type-expander + multi-id + recursive type goes into an infinite loop

[SuzanneSoy]

Workaround: use #:type-noexpand or #:type-expand-once instead of #:type-expander.

Maybe we can detect when recursively expanding a type?

Although it should be possible to have a type which recursively expands, but has e.g. a counter ensuring it will stop after a while. E.g. (homogeneous-list 5 Number) becomes (Pairof Number (homogeneous-list 4 Number)) etc. so that it will expand only 5 times, and then stop at the sixth, producing Null.