rust-pin

Pin and Unpin are Rust traits that guarantee memory stability for async futures across await points, preventing dangling pointers. You need them when implementing custom futures or managing self-referential data structures to ensure memory safety.

To pin a future on the heap in Rust, use the Box::pin function to wrap your async operation. This creates a pinned pointer that prevents the future from being moved in memory, ensuring safe execution across await points.

Pinning projections in Rust require accessing fields within pinned data without violating memory safety guarantees. You must carefully manage field access patterns to ensure self-referential structs remain stable and do not trigger undefined behavior.

Memory unsafety in Rust async futures occurs when self-referential data is moved after creation. Pinning prevents this movement, ensuring pointers within the structure remain valid across await points and avoiding dangling references.

The Unpin marker trait in Rust indicates a type is safe to move even when pinned, allowing you to bypass strict pinning requirements. Most standard types implement Unpin, but custom self-referential futures require explicit pinning.

Common pitfalls with pinned Rust data include unsafe field projections, moving pinned values, and ignoring Unpin restrictions. Verification methods involve checking pointer stability and ensuring self-referential structures maintain valid references throughout their lifecycle.