俱舍論疏 24.16

24.16

論「即斷修惑至不還果向」，此釋不還向也。不還向有兩種：緣不具者但名不還向，三緣具者亦名一間。

The commentary states: "Namely, severing the defilements of cultivation … candidate for the fruit of the non-returner," which explains the candidate for the non-returner. There are two kinds of candidates for the non-returner: those who lack the complete conditions are simply called candidates for the non-returner, whereas those who possess all three conditions are also called single-interval practitioners.