[GHC] #8064: Warning out when "undefined" value has been used.

[GHC]

#8064: Warning out when "undefined" value has been used.
------------------------------------+-------------------------------------
       Reporter:  freizl            |             Owner:
           Type:  feature request   |            Status:  new
       Priority:  normal            |         Milestone:
      Component:  Compiler          |           Version:  7.6.3
       Keywords:                    |  Operating System:  Unknown/Multiple
   Architecture:  Unknown/Multiple  |   Type of failure:  None/Unknown
     Difficulty:  Unknown           |         Test Case:
     Blocked By:                    |          Blocking:
Related Tickets:                    |
------------------------------------+-------------------------------------
 Programmer may like to use "undefined" to define a function or value,
 which usually means "later implementation".

 However, people might forget to implement it thus cause run time error.
 Wish GHC will show some warning/errors at compilation.

 This idea comes from this article (http://www.devalot.com/articles/2013/07
 /why-haskell.html)

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8064>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler