[GHC] #15321: Typed holes in Template Haskell splices produce bewildering error messages

[GHC]

#15321: Typed holes in Template Haskell splices produce bewildering error messages
-------------------------------------+-------------------------------------
        Reporter:  RyanGlScott       |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.8.1
       Component:  Template Haskell  |              Version:  8.4.3
      Resolution:                    |             Keywords:  TypedHoles
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:                    |
-------------------------------------+-------------------------------------

Comment (by Tritlo):

 I agree, it would both be faster and produce better output in the tc
 trace, but just discarding candidates that cause errors is the right thing
 to do, since those aren't valid hole fits anyway (since they cause an
 error).  I think that further work to optimize and improve is in order,
 but I hope that the current patch is small enough to make it into 8.6
 without issue, and leave the more thoughtful overhaul for later.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15321#comment:10>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler