{"record":{"id":"83e7db9f8dcc14c8","repo":"swc-project/swc","slug":"expected-declaration-in-parens","errorCode":null,"errorMessage":"Expected declaration in parens","messagePattern":"Expected declaration in parens","errorType":"validation","errorClass":"swc_css_parser::Error","httpStatus":null,"severity":"error","filePath":"crates/swc_css_parser/src/parser/at_rules/mod.rs","lineNumber":1182,"sourceCode":"}\n\nimpl<I> Parse<SupportsFeature> for Parser<I>\nwhere\n    I: ParserInput,\n{\n    fn parse(&mut self) -> PResult<SupportsFeature> {\n        match cur!(self) {\n            tok!(\"(\") => {\n                bump!(self);\n\n                self.input.skip_ws();\n\n                let declaration = match self.try_to_parse_declaration_in_parens() {\n                    Some(declaration) => declaration,\n                    None => {\n                        let span = self.input.cur_span();\n\n                        return Err(Error::new(\n                            span,\n                            ErrorKind::Expected(\"declaration in parens\"),\n                        ));\n                    }\n                };\n\n                expect!(self, \")\");\n\n                Ok(SupportsFeature::Declaration(Box::new(declaration)))\n            }\n            Token::Function { value, .. }\n                if matches_eq_ignore_ascii_case!(&**value, \"selector\") =>\n            {\n                // TODO improve me\n                let ctx = Ctx {\n                    in_supports_at_rule: true,\n                    ..self.ctx\n                };","sourceCodeStart":1164,"sourceCodeEnd":1200,"githubUrl":"https://github.com/swc-project/swc/blob/5176682b65416c6b5de6b47379ae1588ea3ecb3f/crates/swc_css_parser/src/parser/at_rules/mod.rs#L1164-L1200","documentation":"Inside a @supports parenthesized feature, try_to_parse_declaration_in_parens returned None — the content of the parentheses is neither a valid declaration nor a condition — so the parser reports this error at the current span.","triggerScenarios":"Thrown at crates/swc_css_parser/src/parser/at_rules/mod.rs:1182 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":["Write a valid declaration such as (display: flex) inside the parens","Report the diagnostic from collected errors","Fix the @supports feature query"],"exampleFix":null,"handlingStrategy":"validation","validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"5176682b65416c6b5de6b47379ae1588ea3ecb3f","analyzedAt":"2026-08-17T16:16:52.067Z","contentChangedAt":"2026-08-17T16:16:52.067Z","schemaVersion":2},"datasetVersion":"2026-09-14T05:17:10.506Z"}