Unclear warning on dummy constraint

[artwyman]

I'm using a dummy constraint which exists to ensure a signal doesn't get removed by the compiler. It looks like this:

signal watermarkSquared <== watermark * watermark;

This gets a warning with a message which seems incomplete, saying "The intermediate signal watermarkSquared is declared here."

I'd guess that it's warning me that watermarkSquared is unused, which is intentional and unavoidable here, but I can't be sure as it's not actually saying so.