[GHC] #14187: Transpose hangs on infinite by finite lists

[GHC]

#14187: Transpose hangs on infinite by finite lists
-------------------------------------+-------------------------------------
           Reporter:  utikeev        |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.2.1
           Keywords:  transpose      |  Operating System:  Windows
       Architecture:  x86_64         |   Type of failure:  Runtime
  (amd64)                            |  performance bug
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
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 I found out that this code

 {{{#!hs
 take 5 $ map (take 3) (transpose (repeat [0..1]))
 }}}

 isn't equivalent to this one

 {{{#!hs
 take 5 $ map (take 3) [[0,0..], [1,1..]]
 }}}

 The second piece of code gives expectable output of
 {{{[[0,0,0],[1,1,1]]}}}, while first one just hangs with outpit
 {{{[[0,0,0],[1,1,1],}}} also probably screwing up some descriptors after
 interruption with Ctrl+C (as in 8.2.1, didn't have such problem in 8.0.2.
 I attach the screenshot of my cmd after interruption and pressing Up and
 Down buttons randomly for a few times. The history seems to be broken).

 In my homework I had to make a function zipN, which is actually zipWith
 but for more than two lists. The solution which dealt with stuck was to
 write my own transpose and apply {{{takeWhile (not . null)}}} to the
 remaining part of transposed matrix.

 P.S.:
 {{{#!hs
 [[0,0..],[1,1..]] == transpose (repeat [0..1])
 }}}
 also hangs ghci.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14187>
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