1// SPDX-License-Identifier: GPL-2.0 2 3//! Build-time error. 4//! 5//! This crate provides a [const function][const-functions] `build_error`, which will panic in 6//! compile-time if executed in [const context][const-context], and will cause a build error 7//! if not executed at compile time and the optimizer does not optimise away the call. 8//! 9//! It is used by `build_assert!` in the kernel crate, allowing checking of 10//! conditions that could be checked statically, but could not be enforced in 11//! Rust yet (e.g. perform some checks in [const functions][const-functions], but those 12//! functions could still be called in the runtime). 13//! 14//! For details on constant evaluation in Rust, please see the [Reference][const-eval]. 15//! 16//! [const-eval]: https://doc.rust-lang.org/reference/const_eval.html 17//! [const-functions]: https://doc.rust-lang.org/reference/const_eval.html#const-functions 18//! [const-context]: https://doc.rust-lang.org/reference/const_eval.html#const-context 19 20#![no_std] 21 22/// Panics if executed in [const context][const-context], or triggers a build error if not. 23/// 24/// [const-context]: https://doc.rust-lang.org/reference/const_eval.html#const-context 25#[inline(never)] 26#[cold] 27#[export_name = "rust_build_error"] 28#[track_caller] 29pub const fn build_error(msg: &'static str) -> ! { 30 panic!("{}", msg); 31} 32