size-trait

This crate provides traits for restricting the size of type parameters.

Example

Zero-sized types

#![feature(generic_const_exprs)]

use size_trait::ZeroSize;

// This struct can only contain `T` when `T` has a size of 0.
struct Zst<T: ZeroSize<true>>(T);

let _ = Zst([0u8; 0]);
let _ = Zst(());

Fixed-sized types

#![feature(generic_const_exprs)]

use size_trait::Size;

// This struct can only contain `T` when `T` has a size of 4 bytes.
struct Fixed4Bytes<T: Size<4>>(T);

let _ = Fixed4Bytes([0u8; 4]);
let _ = Fixed4Bytes(0u32);

Warning

This crate relies on the unstable feature generic_const_exprs. This feature is only available on nightly Rust. It is also not guaranteed to be stable in the future. Tracking issue #76560.

In order for this crate to work properly, you must enable the generic_const_exprs feature in your crate:

#![feature(generic_const_exprs)]

Author

• Jacob Lindahl @sudo_build geeklaunch.io