Replace `Void` with never type

18 files changed, 44 insertions, 60 deletions

diff --git a/library/std/src/sys/hermit/fs.rs b/library/std/src/sys/hermit/fs.rs
index 0f33282fa83..fb6b4a8b54e 100644
--- a/library/std/src/sys/hermit/fs.rs
+++ b/library/std/src/sys/hermit/fs.rs
@@ -9,7 +9,7 @@ use crate::sys::hermit::abi;
 use crate::sys::hermit::abi::{O_APPEND, O_CREAT, O_EXCL, O_RDONLY, O_RDWR, O_TRUNC, O_WRONLY};
 use crate::sys::hermit::fd::FileDesc;
 use crate::sys::time::SystemTime;
-use crate::sys::{unsupported, Void};
+use crate::sys::unsupported;
 use crate::sys_common::os_str_bytes::OsStrExt;
 
 pub use crate::sys_common::fs::copy;
@@ -22,11 +22,11 @@ fn cstr(path: &Path) -> io::Result<CString> {
 #[derive(Debug)]
 pub struct File(FileDesc);
 
-pub struct FileAttr(Void);
+pub struct FileAttr(!);
 
-pub struct ReadDir(Void);
+pub struct ReadDir(!);
 
-pub struct DirEntry(Void);
+pub struct DirEntry(!);
 
 #[derive(Clone, Debug)]
 pub struct OpenOptions {
@@ -41,9 +41,9 @@ pub struct OpenOptions {
     mode: i32,
 }
 
-pub struct FilePermissions(Void);
+pub struct FilePermissions(!);
 
-pub struct FileType(Void);
+pub struct FileType(!);
 
 #[derive(Debug)]
 pub struct DirBuilder {}
diff --git a/library/std/src/sys/hermit/mod.rs b/library/std/src/sys/hermit/mod.rs
index f8c1612d1ca..56497162c03 100644
--- a/library/std/src/sys/hermit/mod.rs
+++ b/library/std/src/sys/hermit/mod.rs
@@ -61,11 +61,6 @@ pub fn unsupported_err() -> crate::io::Error {
     )
 }
 
-// This enum is used as the storage for a bunch of types which can't actually
-// exist.
-#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
-pub enum Void {}
-
 pub unsafe fn strlen(start: *const c_char) -> usize {
     let mut str = start;
 
diff --git a/library/std/src/sys/hermit/net.rs b/library/std/src/sys/hermit/net.rs
index a9c09b6ceef..bdb7b81fdc0 100644
--- a/library/std/src/sys/hermit/net.rs
+++ b/library/std/src/sys/hermit/net.rs
@@ -6,7 +6,7 @@ use crate::str;
 use crate::sync::Arc;
 use crate::sys::hermit::abi;
 use crate::sys::hermit::abi::IpAddress::{Ipv4, Ipv6};
-use crate::sys::{unsupported, Void};
+use crate::sys::unsupported;
 use crate::sys_common::AsInner;
 use crate::time::Duration;
 
@@ -411,7 +411,7 @@ impl fmt::Debug for UdpSocket {
     }
 }
 
-pub struct LookupHost(Void);
+pub struct LookupHost(!);
 
 impl LookupHost {
     pub fn port(&self) -> u16 {
diff --git a/library/std/src/sys/hermit/os.rs b/library/std/src/sys/hermit/os.rs
index 78eabf8f81e..ab5e0ea0bc4 100644
--- a/library/std/src/sys/hermit/os.rs
+++ b/library/std/src/sys/hermit/os.rs
@@ -9,7 +9,7 @@ use crate::path::{self, PathBuf};
 use crate::str;
 use crate::sync::Mutex;
 use crate::sys::hermit::abi;
-use crate::sys::{unsupported, Void};
+use crate::sys::unsupported;
 use crate::sys_common::os_str_bytes::*;
 use crate::vec;
 
@@ -29,7 +29,7 @@ pub fn chdir(_: &path::Path) -> io::Result<()> {
     unsupported()
 }
 
-pub struct SplitPaths<'a>(&'a Void);
+pub struct SplitPaths<'a>(&'a !);
 
 pub fn split_paths(_unparsed: &OsStr) -> SplitPaths<'_> {
     panic!("unsupported")
diff --git a/library/std/src/sys/sgx/mod.rs b/library/std/src/sys/sgx/mod.rs
index da37d1aeb7e..d6a56830733 100644
--- a/library/std/src/sys/sgx/mod.rs
+++ b/library/std/src/sys/sgx/mod.rs
@@ -115,11 +115,6 @@ pub fn decode_error_kind(code: i32) -> ErrorKind {
     }
 }
 
-// This enum is used as the storage for a bunch of types which can't actually
-// exist.
-#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
-pub enum Void {}
-
 pub unsafe fn strlen(mut s: *const c_char) -> usize {
     let mut n = 0;
     while unsafe { *s } != 0 {
diff --git a/library/std/src/sys/sgx/net.rs b/library/std/src/sys/sgx/net.rs
index c0c5d55548c..9ddd17303db 100644
--- a/library/std/src/sys/sgx/net.rs
+++ b/library/std/src/sys/sgx/net.rs
@@ -5,7 +5,7 @@ use crate::io::{self, IoSlice, IoSliceMut};
 use crate::net::{Ipv4Addr, Ipv6Addr, Shutdown, SocketAddr, ToSocketAddrs};
 use crate::sync::Arc;
 use crate::sys::fd::FileDesc;
-use crate::sys::{sgx_ineffective, unsupported, AsInner, FromInner, IntoInner, TryIntoInner, Void};
+use crate::sys::{sgx_ineffective, unsupported, AsInner, FromInner, IntoInner, TryIntoInner};
 use crate::time::Duration;
 
 use super::abi::usercalls;
@@ -310,7 +310,7 @@ impl FromInner<Socket> for TcpListener {
     }
 }
 
-pub struct UdpSocket(Void);
+pub struct UdpSocket(!);
 
 impl UdpSocket {
     pub fn bind(_: io::Result<&SocketAddr>) -> io::Result<UdpSocket> {
@@ -462,7 +462,7 @@ impl fmt::Display for NonIpSockAddr {
     }
 }
 
-pub struct LookupHost(Void);
+pub struct LookupHost(!);
 
 impl LookupHost {
     fn new(host: String) -> io::Result<LookupHost> {
diff --git a/library/std/src/sys/sgx/os.rs b/library/std/src/sys/sgx/os.rs
index 56fc84b4a3f..ff1f9c368a3 100644
--- a/library/std/src/sys/sgx/os.rs
+++ b/library/std/src/sys/sgx/os.rs
@@ -10,7 +10,7 @@ use crate::str;
 use crate::sync::atomic::{AtomicUsize, Ordering};
 use crate::sync::Mutex;
 use crate::sync::Once;
-use crate::sys::{decode_error_kind, sgx_ineffective, unsupported, Void};
+use crate::sys::{decode_error_kind, sgx_ineffective, unsupported};
 use crate::vec;
 
 pub fn errno() -> i32 {
@@ -35,7 +35,7 @@ pub fn chdir(_: &path::Path) -> io::Result<()> {
     sgx_ineffective(())
 }
 
-pub struct SplitPaths<'a>(&'a Void);
+pub struct SplitPaths<'a>(&'a !);
 
 pub fn split_paths(_unparsed: &OsStr) -> SplitPaths<'_> {
     panic!("unsupported")
diff --git a/library/std/src/sys/unsupported/common.rs b/library/std/src/sys/unsupported/common.rs
index 64ec50fa9ec..0ef84c84ee8 100644
--- a/library/std/src/sys/unsupported/common.rs
+++ b/library/std/src/sys/unsupported/common.rs
@@ -36,11 +36,6 @@ pub fn hashmap_random_keys() -> (u64, u64) {
     (1, 2)
 }
 
-// This enum is used as the storage for a bunch of types which can't actually
-// exist.
-#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
-pub enum Void {}
-
 pub unsafe fn strlen(mut s: *const c_char) -> usize {
     // SAFETY: The caller must guarantee `s` points to a valid 0-terminated string.
     unsafe {
diff --git a/library/std/src/sys/unsupported/fs.rs b/library/std/src/sys/unsupported/fs.rs
index 4271d9b3345..f5a0c89fe10 100644
--- a/library/std/src/sys/unsupported/fs.rs
+++ b/library/std/src/sys/unsupported/fs.rs
@@ -4,22 +4,22 @@ use crate::hash::{Hash, Hasher};
 use crate::io::{self, IoSlice, IoSliceMut, SeekFrom};
 use crate::path::{Path, PathBuf};
 use crate::sys::time::SystemTime;
-use crate::sys::{unsupported, Void};
+use crate::sys::unsupported;
 
-pub struct File(Void);
+pub struct File(!);
 
-pub struct FileAttr(Void);
+pub struct FileAttr(!);
 
-pub struct ReadDir(Void);
+pub struct ReadDir(!);
 
-pub struct DirEntry(Void);
+pub struct DirEntry(!);
 
 #[derive(Clone, Debug)]
 pub struct OpenOptions {}
 
-pub struct FilePermissions(Void);
+pub struct FilePermissions(!);
 
-pub struct FileType(Void);
+pub struct FileType(!);
 
 #[derive(Debug)]
 pub struct DirBuilder {}
diff --git a/library/std/src/sys/unsupported/net.rs b/library/std/src/sys/unsupported/net.rs
index 5c9f1098f9b..204a24cfc71 100644
--- a/library/std/src/sys/unsupported/net.rs
+++ b/library/std/src/sys/unsupported/net.rs
@@ -2,10 +2,10 @@ use crate::convert::TryFrom;
 use crate::fmt;
 use crate::io::{self, IoSlice, IoSliceMut};
 use crate::net::{Ipv4Addr, Ipv6Addr, Shutdown, SocketAddr};
-use crate::sys::{unsupported, Void};
+use crate::sys::unsupported;
 use crate::time::Duration;
 
-pub struct TcpStream(Void);
+pub struct TcpStream(!);
 
 impl TcpStream {
     pub fn connect(_: io::Result<&SocketAddr>) -> io::Result<TcpStream> {
@@ -107,7 +107,7 @@ impl fmt::Debug for TcpStream {
     }
 }
 
-pub struct TcpListener(Void);
+pub struct TcpListener(!);
 
 impl TcpListener {
     pub fn bind(_: io::Result<&SocketAddr>) -> io::Result<TcpListener> {
@@ -157,7 +157,7 @@ impl fmt::Debug for TcpListener {
     }
 }
 
-pub struct UdpSocket(Void);
+pub struct UdpSocket(!);
 
 impl UdpSocket {
     pub fn bind(_: io::Result<&SocketAddr>) -> io::Result<UdpSocket> {
@@ -291,7 +291,7 @@ impl fmt::Debug for UdpSocket {
     }
 }
 
-pub struct LookupHost(Void);
+pub struct LookupHost(!);
 
 impl LookupHost {
     pub fn port(&self) -> u16 {
diff --git a/library/std/src/sys/unsupported/os.rs b/library/std/src/sys/unsupported/os.rs
index 3754aebf455..11583ae99d6 100644
--- a/library/std/src/sys/unsupported/os.rs
+++ b/library/std/src/sys/unsupported/os.rs
@@ -1,4 +1,4 @@
-use super::{unsupported, Void};
+use super::unsupported;
 use crate::error::Error as StdError;
 use crate::ffi::{OsStr, OsString};
 use crate::fmt;
@@ -21,7 +21,7 @@ pub fn chdir(_: &path::Path) -> io::Result<()> {
     unsupported()
 }
 
-pub struct SplitPaths<'a>(&'a Void);
+pub struct SplitPaths<'a>(&'a !);
 
 pub fn split_paths(_unparsed: &OsStr) -> SplitPaths<'_> {
     panic!("unsupported")
@@ -62,7 +62,7 @@ pub fn current_exe() -> io::Result<PathBuf> {
     unsupported()
 }
 
-pub struct Env(Void);
+pub struct Env(!);
 
 impl Iterator for Env {
     type Item = (OsString, OsString);
diff --git a/library/std/src/sys/unsupported/pipe.rs b/library/std/src/sys/unsupported/pipe.rs
index 10d0925823e..7ea46990d77 100644
--- a/library/std/src/sys/unsupported/pipe.rs
+++ b/library/std/src/sys/unsupported/pipe.rs
@@ -1,7 +1,6 @@
 use crate::io::{self, IoSlice, IoSliceMut};
-use crate::sys::Void;
 
-pub struct AnonPipe(Void);
+pub struct AnonPipe(!);
 
 impl AnonPipe {
     pub fn read(&self, _buf: &mut [u8]) -> io::Result<usize> {
diff --git a/library/std/src/sys/unsupported/process.rs b/library/std/src/sys/unsupported/process.rs
index 3ede2291d5a..f777e40873f 100644
--- a/library/std/src/sys/unsupported/process.rs
+++ b/library/std/src/sys/unsupported/process.rs
@@ -5,7 +5,7 @@ use crate::marker::PhantomData;
 use crate::path::Path;
 use crate::sys::fs::File;
 use crate::sys::pipe::AnonPipe;
-use crate::sys::{unsupported, Void};
+use crate::sys::unsupported;
 use crate::sys_common::process::{CommandEnv, CommandEnvs};
 
 pub use crate::ffi::OsString as EnvKey;
@@ -94,7 +94,7 @@ impl fmt::Debug for Command {
     }
 }
 
-pub struct ExitStatus(Void);
+pub struct ExitStatus(!);
 
 impl ExitStatus {
     pub fn success(&self) -> bool {
@@ -146,7 +146,7 @@ impl ExitCode {
     }
 }
 
-pub struct Process(Void);
+pub struct Process(!);
 
 impl Process {
     pub fn id(&self) -> u32 {
diff --git a/library/std/src/sys/unsupported/thread.rs b/library/std/src/sys/unsupported/thread.rs
index 20ae309db30..7d5d2c61157 100644
--- a/library/std/src/sys/unsupported/thread.rs
+++ b/library/std/src/sys/unsupported/thread.rs
@@ -1,9 +1,9 @@
-use super::{unsupported, Void};
+use super::unsupported;
 use crate::ffi::CStr;
 use crate::io;
 use crate::time::Duration;
 
-pub struct Thread(Void);
+pub struct Thread(!);
 
 pub const DEFAULT_MIN_STACK_SIZE: usize = 4096;
 
diff --git a/library/std/src/sys/wasi/net.rs b/library/std/src/sys/wasi/net.rs
index 3f294e7df41..30c21a05a32 100644
--- a/library/std/src/sys/wasi/net.rs
+++ b/library/std/src/sys/wasi/net.rs
@@ -5,7 +5,7 @@ use crate::convert::TryFrom;
 use crate::fmt;
 use crate::io::{self, IoSlice, IoSliceMut};
 use crate::net::{Ipv4Addr, Ipv6Addr, Shutdown, SocketAddr};
-use crate::sys::{unsupported, Void};
+use crate::sys::unsupported;
 use crate::sys_common::FromInner;
 use crate::time::Duration;
 
@@ -343,7 +343,7 @@ impl fmt::Debug for UdpSocket {
     }
 }
 
-pub struct LookupHost(Void);
+pub struct LookupHost(!);
 
 impl LookupHost {
     pub fn port(&self) -> u16 {
diff --git a/library/std/src/sys/wasi/os.rs b/library/std/src/sys/wasi/os.rs
index 185d6109cb9..a349c149249 100644
--- a/library/std/src/sys/wasi/os.rs
+++ b/library/std/src/sys/wasi/os.rs
@@ -10,7 +10,7 @@ use crate::os::wasi::prelude::*;
 use crate::path::{self, PathBuf};
 use crate::str;
 use crate::sys::memchr;
-use crate::sys::{unsupported, Void};
+use crate::sys::unsupported;
 use crate::vec;
 
 // Add a few symbols not in upstream `libc` just yet.
@@ -87,7 +87,7 @@ pub fn chdir(p: &path::Path) -> io::Result<()> {
     }
 }
 
-pub struct SplitPaths<'a>(&'a Void);
+pub struct SplitPaths<'a>(&'a !);
 
 pub fn split_paths(_unparsed: &OsStr) -> SplitPaths<'_> {
     panic!("unsupported")
diff --git a/library/std/src/sys/wasi/thread.rs b/library/std/src/sys/wasi/thread.rs
index 8eaa5f09cb6..2efa91f8b70 100644
--- a/library/std/src/sys/wasi/thread.rs
+++ b/library/std/src/sys/wasi/thread.rs
@@ -3,10 +3,10 @@
 use crate::ffi::CStr;
 use crate::io;
 use crate::mem;
-use crate::sys::{unsupported, Void};
+use crate::sys::unsupported;
 use crate::time::Duration;
 
-pub struct Thread(Void);
+pub struct Thread(!);
 
 pub const DEFAULT_MIN_STACK_SIZE: usize = 4096;
 
diff --git a/library/std/src/sys/wasm/thread.rs b/library/std/src/sys/wasm/thread.rs
index 5eafb77da1d..77f8c79ced9 100644
--- a/library/std/src/sys/wasm/thread.rs
+++ b/library/std/src/sys/wasm/thread.rs
@@ -1,9 +1,9 @@
 use crate::ffi::CStr;
 use crate::io;
-use crate::sys::{unsupported, Void};
+use crate::sys::unsupported;
 use crate::time::Duration;
 
-pub struct Thread(Void);
+pub struct Thread(!);
 
 pub const DEFAULT_MIN_STACK_SIZE: usize = 4096;