test(codegen): fix number-context coupled-arms test after #11588 + #11589

[proggeramlug]

Follow-up to #11588 and #11589

main is red in perry-codegen lib tests: expr::index_get_claim_tests::the_number_context_coercion_is_coupled_across_every_arm fails with left: 27, right: 24.

Root cause

It was a test merge collision, not a codegen defect. The coupled-coercion test asserted the dynamic obj[i] site's block count as a literal. #11588 (a growth-forwarding hop: fwd_check/fwd_follow/fwd_header) and #11589 (the byte-view arm: u8.brand/u8.bounds/u8.load) each bumped that literal from 21 to 24 on its own. Together the site has 27 blocks. The sibling test's full block list merged cleanly, but the count literal did not.

The codegen already satisfies the invariant. The byte-view arm's value is a uitofp byte, which is a Number by construction, the same as the tav.w* typed-array arms (these never coerce by design; see the lower_inline_dyn_typed_array_get doc). The forwarding hop produces no value and only re-enters arrlike.ic.brand. The number-context and plain IR shapes are identical.

Fix (test-only, and stricter)

• One shared DYNAMIC_INDEX_SITE_BLOCKS list now pins the full ordered site shape. Both tests compare against it, so the coupled test checks the exact sequence instead of just a length. A future arm updates one list.
• The coupled test now also covers the arms it didn't check before: arrlike.u8.load and tav.w8/w4/w2/w1 must never call js_number_coerce, and the u8 value must be a uitofp i8.

No emitted IR changes, so there is no perf impact on the #11588/#11589 wins.

Validation

• Fails on pristine origin/main (efc0cb5): left: 27, right: 24. Passes with this change.
• cargo test -p perry-codegen: 42 test binaries, 0 failures (lib: 1787 passed, 1 ignored).
• cargo fmt --all -- --check OK. scripts/check_file_size.sh OK.

Not run: the gap suite, other crates' tests, and run_lint_gates.sh. This is a codegen test-only change.

Summary by CodeRabbit

• Tests
  • Updated checks for dynamic indexed reads to verify the expected generated code paths, including that byte-view and typed-array loads avoid unnecessary number coercion.
  • Confirmed byte-view loads preserve the expected byte value behavior. These updates improve test accuracy; no end-user behavior changes are included.

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ℹ️ Recent review info

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Run ID: d03e228e-9230-4371-b999-fabf066aac6c

📥 Commits

Reviewing files that changed from the base of the PR and between efc0cb5 and 8cec12d.

📒 Files selected for processing (2)

• changelog.d/11603-codegen-number-context-coupled-arms.md
• crates/perry-codegen/src/expr/index_get_claim_tests.rs

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📝 Walkthrough

Walkthrough

Dynamic index read tests now use one shared ordered block-label list for site-shape checks. The number-context test also checks that byte-view and typed-array load arms do not coerce their results, and that byte-view loads use unsigned-byte conversion.

Changes

Dynamic Index Read Tests

Layer / File(s)	Summary
Emitted shape and load conversions crates/perry-codegen/src/expr/index_get_claim_tests.rs, changelog.d/11603-codegen-number-context-coupled-arms.md	Site-shape assertions use a shared ordered block-label list. Number-context assertions check that byte-view and typed-array load arms do not call js_number_coerce, and that byte-view loads use unsigned-byte conversion. The changelog records these test updates.

Priority: ⬇️ Low

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Other

Merge Risk: ⚪ Minimal · up to 8cec1

This PR strengthens dynamic-index codegen regression tests without changing production code. The added checks cover the stated load arms, and no merge-blocking risk is evident.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 3 functions across 1 files. (1 skipped: 1 …
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title clearly identifies a codegen test fix caused by the changes in #11588 and #11589. It is concise and specific.
Description check	✅ Passed	The description explains the failure, root cause, test-only fix, stricter assertions, validation results, and tests that were not run. It provides the required information, although it does not use al…

✨ Finishing Touches 💡 1

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