recursive group context bug?

Simon Peyton-Jones simonpj at microsoft.com
Fri Jan 28 04:29:45 EST 2005


The Report says that the functions of a mutually recursive group must
all have the same context.  It's a bit of a funny rule, and it's more
restrictive than absolutely necessary, but that's what Haskell says.  I
could work to lift the restriction in GHC, but it only seems to come up
in toy programs, never in real ones.  So it's low (very low) priority at
the moment.


Simon

| -----Original Message-----
| From: glasgow-haskell-users-bounces at haskell.org
[mailto:glasgow-haskell-users-
| bounces at haskell.org] On Behalf Of Keean Schupke
| Sent: 17 January 2005 13:52
| To: Carsten Schultz
| Cc: Simon Marlow; glasgow-haskell-users at haskell.org
| Subject: Re: recursive group context bug?
| 
| This must be a bug then, because the following works!
| 
| y :: Num a => a
| y = fromIntegral (y::Int)
| 
| >A simpler example might be:
| >
| >    x :: Int
| >    x = y
| >
| >    y :: Num a => a
| >    y = fromIntegral x
| >
| >I have not studied the report to see if this should be legal.
| >
| >
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