Symptom
On main f3f405271c (and 744df26d8e), the issue_8690_loop_versioned_arraylike case read_only_loops_have_preheader_proofs_and_fallback_free_fast_blocks fails its shape assertion: scan()'s IR contains 0 js_packed_arraylike_loop_guard( sites where 3 are expected — the outer fast/slow copies no longer own preheader-versioned inner loops. issue_8773_closure_capture_packed_loops fails 1 case the same way. Program output stays correct; the flagship nested-subclass-loop shape silently runs at generic-loop speed.
Window
Both suites were green on macOS at 8b40634abd (the #9071 replay) and fail at f3f405271c. The window contains the packed/versioned-loop landings #9070 (versioned length-bound hoist), #9084 (read admissions), #9091 (unboxed accumulators), plus #9075/#9080/#9085. The shape gates were doing their job — this was caught only because an unrelated branch ran the full battery.
Repro
cargo test -p perry --test issue_8690_loop_versioned_arraylike
(macOS; needs the default-target libperry_runtime.a — on a fresh box cargo build -p perry-runtime-static first, and note the suite fails in ~0.5s with an archive-mismatch harness error otherwise, which is NOT this regression.)
Notes
The fixture is the wolf-ecs Query extends Array / Archetype extends Array nested scan — the exact shape the ECS campaign optimized to 2.3×/1.5× of node, so this likely walks back part of that standing until fixed. Independent of PR #9105 (verified by running both suites on detached main in the same worktree).
Reported by the ECS/ops perf campaign, session https://claude.ai/code/session_019WVcWKmYsUBnnFB7nBgbBJ; the loop lane's owner (85-successor / whoever holds #9084/#9091) is the natural assignee — coordination on the cc-socks channel.
Symptom
On main
f3f405271c(and744df26d8e), theissue_8690_loop_versioned_arraylikecaseread_only_loops_have_preheader_proofs_and_fallback_free_fast_blocksfails its shape assertion:scan()'s IR contains 0js_packed_arraylike_loop_guard(sites where 3 are expected — the outer fast/slow copies no longer own preheader-versioned inner loops.issue_8773_closure_capture_packed_loopsfails 1 case the same way. Program output stays correct; the flagship nested-subclass-loop shape silently runs at generic-loop speed.Window
Both suites were green on macOS at
8b40634abd(the #9071 replay) and fail atf3f405271c. The window contains the packed/versioned-loop landings #9070 (versioned length-bound hoist), #9084 (read admissions), #9091 (unboxed accumulators), plus #9075/#9080/#9085. The shape gates were doing their job — this was caught only because an unrelated branch ran the full battery.Repro
(macOS; needs the default-target
libperry_runtime.a— on a fresh boxcargo build -p perry-runtime-staticfirst, and note the suite fails in ~0.5s with an archive-mismatch harness error otherwise, which is NOT this regression.)Notes
The fixture is the wolf-ecs
Query extends Array/Archetype extends Arraynested scan — the exact shape the ECS campaign optimized to 2.3×/1.5× of node, so this likely walks back part of that standing until fixed. Independent of PR #9105 (verified by running both suites on detached main in the same worktree).Reported by the ECS/ops perf campaign, session https://claude.ai/code/session_019WVcWKmYsUBnnFB7nBgbBJ; the loop lane's owner (85-successor / whoever holds #9084/#9091) is the natural assignee — coordination on the cc-socks channel.