I found something on a webpage, but it is not attributed to a Pope…
*Just so, it is a lie for someone who is not Catholic to receive Communion in the Catholic Church, when there is first no union with the Catholic Church. When you receive Communion in the Catholic Church, you are saying with your body that you are in union with the Church and that you believe as we believe. And not just in regard to the Real Presence, but also in regard to the Pope, to Mary, to the other Sacraments, to the Communion of Saints, the priesthood, salvation, and so on. If there is no union, there should be no Communion.
The same holds when you receive communion in a non-Catholic faith tradition. You are saying, with your body, that you believe as they believe. You are telling everyone present that there is essentially no difference between what they believe about communion and what you, as a Catholic, believe about Communion. **You are telling a lie with your body. *** That is why Catholics should not receive communion, or the Lord’s Supper, outside the bounds of the Catholic Church.
This is the site:
biblechristiansociety.com/newsletter/detail/171
Couldn’t find anything from either of these Popes with similar language.