I signed up to github to fix this
You forgot to remove const after changing the variable initialisation to NULL. Not sure why you haven't been getting assert errors caused by this, because I do! Can't change const after initialisation!! -himselfe
@@ -16,7 +16,7 @@ hide_goal(void *param, Gc *gc, struct Scope *scope, struct Expr args)
assert(scope);
Level * const level = (Level*)param;
- const char * const goal_id = NULL;
+ char * goal_id = NULL;
struct EvalResult result = match_list(gc, "s", args, &goal_id);
if (result.is_error) {
