Brummel
8bc2972594
plan-recon flagged that monomorphise_workspace runs between check and codegen, and codegen lowers the post-mono workspace. The first draft of this spec placed lower_to_mir as the final phase of check_workspace (pre-mono) and claimed "nothing re-walks the AST". That is wrong on both counts: - Built pre-mono, MIR would not carry the monomorphic specialisations monomorphise_workspace appends — exactly the post-mono bodies codegen emits today — reintroducing the check↔codegen gap this milestone exists to close. - synth is a pure `&Term → Type` function and the authoring AST carries no node-ids, so MIR cannot be a side-table read off a check pass; it is built inline by a walk. The honest property is therefore not "no second walk" but "no second *engine*": codegen's synth_with_extras is a hand-copied mirror of synth that drifts (every raw-buf bug is a drift point). The milestone replaces the mirror with a single post-mono call to canonical synth, materialised as MIR. Corrections: architecture diagram and data flow now run check → lift → monomorphise → lower_to_mir; lower_to_mir is wrapped by a new front-end entry elaborate_workspace that subsumes the lift+mono orchestration the CLI does today; check_workspace stays for the diagnostics-only path (`ail check`). Node count fixed 27 → 17 Term variants (ast.rs:436). Re-dispatched grounding-check after the edit (post-PASS edit invalidates the prior report) — PASS, all load-bearing post-mono assumptions ratified against live code (main.rs build order, mono.rs synth use, 17-variant Term, no node-ids).