syntax_data: {"ast_node_type":"other","tokens":[{"end":45,"kind":"keyword","start":0,"text":".leaf_def(tcx,"}]}
source_snippet:                 .leaf_def(tcx, trait_item_id)
context_before:                 .ancestors(tcx, impl_data.impl_def_id)?
context_after:                 .unwrap_or_else(|| {