fix: resolve compiler warnings in binary and miscellaneous Index files

[maxwbuckley]

Summary

• Fix compiler warnings in Index2Layer, IndexAdditiveQuantizer, IndexAdditiveQuantizerFastScan, IndexBinaryFlat, IndexBinaryFromFloat, IndexBinaryHash, IndexBinaryIVF, IndexFastScan, IndexIDMap, IndexLSH, IndexLattice
• Fixes include -Wshadow, -Wunused-parameter, and signed/unsigned comparisons

All changes are mechanical. No functional changes.

Part 9/13 of the compiler warnings cleanup (split from #4810 per maintainer request).

Test plan

• No functional changes — all fixes are mechanical renames and annotations

🤖 Generated with Claude Code

Co-Authored-By: Claude Opus 4.6 (1M context) noreply@anthropic.com

[meta-codesync]

@alibeklfc has imported this pull request. If you are a Meta employee, you can view this in D96996483.

[alibeklfc]

Hi, @maxwbuckley. Thank you for your contributions!

Could you please rebase all your PRs on the current version of FAISS and resolve any conflicts?

[maxwbuckley]

Done — all PRs have been rebased onto current main and conflicts resolved.

One PR (#4958, part 7 — SIMD/sorting/misc utilities) was closed as its changes are already upstream.

The remaining 11 PRs are now up to date:

• fix: add CMake warning infrastructure (opt-in strict compiler warnings) #4932 (part 1) — CMake warning infrastructure
• fix: resolve compiler warnings in core base classes and headers #4933 (part 2) — Core base classes and headers
• fix: resolve compiler warnings in graph-based index implementations #4956 (part 3) — Graph-based indexes
• fix: resolve compiler warnings in quantizer implementations #4957 (part 4) — Quantizer implementations
• fix: resolve compiler warnings in IO, result handlers, and misc impl #4936 (part 5) — IO, result handlers, misc impl
• fix: resolve compiler warnings in inverted lists and cppcontrib #4939 (part 8) — Inverted lists and cppcontrib
• fix: resolve compiler warnings in binary and miscellaneous Index files #4940 (part 9) — Binary and misc Index files
• fix: resolve compiler warnings in PQ, PreTransform, and Refine Index files #4941 (part 10) — PQ, PreTransform, Refine Index
• fix: resolve compiler warnings in IVF Index implementations #4942 (part 11) — IVF Index implementations
• fix: resolve compiler warnings in top-level FAISS source files #4943 (part 12) — Top-level FAISS source files
• fix: resolve compiler warnings in test files #4944 (part 13) — Test files

[meta-codesync]

@alibeklfc merged this pull request in e5114c2.