syntax_data: {"ast_node_type":"variable","tokens":[{"end":35,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:     let def_id = instance.def_id();
context_before: ) -> String {
context_after:     debug_assert_matches!(tcx.def_kind(def_id), DefKind::Fn | DefKind::AssocFn);