[GHC] #15039: Bizarre pretty-printing of inferred Coercible constraint in partial type signature

[GHC]

#15039: Bizarre pretty-printing of inferred Coercible constraint in partial type
signature
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        Reporter:  RyanGlScott       |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.6.1
       Component:  Compiler (Type    |              Version:  8.4.1
  checker)                           |             Keywords:
      Resolution:                    |  PartialTypeSignatures, TypeInType
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Poor/confusing    |  Unknown/Multiple
  error message                      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by RyanGlScott):

 comment:5 sounds fine, but it only addresses problem (2). What about
 problem (1)? We still have GHC reporting that the kind of `Coercible a b`
 is `TYPE (TupleRep '[])`, which is utterly bogus.

 It seems like if `-fprint-equality-relations` is disabled, then we'd want
 to print the kind `Constraint` instead, yes? Is that feasible with the way
 partial type signature reporting currently works?

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15039#comment:6>
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