reify RHS of "value" variable

According to the 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:

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.

Trac metadata

Trac field	Value
Version	8.2.1
Type	FeatureRequest
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Template Haskell
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reify RHS of "value" variable