[PATCH 09/11] rust: macros: allow arbitrary types to be used in `module!` macro

Gary Guo
2025-12-11T19:30:15Z

From: Gary Guo <gary@garyguo.net>

Previously this only accepts an identifier, but now with `syn` it is
easy to make it accepts any type.

With this change, the span of types are preserved -- as a benefit, Rust
analyzer will be able to use the "navigate to definition" feature on
type name inside `module!` macro invocation.

Signed-off-by: Gary Guo <gary@garyguo.net>
---
rust/macros/module.rs | 29 +++++++++++++++--------------
1 file changed, 15 insertions(+), 14 deletions(-)

diff --git a/rust/macros/module.rs b/rust/macros/module.rs
index 4a02aadef25a7..d6298d04c86f4 100644
--- a/rust/macros/module.rs
+++ b/rust/macros/module.rs
@@ -4,7 +4,6 @@

use proc_macro2::{
Literal,
- Span,
TokenStream, //
};
use quote::{
@@ -23,7 +22,8 @@
Ident,
LitStr,
Result,
- Token, //
+ Token,
+ Type, //
};

use crate::helpers::*;
@@ -105,7 +105,7 @@ mod kw {

#[allow(dead_code, reason = "some fields are only parsed into")]
enum ModInfoField {
- Type(Token![type], Token![:], Ident),
+ Type(Token![type], Token![:], Type),
Name(kw::name, Token![:], AsciiLitStr),
Authors(
kw::authors,
@@ -193,9 +193,9 @@ fn parse(input: ParseStream<'_>) -> Result<Self> {
}
}

-#[derive(Debug, Default)]
+#[derive(Default)]
pub(crate) struct ModuleInfo {
- type_: String,
+ type_: Option<Type>,
license: String,
name: String,
authors: Option<Vec<String>>,
@@ -237,7 +237,7 @@ fn parse(input: ParseStream<'_>) -> Result<Self> {
seen_keys.push(key);

match field {
- ModInfoField::Type(_, _, ty) => info.type_ = ty.to_string(),
+ ModInfoField::Type(_, _, ty) => info.type_ = Some(ty),
ModInfoField::Name(_, _, name) => info.name = name.value(),
ModInfoField::Authors(_, _, _, list) => {
info.authors = Some(list.into_iter().map(|x| x.value()).collect())
@@ -286,16 +286,17 @@ fn parse(input: ParseStream<'_>) -> Result<Self> {

pub(crate) fn module(info: ModuleInfo) -> Result<TokenStream> {
let ModuleInfo {
- type_,
+ type_: Some(type_),
license,
name,
authors,
description,
alias,
firmware,
- } = info;
-
- let type_ = Ident::new(&type_, Span::mixed_site());
+ } = info
+ else {
+ unreachable!();
+ };

// Rust does not allow hyphens in identifiers, use underscore instead.
let ident = name.replace('-', "_");
@@ -376,7 +377,6 @@ impl ::kernel::ModuleMetadata for #type_ {
// Double nested modules, since then nobody can access the public items inside.
mod __module_init {
mod __module_init {
- use super::super::#type_;
use pin_init::PinInit;

/// The "Rust loadable module" mark.
@@ -388,7 +388,7 @@ mod __module_init {
#[used(compiler)]
static __IS_RUST_MODULE: () = ();

- static mut __MOD: ::core::mem::MaybeUninit<#type_> =
+ static mut __MOD: ::core::mem::MaybeUninit<super::super::LocalModule> =
::core::mem::MaybeUninit::uninit();

// Loadable modules need to export the `{init,cleanup}_module` identifiers.
@@ -475,8 +475,9 @@ pub extern "C" fn #ident_exit() {
///
/// This function must only be called once.
unsafe fn __init() -> ::kernel::ffi::c_int {
- let initer =
- <#type_ as ::kernel::InPlaceModule>::init(&super::super::THIS_MODULE);
+ let initer = <super::super::LocalModule as ::kernel::InPlaceModule>::init(
+ &super::super::THIS_MODULE
+ );
// SAFETY: No data race, since `__MOD` can only be accessed by this module
// and there only `__init` and `__exit` access it. These functions are only
// called once and `__exit` cannot be called before or during `__init`.
--
2.51.2