[GHC] #10752: Print which warning-flag controls/enabled an emitted warning

[GHC]

#10752: Print which warning-flag controls/enabled an emitted warning
-------------------------------------+-------------------------------------
        Reporter:  hvr               |                Owner:  barrucadu
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:  8.2.1
       Component:  Compiler          |              Version:
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Incorrect         |  Unknown/Multiple
  warning at compile-time            |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D1943
       Wiki Page:  Design/Warnings   |
-------------------------------------+-------------------------------------

Comment (by Herbert Valerio Riedel <hvr@…>):

 In [changeset:"3cd4c9ca4564982cf159f11f59d434235ba28808/ghc"
 3cd4c9ca/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="3cd4c9ca4564982cf159f11f59d434235ba28808"
 Annotate `[-Wdeferred-type-errors]` in warnings (re #10752)

 This was missed in bb5afd3c274011c5ea302210b4c290ec1f83209c
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10752#comment:20>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler