Attempting to reduce the number of places that care about the details of
how type casting occurs. We remove the type casting of the primary key
in `JoinDependecy`, rather than encapsulating it. It was originally
added for consistency with
40898c8c19 (diff-06059df8d3dee3101718fb2c01151ad0R211),
but that conditional was later removed in
d7ddaa530f.
What is important is that the same row twice will have the same value
for the primary key, which it will.
