Directly navigating to a submodule leads to "empty file"

Summary

Attempting to view a submodule in the web interface results shows an 'empty file'. There's no link to this in the UI, but a user might reasonably navigate to this page:

http://gitlab.example.com/group/project/blob/master/my-submodule

What is the current bug behavior?

The file displays as "Empty file"

What is the expected correct behavior?

"Submodule at [SHA]"

(I'm using gitlab master at, arbitrarily, gitlab-ce@b2e1d32e7a74b22b23e8ab052bd29e15bb8a4f1e)