[GHC] #13087: AlternativeLayoutRule breaks LambdaCase

[GHC]

#13087: AlternativeLayoutRule breaks LambdaCase
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        Reporter:  ohhellojoe        |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
  (Parser)                           |
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by osa1):

 You're looking for `-XNondecreasingIndentation`:

 {{{
 > t13087 cat test.hs
 {-# LANGUAGE LambdaCase               #-}
 {-# LANGUAGE NondecreasingIndentation #-}

 isOne :: Int -> Bool
 isOne = \case 1 -> True
               _ -> False

 foobar :: IO (Maybe ())
 foobar = do putStrLn ""
             return $ do
             Just ()

 main = return ()
 > t13087 ghc test.hs
 [1 of 1] Compiling Main             ( test.hs, test.o )
 Linking test ...
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13087#comment:3>
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