Skip to content

Optimize enums with all unit variants and empty arrays with Lazy #4237

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
acheroncrypto merged 2 commits into from
Mar 8, 2026
Merged

Optimize enums with all unit variants and empty arrays with Lazy #4237

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
56b8668
fix(lang/lazy): Correct `SIZED` for empty arrays
jamie-osec Feb 12, 2026
25dc6e8
fix(lang/lazy): Unit-only enums are fixed-size
jamie-osec Feb 12, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
9 changes: 6 additions & 3 deletions lang/derive/serde/src/lazy.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
use proc_macro2::Literal;
use quote::{format_ident, quote};
use quote::{format_ident, quote, ToTokens};
use syn::{spanned::Spanned, Fields, Item};

pub fn gen_lazy(input: proc_macro::TokenStream) -> syn::Result<proc_macro2::TokenStream> {
Expand All @@ -24,7 +24,10 @@ pub fn gen_lazy(input: proc_macro::TokenStream) -> syn::Result<proc_macro2::Toke
.enumerate()
.map(|(i, size)| (Literal::usize_unsuffixed(i), size))
.map(|(i, size)| quote! { Some(#i) => { #size } });

let sized = enm
.variants
.iter()
.all(|variant| matches!(variant.fields, Fields::Unit));
(
&enm.ident,
&enm.generics,
Expand All @@ -34,7 +37,7 @@ pub fn gen_lazy(input: proc_macro::TokenStream) -> syn::Result<proc_macro2::Toke
_ => unreachable!(),
}
},
quote!(false),
sized.to_token_stream(),
)
}
Item::Union(_) => return Err(syn::Error::new(item.span(), "Unions are not supported")),
Expand Down
11 changes: 10 additions & 1 deletion lang/src/lazy.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -64,7 +64,7 @@ impl_sized!(f64);
impl_sized!(Pubkey);

impl<T: Lazy, const N: usize> Lazy for [T; N] {
const SIZED: bool = T::SIZED;
const SIZED: bool = N == 0 || T::SIZED;

#[inline(always)]
fn size_of(buf: &[u8]) -> usize {
Expand Down Expand Up @@ -196,6 +196,15 @@ mod tests {
len!(MyEnum::Unnamed(1, 2))
);
assert!(!MyEnum::SIZED);

#[derive(AnchorSerialize, AnchorDeserialize)]
enum UnitEnum {
A,
B,
}
assert_eq!(UnitEnum::size_of(&[0]), len!(UnitEnum::A));
assert_eq!(UnitEnum::size_of(&[1]), len!(UnitEnum::B));
assert!(UnitEnum::SIZED);
}

#[test]
Expand Down
⚡