[GHC] #12379: WARN pragma gives warning `warning: [-Wdeprecations]'

11 Jul 2016

      #12379: WARN pragma gives warning `warning: [-Wdeprecations]'
-------------------------------------+-------------------------------------
           Reporter:  zilinc         |             Owner:
               Type:  bug            |            Status:  new
           Priority:  low            |         Milestone:
          Component:  Compiler       |           Version:  8.0.1
           Keywords:                 |  Operating System:  Linux
       Architecture:  x86_64         |   Type of failure:  Incorrect
  (amd64)                            |  warning at compile-time
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
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 Example:

 {{{#!hs
 -- Warn.hs

 module Warn where

 __todo :: String -> a
 {-# WARNING __todo "TODO" #-}
 __todo msg = error $ "TODO: " ++ msg
 }}}

 {{{#!hs
 -- Main.hs

 {- OPTIONS_GHC -Wall #-}

 import Warn

 inc :: Int -> Int
 inc n | n >= 0 = n + 1
 inc _ = __todo "what about negatives?"
 }}}

 When compile the files (or ghci), I get
 {{{
 UseWarn.hs:9:9: warning: [-Wdeprecations]
     In the use of ‘__todo’ (imported from Warn): "TODO"
 }}}

 Should the flag be `-Wwarnings-deprecations`? And `-Wdeprecations` is not
 in the user guide, if it is a genuine flag.

--
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12379
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