[GHC] #10314: ApiAnnotations: mkHsForAllTy discards parens

[GHC]

#10314: ApiAnnotations: mkHsForAllTy discards parens
-------------------------------------+-------------------------------------
              Reporter:  alanz       |             Owner:  alanz
                  Type:  bug         |            Status:  new
              Priority:  normal      |         Milestone:  7.10.2
             Component:  Compiler    |           Version:  7.10.1
              Keywords:              |  Operating System:  Unknown/Multiple
  ApiAnnotations                     |   Type of failure:  None/Unknown
          Architecture:              |        Blocked By:
  Unknown/Multiple                   |   Related Tickets:
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
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 The code for `HsForAllTy` is

 {{{#!hs
 mkHsForAllTy exp tvs ctxt     ty = HsForAllTy exp extra (mkHsQTvs tvs)
 cleanCtxt ty
   where -- Separate the extra-constraints wildcard when present
         (cleanCtxt, extra)
           | (L l HsWildcardTy) <- ignoreParens (last (unLoc ctxt)) = (init
 `fmap` ctxt, Just l)
           | otherwise = (ctxt, Nothing)
         ignoreParens (L _ (HsParTy ty)) = ty
         ignoreParens ty                 = ty
 }}}

 The process of cleaning the context calls `ignoreParens` which strips out
 the `HsParTy`. In the process the `AnnOpenP` and `AnnCloseP` attached to
 this are discarded.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10314>
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