[GHC] #14296: Add `Lift Exp` instance to `Language.Haskell.TH.Syntax`

[GHC]

#14296: Add `Lift Exp` instance to `Language.Haskell.TH.Syntax`
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        Reporter:  heisenbug         |                Owner:  (none)
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Template Haskell  |              Version:  8.2.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Poor/confusing    |  Unknown/Multiple
  error message                      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #14030            |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by RyanGlScott):

 Replying to [comment:5 heisenbug]:
 > You mean
 > {{{#!hs
 > uhOh :: ExpQ
 > uhOh = lift "uhOh"
 > }}}

 Oops. That's right.

 > My question is when this happens in a `[p|($uhOh -> binding)|]` and this
 ends up in a splice, ultimately being compiled by GHC, then I'll get a
 type error "Expected `Exp`, got: `String`", correct?

 Sure, GHC will definitely catch the mistake in the form of a (sometimes
 hard-to-scrutinize) type error. But I would still be frustrated that that
 happened in the first place, since it would violate my intuition of how
 `lift` interacts with splicing.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14296#comment:6>
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