[Haskell] A problem with overlapping instances and super-classes

[Ian Lynagh]

On Mon, Jun 09, 2008 at 09:21:02AM +0100, Simon Peyton-Jones wrote:
> 
> This isn't great, but it's not really different than is the case for
> non-overlapping instances.  Suppose module B1 declares 'instance C T',
> and uses that instance; and module B2 declares a *different* 'instance
> C T', and uses that instance; and Main imports B1 and B2, but does not
> use either instance directly.  Then GHC will compile the program
> without complaint, although it is incoherent.

Isn't this a divergence from H98? Shouldn't we therefore list it on
    http://www.haskell.org/ghc/docs/latest/html/users_guide/bugs-and-infelicities.html#haskell98-divergence
?


Thanks
Ian