Is this bad Ruby or is Rubymine broken again?

What does the Rubymine warning "implicit required file; not inspected" mean?

This inspection warns about the references in Ruby code which can't be resolved to any valid target. 

The Rubymine message goes on to say: This most likely indicates a typo or some other error which may occur at runtime.

Why does Rubymine spew this crap when the code works as expected? 

Please, dear reader, if there something improper about this Ruby, then I would like to be informed. 

Many thanks!