Fix for CollisionSystem depending on object order

src/collision/collision_system.cpp

@@ -160,12 +160,6 @@ collision::Constraints check_collisions(const Vector& obj_movement, const Rectf&
 
   if (!shiftout)
   {
-    if (other_object != nullptr && moving_object != nullptr) {
-      const HitResponse response = other_object->collision(*moving_object, dummy);
-      if (response == ABORT_MOVE)
-        return constraints;
-    }
-
     if (other_object && other_object->is_unisolid())
     {
       // Constrain only on fall on top of the unisolid object.
@@ -198,6 +192,16 @@ collision::Constraints check_collisions(const Vector& obj_movement, const Rectf&
         constraints.hit.left = true;
       }
     }
+    if (other_object && moving_object)
+    {
+      CollisionHit hit = constraints.hit;
+      moving_object->collision(*other_object, hit);
+      std::swap(hit.left, hit.right);
+      std::swap(hit.top, hit.bottom);
+      const HitResponse response = other_object->collision(*moving_object, hit);
+      if(response==ABORT_MOVE)
+        return collision::Constraints();
+    }
   }
 
   return constraints;