3,4,5],[2,3,4,5],[3,4,5],[4,5],[5],[]
 }}}

 This is not the same issue as
 [http://hackage.haskell.org/trac/ghc/ticket/3053] (closed, invalid) as
 there are no elements to filter. (This may be a well-known black hole, but
 not to me; I was hoping a similar list would just terminate, trying to
 avoid the Nothing case boilerplate in an unfoldl.)

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Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/3454>
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