CAT 049

CAT-049 — Thread.new → spawn

Severity: warning • Confidence: high • Auto-fix: ❌

Description

Thread.new → spawn — Use Crystal's spawn (fiber-based concurrency) instead of Thread.new for lightweight concurrency.

Bad code

Thread.new { do_work }

Performance Impact

Tip

This rule can significantly improve performance in hot code paths.

Benchmark

Note

See bench results at bench/cat-049/