Sema: rework peer type logic for pointers

Now it's centered around a switch on the chosen type tag which gives us
easy access to pointer data.

The logic is simplied and in some cases logic is removed when it is
sufficient to choose the type that is a better coercion target without
knowing whether such coercion will succeed ahead of time.

A bug is fixed at the bottom of the function; we were doing the opposite
of what we were supposed to with `seen_const`.

Also the bottom of the function has a more complete handling of the
possible combinations of `any_are_null`, `convert_to_slice`, and
`err_set_ty`.

In the behavior tests, not as many backends needed to be skipped.

0 files changed, 0 insertions, 0 deletions