Merge Request changes missing when folder & file have same name

Summary

The "Changes" tab on an MR does not report a file as "deleted" if a folder was created with the same name.

Steps to reproduce

1. Delete a file in your repo.
2. Create a folder with the same name & add some files within it. (E.g. you might be splitting a large file into a module of multiple files.)
3. Raise an MR with the changes.

What is the current bug behavior?

In the changes tab of the MR, any new files in the folder will be shown as additions. The deletion of the original file will not be shown.

What is the expected correct behavior?

Both the original, deleted file and the new, changed files are shown in the MR and their changes are factored into the computed line additions/deletions

Relevant logs and/or screenshots

Correct changes reported on the dashboard/merge_requests page:

Incorrect changes reported on the merge_requests/427/diffs page:

Output of checks

This bug happens on GitLab.com