Macro fixed_generic_alias 

macro_rules! fixed_generic_alias {
    ($vis:vis $name:ident, $doc:literal) => { ... };
    ($vis:vis $name:ident) => { ... };
}

Creates a const-generic type alias Name<const N: usize> for Fixed<[u8; N]>.

Useful when you need a single reusable name for fixed-size secrets across multiple sizes.

Syntax

fixed_generic_alias!(pub Name, "doc string"); // public with custom doc
fixed_generic_alias!(pub(crate) Name);        // crate-visible, auto-generated doc

Examples

use secure_gate::{fixed_generic_alias, RevealSecret};

fixed_generic_alias!(pub SecretBuffer, "Generic fixed-size secret buffer.");

let key: SecretBuffer<32> = [0u8; 32].into();
key.with_secret(|b| assert_eq!(b.len(), 32));

let nonce: SecretBuffer<12> = [0u8; 12].into();
nonce.with_secret(|b| assert_eq!(b.len(), 12));

Implementation Notes

Unlike fixed_alias!, which rejects N = 0 at the call site via a compile-time index-out-of-bounds trick, fixed_generic_alias! cannot apply that guard because N is a const generic parameter not known at macro-invocation time. As a result, SecretBuffer::<0> compiles successfully and produces a zero-byte Fixed<[u8; 0]>. Such a type is valid Rust but has no cryptographic utility and should never appear in production code. Unlike the non-generic fixed_alias! macro, which rejects N = 0 at compile time, this generic version cannot perform that check because N is a const generic parameter resolved later. Validate that N > 0 in your tests (e.g. assert!(core::mem::size_of::<SecretBuffer<32>>() == 32);).