diff --git a/ext/iodine/iodine_json.h b/ext/iodine/iodine_json.h
index 632fd70..76f9aa9 100644
--- a/ext/iodine/iodine_json.h
+++ b/ext/iodine/iodine_json.h
@@ -85,8 +85,8 @@ FIO_SFUNC void *iodine___json_on_true(void) { return (void *)Qtrue; }
 /** FALSE object was detected. Returns new object as `void *`. */
 FIO_SFUNC void *iodine___json_on_false(void) { return (void *)Qfalse; }
 /** Number was detected (long long). Returns new object as `void *`. */
-FIO_SFUNC void *iodine___json_on_number(uint64_t i) {
-  return (void *)LL2NUM(((long long)i));
+FIO_SFUNC void *iodine___json_on_number(int64_t i) {
+  return (void *)(LL2NUM(((long long)i)));
 }
 /** Float was detected (double).Returns new object as `void *`.  */
 FIO_SFUNC void *iodine___json_on_float(double f) { return (void *)DBL2NUM(f); }