1 files changed, 1 insertions, 1 deletions
diff --git a/Object.h b/Object.h
index 462797c2..ba213c89 100644
--- a/Object.h
+++ b/Object.h
@@ -50,7 +50,7 @@ extern ObjectClass Object_class;
 
 #ifndef NDEBUG
 
-bool Object_isA(Object* o, const ObjectClass* klass);
+bool Object_isA(const Object* o, const ObjectClass* klass);
 
 #endif /* NDEBUG */