syntax_data: {"ast_node_type":"variable","tokens":[{"end":46,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                 let sig = self_ty.fn_sig(tcx);
context_before:             ty::FnDef(..) | ty::FnPtr(..) => {
context_after:                 let trait_ref = sig.map_bound(|sig| {