syntax_data: {"ast_node_type":"variable","tokens":[{"end":53,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:     let LitToConstInput { lit, ty, neg } = lit_input;
context_before: fn lit_to_mir_constant<'tcx>(tcx: TyCtxt<'tcx>, lit_input: LitToConstInput<'tcx>) -> Const<'tcx> {