-- Hoogle documentation, generated by Haddock
-- See Hoogle, http://www.haskell.org/hoogle/


-- | For when a type should never be an instance of a class
--   
--   
--   Banning an instance allows the programmer to actively declare that an
--   instance should never be defined, and provide a reason why:
--   
--   <pre>
--   data Foo = -- ...
--   $(banInstance [t|ToJSON Foo|] "why ToJSON Foo should never be defined")
--   </pre>
@package ban-instance
@version 0.1.0.1


module Language.Haskell.Instance.Ban

-- | Ban an instance of a typeclass; code which tries to use the banned
--   instance will fail at compile time. This works by generating an
--   instance that depends on a custom type error:
--   
--   <pre>
--   instance TypeError (..) =&gt; ToJSON Foo where
--     ...
--   </pre>
--   
--   Use it like this:
--   
--   <pre>
--   $(banInstance [t|ToJSON Foo|] "why ToJSON Foo should never be defined")
--   </pre>
banInstance :: TypeQ -> String -> DecsQ