{"ast_node_type":"other","tokens":[{"end":67,"kind":"keyword","start":0,"text":"Err(CopyImplementationError::InfringingFields(fields))"}]}
        Err(CopyImplementationError::InfringingFields(fields)) => {
        Ok(()) => Ok(()),
            let span = tcx.hir_expect_item(impl_did).expect_impl().self_ty.span;