patch applied (ghc): Instance declaration overlap allowed if *either* has -XOverlappingInstances

[Simon Peyton Jones]

Tue Dec 14 10:05:00 PST 2010  simonpj at microsoft.com
  * Instance declaration overlap allowed if *either* has -XOverlappingInstances
  
  This satisfies Trac #3877.  Documentation is changed too.
  I'm not sure if this should go in 7.0.2.

    M ./compiler/types/InstEnv.lhs -8 +12
    M ./docs/users_guide/glasgow_exts.xml -19 +10

View patch online:
http://darcs.haskell.org/cgi-bin/darcsweb.cgi?r=ghc;a=darcs_commitdiff;h=20101214180500-1287e-152d3a6b7007f77e61008171369963f1338cf503.gz