WhileUntil complains when alternative is not legal Ruby

[agrimm]

The following code will cause the WhileUntil cop to complain.

lines = %w{first second third}

while (line = lines.shift)
  puts line
end

However, the alternative is not legal Ruby. The following code

lines = ["first", "second", "third"]
puts line while (line = lines.shift)

would give the error message

-:2:in `<main>': undefined local variable or method `line' for main:Object (NameError)