ghci sometimes displays Word32 as Word64

Given this code:

module Main
    where

import Data.Word
import Unsafe.Coerce
import System.IO

nanFloat :: Float
nanFloat = unsafeCoerce (maxBound :: Word32)

float2word32 :: Float -> Word32
float2word32 = unsafeCoerce

nanDouble :: Double
nanDouble = unsafeCoerce (maxBound :: Word64)

double2word64 :: Double -> Word64
double2word64 = unsafeCoerce

main = do
    putStrLn $ "nanFloat  = " ++ show (float2word32 nanFloat)
    putStrLn $ "nanFloat  = " ++ show (float2word32 $ nanFloat + 1)
    putStrLn $ "nanDouble = " ++ show (double2word64 nanDouble)
    putStrLn $ "nanDouble = " ++ show (double2word64 $ nanDouble + 1)

If we compile with GHC and run, we correctly output:

nanFloat  = 4294967295
nanFloat  = 4294967295
nanDouble = 18446744073709551615
nanDouble = 18446744073709551615

But if we instead load in ghci, we get the following output:

nanFloat  = 4294967295
nanFloat  = 140247862083583
nanDouble = 18446744073709551615
nanDouble = 18446744073709551615

For some reason, ghci is displaying (nanFloat+1) as having significantly more digits than can possibly stored in a Word32 value.

Test system: Intel Core 2 Duo running Debian with GHC 7.8.2

Trac metadata

Trac field	Value
Version	7.8.2
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	GHCi
Test case
Differential revisions
BlockedBy
Related
Blocking
CC	hvr
Operating system
Architecture