{"ast_node_type":"function","tokens":[{"end":69,"kind":"keyword","start":0,"text":"fn"}]}
fn constness(tcx: TyCtxt<'_>, def_id: LocalDefId) -> hir::Constness {
/// Checks whether a function-like definition is considered to be `const`.
    let node = tcx.hir_node_by_def_id(def_id);