Re: Overlapping and incoherent instances

On Wed, Jul 30, 2014 at 2:50 PM, Ivan Lazar Miljenovic wrote:

On 30 July 2014 22:07, Andreas Abel wrote:

...

I am a bit surprised by the distinction you outline below. This is maybe because I am native German, not English. The German equivalent of "overlap", "überschneiden/überlappen", is used exclusively in a symmetrical fashion. It's like in English, if I say "our interests overlap", then it is pointless to ask whether my interest are overlapping yours or are overlapped by yours. I want to alert you to the fact that non-native English speaker might have little understanding for a distinction between "OVERLAPPING" and "OVERLAPPABLE".

Let's try to guess what it meant: Given

A) instance Bla Char B) instance Bla a => Bla [a] C) instance Bla String

you will in context A,B write C as OVERLAPPING, and in context A,C write B as OVERLAPPABLE?

IIUC, B will be OVERLAPPABLE ("you can overlap this") and C will be OVERLAPPING ("I'm overlapping an existing one") whereas C will be plain.

Apologies if this question doesn't make sense. Can we really talk about overlapping, given that instances can be written in different modules, moved between modules, or removed?