(require 'filename) doesn't find the file

[hector]

The file called BASENAME.el that I want to (require) is in the load-path.
If I add to it the line

(provide 'basename)

it works.

But if I remove the line when I try to compile it says:

syntax.el:26:1:Error: Required feature `basename' was not provided

The part that I think isn't working:
If FEATURE is not a member of the list `features', then the feature
is not loaded; so load the file FILENAME.

Why doesn't it find the file even if it does not contain a (provide)?

I searched for an answer in the list but couldn't find it.
The topic "Requiring elisp that comes with Emacs" comes close
but not to the point.