[GHC] #14428: Rework HsValBindsLR

[GHC]

#14428: Rework HsValBindsLR
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           Reporter:  alanz          |             Owner:  (none)
               Type:  task           |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.2.1
           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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 Once Trees that Grow has been applied to the hsSyn AST, rework
 `HsValBindsLR` to simplify it.

 From a comment on https://phabricator.haskell.org/D4147

 > Nothing here gives any clue that this is intended for the output of the
 renamer. And typechecker I think.

 > Plus I wonder if we'd be better served by

 {{{#!hs
 data HsValBindsLR idL idR
  = ValBinds
       [(RecFlag, LHsBindsLR idL idR)]
      [LSig GhcRn]
 }}}

 > Then the parser can generate a giant singleton Rec and the renamer can
 sort it out. Less fuss.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14428>
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