Running `arc lint` on the following code produces a syntax error:
```lang=php
<?php
echo $x * 2 . '%';
```
Specifically, the following fix with be applied:
```lang=diff, counterexample
<?php
-echo $x * 2.'%';
+echo $x * 2 . '%';
```
This change introduces a syntax error:
```
> php -l test.php
PHP Parse error: syntax error, unexpected ''%'' (T_CONSTANT_ENCAPSED_STRING), expecting ',' or ';' in test.php on line 3
Errors parsing test.php
```