Change new() parser to make use of matching-) functionality

rottlib/src/parser/grammar/expression/primary/new.rs

@@ -223,7 +223,7 @@ impl<'src, 'arena> Parser<'src, 'arena> {
         state: &mut NewArgumentListParseState<'src, 'arena>,
     ) -> Option<NewClassSpecifierParseAction> {
         let has_parsed_all_allowed_arguments =
-            state.call_argument_list_parse_state.parsed_slot_count > 2;
+            state.call_argument_list_parse_state.parsed_slot_count >= 3;
         let likely_missing_comma = !self.next_token_definitely_cannot_start_expression()
             && !has_parsed_all_allowed_arguments;
         if likely_missing_comma {
@@ -282,29 +282,42 @@ impl<'src, 'arena> Parser<'src, 'arena> {
         }
     }
 
-    /// Reports a missing closing `)` in a `new(...)` argument list and
+    /// Recovers from a missing closing `)` in a `new(...)` argument list.
-    /// determines whether the class specifier should be parsed or skipped.
+    ///
+    /// Returns whether class-specifier parsing should continue after recovery.
     #[must_use]
     fn recover_from_missing_new_closing_parenthesis(
         &mut self,
         state: &NewArgumentListParseState<'src, 'arena>,
     ) -> NewClassSpecifierParseAction {
-        let mut error = self
+        self.make_error_at_last_consumed(ParseErrorKind::NewMissingClosingParenthesis)
-            .make_error_at_last_consumed(ParseErrorKind::NewMissingClosingParenthesis)
             .widen_error_span_from(state.left_parenthesis_position)
             .blame_token(self.peek_position_or_eof())
             .related_token("new_keyword", state.new_keyword_position)
-            .related_token("left_parenthesis", state.left_parenthesis_position);
+            .related_token("left_parenthesis", state.left_parenthesis_position)
-        let class_specifier_parse_action = if self.next_token_definitely_cannot_start_expression() {
+            .report(self);
-            error = error.sync_error_at_matching_delimiter(self, state.left_parenthesis_position);
+        // Missing-delimiter recovery normally syncs to the matching `)`.
-            // Skipping the class specifier avoids cascading errors when
+        // `new(...) ClassName` is an exception: after a missing `)`, the next
-            // the next token cannot start an expression anyway.
+        // expression may already be the class specifier, not another argument.
+        let matching_right_parenthesis_ahead = self
+            .file
+            .matching_delimiter(state.left_parenthesis_position)
+            .is_some_and(|right_parenthesis_position| {
+                self.peek_position_or_eof() <= right_parenthesis_position
+            });
+        if matching_right_parenthesis_ahead {
+            self.recover_at_matching_delimiter_or_sync(state.left_parenthesis_position);
+            // After syncing through the matched `)`, the argument-list error is
+            // contained, so class-specifier parsing can proceed normally.
+            return NewClassSpecifierParseAction::Parse;
+        }
+        if self.next_token_definitely_cannot_start_expression() {
+            // There is no plausible class specifier to parse, so skip it to
+            // avoid error cascade.
             NewClassSpecifierParseAction::Skip
         } else {
             NewClassSpecifierParseAction::Parse
-        };
+        }
-        error.report_error(self);
-        class_specifier_parse_action
     }
 
     /// Parses the class specifier of a `new` expression after argument-list