From 36d22d82aa202bb199967e9512281e9a53db42c9 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 21:33:14 +0200 Subject: Adding upstream version 115.7.0esr. Signed-off-by: Daniel Baumann --- third_party/rust/void/src/lib.rs | 121 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 121 insertions(+) create mode 100644 third_party/rust/void/src/lib.rs (limited to 'third_party/rust/void/src') diff --git a/third_party/rust/void/src/lib.rs b/third_party/rust/void/src/lib.rs new file mode 100644 index 0000000000..3b6287c1b2 --- /dev/null +++ b/third_party/rust/void/src/lib.rs @@ -0,0 +1,121 @@ +#![cfg_attr(test, deny(warnings))] +#![deny(missing_docs)] +#![cfg_attr(not(feature = "std"), no_std)] + +//! # Void +//! +//! The uninhabited void type for use in statically impossible cases. +//! +//! In its own crate so all the users in the ecosystem can share the same type. +//! This crate also comes ready with several extension traits for Result that add +//! extra functionality to `Result` and `Result`. +//! + +#[cfg(not(feature = "std"))] +mod coreprovider { + extern crate core; + pub use core::{fmt, cmp}; +} + +#[cfg(feature = "std")] +mod coreprovider { + pub use std::{fmt, cmp, error}; +} + +use coreprovider::*; + +/// The empty type for cases which can't occur. +#[derive(Copy)] +pub enum Void { } + +impl Clone for Void { + fn clone(&self) -> Void { + unreachable(*self) + } +} + +impl fmt::Debug for Void { + fn fmt(&self, _: &mut fmt::Formatter) -> fmt::Result { + unreachable(*self) + } +} + +impl fmt::Display for Void { + fn fmt(&self, _: &mut fmt::Formatter) -> fmt::Result { + unreachable(*self) + } +} + +impl cmp::PartialEq for Void { + fn eq(&self, _: &T) -> bool { + unreachable(*self) + } +} + +impl cmp::PartialOrd for Void { + fn partial_cmp(&self, _: &T) -> Option { + unreachable(*self) + } +} + +#[cfg(feature = "std")] +impl error::Error for Void { + fn description(&self) -> &str { + unreachable(*self) + } + + fn cause(&self) -> Option<&error::Error> { + unreachable(*self) + } +} + +/// A safe version of `intrinsincs::unreachable`. +/// +/// If this typechecks, anything that causes this to run is unreachable code. +/// +/// Calling this function in reachable code invokes undefined behavior, but +/// should not be possible unless `unsafe` was used elsewhere to construct +/// an instance of `Void` (which is already undefined behavior). +#[inline(always)] +pub fn unreachable(x: Void) -> ! { + match x {} +} + +/// Extensions to `Result` +pub trait ResultVoidExt: Sized { + /// Get the value out of a wrapper. + fn void_unwrap(self) -> T; +} + +impl ResultVoidExt for Result { + /// Get the value out of an always-ok Result. + /// + /// Never panics, since it is statically known to be Ok. + #[inline] + fn void_unwrap(self) -> T { + match self { + Ok(val) => val, + Err(e) => unreachable(e) + } + } +} + +/// Extensions to `Result` +pub trait ResultVoidErrExt: Sized { + /// Get the error out of a wrapper. + fn void_unwrap_err(self) -> E; +} + +impl ResultVoidErrExt for Result { + /// Get the error out of an always-err Result. + /// + /// Never panics, since it is statically known to be Err. + #[inline] + fn void_unwrap_err(self) -> E { + match self { + Ok(v) => unreachable(v), + Err(e) => e + } + } +} + -- cgit v1.2.3