[Haskell] deriving with newtypes

Simon Peyton-Jones simonpj at microsoft.com
Thu Mar 25 16:41:09 EST 2004

[Redirecting to GHC users.]

This seems like a very reasonable point.   Not possible today, but it
should be.  It'll go on my to-do list.  Meanwhile, I guess you can
always do it by steam.


| -----Original Message-----
| From: haskell-bounces at haskell.org [mailto:haskell-bounces at haskell.org]
On Behalf Of Wolfgang
| Jeltsch
| Sent: 21 March 2004 17:55
| To: The Haskell Mailing List
| Subject: [Haskell] deriving with newtypes
| Hello,
| I'm trying to use GHC's deriving mechanism for newtypes in the
following way:
|     class C a b
|     instance C [a] Char
|     newtype T = T Char deriving C [a]
| Unfortunately, this isn't possible. Is there a reason for this? Can I
| circumvent this restriction?
| Wolfgang
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