syntax_data: {"ast_node_type":"other","tokens":[{"end":43,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:         // Watch out for region highlights.
context_before:     pub fn pretty_print_region(&mut self, region: ty::Region<'tcx>) -> Result<(), fmt::Error> {
context_after:         let highlight = self.region_highlight_mode;