Using arcanist on git commit 59640f7eae3f7c0a352c18e784fb55acb7967991, the following error can be seen:
```
$ bin/arc unit --everything --no-coverage
```
```
FAIL ArcanistXMLLinterTestCase::testLinter
In 'attr3.lint-test', expected lint to raise warning on line 4 at char 24, but no warning was raised. Actually raised:
warning at line 4, char 28: XML501 LibXML Error
```