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

[GHC]

#15321: Typed holes in Template Haskell splices produce bewildering error messages
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        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:                    |
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Comment (by mgsloan):

 I've considered this further, and I'm thinking my concerns about masking
 errors may be unfounded.  Problems typechecking candidates are likely to
 be discovered other ways.  On the other hand, this might be an interesting
 way to have users fuzz testing the typechecker ;)

 Your change looks good to me.

 I think something like https://phabricator.haskell.org/D4907 may still
 make sense, but I'll leave it up to y'all.  It is certainly an efficiency
 / complexity tradeoff.  One benefit beyond efficiency is that `-ddump-tc-
 trace` might be slightly more comprehensible if it isn't evaluating holes
 that the typechecker errors on.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15321#comment:9>
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