diff --git a/nac3artiq/src/codegen.rs b/nac3artiq/src/codegen.rs
index dbde7ec3..5aef9c80 100644
--- a/nac3artiq/src/codegen.rs
+++ b/nac3artiq/src/codegen.rs
@@ -1141,7 +1141,7 @@ pub fn gen_rtio_log<'ctx>(
     generator: &mut dyn CodeGenerator,
 ) -> Result<(), String> {
     assert!(obj.is_none());
-    assert_eq!(args.len(), 1);
+    assert_eq!(args.len(), 2);
 
     let channel_ty = fun.0.args[0].ty;
     assert!(ctx.unifier.unioned(channel_ty, ctx.primitives.str));