syntax_data: {"ast_node_type":"variable","tokens":[{"end":79,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:     let mut params_in_repr = DenseBitSet::new_empty(generics.own_params.len());
context_before:     let generics = tcx.generics_of(def_id);
context_after:     for variant in adt_def.variants() {