[qartik]

Converting a borrow array to an ordinary array transfers the element buffer but leaves the borrow mask allocated. Free the mask after checking that no elements remain borrowed.

The borrow-array lowering was introduced in #2574.

Stacked on #3321.

Validation: the HUGR LLVM borrow-array tests pass, including a JIT allocation-accounting regression.

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-11-04T21:33:27.711273Z	b71c0bd	Draft marked ready
🔒 Security Review	✅ Completed 2026-11-04T21:35:37.988770Z	b71c0bd	Draft marked ready

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[codecov]

Codecov Report

❌ Patch coverage is 94.87179% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 82.11%. Comparing base (f283f3b) to head (b71c0bd).

Files with missing lines	Patch %	Lines
...ugr-llvm/src/extension/collections/borrow_array.rs	94.87%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@                        Coverage Diff                         @@
##           codex-fix-borrow-array-discard    #3322      +/-   ##
==================================================================
+ Coverage                           82.10%   82.11%   +0.01%     
==================================================================
  Files                                 245      245              
  Lines                               47612    47651      +39     
  Branches                            41177    41216      +39     
==================================================================
+ Hits                                39090    39127      +37     
- Misses                               6617     6618       +1     
- Partials                             1905     1906       +1     

Flag	Coverage Δ
python	89.72% <ø> (ø)
rust	80.92% <94.87%> (+0.01%)	⬆️

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[Copilot]

🟢 Approval recommended

No active review issues remain for the borrow-array conversion memory-leak fix.

No open issues 🎉

What changed in this PR

Fixes a memory leak in HUGR LLVM borrow-array conversion by freeing the borrow mask while transferring the element buffer to the ordinary array.

Changes:

• Frees the mask after verifying that no elements remain borrowed.
• Adds a JIT regression test that repeats conversion, access, and disposal 100 times, checking returned values, allocation counts, invalid frees, and outstanding allocations.

File	Description
hugr-llvm/​src/​extension/​collections/​borrow_array.rs	Frees the mask during conversion and adds allocation-accounting regression coverage.

_{Review effort: Balanced}