Differences in pattern matching syntax?

[David Menendez]

On Fri, Jan 16, 2009 at 11:07 AM, Simon Peyton-Jones
<simonpj at microsoft.com> wrote:
>
> So, clearly not a bug in GHC; but it would be more felicitous if it gave you a warning about the instance declaration for Eq RuleType.  The difficulty is that it's not clear when to warn; it's ok to use default methods, but you must define *either* (==) *or* (/=).

Why is (/=) a member of Eq in the first place? Is there any code that
defines (/=) and uses the default for (==)?

-- 
Dave Menendez <dave at zednenem.com>
<http://www.eyrie.org/~zednenem/>