--- a/servo/components/selectors/parser.rs
+++ b/servo/components/selectors/parser.rs
@@ -2686,16 +2686,20 @@ pub mod tests {
         fn parse_slotted(&self) -> bool {
             true
         }
 
         fn parse_is_and_where(&self) -> bool {
             true
         }
 
+        fn is_and_where_error_recovery(&self) -> ParseErrorRecovery {
+            ParseErrorRecovery::DiscardList
+        }
+
         fn parse_part(&self) -> bool {
             true
         }
 
         fn parse_non_ts_pseudo_class(
             &self,
             location: SourceLocation,
             name: CowRcStr<'i>,