negative `bytes' in :set +s

Dear GHC team,

My DoCon test under  ghc-6-2-branch  performs like this

              ghc $pcpdocon --make T_
              ...
              ghci $pcpdocon T_ ...
              ... 
              Prelude T_> :set +s
              Prelude T_> test "log"
              ...
              *** Test FINISHED ***
              ...
              (35.02 secs, -990807880 bytes)

`:set +s'  is very usable, and the spent number of bytes is 
informative.
And it shows as negative.
Maybe, this can fixed by replacing of  Int  with  Integer ?
Just one more avidence of Int being a bug?

Recall also of the Set cardinality and such.

With kind regards,

-----------------
Serge Mechveliani
mechvel@xxxxxxxx