[GHC] #5688: instance Read Integer/Rational/Double readsPrec out of memory and crash due to exponential notation

[GHC]

#5688: instance Read Integer/Rational/Double readsPrec out of memory and crash due
to exponential notation
-------------------------------+--------------------------------------------
  Reporter:  gracjan           |          Owner:                  
      Type:  bug               |         Status:  new             
  Priority:  highest           |      Milestone:  7.4.2           
 Component:  libraries/base    |        Version:  6.12.3          
Resolution:                    |       Keywords:                  
        Os:  Unknown/Multiple  |   Architecture:  Unknown/Multiple
   Failure:  Runtime crash     |     Difficulty:  Unknown         
  Testcase:                    |      Blockedby:                  
  Blocking:                    |        Related:                  
-------------------------------+--------------------------------------------

Comment(by maeder):

 Another advantage of removing `Rat` is, that code duplication to treat the
 `Rational` within `Rat` and `Exp`(i.e. the conversion to `Double`) is
 avoided.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5688#comment:38>
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