[GHC] #8155: Defaulting bug or unfortunate error message with closed type families

[GHC]

#8155: Defaulting bug or unfortunate error message with closed type families
-------------------------------------+------------------------------------
        Reporter:  nh2               |            Owner:
            Type:  bug               |           Status:  new
        Priority:  normal            |        Milestone:
       Component:  Compiler          |          Version:  7.6.3
      Resolution:                    |         Keywords:
Operating System:  Unknown/Multiple  |     Architecture:  Unknown/Multiple
 Type of failure:  None/Unknown      |       Difficulty:  Unknown
       Test Case:                    |       Blocked By:
        Blocking:                    |  Related Tickets:
-------------------------------------+------------------------------------
Changes (by simonpj):

 * status:  closed => new
 * resolution:  invalid =>


Comment:

 Thank you for identifying this problem.  Once I understood it, the fix was
 easy.  New error message is much more sensible
 {{{
 T8155.hs:26:14:
     Could not deduce (Integral (BoundsOf (a -> a)))
       arising from a use of ‛buildV’
     from the context (Num a)
       bound by the instance declaration at T8155.hs:25:10-32
     In the expression: buildV
     In an equation for ‛build'’: build' = buildV
     In the instance declaration for ‛Build (a -> a)’
 }}}
 Simon

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8155#comment:6>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler