syntax_data: {"ast_node_type":"variable","tokens":[{"end":66,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let (value, mapped_regions, mapped_types, mapped_consts) =
context_before:     if value.has_escaping_bound_vars() {
context_after:             BoundVarReplacer::replace_bound_vars(infcx, universe_indices, value);