[GHC] #11245: Non-exhaustive pattern, "Patterns not matched" list is empty

[GHC]

#11245: Non-exhaustive pattern, "Patterns not matched" list is empty
-------------------------------------+-------------------------------------
        Reporter:  osa1              |                Owner:  gkaracha
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.11
      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:                    |
-------------------------------------+-------------------------------------

Comment (by Ben Gamari <ben@…>):

 In [changeset:"bb7f2e33197e667eb694bd1243f125c722a0a868/ghc"
 bb7f2e33/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="bb7f2e33197e667eb694bd1243f125c722a0a868"
 Address #11245: Ensure the non-matched list is always non-empty

 When there is an uncovered vector of length 0 (which in turn means that
 it represents a guard failure) print "(incomplete guards)" instead of an
 empty list of non-covered vectors.

 Test Plan: validate

 Reviewers: austin, bgamari

 Reviewed By: bgamari

 Subscribers: thomie

 Differential Revision: https://phabricator.haskell.org/D1717

 GHC Trac Issues: #11245
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11245#comment:7>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler