Style/LineEndConcatenation breaks code

[ptarjan]

Expected behavior

$ cat /tmp/a.rb
'a' + \
  'b'
$ rubocop /tmp/a.rb -a
...
$ cat /tmp/a.rb
'a' \
  'b'
$ ruby /tmp/a.rb
$

Actual behavior

$ cat /tmp/a.rb
'a' + \
  'b'
$ rubocop /tmp/a.rb -a
Inspecting 1 file
E

Offenses:

/tmp/a.rb:1:5: C: [Corrected] Use \ instead of + or << to concatenate those strings.
'a' + \
    ^
/tmp/a.rb:1:5: E: bare backslash only allowed before newline
(Using Ruby 2.0 parser; configure using TargetRubyVersion parameter, under AllCops)
'a' \\
    ^

1 file inspected, 2 offenses detected, 1 offense corrected
$ cat /tmp/a.rb
'a' \\
  'b'
$ ruby /tmp/a.rb
/tmp/a.rb:1: syntax error, unexpected $undefined, expecting end-of-input
'a' \\
     ^
$

Steps to reproduce the problem

See my /tmp/a.rb

RuboCop version

$ rubocop -V
0.39.0 (using Parser 2.3.0.7, running on ruby 2.1.2 x86_64-darwin15.0)