[GHC] #15518: -ddump-splices pretty-prints LambdaCase nonsensically

14 Aug 2018

      #15518: -ddump-splices pretty-prints LambdaCase nonsensically
-------------------------------------+-------------------------------------
           Reporter:  RyanGlScott    |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:  8.8.1
          Component:  Template       |           Version:  8.4.3
  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:
-------------------------------------+-------------------------------------
 {{{#!hs
 {-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE TemplateHaskell #-}
 {-# OPTIONS_GHC -ddump-splices #-}
 module Bug where

 $([d| f :: Bool -> ()
       f = \case True  -> ()
                 False -> ()
     |])
 }}}
 {{{
 $ /opt/ghc/8.4.3/bin/ghci Bug.hs
 GHCi, version 8.4.3: http://www.haskell.org/ghc/  :? for help
 Loaded GHCi configuration from /home/ryanglscott/.ghci
 [1 of 1] Compiling Bug              ( Bug.hs, interpreted )
 Bug.hs:(6,3)-(9,6): Splicing declarations
     [d| f_a1xr :: Bool -> ()
         f_a1xr
           = \case
               True -> ()
               False -> () |]
   ======>
     f_a48E :: Bool -> ()
     f_a48E
       = \case
           \ True -> GHC.Tuple.()
           \ False -> GHC.Tuple.()
 Ok, one module loaded.
 }}}

 Notice the use of `\ True` and `\ False`. Those patterns should not be
 preceded with backslashes.

-- 
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15518
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