This backport I would describe as mildly important. Without it there would be some static initialization code that causes the compiler to crash. It isn't common, but it isn't fuzz-generated either. Real people have run into it. I suspect it is not too hard to work around.
The fix for #56105 was for the same underlying issue, but was incomplete. This issue+CL fixes that incompleteness.
The backport is very safe. It just does some extra typechecking.
As #56727 (comment) mentioned, this issue was not in Go 1.19.2 but caused by a backport of #56105 in 1.19.3. I guess another option would be reverting that backport. The input in #56105 does look a bit contrived. The concern here is that the backport of #56105 has caused a chain of more issues and backports. How would that sound? Thanks.