When a feast falls on a Sunday, it is transferred to the Monday.
This year, the feast of the Visitation (31 May) was impeded by the solemnity of Corpus Christi (in most places). However, today, 1 June, is kept as the memoria of Justin Martyr, and the feast of the Visitation is omitted.
Why is the Visitation not transferred to 1 June when impeded by Corpus Christi?
(I am, obviously, talking about the ordinary form Catholic calendar.)
The Visitation, celebrating the vist of Mary to Elizabeth while expecting Jesus and John respectively, is classed as a feast rather than a solemnity. Only the most important celebrations count as solemnities.
Paragraph 60 of the General Norms for the Liturgical Year http://www.romcal.net/norms.html says what happens when days coincide.
If several celebrations fall on the same day the one that has the highest rank ... is observed. But a solemnity impeded by a liturgical day that takes precedence over it should be transferred... Other celebrations are omitted that year.
Because the Visitation is not a solemnity it is never transferred. If May 31 is a Sunday, Ascension Day or Corpus Christi then the celebration of the Visitation is omitted that year.
Other feasts omitted this year include Mary Magdalene (22 July) and Simon and Jude (28 October). These both fall on Sundays.
If a solemnity falls on a Sunday then the solemnity usually takes precedence over the Sunday. The Nativity of John the Baptist is a solemnity on June 24 which this year (2018) is a Sunday. It is not transferred, or omitted, but will be observed on the Sunday.
However if a solemnity falls on a Sunday in Advent, Lent or Easter season, or a weekday in Holy Week or Easter week, in that case the solemnity is transfered.
In the ordinary general calendar, ignoring local propers, only the Conception of Mary (8 December), St Joseph (19 March) and the Annunciation (25 March) are transferred if they fall on Sundays, usually to the following day, if that is not in Holy Week or Easter Week. Only these are transferred because they are the only ones that can fall on Sundays in Advent, Lent or Easter. In Ireland St Patrick (March 17) is a solemnity and is transferred if it falls on a Sunday.
This year the Annunciation fell on Palm Sunday and so it was transferred 15 days, past Holy Week and Easter Week to the Monday April 9th.
This link, from OP, corroborates: http://www.universalis.com/general/100/calendar.htm
In 2038 Corpus Christi is on June 24th and so two solemnities would fall on the same weekday. John the Baptist will be transferred to Friday June 25th.
But the Visitation, being a mere feast and not a solemnity, is never transferred but simply omitted if impeded by a Sunday or a solemnity.
