Proposal for stand-alone deriving declarations?

[Ross Paterson]

On Wed, Nov 01, 2006 at 03:51:57PM -0800, John Meacham wrote:
> On Wed, Nov 01, 2006 at 03:15:38PM -0600, Brian Smith wrote:
> > Instance hiding is an important feature in its own right.
> 
> selective importing and exporting of instances is a really tricky
> technical issue for a lot of reasons, and a bad idea for many others.

As an example of the technical difficulties, recall that with ghc
-fglasgow-exts and hugs -98 defer reducing contexts using instances
until forced to (see FlexibleContexts).  If instances can come and go,
this will be even more confusing.