Crates.io | rustversion-msrv |
lib.rs | rustversion-msrv |
version | 0.99.16 |
source | src |
created_at | 2024-05-12 17:23:41.188465 |
updated_at | 2024-05-12 17:23:41.188465 |
description | Conditional compilation according to rustc compiler version + MSRV support |
homepage | |
repository | https://github.com/robjtede/rustversion-msrv |
max_upload_size | |
id | 1237674 |
size | 62,594 |
This crate provides macros for conditional compilation according to rustc
compiler version, analogous to #[cfg(...)]
and
#[cfg_attr(...)]
.
[dependencies]
rustversion-msrv = "1.0"
#[rustversion_msrv::stable]
—
True on any stable compiler.
#[rustversion_msrv::stable(1.34)]
—
True on exactly the specified stable compiler.
#[rustversion_msrv::beta]
—
True on any beta compiler.
#[rustversion_msrv::nightly]
—
True on any nightly compiler or dev build.
#[rustversion_msrv::msrv]
—
True on the call-site crate's rust-version
field (a.k.a, its minimum supported Rust version).
#[rustversion_msrv::nightly(2019-01-01)]
—
True on exactly one nightly.
#[rustversion_msrv::since(1.34)]
—
True on that stable release and any later compiler, including beta and
nightly.
#[rustversion_msrv::since(2019-01-01)]
—
True on that nightly and all newer ones.
#[rustversion_msrv::before(
version or date)]
—
Negative of #[rustversion_msrv::since(...)].
#[rustversion_msrv::not(
selector)]
—
Negative of any selector; for example #[rustversion_msrv::not(nightly)].
#[rustversion_msrv::any(
selectors...)]
—
True if any of the comma-separated selectors is true; for example
#[rustversion_msrv::any(stable, beta)].
#[rustversion_msrv::all(
selectors...)]
—
True if all of the comma-separated selectors are true; for example
#[rustversion_msrv::all(since(1.31), before(1.34))].
#[rustversion_msrv::attr(
selector,
attribute)]
—
For conditional inclusion of attributes; analogous to cfg_attr
.
Providing additional trait impls as types are stabilized in the standard library without breaking compatibility with older compilers; in this case Pin<P> stabilized in Rust 1.33:
#[rustversion_msrv::since(1.33)]
use std::pin::Pin;
#[rustversion_msrv::since(1.33)]
impl<P: MyTrait> MyTrait for Pin<P> {
/* ... */
}
Similar but for language features; the ability to control alignment greater than 1 of packed structs was stabilized in Rust 1.33.
#[rustversion_msrv::attr(before(1.33), repr(packed))]
#[rustversion_msrv::attr(since(1.33), repr(packed(2)))]
struct Six(i16, i32);
fn main() {
println!("{}", std::mem::align_of::<Six>());
}
Augmenting code with const
as const impls are stabilized in the standard
library. This use of const
as an attribute is recognized as a special case by
the rustversion_msrv::attr macro.
use std::time::Duration;
#[rustversion_msrv::attr(since(1.32), const)]
fn duration_as_days(dur: Duration) -> u64 {
dur.as_secs() / 60 / 60 / 24
}