Auto merge of #137046 - workingjubilee:rollup-u56aw1m, r=workingjubilee

Rollup of 10 pull requests

Successful merges:

 - #133312 (triagebot: automatically add more rustdoc related labels)
 - #134016 (Stabilize `const_is_char_boundary` and `const_str_split_at`.)
 - #136971 (Add a new check-pass UI test for returning `impl Fn(T) -> impl Trait`)
 - #136983 (Prepare standard library for Rust 2024 migration)
 - #137002 (Fix early lint check desc in query)
 - #137006 (borrowck diagnostics cleanup: remove an unused and a barely-used field)
 - #137032 (Decode metadata buffer in one go)
 - #137035 (Normalize closure instance before eagerly monomorphizing it)
 - #137037 (add x86-sse2 (32bit) ABI that requires SSE2 target feature)
 - #137038 (llvm: Tolerate captures in tests)

r? `@ghost`
`@rustbot` modify labels: rollup

19 files changed, 39 insertions, 37 deletions

diff --git a/library/std/src/sys/alloc/sgx.rs b/library/std/src/sys/alloc/sgx.rs
index fca9d087e5b..f5c27688fbc 100644
--- a/library/std/src/sys/alloc/sgx.rs
+++ b/library/std/src/sys/alloc/sgx.rs
@@ -11,7 +11,7 @@ use crate::sys::pal::waitqueue::SpinMutex;
 // in the rust-lang/rust repository as a submodule. The crate is a port of
 // dlmalloc.c from C to Rust.
 #[cfg_attr(test, linkage = "available_externally")]
-#[export_name = "_ZN16__rust_internals3std3sys3sgx5alloc8DLMALLOCE"]
+#[unsafe(export_name = "_ZN16__rust_internals3std3sys3sgx5alloc8DLMALLOCE")]
 static DLMALLOC: SpinMutex<dlmalloc::Dlmalloc<Sgx>> =
     SpinMutex::new(dlmalloc::Dlmalloc::new_with_allocator(Sgx {}));
 
@@ -85,13 +85,13 @@ unsafe impl GlobalAlloc for System {
 // The following functions are needed by libunwind. These symbols are named
 // in pre-link args for the target specification, so keep that in sync.
 #[cfg(not(test))]
-#[no_mangle]
+#[unsafe(no_mangle)]
 pub unsafe extern "C" fn __rust_c_alloc(size: usize, align: usize) -> *mut u8 {
     unsafe { crate::alloc::alloc(Layout::from_size_align_unchecked(size, align)) }
 }
 
 #[cfg(not(test))]
-#[no_mangle]
+#[unsafe(no_mangle)]
 pub unsafe extern "C" fn __rust_c_dealloc(ptr: *mut u8, size: usize, align: usize) {
     unsafe { crate::alloc::dealloc(ptr, Layout::from_size_align_unchecked(size, align)) }
 }
diff --git a/library/std/src/sys/alloc/xous.rs b/library/std/src/sys/alloc/xous.rs
index 9d22e16fdf2..ccaa972c22d 100644
--- a/library/std/src/sys/alloc/xous.rs
+++ b/library/std/src/sys/alloc/xous.rs
@@ -4,7 +4,7 @@
 use crate::alloc::{GlobalAlloc, Layout, System};
 
 #[cfg(not(test))]
-#[export_name = "_ZN16__rust_internals3std3sys4xous5alloc8DLMALLOCE"]
+#[unsafe(export_name = "_ZN16__rust_internals3std3sys4xous5alloc8DLMALLOCE")]
 static mut DLMALLOC: dlmalloc::Dlmalloc = dlmalloc::Dlmalloc::new();
 
 #[cfg(test)]
diff --git a/library/std/src/sys/pal/hermit/mod.rs b/library/std/src/sys/pal/hermit/mod.rs
index a746b853cbd..21cbac643bb 100644
--- a/library/std/src/sys/pal/hermit/mod.rs
+++ b/library/std/src/sys/pal/hermit/mod.rs
@@ -53,7 +53,7 @@ pub fn abort_internal() -> ! {
 // This function is needed by the panic runtime. The symbol is named in
 // pre-link args for the target specification, so keep that in sync.
 #[cfg(not(test))]
-#[no_mangle]
+#[unsafe(no_mangle)]
 // NB. used by both libunwind and libpanic_abort
 pub extern "C" fn __rust_abort() {
     abort_internal();
@@ -72,7 +72,7 @@ pub unsafe fn init(argc: isize, argv: *const *const u8, _sigpipe: u8) {
 pub unsafe fn cleanup() {}
 
 #[cfg(not(test))]
-#[no_mangle]
+#[unsafe(no_mangle)]
 pub unsafe extern "C" fn runtime_entry(
     argc: i32,
     argv: *const *const c_char,
diff --git a/library/std/src/sys/pal/sgx/abi/mod.rs b/library/std/src/sys/pal/sgx/abi/mod.rs
index f52acc41509..90981bd6a6a 100644
--- a/library/std/src/sys/pal/sgx/abi/mod.rs
+++ b/library/std/src/sys/pal/sgx/abi/mod.rs
@@ -23,7 +23,7 @@ global_asm!(include_str!("entry.S"), options(att_syntax));
 struct EntryReturn(u64, u64);
 
 #[cfg(not(test))]
-#[no_mangle]
+#[unsafe(no_mangle)]
 unsafe extern "C" fn tcs_init(secondary: bool) {
     // Be very careful when changing this code: it runs before the binary has been
     // relocated. Any indirect accesses to symbols will likely fail.
@@ -60,7 +60,7 @@ unsafe extern "C" fn tcs_init(secondary: bool) {
 // (main function exists). If this is a library, the crate author should be
 // able to specify this
 #[cfg(not(test))]
-#[no_mangle]
+#[unsafe(no_mangle)]
 extern "C" fn entry(p1: u64, p2: u64, p3: u64, secondary: bool, p4: u64, p5: u64) -> EntryReturn {
     // FIXME: how to support TLS in library mode?
     let tls = Box::new(tls::Tls::new());
@@ -103,7 +103,7 @@ pub(super) fn exit_with_code(code: isize) -> ! {
 }
 
 #[cfg(not(test))]
-#[no_mangle]
+#[unsafe(no_mangle)]
 extern "C" fn abort_reentry() -> ! {
     usercalls::exit(false)
 }
diff --git a/library/std/src/sys/pal/sgx/abi/tls/mod.rs b/library/std/src/sys/pal/sgx/abi/tls/mod.rs
index 7131797003b..8e2b271f1c9 100644
--- a/library/std/src/sys/pal/sgx/abi/tls/mod.rs
+++ b/library/std/src/sys/pal/sgx/abi/tls/mod.rs
@@ -12,14 +12,14 @@ const TLS_KEYS: usize = 128; // Same as POSIX minimum
 const TLS_KEYS_BITSET_SIZE: usize = (TLS_KEYS + (USIZE_BITS - 1)) / USIZE_BITS;
 
 #[cfg_attr(test, linkage = "available_externally")]
-#[export_name = "_ZN16__rust_internals3std3sys3sgx3abi3tls14TLS_KEY_IN_USEE"]
+#[unsafe(export_name = "_ZN16__rust_internals3std3sys3sgx3abi3tls14TLS_KEY_IN_USEE")]
 static TLS_KEY_IN_USE: SyncBitset = SYNC_BITSET_INIT;
 macro_rules! dup {
     ((* $($exp:tt)*) $($val:tt)*) => (dup!( ($($exp)*) $($val)* $($val)* ));
     (() $($val:tt)*) => ([$($val),*])
 }
 #[cfg_attr(test, linkage = "available_externally")]
-#[export_name = "_ZN16__rust_internals3std3sys3sgx3abi3tls14TLS_DESTRUCTORE"]
+#[unsafe(export_name = "_ZN16__rust_internals3std3sys3sgx3abi3tls14TLS_DESTRUCTORE")]
 static TLS_DESTRUCTOR: [AtomicUsize; TLS_KEYS] = dup!((* * * * * * *) (AtomicUsize::new(0)));
 
 unsafe extern "C" {
diff --git a/library/std/src/sys/pal/sgx/args.rs b/library/std/src/sys/pal/sgx/args.rs
index a72a041da6c..e62bf383954 100644
--- a/library/std/src/sys/pal/sgx/args.rs
+++ b/library/std/src/sys/pal/sgx/args.rs
@@ -7,7 +7,7 @@ use crate::sys_common::FromInner;
 use crate::{fmt, slice};
 
 #[cfg_attr(test, linkage = "available_externally")]
-#[export_name = "_ZN16__rust_internals3std3sys3sgx4args4ARGSE"]
+#[unsafe(export_name = "_ZN16__rust_internals3std3sys3sgx4args4ARGSE")]
 static ARGS: AtomicUsize = AtomicUsize::new(0);
 type ArgsStore = Vec<OsString>;
 
diff --git a/library/std/src/sys/pal/sgx/libunwind_integration.rs b/library/std/src/sys/pal/sgx/libunwind_integration.rs
index debfd324c86..6d0d78d1eb9 100644
--- a/library/std/src/sys/pal/sgx/libunwind_integration.rs
+++ b/library/std/src/sys/pal/sgx/libunwind_integration.rs
@@ -15,7 +15,7 @@ const _: () = unsafe {
 
 const EINVAL: i32 = 22;
 
-#[no_mangle]
+#[unsafe(no_mangle)]
 pub unsafe extern "C" fn __rust_rwlock_rdlock(p: *mut RwLock) -> i32 {
     if p.is_null() {
         return EINVAL;
@@ -27,7 +27,7 @@ pub unsafe extern "C" fn __rust_rwlock_rdlock(p: *mut RwLock) -> i32 {
     return 0;
 }
 
-#[no_mangle]
+#[unsafe(no_mangle)]
 pub unsafe extern "C" fn __rust_rwlock_wrlock(p: *mut RwLock) -> i32 {
     if p.is_null() {
         return EINVAL;
@@ -36,7 +36,7 @@ pub unsafe extern "C" fn __rust_rwlock_wrlock(p: *mut RwLock) -> i32 {
     return 0;
 }
 
-#[no_mangle]
+#[unsafe(no_mangle)]
 pub unsafe extern "C" fn __rust_rwlock_unlock(p: *mut RwLock) -> i32 {
     if p.is_null() {
         return EINVAL;
diff --git a/library/std/src/sys/pal/sgx/mod.rs b/library/std/src/sys/pal/sgx/mod.rs
index 9a04fa4b97e..37ca6b08c95 100644
--- a/library/std/src/sys/pal/sgx/mod.rs
+++ b/library/std/src/sys/pal/sgx/mod.rs
@@ -123,7 +123,7 @@ pub fn abort_internal() -> ! {
 // This function is needed by the panic runtime. The symbol is named in
 // pre-link args for the target specification, so keep that in sync.
 #[cfg(not(test))]
-#[no_mangle]
+#[unsafe(no_mangle)]
 // NB. used by both libunwind and libpanic_abort
 pub extern "C" fn __rust_abort() {
     abort_internal();
diff --git a/library/std/src/sys/pal/sgx/os.rs b/library/std/src/sys/pal/sgx/os.rs
index 46af710aa39..b1ec2afd764 100644
--- a/library/std/src/sys/pal/sgx/os.rs
+++ b/library/std/src/sys/pal/sgx/os.rs
@@ -74,10 +74,10 @@ pub fn current_exe() -> io::Result<PathBuf> {
 }
 
 #[cfg_attr(test, linkage = "available_externally")]
-#[export_name = "_ZN16__rust_internals3std3sys3sgx2os3ENVE"]
+#[unsafe(export_name = "_ZN16__rust_internals3std3sys3sgx2os3ENVE")]
 static ENV: AtomicUsize = AtomicUsize::new(0);
 #[cfg_attr(test, linkage = "available_externally")]
-#[export_name = "_ZN16__rust_internals3std3sys3sgx2os8ENV_INITE"]
+#[unsafe(export_name = "_ZN16__rust_internals3std3sys3sgx2os8ENV_INITE")]
 static ENV_INIT: Once = Once::new();
 type EnvStore = Mutex<HashMap<OsString, OsString>>;
 
diff --git a/library/std/src/sys/pal/sgx/stdio.rs b/library/std/src/sys/pal/sgx/stdio.rs
index e79a3d971c6..726a93acae4 100644
--- a/library/std/src/sys/pal/sgx/stdio.rs
+++ b/library/std/src/sys/pal/sgx/stdio.rs
@@ -76,7 +76,7 @@ pub fn panic_output() -> Option<impl io::Write> {
 // This function is needed by libunwind. The symbol is named in pre-link args
 // for the target specification, so keep that in sync.
 #[cfg(not(test))]
-#[no_mangle]
+#[unsafe(no_mangle)]
 pub unsafe extern "C" fn __rust_print_err(m: *mut u8, s: i32) {
     if s < 0 {
         return;
diff --git a/library/std/src/sys/pal/sgx/thread.rs b/library/std/src/sys/pal/sgx/thread.rs
index cecd53c352c..b6932df431f 100644
--- a/library/std/src/sys/pal/sgx/thread.rs
+++ b/library/std/src/sys/pal/sgx/thread.rs
@@ -46,7 +46,7 @@ mod task_queue {
     }
 
     #[cfg_attr(test, linkage = "available_externally")]
-    #[export_name = "_ZN16__rust_internals3std3sys3sgx6thread10TASK_QUEUEE"]
+    #[unsafe(export_name = "_ZN16__rust_internals3std3sys3sgx6thread10TASK_QUEUEE")]
     static TASK_QUEUE: Mutex<Vec<Task>> = Mutex::new(Vec::new());
 
     pub(super) fn lock() -> MutexGuard<'static, Vec<Task>> {
diff --git a/library/std/src/sys/pal/uefi/mod.rs b/library/std/src/sys/pal/uefi/mod.rs
index 4766e2ef0a9..8e6aea452f8 100644
--- a/library/std/src/sys/pal/uefi/mod.rs
+++ b/library/std/src/sys/pal/uefi/mod.rs
@@ -169,7 +169,7 @@ pub fn abort_internal() -> ! {
 // This function is needed by the panic runtime. The symbol is named in
 // pre-link args for the target specification, so keep that in sync.
 #[cfg(not(test))]
-#[no_mangle]
+#[unsafe(no_mangle)]
 pub extern "C" fn __rust_abort() {
     abort_internal();
 }
diff --git a/library/std/src/sys/pal/uefi/process.rs b/library/std/src/sys/pal/uefi/process.rs
index 0757f1cb490..9efe9a314f2 100644
--- a/library/std/src/sys/pal/uefi/process.rs
+++ b/library/std/src/sys/pal/uefi/process.rs
@@ -154,8 +154,8 @@ impl Command {
         if let Some(e) = &env {
             for (k, (_, v)) in e {
                 match v {
-                    Some(v) => crate::env::set_var(k, v),
-                    None => crate::env::remove_var(k),
+                    Some(v) => unsafe { crate::env::set_var(k, v) },
+                    None => unsafe { crate::env::remove_var(k) },
                 }
             }
         }
@@ -166,8 +166,8 @@ impl Command {
         if let Some(e) = env {
             for (k, (v, _)) in e {
                 match v {
-                    Some(v) => crate::env::set_var(k, v),
-                    None => crate::env::remove_var(k),
+                    Some(v) => unsafe { crate::env::set_var(k, v) },
+                    None => unsafe { crate::env::remove_var(k) },
                 }
             }
         }
diff --git a/library/std/src/sys/pal/unix/linux/pidfd/tests.rs b/library/std/src/sys/pal/unix/linux/pidfd/tests.rs
index fb928c76fbd..17b06bea912 100644
--- a/library/std/src/sys/pal/unix/linux/pidfd/tests.rs
+++ b/library/std/src/sys/pal/unix/linux/pidfd/tests.rs
@@ -45,8 +45,8 @@ fn test_command_pidfd() {
         .expect_err("pidfd should not have been created");
 
     // exercise the fork/exec path since the earlier attempts may have used pidfd_spawnp()
-    let mut child =
-        unsafe { Command::new("false").pre_exec(|| Ok(())) }.create_pidfd(true).spawn().unwrap();
+    let mut cmd = Command::new("false");
+    let mut child = unsafe { cmd.pre_exec(|| Ok(())) }.create_pidfd(true).spawn().unwrap();
 
     assert!(child.id() > 0 && child.id() < -1i32 as u32);
 
diff --git a/library/std/src/sys/pal/wasi/fs.rs b/library/std/src/sys/pal/wasi/fs.rs
index 7705e7f6b88..faf3edd5da6 100644
--- a/library/std/src/sys/pal/wasi/fs.rs
+++ b/library/std/src/sys/pal/wasi/fs.rs
@@ -183,7 +183,7 @@ impl Iterator for ReadDir {
 
     fn next(&mut self) -> Option<io::Result<DirEntry>> {
         match &mut self.state {
-            ReadDirState::FillBuffer { next_read_offset, ref mut buf } => {
+            ReadDirState::FillBuffer { next_read_offset, buf } => {
                 let result = self.inner.dir.fd.readdir(buf, *next_read_offset);
                 match result {
                     Ok(read_bytes) => {
@@ -207,7 +207,7 @@ impl Iterator for ReadDir {
                     }
                 }
             }
-            ReadDirState::ProcessEntry { ref mut buf, next_read_offset, offset } => {
+            ReadDirState::ProcessEntry { buf, next_read_offset, offset } => {
                 let contents = &buf[*offset..];
                 const DIRENT_SIZE: usize = crate::mem::size_of::<wasi::Dirent>();
                 if contents.len() >= DIRENT_SIZE {
diff --git a/library/std/src/sys/pal/wasip2/cabi_realloc.rs b/library/std/src/sys/pal/wasip2/cabi_realloc.rs
index 820063173d6..78adf9002fd 100644
--- a/library/std/src/sys/pal/wasip2/cabi_realloc.rs
+++ b/library/std/src/sys/pal/wasip2/cabi_realloc.rs
@@ -32,7 +32,7 @@ static FORCE_CODEGEN_OF_CABI_REALLOC: unsafe extern "C" fn(
 ) -> *mut u8 = cabi_realloc;
 
 #[linkage = "weak"]
-#[no_mangle]
+#[unsafe(no_mangle)]
 pub unsafe extern "C" fn cabi_realloc(
     old_ptr: *mut u8,
     old_len: usize,
diff --git a/library/std/src/sys/pal/windows/process/tests.rs b/library/std/src/sys/pal/windows/process/tests.rs
index 90f1157d7c4..1377e12162f 100644
--- a/library/std/src/sys/pal/windows/process/tests.rs
+++ b/library/std/src/sys/pal/windows/process/tests.rs
@@ -138,8 +138,10 @@ fn windows_env_unicode_case() {
         let mut cmd = Command::new("cmd");
         cmd.env(a, "1");
         cmd.env(b, "2");
-        env::set_var(a, "1");
-        env::set_var(b, "2");
+        unsafe {
+            env::set_var(a, "1");
+            env::set_var(b, "2");
+        }
 
         for (key, value) in cmd.get_envs() {
             assert_eq!(
diff --git a/library/std/src/sys/pal/xous/os.rs b/library/std/src/sys/pal/xous/os.rs
index 307623c0425..2c87e7d91f2 100644
--- a/library/std/src/sys/pal/xous/os.rs
+++ b/library/std/src/sys/pal/xous/os.rs
@@ -41,12 +41,12 @@ mod c_compat {
         fn main() -> u32;
     }
 
-    #[no_mangle]
+    #[unsafe(no_mangle)]
     pub extern "C" fn abort() {
         exit(1);
     }
 
-    #[no_mangle]
+    #[unsafe(no_mangle)]
     pub extern "C" fn _start(eh_frame: usize, params_address: usize) {
         #[cfg(feature = "panic_unwind")]
         {
@@ -67,7 +67,7 @@ mod c_compat {
 
     // This function is needed by the panic runtime. The symbol is named in
     // pre-link args for the target specification, so keep that in sync.
-    #[no_mangle]
+    #[unsafe(no_mangle)]
     // NB. used by both libunwind and libpanic_abort
     pub extern "C" fn __rust_abort() -> ! {
         exit(101);
diff --git a/library/std/src/sys/thread_local/key/xous.rs b/library/std/src/sys/thread_local/key/xous.rs
index 6c5e6447d19..55ac5b20e1a 100644
--- a/library/std/src/sys/thread_local/key/xous.rs
+++ b/library/std/src/sys/thread_local/key/xous.rs
@@ -51,11 +51,11 @@ const TLS_MEMORY_SIZE: usize = 4096;
 
 /// TLS keys start at `1`. Index `0` is unused
 #[cfg(not(test))]
-#[export_name = "_ZN16__rust_internals3std3sys4xous16thread_local_key13TLS_KEY_INDEXE"]
+#[unsafe(export_name = "_ZN16__rust_internals3std3sys4xous16thread_local_key13TLS_KEY_INDEXE")]
 static TLS_KEY_INDEX: AtomicUsize = AtomicUsize::new(1);
 
 #[cfg(not(test))]
-#[export_name = "_ZN16__rust_internals3std3sys4xous16thread_local_key9DTORSE"]
+#[unsafe(export_name = "_ZN16__rust_internals3std3sys4xous16thread_local_key9DTORSE")]
 static DTORS: AtomicPtr<Node> = AtomicPtr::new(ptr::null_mut());
 
 #[cfg(test)]