Justin Bieber Thinks Selena Gomez Is Using The Weeknd

Justin Bieber can spot an opportunist from a mile away ... at least now he can, and the opportunist is Selena Gomez.

Our Bieber sources tell us ... the singer says he's been there, and believes Selena's using The Weeknd for promotion. Bieber's intel -- and ours -- is that Selena and The Weeknd are working on music together.

We're told Justin feels this is all cookie-cutter stuff ... she did it with him, Nick Jonas, Zedd and now with good ol' Abel. When Selena wants to push new music, it seems she dates stars with whom she wants to collab.

Long story short ... we're told Justin's rolling his eyes at the Selena/Weeknd love story. Can you tell?