Incorrectly parsing incorrect Ruby

[Rob Rix]

def bar
en

should result in an error, but instead parses:

(program [0, 0] - [2, 0]
  (method [0, 0] - [2, 0]
    (identifier [0, 4] - [0, 7])
    (identifier [1, 0] - [1, 2])
    (string [2, 0] - [2, 0])))

[Rob Rix]

(Further, it did result in an error until recently.)