Before submitting an issue to ANTLR, please check off these boxes:
 
- [ ] I am not submitting a question on how to use ANTLR; instead, go to [antlr4-discussion google group](https://groups.google.com/forum/#!forum/antlr-discussion) or ask at [stackoverflow](http://stackoverflow.com/questions/tagged/antlr4)
- [ ] I have done a search of the existing issues to make sure I'm not sending in a duplicate

### Expected behavior

### Actual behavior

### Steps to reproduce the behavior