Description:
------------
It seems there is a small problem with the \ char in single quotes.

I think the char \ is *not* an escape char in single quotes, as

echo 'abc\x';

outputs

abc\x

But, the following code

echo 'abc\';

gives an error:

PHP Parse error:  syntax error, unexpected T_STRING, expecting ',' or ';' in x:\test.php on line 1

However, the code
echo 'abc\\';

has no runtime error and it outputs

abc\

but it should output (with two \ chars)

abc\\


Reproduce code:
---------------
echo 'abc\x';
echo 'abc\\';
echo 'abc\';


Expected result:
----------------
abc\x
abc\\
abc\

Actual result:
--------------
abc\x
abc\
PHP Parse error:  syntax error, unexpected T_STRING, expecting ',' or ';' in x:\test.php on line 1