Functions fail to parse closure parameters

[justin]

Example

func foo(completion: (Result<Int, Error>) -> Void)) {}

Result

(program [0, 0] - [1, 0]
  (function_declaration [0, 0] - [0, 53]
    name: (identifier [0, 5] - [0, 8])
    (parameter_list [0, 8] - [0, 41]
      (parameter_declaration [0, 9] - [0, 41]
        (identifier [0, 9] - [0, 19])
        (type [0, 21] - [0, 41]
          (tuple_type [0, 21] - [0, 41]
            (type [0, 22] - [0, 28]
              (identifier [0, 22] - [0, 28]))
            (ERROR [0, 28] - [0, 32]
              (identifier [0, 29] - [0, 32]))
            (type [0, 34] - [0, 39]
              (identifier [0, 34] - [0, 39]))
            (ERROR [0, 39] - [0, 40]
              (ERROR [0, 39] - [0, 40]))))))
    return: (type [0, 45] - [0, 49]
      (identifier [0, 45] - [0, 49]))
    (ERROR [0, 49] - [0, 50])))
parse_test.swift	0 ms	(ERROR [0, 28] - [0, 32])