Add warnings for partial functions (#70)

src/Debug.hs

@@ -1,5 +1,6 @@
 {-# LANGUAGE Trustworthy #-}
 {-# LANGUAGE NoImplicitPrelude #-}
+{-# OPTIONS_GHC -fno-warn-warnings-deprecations #-}
 
 module Debug (
   undefined,
@@ -55,8 +56,10 @@ traceM s = trace (unpack s) (return ())
 traceId :: Text -> Text
 traceId s = trace s s
 
+{-# WARNING notImplemented "'notImplemented' remains in code" #-}
 notImplemented :: a
 notImplemented = error "Not implemented"
 
+{-# WARNING undefined "'undefined' remains in code" #-}
 undefined :: a
 undefined = error "Prelude.undefined"

src/Protolude/Error.hs

@@ -25,6 +25,7 @@ import GHC.Types (RuntimeRep)
 import Protolude.CallStack (HasCallStack)
 import GHC.Exception (errorCallWithCallStackException)
 
+{-# WARNING error "'error' remains in code" #-}
 error :: forall (r :: RuntimeRep) . forall (a :: TYPE r) . HasCallStack => Text -> a
 error s = raise# (errorCallWithCallStackException (unpack s) ?callstack)
 
@@ -33,6 +34,7 @@ error s = raise# (errorCallWithCallStackException (unpack s) ?callstack)
 
 import GHC.Exception (errorCallException)
 
+{-# WARNING error "'error' remains in code" #-}
 error :: Text -> a
 error s = raise# (errorCallException (unpack s))
 
@@ -42,6 +44,7 @@ error s = raise# (errorCallException (unpack s))
 import GHC.Types
 import GHC.Exception
 
+{-# WARNING error "'error' remains in code" #-}
 error :: Text -> a
 error s = throw (ErrorCall (unpack s))