[GHC] #10596: Template Haskell : getQ and putQ doesn't work

2 Jul 2015

      #10596: Template Haskell : getQ and putQ doesn't work
-------------------------------------+-------------------------------------
              Reporter:  kiripon     |             Owner:
                  Type:  bug         |            Status:  new
              Priority:  normal      |         Milestone:
             Component:  Template    |           Version:  7.10.1
  Haskell                            |  Operating System:  Unknown/Multiple
              Keywords:  getQ putQ   |   Type of failure:  None/Unknown
          Architecture:              |        Blocked By:
  Unknown/Multiple                   |   Related Tickets:
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
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 Functions `getQ` and `putQ` in the module `Language.Haskell.TH.Syntax` do
 not work.

 Following code is an example of this problem. The variable `x` should be
 `(Just B)`, but `x` is  `Nothing`.

 {{{#!hs
 {-# LANGUAGE TemplateHaskell #-}
 module X where
 import Language.Haskell.TH
 import Language.Haskell.TH.Syntax
 do
   putQ (100 :: Int)
   x <- getQ :: Q (Maybe Int)

   -- It should print "Just 100" but "Nothing"
   runIO $ print x
   return []
 }}}

 As a result, I get following output on compile.
 {{{#!hs
 $ ghc -fforce-recomp X.hs
 [1 of 1] Compiling X                ( X.hs, X.o )
 Nothing
 }}}

--
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10596
GHC http://www.haskell.org/ghc/
The Glasgow Haskell Compiler