Requirements: PHP7 CLI
run `arc unit --everything`
Result:
```
libphutil herpa-derpa$ arc unit --everything
PHP Fatal error: Uncaught TypeError: Argument 1 passed to PhutilErrorHandler::handleException() must be an instance of Exception, instance of ParseError given in /herp/arc/libphutil/src/error/PhutilErrorHandler.php:247
Stack trace:
#0 [internal function]: PhutilErrorHandler::handleException(Object(ParseError))
#1 {main}
thrown in /herp/arc/libphutil/src/error/PhutilErrorHandler.php on line 247
Fatal error: Uncaught TypeError: Argument 1 passed to PhutilErrorHandler::handleException() must be an instance of Exception, instance of ParseError given in /herp/arc/libphutil/src/error/PhutilErrorHandler.php:247
Stack trace:
#0 [internal function]: PhutilErrorHandler::handleException(Object(ParseError))
#1 {main}
thrown in /herp/arc/libphutil/src/error/PhutilErrorHandler.php on line 247
```
Possible solution is to have it use the `\Throwable` typehint instead, the problem, is that Throwable only exists in PHP7+, so this would break PHP5... ideas?