syntax_data: {"ast_node_type":"variable","tokens":[{"end":54,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:             let sig = tcx.liberate_late_bound_regions(
context_before:         DefKind::Ctor(..) | DefKind::Fn | DefKind::AssocFn => {
context_after:                 def_id.to_def_id(),