{"ast_node_type":"function","tokens":[{"end":83,"kind":"keyword","start":0,"text":"fn"}]}
            fn replace_region(&mut self, br: ty::BoundRegion) -> ty::Region<'tcx> {
        impl<'tcx> BoundVarReplacerDelegate<'tcx> for ToFreshVars<'tcx> {
                self.args[br.var.index()].expect_region()