{"ast_node_type":"other","tokens":[{"end":98,"kind":"keyword","start":0,"text":"UnreachableLabel"}]}
    UnreachableLabel { name: Symbol, definition_span: Span, suggestion: Option<LabelSuggestion> },
    /// Error E0767: use of unreachable label
    /// Error E0323, E0324, E0325: mismatch between trait item and impl item.