[GHC] #13600: surprising error message with bang pattern

[GHC]

#13600: surprising error message with bang pattern
-------------------------------------+-------------------------------------
        Reporter:  andrewufrank      |                Owner:  v0d1ch
            Type:  bug               |               Status:  patch
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.2
      Resolution:                    |             Keywords:  BangPatterns,
                                     |  newcomer
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Poor/confusing    |  Unknown/Multiple
  error message                      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #15166, #15458    |  Differential Rev(s):  Phab:D5040
       Wiki Page:                    |
-------------------------------------+-------------------------------------
Changes (by erikd):

 * cc: erikd (added)


Comment:

 Seeing this with ghc 8.4.3 as well.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13600#comment:15>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler