Judge Martha Pacold dismissed a suit filed by a man named DaQuan Robinson -- who sued Future 2 years ago for what he claimed was a lot of lifted elements from the guy's song "When I Think About It" ... which he says mirrored his own track, "When U Think About It."

Robinson alleged he'd emailed a draft of the song to Future's team before the official version came out -- and claims Future's track ended up being eerily similar to his original tune.

Specifically, Robinson claimed Future's song touched on a lot of the same content his track did -- namely, guns, money and jewelry -- but Judge Pacold cut him off there ... saying those general themes are not protected by copyright -- and are omnipresent throughout rap.

To make her point, she cites countless examples where these topics are addressed ... such as Biggie's 'Machine Gun Funk,' 'Wu-Tang Clan's 'C.R.E.A.M.' and even Kanye's 'Diamonds from Sierra Leone.' In all of those, she says, these references exist ... and therefore, they're part of the larger hip hop well of content that no one person can claim copyright to in a given song.

The judge didn't even get to the point about Robinson claiming he sent his tune to Future beforehand because the court found the two songs weren't substantially similar enough for it to matter anyway.

There's more musical shout-outs beyond this, too -- including a nod to Crosby, Stills, Nash & Young (Neil Young, that is). Specifically, the judge mentions their song "Our House" to dispute Robinson's claim about Future's alleged misuse of a "core lyric" that he thought was the same as his.

Basically, she says core lyrics are yet another basic element of songwriting ... and not subject to copyright protection in and of itself.

Bottom line ... there isn't enough there to claim copyright infringement -- and the judge ruled in Future's favor -- tossing Robinson's claim with prejudice. He can appeal if he wants to.