[GHC] #15646: ghci takes super long time to find the type of large fractional number

[GHC]

#15646: ghci takes super long time to find the type of large fractional number
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        Reporter:  Johannkokos       |                Owner:
                                     |  JulianLeviston
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.6.1
       Component:  GHCi              |              Version:  8.4.3
      Resolution:                    |             Keywords:  newcomer
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by simonpj):

 >  the proposed solution will still blow up when desugaring

 No, it won'r blow up when desugaring. Just desugar the constant to
 `fromRational (readRational "1E1000")`.  Nothing blows up there!

 > One problem with removing fl_value may be that any users of this type
 (maybe source plugins?) will have to provide a string instead of an actual
 float

 Well `(show f)` is a good string.  And I quite like the
 `fl_before/after/exp` version too.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15646#comment:16>
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