What Constitutes a Valid Vigil Mass for Catholics?

Today is December 8---the Feast of the Immaculate Conception---a Holy Day of obligation. Last night, I went to what was advertised (in the bulletin) as a 7pm *Vigil Mass.* However, the readings were those for December 7 and the homily had nothing to do with the Immaculate Conception. The only thing that was mentioned to that regard was at the beginning of Mass when the priest said that because the Mass started on or after 4pm, it would fulfill the Holy Day obligation. I believe that the priest is in error. I believe that: - (1) a Vigil Mass for the Feast of the Immaculate Conception must occur on or after 4pm the day before, - (2) that the readings will be *the same* as those for the actual Holy Day, and - (3) that (1) and (2) apply to all holy days of obligation in the Catholic Church. Can someone either confirm this or provide evidence to the contrary? Thank you.