[GHC] #11248: Ambiguous Types with Constraint Synonyms

[GHC]

#11248: Ambiguous Types with Constraint Synonyms
-------------------------------------+-------------------------------------
        Reporter:  crockeea          |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.0.1
       Component:  Compiler          |              Version:  7.10.2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  GHC rejects       |            Test Case:
  valid program                      |  polykinds/T11248
      Blocked By:                    |             Blocking:
 Related Tickets:  #11330            |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------
Changes (by thomie):

 * status:  closed => new
 * resolution:  fixed =>
 * related:   => #11330


Comment:

 Actually,`T11248` fails with core lint errors for WAY=optasm and WAY=hpc
 with HEAD (8.1.20151231):

 {{{
  *** Core Lint errors : in result of Float out(FOS {Lam = Just 0,
                                                     Consts = True,
                                                     OverSatApps = True})
 ***
  <no location info>: warning:
      [in body of lambda with binder eta_B1 :: CT
                                                 r_a1JX (FLCM r_a1JX
 t_a1KA)]
      No alternatives for a case scrutinee in head-normal form: lvl_s1UO
                                                                  @ s_a1JY
                                                                  @ r_a1JX
                                                                  @ t_a1KA
                                                                  @~
 (cobox_a1KB
                                                                      ::
 FMul
 (FGCD r_a1JX s_a1JY)
 (FDiv
 (FLCM r_a1JX t_a1KA)
 r_a1JX)
                                                                         ~#
 t_a1KA)
                                                                  @~
 (cobox_a1KC
                                                                      ::
 FGCD r_a1JX t_a1KA
                                                                         ~#
 FGCD r_a1JX s_a1JY)
                                                                  @ s'_a1K1
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11248#comment:6>
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