A record field can carry a type hint — ^Vec3 (a defined record type) or ^:num —
and the inference now resolves it so reading the field back yields that exact type
instead of :any. A Vec3 stored in a Ray field reads out as Vec3, so the vec ops on
field-read values prove their reads (bare-index). This is Stalin's per-slot type
sets, but DECLARED rather than inferred: the exact shape is known up front.
- deftype captures each field's :tag / :num metadata (was stripped) and passes it
to make-deftype-ctor; the ctor registers per-field tags, resolving a record-type
hint to its ctor-key (same-ns) so the inference can look it up directly.
- call-ret-type builds a record's struct type with field types resolved from the
hints, recursing into nested record types (depth-bounded for self/cyclic types).
Measured: a nested-record read loop (:r (:origin ray)) runs 1.3s with ^Vec3 hints
vs 7.1s without — 5.5x. This is the lever the ray tracer needed (vecs flow through
container fields); records without it read back as :any and stay unproven.