Give some stream of consciousness and then the answer. Fifteen years after the original recording, Luther Vandross and Cheryl Lynn re-recorded it for her album Instant Love and made the song a R&B top five smash peaking at number four in 1982 on the Billboard Hot R&B Singles chart.

Based on this passage, who sings if this world were mine with luther?
To answer this question, we should know that: Fifteen years after the original recording, Luther Vandross and Cheryl Lynn re-recorded it for her album Instant Love and made the song a R&B top five smash peaking at number four in 1982 on the Billboard Hot R&B Singles chart.
Therefore, the answer is Cheryl Lynn.