[GHC] #14034: GHC crash instead of compile error on GHC 8.2 with ApplicativeDo

[GHC]

#14034: GHC crash instead of compile error on GHC 8.2 with ApplicativeDo
-------------------------------------+-------------------------------------
           Reporter:  nh2            |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.2.1
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  Compile-time
  Unknown/Multiple                   |  crash or panic
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 I'm filing this a sa proxy for user `sam2_` from IRC:

 {{{
 $ cat Bug.hs
 {-# LANGUAGE ApplicativeDo #-}
 module Bug where

 doc = do
   () <- a
   () <- b
   c' <- c
   return d
 }}}
 {{{
 $ ghc-8.2.1 Bug.hs
 [1 of 1] Compiling Bug              ( Bug.hs, Bug.o )
 ghc: out of memory (requested 1048576 bytes)
 }}}
 {{{
 $ ghc-8.0.2 Bug.hs
 [1 of 1] Compiling Bug              ( Bug.hs, Bug.o )

 Bug.hs:5:9: error: Variable not in scope: a :: f ()

 Bug.hs:6:9: error: Variable not in scope: b :: f ()

 Bug.hs:7:9: error: Variable not in scope: c :: f a0

 Bug.hs:8:10: error: Variable not in scope: d
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14034>
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