[GHC] #13984: Panic when using a TH splice in a do bind pattern

[GHC]

#13984: Panic when using a TH splice in a do bind pattern
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        Reporter:  mbieleck          |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.2.1-rc3
      Resolution:                    |             Keywords:  panic
                                     |  template-haskell
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash or panic                     |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by mbieleck):

 Replying to [comment:2 RyanGlScott]:
 > `isIrrefutableHsPat` has as an invariant that it should be called
 //after// the renamer (see
 [http://git.haskell.org/ghc.git/blob/f656fba19d0cefe05643ddea35d080ea332a6584:/compiler/hsSyn/HsPat.hs#l639
 here]), but your patch calls `isIrrefutableHsPat` directly from the
 renamer.

 I think the comment you mentioned

 > Both should be gotten rid of by renamer before isIrrefutablePat is
 called

 may be wrong. The comment
 [http://git.haskell.org/ghc.git/blob/f656fba19d0cefe05643ddea35d080ea332a6584:/compiler/hsSyn/HsExpr.hs#l2088
 here] says:

 > This is the result of splicing a splice. It is produced by the renamer
 and consumed by the typechecker. It lives only between the two.

 (this is not directly related to the issue, just stumbled upon this while
 trying to fix this)

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13984#comment:3>
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