Transfer is to move what clone is to copy

Note: This crate, as well as stackpin is very much a work in progress, and is published in the hope that it will be of interest for further work.

The Transfer trait executes user code to take a value from an unmovable instance of a struct to another instance.

In this way, it is similar to the Clone trait, that allows to execute user code to clone a value that is not copiable.

The Transfer trait is also comparable to the move constructor of C++.

Hold on, what is an unmovable struct?

Rust does not natively expose the concept of "unmovable types". However, thanks to Pin and unsafe, it is possible to express this concept in the type system. Transfer leverages the stackpin crate (by the same author) to build type safe abstractions for Unmovable types.

Examples

• The unit tests for Transfer demonstrate a SecretU64 type, that attempt to erase itself securely when it gets out of scope.
• An example for Transfer is DynRef, a type of reference that uses an external Lifetime struct to represent the lifetime of DynRef.