Rust errors / Attributes, macros and features
Rust compiler error · checked with rustc 1.99.0
Rust error E0545: `issue` must be a non-zero numeric string or "none"
What it meansThe issue value is incorrect in a stability attribute.
What rustc prints
error[E0545]: `issue` must be a non-zero numeric string or "none"
--> main.rs:5:38
|
5 | #[unstable(feature = "_unstable_fn", issue = "0")] // invalid
| ^^^^^^^^---
| |
| `issue` must not be "0", use "none" insteadReal output of rustc 1.99.0 compiling the official example below (2021 edition). Your names and line numbers will differ; the first line is the part to match.
The compiler team's explanation
The issue value is incorrect in a stability attribute.
Erroneous code example:
#![feature(staged_api)]
#![allow(internal_features)]
#![stable(since = "1.0.0", feature = "test")]
#[unstable(feature = "_unstable_fn", issue = "0")] // invalid
fn _unstable_fn() {}
#[rustc_const_unstable(feature = "_unstable_const_fn", issue = "0")] // invalid
const fn _unstable_const_fn() {}To fix this issue, you need to provide a correct value in the issue field. Example:
#![feature(staged_api)]
#![allow(internal_features)]
#![stable(since = "1.0.0", feature = "test")]
#[unstable(feature = "_unstable_fn", issue = "none")] // ok!
fn _unstable_fn() {}
#[rustc_const_unstable(feature = "_unstable_const_fn", issue = "1")] // ok!
const fn _unstable_const_fn() {}See the How Rust is Made and “Nightly Rust” appendix of the Book and the Stability attributes section of the Rustc Dev Guide for more details.
From rustc --explain E0545 (1.99.0), part of the Rust project, MIT or Apache-2.0. Official page.
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