UPSTREAM PR #16708: Fix confusing double negation with empty else if

[loci-dev]

Note

Source pull request: nushell/nushell#16708

This else if branch being empty makes no sense if there is no comment.
Can be collapsed by removing the negation on the matches!

Stumbled over this while reading nushell/nushell#16688 (comment)

Release notes summary - What our users need to know

N/A

Tasks after submitting

• Figure out an ast-grep rule for that, sadly clippy::needless_else doesn't seem to catch it.

[loci-review]

Overview

Analysis of 29,125 functions shows negligible performance impact with 0.006% power consumption reduction. The 3 commits refactor conditional expressions to eliminate confusing double negations—a code quality improvement with no performance regressions.

Function counts: 97 modified, 129 new, 129 removed, 28,770 unchanged

Binary: target.aarch64-unknown-linux-gnu.release.nu

• Power consumption: 795,579 nJ → 795,532 nJ (-0.006%)

Function Analysis

std::sys::fs::read_dir (Rust standard library): Response time improved 21.8% (551ns → 431ns). Self-time reduced 46% through compiler optimizations (memory fence insertion, improved code layout). Used extensively in ls, completions, and directory operations—120ns improvement per call compounds in directory-heavy workloads.

nu_plugin_engine::interface::PluginInterfaceManager::send_engine_call::: Response time improved 13.4% (791ns → 685ns). Compiler eliminated logging overhead (105ns) from error path. No source code changes; optimization from release build configuration.

SQLite functions (sqlite3FkOldmask, appendOnePathElement): Minor regressions of 1.1% and 0.08% respectively (+21ns each) from stack canary consolidation. Non-critical paths in history database operations—absolute impact negligible for I/O-bound operations.

No changes to performance-critical areas (IR execution, pipeline data flow, parser, REPL loop).

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