diff --git a/lib/Properties.hs b/lib/Properties.hs
index 0b9a71f414b952eb95ec62c56b1d549546278f0a..10cbf2c2f7937f43771fe22efe62a5c7f90a5077 100644
--- a/lib/Properties.hs
+++ b/lib/Properties.hs
@@ -5,7 +5,7 @@
 module Properties (checkProperty) where
 
 
-import           Control.Monad             (unless, when)
+import           Control.Monad             (unless)
 import           Control.Monad.Trans.Class (lift)
 import           Data.Aeson                as Aeson (Value (String))
 import           Data.Map                  (Map, (!?))
@@ -33,7 +33,7 @@ type Properties = Map Text Aeson.Value
 -- The tests in here are meant to comply with the informal spec
 -- at https://workadventu.re/map-building
 --
--- In practice, the actual specifiaction of what is allowed is
+-- In practice, the actual specification of what is allowed is
 -- handled in checkProperty', since apparently all possible layerProperties
 -- are strings anyways, so this just extracts that string and then
 -- calls that.
@@ -84,9 +84,6 @@ checkProperty' layer prop ty = case ty of
       -- | require some property in this layer
       requireProperty name = unless (hasProperty name layer)
         $ complain $ "property "<>quote name<>" requires property "<>quote ty
-      -- | forbid some property in this layer
-      forbidProperty name = when (hasProperty name layer)
-        $ forbid $ "property " <> quote name <> " should not be used"
       -- | This property is forbidden and should not be used
       isForbidden = forbid $ "property " <> quote ty <> " should not be used"
       -- TODO: check if the property has the correct value