1 files changed, 1 insertions, 1 deletions
diff --git a/Object.c b/Object.c
index 9ac2be67..982f7bda 100644
--- a/Object.c
+++ b/Object.c
@@ -14,7 +14,7 @@ ObjectClass Object_class = {
 
 #ifndef NDEBUG
 
-bool Object_isA(Object* o, const ObjectClass* klass) {
+bool Object_isA(const Object* o, const ObjectClass* klass) {
    if (!o)
       return false;
    const ObjectClass* type = o->klass;