Robert Downey Jr.'s Son Indio -- Arraignment Delayed While He Gets Drug Treatment

Robert Downey Jr.'s son Indio won't have his day in court just yet ... TMZ has learned his arraignment scheduled for Thursday was pushed back because the 20-year-old is still getting treatment in rehab.

As TMZ first reported, Indio was arrested in West Hollywood back on June 29 after cops observed him smoking something out of a pipe while riding in the passenger seat of a car.

Indio is facing charges of felony possession of a controlled substance and misdemeanor possession of drug paraphernalia.

Thursday in court, his attorney, Blair Berk, told the judge Indio is doing well in his live-in treatment facility.

He's due back in court next month.