Add comment about Any usage to SomeFunctor

src/MA/Functors/SomeFunctor.hs

@@ -58,6 +58,15 @@ someFunctor ::
 someFunctor fd =
   fd { functorExprParser = transParser SomeFunctor (functorExprParser fd )}
 
+
+-- A note on all this Any stuff:
+--
+-- It's safe to unsafeCoerce a type to Any and than coerce it back, but what we
+-- do here is actually "unsafeCoerce :: [Any] -> [Label]" instead of the more
+-- obviously safe "map (unsafeCoerce :: Any -> Label)". According to #haskell,
+-- it's "about as safe".
+
+
 #ifdef RELEASE
 newtype SomeLabel = SomeLabel Any