diff --git a/Zend/zend_inheritance.c b/Zend/zend_inheritance.c
index e623e1e7aba..3313b075586 100644
--- a/Zend/zend_inheritance.c
+++ b/Zend/zend_inheritance.c
@@ -671,7 +671,7 @@ static inheritance_status zend_is_intersection_subtype_of_type(
 	return early_exit_status == INHERITANCE_ERROR ? INHERITANCE_SUCCESS : INHERITANCE_ERROR;
 }
 
-ZEND_API inheritance_status zend_perform_covariant_type_check(
+static inheritance_status zend_perform_covariant_type_check(
 		zend_class_entry *fe_scope, const zend_type fe_type,
 		zend_class_entry *proto_scope, const zend_type proto_type)
 {