Yevamot 58A

לרבי מאיר, דאמר קדושין פסלי ⁠— חופה נמי פסלה. לרבי אלעזר ורבי שמעון, דאמרי קדושין לא פסלי ⁠— חופה נמי לא פסלה.

According to R' Meir, who says that betrothal to a priest disqualifies a woman who is unfit to marry him from partaking of teruma even if she is the daughter of a priest, entering the wedding canopy with a priest also disqualifies her. Conversely, according to R' Elazar and R' Shimon, who say that betrothal does not disqualify her, entering the wedding canopy also does not disqualify her.

וממאי? דלמא עד כאן לא קאמר רבי מאיר התם אלא בקדושין, דקני לה, אבל חופה דלא קני לה ⁠— לא.

The Talmud refutes this claim: And from where do we know that these tanna’im would apply their opinions with regard to betrothal to entering the wedding canopy? Perhaps R' Meir only stated his opinion there, with regard to betrothal, which acquires her. However, in the case of a wedding canopy, which does not acquire her, no, she is not disqualified.

אי נמי: עד כאן לא קאמרי רבי אלעזר ורבי שמעון התם אלא בקדושין, דלא קריבי לביאה, אבל חופה דקריבא לביאה ⁠— הכי נמי דפסלה.

Alternatively, perhaps R' Elazar and R' Shimon stated their opinion only there, with regard to betrothal, as it is not close to an act of sex. However, with regard to entering the wedding canopy, which is close to an act of sex, as it is the place where the bride and groom are secluded together and symbolizes the woman’s entrance into her husband’s home, it is possible that it also disqualifies her from partaking of teruma.

אלא אי איכא למימר, בפלוגתא דהני תנאי, דתניא: נישאו זו וזו, כשרות ופסולות, או שנכנסו לחופה ולא נבעלו ⁠— אוכלות משלו, ואוכלות בתרומה.

Rather, if it can be said that this issue was already discussed by earlier rabbis, it was in the dispute between these other tanna’im, as it is taught in a baraita: If they married one another, i.e., either a woman who is fit or a woman who is unfit married a priest, or they entered the wedding canopy and did not yet have sex with him, they are entitled to eat of his food and to partake of teruma.