diff --git a/study_coroutine_util.cc b/study_coroutine_util.cc
index 1efbb48a42e88bb157794480a908b4e920e53575..d865efbd0512dee59056d513c82b2134c6c8ae34 100644
--- a/study_coroutine_util.cc
+++ b/study_coroutine_util.cc
@@ -12,7 +12,6 @@ PHP_METHOD(study_coroutine_util, create)
 {
     zend_fcall_info fci = empty_fcall_info;
     zend_fcall_info_cache fcc = empty_fcall_info_cache;
-    zval result;
 
     ZEND_PARSE_PARAMETERS_START(1, -1)
         Z_PARAM_FUNC(fci, fcc)