syntax_data: {"ast_node_type":"function","tokens":[{"end":78,"kind":"keyword","start":0,"text":"fn"}]}
source_snippet:     fn into_diag(self, dcx: DiagCtxtHandle<'_>, level: Level) -> Diag<'_, G> {
context_before: impl<G: EmissionGuarantee> Diagnostic<'_, G> for TestOutput {
context_after:         let TestOutput { span, kind, content } = self;