syntax_data: {"ast_node_type":"other","tokens":[{"end":80,"kind":"keyword","start":0,"text":"bug!(\"can"}]}
source_snippet:                 bug!("can only highlight {} placeholders at a time", num_slots,)
context_before:             self.highlight_regions.iter_mut().find(|s| s.is_none()).unwrap_or_else(|| {
context_after:             });