{"ast_node_type":"function","tokens":[{"end":58,"kind":"keyword","start":0,"text":"\"impl"}]}
            "impl z { fn a (&mut self, &myarg: i32) {} }",
            "impl z { fn a (&self, &myarg: i32) {} }",
            "impl z { fn a (&'a self, &myarg: i32) {} }",