syntax_data: {"ast_node_type":"other","tokens":[{"end":36,"kind":"keyword","start":0,"text":".unwrap_or_else(||"}]}
source_snippet:                 .unwrap_or_else(|| {
context_before:                 .leaf_def(tcx, trait_item_id)
context_after:                     bug!("{:?} not found in {:?}", trait_item_id, impl_data.impl_def_id);