Fluid inline notation: Namespace declaration is never used

If a fluid namespace is only used in inline notations (https://wiki.typo3.org/Fluid_Inline_Notation) PHPStorm can't detect the usage. So it outputs the warning "Namespace declaration is never used": http://imgur.com/a/MGryB

It would be nice if the fluid plugin could tell PHPStorm, that the namespace is used.