syntax_data: {"ast_node_type":"other","tokens":[{"end":17,"kind":"keyword","start":0,"text":")"}]}
source_snippet:     ) -> String {
context_before:         filename_display_pref: FileNameDisplayPreference,
context_after:         let (source_file, lo_line, lo_col, hi_line, hi_col) = self.span_to_location_info(sp);