syntax_data: {"ast_node_type":"other","tokens":[{"end":42,"kind":"keyword","start":0,"text":"_"}]}
source_snippet:         _ if thir.params.is_empty() => "",
context_before:         // categorize those for the irrefutable check.
context_after:         kind => bug!("unexpected function parameters in THIR: {kind:?} {def_id:?}"),