swc-project/swc · error

Expected '?' delim token

Error message

Expected '?' delim token

What it means

Fired while parsing a <urange> with the '?' wildcard form: after the hex prefix, a Delim token '?' was required but the token was something else. The wildcard form (e.g. 'U+00??') only accepts question marks after the start digits.

Source

Thrown at crates/swc_css_parser/src/parser/values_and_units/mod.rs:2760

                    loop {
                        if !is!(self, "?") {
                            break;
                        }

                        let question = match bump!(self) {
                            Token::Delim { value } => value,
                            _ => {
                                unreachable!();
                            }
                        };

                        unicode_range.push(question);
                    }
                } else {
                    let question = match bump!(self) {
                        Token::Delim { value } if value == '?' => value,
                        _ => {
                            return Err(Error::new(span, ErrorKind::Expected("'?' delim token")));
                        }
                    };

                    unicode_range.push(question);

                    loop {
                        if !is!(self, "?") {
                            break;
                        }

                        let question = match bump!(self) {
                            Token::Delim { value } => value,
                            _ => {
                                unreachable!();
                            }
                        };

                        unicode_range.push(question);

View on GitHub (pinned to 5176682b65)

Solutions

1. Use only '?' characters for wildcard positions: 'U+00??'
2. Use explicit start-end form ('U+0-FF') instead of wildcards

When it happens

Trigger: Thrown at crates/swc_css_parser/src/parser/values_and_units/mod.rs:2760 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of swc-project/swc@5176682b65 (2026-08-17). Data as JSON: /api/errors/13b990a37f463311. Report an issue: GitHub.