Pure-PHP CLI heuristic checker for ph-string-dot-hot–ph-echo-hot.

Rule	Message
ph-string-dot-hot	string `.=` in loop; prefer `implode` / collector
ph-array-merge-rebind	`array_merge` rebinding in loop; prefer `$a[] = …`
ph-echo-hot	`echo` / `print` in loop; gate or buffer

Default severity: ph-string-dot-hot=off, ph-array-merge-rebind=error (G4 evidence), ph-echo-hot=hint. Re-enable ph-string-dot-hot with --severity ph-string-dot-hot=hint; demote ph-array-merge-rebind with --severity ph-array-merge-rebind=hint. Self-dogfood: bash ../scripts/self-lint.sh.

phpperf-lint