Re: Narrower (per-method) GND

On Mon, Jan 9, 2017 at 5:11 PM, David Feuer wrote:

On Mon, Jan 9, 2017 at 1:32 PM, Richard Eisenberg wrote:

...

2. Defaulting to the implementation written in the class (or `error "undefined method"` in the absence of a default. This is essentially the default default.)

I want to be able to specify that a certain default definition is good enough not to worry about.

Is this the same as the purpose of the MINIMAL pragma? http://ghc.readthedocs.io/en/latest/glasgow_exts.html#minimal-pragma Imagine GND provides implementations for those methods whose types are amenable to `coerce`ion and leaves the other methods without definitions. Then, taking into account the MINIMAL pragma, GHC either does or does not produce a warning/error about missing class methods, maybe customized to mention the failure to `coerce` a method in GND. Would that be adequate? Regards, Reid Barton