diff --git a/nac3artiq/src/codegen.rs b/nac3artiq/src/codegen.rs
index e76ef31c..70c774f4 100644
--- a/nac3artiq/src/codegen.rs
+++ b/nac3artiq/src/codegen.rs
@@ -748,6 +748,9 @@ fn polymorphic_print<'ctx>(
                   generator: &mut dyn CodeGenerator,
                   fmt: String,
                   args: Vec<BasicValueEnum<'ctx>>| {
+        assert!(!fmt.is_empty());
+        assert_eq!(fmt.as_bytes().last().unwrap(), &0u8);
+
         let fn_name = if as_rtio { "rtio_log" } else { "core_log" };
         let print_fn = ctx.module.get_function(fn_name).unwrap_or_else(|| {
             let llvm_pi8 = ctx.ctx.i8_type().ptr_type(AddressSpace::default());
@@ -763,8 +766,15 @@ fn polymorphic_print<'ctx>(
 
         println!("printf({fmt}, [{}])", args.iter().map(|arg| arg.to_string()).join(", "));
 
+        let fmt_val = ctx.gen_string(generator, "hi :)\0");
+        let fmt_val = unsafe { fmt_val.get_field_at_index_unchecked(0) }.into_pointer_value();
+        println!("fmt_val: {}", fmt_val);
+
+        ctx.builder.build_call(print_fn, &[fmt_val.into()], "").unwrap();
+
         let fmt = ctx.gen_string(generator, fmt);
         let fmt = unsafe { fmt.get_field_at_index_unchecked(0) }.into_pointer_value();
+        println!("fmt: {}", fmt);
 
         ctx.builder
             .build_call(