syntax_data: {"ast_node_type":"variable","tokens":[{"end":82,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                     let iter = in_trait_def[&trait_item_def_id].iter().map(|&id| {
context_before:                     };
context_after:                         associated_type_for_impl_trait_in_impl(tcx, id, item, disambiguator)