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A friend is coming over to visit tomorrow.
Literal
Friend [subject-が] tomorrow house [to-に] play [purpose-に] come.
遊びに来る ('come to hang out') is one of the most common casual-visit expressions. 遊ぶ literally means 'to play' but in this context means social visiting. The double に — one marking destination (家に), one marking purpose (遊びに) — is natural and unambiguous.