{"ast_node_type":"function","tokens":[{"end":83,"kind":"keyword","start":0,"text":"fn"}]}
    fn new_ref_ty(&self, span: Span, mutbl: Mutability, ty: Ty<'tcx>) -> Ty<'tcx> {
    /// Create a reference type with a fresh region variable.
        let region = self.next_region_var(RegionVariableOrigin::PatternRegion(span));