Hi Simon,
Thanks. So there was a bug in the type checker. Do you have a link to
the ticket or commits which fixed the issue?
Mitsutoshi
2014-12-30 19:56 GMT+09:00 Simon Peyton Jones simo...@microsoft.com:
UndecidableInstances is supposed to be needed if GHC can’t prove that the
instance
UndecidableInstances is supposed to be needed if GHC can't prove that the
instance declarations terminate. But here it can be sure they terminate. GHC
7.6.3 didn't realise this.
I'll modify the user manual to be clearer on this point.
Simon
From: Glasgow-haskell-users
