[GHC] #7737: t7319: Oops! Entered absent arg w_s1Du{v} [lid] [base:GHC.Base.String{tc 36u}]

[GHC]

#7737: t7319: Oops!  Entered absent arg w_s1Du{v} [lid] [base:GHC.Base.String{tc
36u}]
-----------------------------+----------------------------------------------
Reporter:  luite             |          Owner:                  
    Type:  bug               |         Status:  new             
Priority:  normal            |      Component:  Compiler        
 Version:  7.7               |       Keywords:                  
      Os:  Unknown/Multiple  |   Architecture:  Unknown/Multiple
 Failure:  None/Unknown      |      Blockedby:                  
Blocking:                    |        Related:                  
-----------------------------+----------------------------------------------

Comment(by simonpj@…):

 commit a37a7f7beee0d12a1cf600e96c6d4450e01e6607
 {{{
 Author: Simon Peyton Jones <simonpj at microsoft.com>
 Date:   Tue Mar 5 09:26:27 2013 +0000

     Ensure that isStrictDmd is False for Absent (fixes Trac #7737)

     The demand <HyperStr, Absent> for a let-bound value is bit
     strange; it means that the context will diverge, but this
     argument isn't used. We don't want to use call-by-value here,
     even though it's semantically sound if all bottoms mean
     the same.

     The fix is easy; just make "isStrictDmd" a bit more perspicuous.
     See Note [Strict demands] in Demand.lhs

  compiler/basicTypes/Demand.lhs |   29 ++++++++++++++++++++++++-----
  1 files changed, 24 insertions(+), 5 deletions(-)
 }}}

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7737#comment:1>
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