Anonymous types and type aliases do not have spans #7951
Description
In adding a maximum size for any type (#7950, for #7383), I found that in some cases the error messages were not very useful because a span isn't stored with the types in the arena, so it isn't possible to identify what is oversize.
I chose 1 GB as a starting limit, so it's relatively unlikely anyone will hit the limit, and if it does get hit, there probably aren't very many types that could be the culprit.