syntax_data: {"ast_node_type":"import","tokens":[{"end":80,"kind":"keyword","start":0,"text":"ObligationCauseCode::ImplDerived(Box::new(ImplDerivedCause"}]}
source_snippet:                     ObligationCauseCode::ImplDerived(Box::new(ImplDerivedCause {
context_before:                 cause.clone().derived_cause(parent_trait_pred, |derived| {
context_after:                         derived,