Tā zǒng shuō yào yuēfàn, dàn cónglái méi dìng shíjiān.
She always says we should grab a meal, but never sets a time.
Tips
register
Casual, modern colloquialism. Formed by clipping 约 ('make an appointment') + 饭 ('meal'). Friends and coworkers use it; in formal contexts use 一起吃饭 or 共进晚餐.
usage
Often appears with 个 inserted: 约个饭. The phrase has gained the same vague placeholder feel as English 'we should grab lunch sometime' - often more politeness than commitment.