[GHC] #13092: family instance consistency checks are too pessimistic

[GHC]

#13092: family instance consistency checks are too pessimistic
-------------------------------------+-------------------------------------
        Reporter:  rwbarton          |                Owner:  rwbarton
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.2.1
       Component:  Compiler          |              Version:  8.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by rwbarton):

 I think so. My plan is to proceed as in
 608cad595c033ba89e757c8f61a9b791a7085367 though of course it still needs
 explanation and tests. The new code is basically copied from `tcRnImports`
 where it loads orphan modules.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13092#comment:12>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler