syntax_data: {"ast_node_type":"variable","tokens":[{"end":81,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                 let code = ObligationCauseCode::WhereClause(origin_def_id, span);
context_before:             .map(|((pred, span), origin_def_id)| {
context_after:                 let cause = self.cause(code);