{"ast_node_type":"other","tokens":[{"end":57,"kind":"keyword","start":0,"text":"///"}]}
    /// It cannot convert a closure that requires unsafe.
    /// an `unsafe fn (u32, i32)`.
    pub fn signature_unclosure(self, sig: PolyFnSig<'tcx>, safety: hir::Safety) -> PolyFnSig<'tcx> {