metamodel: PartialOrder::[] fail on wrong key

Alike stdlib Map::[] method, PartialOrder::[] aborts if key does not exists.

Signed-off-by: Jean Privat <jean@pryen.org>

diff --git a/src/metamodel/partial_order.nit b/src/metamodel/partial_order.nit
index 4960a51..7e7d936 100644 (file)
--- a/src/metamodel/partial_order.nit
+++ b/src/metamodel/partial_order.nit
@@ -58,11 +58,7 @@ special Collection[E]
        # Return the element associed with the item
        meth [](e: E): PartialOrderElement[E]
        do
-               if _elements.has_key(e) then
-                       return _elements[e]
-               else
-                       return null
-               end
+               return _elements[e]
        end
 
        # Return a dot representation