ABI
The driver↔weavy boundary. Boundary formats calcify into JIT stencils — they are typed FIRST, because stencils turn ABI refactors into breaking changes.
[SETTLED] The slot protocol is one typed boundary struct — Slots (readiness
- awaited values), the host environment, value memories — not positional parallel slices. This lands before stencils bake the layout.
[DESIGN] Slot readiness is bitset words (test = AND, schedule = find-first- set, progress = popcount), not byte-per-bool arrays. Positional protocols whose wrong index reads a valid neighbor are the named hazard.
[SETTLED] The host environment is a type: HostEnv with a trait, methods on
&mut self, a static dispatch table. Inline closure forests and
RefCell::new(&mut x) — runtime borrow-checking to smuggle mutability into
closures — are banned as patterns; the RefCell-of-&mut is a confession the
design has the wrong shape.
[DESIGN] Frame words are reached through one typed accessor. from_le_bytes
on hand-computed frame offsets at call sites is hand-rolled ABI (64
occurrences in the old dispatch region).