Decompose wanted repr. eqs. when no matchable givens.
authorRichard Eisenberg <eir@cis.upenn.edu>
Tue, 9 Jun 2015 02:32:40 +0000 (22:32 -0400)
committerRichard Eisenberg <eir@cis.upenn.edu>
Tue, 16 Jun 2015 18:22:52 +0000 (14:22 -0400)
commitff82387d6fe61762fe4f507e8f9799f5bdc3c43a
tree47203c4693fb04e68ffa6894c7526ff7c6c7c212
parent66440396bef30e5d6c7b536b552cc4f557d70691
Decompose wanted repr. eqs. when no matchable givens.

This is pursuant to a conversion with SPJ, where we agreed that
the logic behind Note [Instance and Given overlap] in TcInteract
applied to newtype decomposition for representational equality.

There is no bug report or test case, as tickling this kind of thing
is quite hard to do!
compiler/typecheck/TcCanonical.hs
compiler/typecheck/TcInteract.hs
compiler/typecheck/TcSMonad.hs