Auto merge of #4064 - mikerite:fix-771, r=matthiaskrgr
Auto merge of #4064 - mikerite:fix-771, r=matthiaskrgr

Add test for #771.

Closes #771

<!--
Thank you for making Clippy better!

We're collecting our changelog from pull request descriptions.
If your PR only updates to the latest nightly, you can leave the
`changelog` entry as `none`. Otherwise, please write a short comment
explaining your change.

If your PR fixes an issue, you can add "fixes #issue_number" into this
PR description. This way the issue will be automatically closed when
your PR is merged.

If you added a new lint, here's a checklist for things that will be
checked during review or continuous integration.

- [ ] Followed [lint naming conventions][lint_naming]
- [ ] Added passing UI tests (including committed `.stderr` file)
- [ ] `cargo test` passes locally
- [ ] Executed `util/dev update_lints`
- [ ] Added lint documentation
- [ ] Run `cargo fmt`

Note that you can skip the above if you are just opening a WIP PR in
order to get feedback.

Delete this line and everything above before opening your PR -->

changelog: none

graydon/rust,graydon/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust