[GHC] #14474: reify RHS of "value" variable

[GHC]

#14474: reify RHS of "value" variable
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           Reporter:  dailectic      |             Owner:  (none)
               Type:  feature        |            Status:  new
  request                            |
           Priority:  normal         |         Milestone:
          Component:  Template       |           Version:  8.2.1
  Haskell                            |
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
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 According to the [https://hackage.haskell.org/package/template-
 haskell-2.12.0.0/docs/Language-Haskell-TH-Syntax.html#t:Info
 documentation], when reifying value variables "returning the RHS has not
 yet been implemented because of lack of interest". I'd like to formally
 request interest since I don't see a ticket here (may have missed it).

 My motivating example is to make source available for documentation and
 better error messages. Something like:

 {{{#!hs
 printSource :: Name -> Q Exp
 printSource n = do
     VarI _ _ (Just dec) <- reify n
     lift $ pprint dec

 foo x = x * 2
 fooSource = $(printSource 'foo) -- === "\x_0 -> x_0 GHC.Num.* 2"
 }}}

 How significant of a change is this? I could take a pass at it if pointed
 to the relevant bits, having not contributed to GHC before.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14474>
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