diff --git a/src/wp-includes/rest-api/class-wp-rest-request.php b/src/wp-includes/rest-api/class-wp-rest-request.php
index 0910ff6f28..1661ce724e 100644
--- a/src/wp-includes/rest-api/class-wp-rest-request.php
+++ b/src/wp-includes/rest-api/class-wp-rest-request.php
@@ -310,7 +310,7 @@ class WP_REST_Request implements ArrayAccess {
 		}
 
 		$value = strtolower( $value );
-		if ( strpos( $value, '/' ) === false ) {
+		if ( false === strpos( $value, '/' ) ) {
 			return null;
 		}