Mono macro

This crate provides the #[mono] macro to force a generic function to be monomorphizied with given types.

Pair with share-generics mode in rustc, this can result less code, for details see https://github.com/rust-lang/rust/pull/48779.

[dependencies]
mono-macro = "0.1"

Usage

Since we are monomorphizing ourselves, you are required to spell out the static dispatch manually:

In a bare function case,

#[mono(T = i32, U = i64)]
fn func<T, U>(t: T, u: U) {
    ...
}

it will be expanded to:

pub const _: *const () = (&foo::<i32, i64>) as *const _ as _;
fn func<T, U>(t: T, u: U) {
    ...
}

For more complicated case, use mono_macro! instead:

trait Tr<T> {
    fn foo(&self, _t: T) {}
}

struct Foo<'a> {
    t: &'a str,
}

impl<'a, T> Tr<T> for Foo<'a> {
    fn foo(&self, _t: T) {}
}

mono_macro!(<Foo<'static> as Tr<i32>>::foo);

this will expand to:

trait Tr<T> {
    fn foo(&self, _t: T) {}
}

struct Foo<'a> {
    t: &'a str,
}

impl<'a, T> Tr<T> for Foo<'a> {
    fn foo(&self, _t: T) {}
}

pub const _: *const () = (&<Foo<'static> as Tr<i32>>::foo) as *const _ as _;

License