Garbage Collection Without Unsafe Code

Article

TL;DR: A Rust GC that avoids unsafe code entirely using a Trace trait and Gc<T> wrapper.

Key Takeaways

• Gc<T> wrapper plus a derive macro enable safe traced references with no unsafe blocks
• Eliminates a whole class of GC-related undefined behavior — rare in systems-level GC work
• Gc<> couples types to the allocator, making adoption and experimentation costly

Discussion

• [the-smug-one]: Gc<> wrapper ties types to one allocator, making trying a GC painful

  trying out a GC is a pain, as you’re stuck first doing the rewrite of your types

• [foota]: Found it while removing C FFI unsafe code but chose pointer-mapping instead
• Main debate: whether Gc<> ergonomic cost is worth the safety guarantee.

Discuss on HN