On Tue, Feb 21, 2017 at 12:21:08PM -0500, David Feuer wrote: > A lot of us would like to get -Werror for only some errors. I don't > think it exists yet. It's implemented in GHC HEAD: https://ghc.haskell.org/trac/ghc/ticket/11219 I'm not sure whether it supports flag deprecation warnings though. Maciej