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] |
29 | pub const fn build_error(msg: &'static str) -> ! { |
30 | panic!("{}" , msg); |
31 | } |
32 | |