{"ast_node_type":"function","tokens":[{"end":81,"kind":"keyword","start":0,"text":"do_check(r#\"fn"}]}
        do_check(r#"fn foo($0x: i32, y: i32) {}"#, &["x", "x: i32", "x: i32, "]);
        do_check(r#"fn foo($0x: i32) {}"#, &["x", "x: i32"]);
        do_check(r#"fn foo($0x: i32,y: i32) {}"#, &["x", "x: i32", "x: i32,", "(x: i32,y: i32)"]);