Type roles for UArray?

[Roman Cheplyaka]

On 24/03/15 16:59, Richard Eisenberg wrote:
> When more than one mechanism is non-trivially applicable, GHC should
> error. (The "non-trivial" is there to rule out errors for, say,
> deriving Eq via Haskell98 or via GND: both result in the same
> behavior.)

This happens all the time — Show instance would differ from the standard
derived one if GND'ed.

But I certainly share your concerns.

Roman