Third and terminal iteration of the standalone loop/recur
milestone (plan eae73bf). Replaces the iter-1 lower_term
CodegenError::Internal stub for Term::Loop/Term::Recur with real
LLVM-IR lowering: loop binders as entry-block allocas (mut.3
pending_entry_allocas, reusing mut_var_allocas so the existing
Term::Var load path is byte-unchanged), a fresh loop-header block,
recur stores + back-edge br, a loop_frames stack saved/restored at
the lambda boundary. clang -O2 mem2reg promotes the allocas to
phi. Four Boss design calls implemented verbatim and journalled
(alloca-not-hand-phi; mut_var_allocas reuse; emergent loop-exit
via the if/match join; single block_terminated field + parallel
SET site). Diff confirmed surgical: codegen/lib.rs 3 hunks (field
+ init + stub->2-arms), lambda.rs 2 hunks (save+restore); zero
edits to any existing block_terminated SET/READ site, tail-app
lowering, or verify_tail_positions (Boss call 4, the spec-pinned
invariant). Three new .ail fixtures: sum_to->55,
deep-n 1e6->500000500000 (clause-2 correctness made executable),
infinite-loop build-only. Codegen-only: no schema/typecheck
change; hash pins + drift trio stay green untouched.
One DONE_WITH_CONCERNS (T3): the plan's `cargo test ... tail`
filter resolved to no tests; ran via real names + the full 619/0
which subsumes it (feedback_plan_pseudo_vs_reality class, no
behaviour change). Boss systemic fix folded in: planner SKILL.md
Step-5 gains item 8 (verification-command filter strings must
resolve) — the second planner-meta-gap this milestone surfaced.
cargo test --workspace 616 -> 619 / 0 red (Boss-reran
independently); the 3 loop/recur e2e explicitly green. All three
components shipped: the loop/recur milestone is structurally
complete. Milestone-close audit + fieldtest is the next step.
Brummel
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