yieldTypes

Source span -> rendered type, for every SCOPE yield call in fir whose type is final at the call itself. Read after resolution: the type argument is inferred from the value, so before it there is nothing to render.

A type that still names a type parameter is not final: yield(r) inside an inline fun <reified R> learns what R is only when the backend inlines that function, once per caller. The snippet's body cannot declare such a function itself — a local function cannot be inline — but a class it declares can hold one as a member, so this is live, not defensive. A string rendered here would be the literal R in every copy; left out, the call keeps yield's default, which the inliner does reify. Where the type IS final, a typeName the snippet passed itself is overwritten all the same — the slot is ours, so the reported type cannot disagree with the value's.

Approximated as a declared type would be. Inference hands back forms no declaration can carry — listOf(1, "a") resolves to List<Comparable<*> & Serializable> — and a single-tick result already reports the approximated one, its property type having gone through this same rule on the way to being declared.