Yes it’s documented in the user manual

http://www.haskell.org/ghc/docs/latest/html/users_guide/data-type-extensions.html#gadt-style

Since you didn’t find it, despite looking, can you suggest how we could improve the manual so that you would?

Thanks

Simon

From: glasgow-haskell-users-bounces@haskell.org [mailto:glasgow-haskell-users-bounces@haskell.org] On Behalf Of Conal Elliott
Sent: 01 April 2009 00:54
To: glasgow-haskell-users@haskell.org
Subject: Re: GADTs with strict fields?

I got an answer:  precede the argument types by a "!".  I didn't realize that type applications then have to be parenthesized.

On Tue, Mar 31, 2009 at 4:18 PM, Conal Elliott <conal@conal.net> wrote:

Do strict fields work with GADTs?  If so, what's the syntax for the strictness annotations?   - Conal