[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:  patch           
    Priority:  highest           |   Milestone:  7.4.1           
   Component:  libraries/base    |     Version:  6.12.3          
    Keywords:                    |          Os:  Unknown/Multiple
Architecture:  Unknown/Multiple  |     Failure:  Runtime crash   
  Difficulty:  Unknown           |    Testcase:                  
   Blockedby:                    |    Blocking:                  
     Related:                    |  
---------------------------------+------------------------------------------

Comment(by maeder):

 While read fails, 10.10 is a legal Rational Haskell value

 {{{
 *Main> 10.10 :: Rational
 101 % 10
 *Main> read "10.10" :: Rational
 *** Exception: Prelude.read: no parse
 }}}

 and

 {{{
 main = print (1E100000000000 :: Rational)
 }}}

 crashes the compiler as happens without type annotation currently.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5688#comment:15>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler