[GHC] #2480: error function is not lazy

[GHC]

#2480: error function is not lazy
--------------------------+-------------------------------------------------
 Reporter:  NeilMitchell  |          Owner:         
     Type:  bug           |         Status:  new    
 Priority:  normal        |      Milestone:         
Component:  Compiler      |        Version:  6.8.3  
 Severity:  normal        |     Resolution:         
 Keywords:                |     Difficulty:  Unknown
 Testcase:  cg016         |   Architecture:  Unknown
       Os:  Windows       |  
--------------------------+-------------------------------------------------
Changes (by simonmar):

  * testcase:  => cg016
  * difficulty:  => Unknown

Comment:

 Trace is supposed to work like this, the idea is that trace messages don't
 get interleaved with each other.

 For error, the exception is passed to the RTS for printing, because in a
 Windows non-console program the error will pop up in a message box.
 Passing the message to the RTS of course involves serialising it.  I
 suppose we could detect whether the program was running on the console and
 use lazy output, but the program will still hang in a non-console
 environment.

 Incedentally, test cg016 tests something very similar (nested errors).

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2480#comment:2>
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