Auto merge of #131078 - tgross35:rollup-66to2u9, r=tgross35

Rollup of 5 pull requests

Successful merges:

 - #129638 (Hook up std::net to wasi-libc on wasm32-wasip2 target)
 - #130877 (rustc_target: Add RISC-V atomic-related features)
 - #130914 (Mark some more types as having insignificant dtor)
 - #130961 (Enable `f16` tests on x86 Apple platforms)
 - #130966 (make ptr metadata functions callable from stable const fn)

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

compiler/rustc_codegen_llvm/src/llvm_util.rs

@@ -264,6 +264,10 @@ pub(crate) fn to_llvm_features<'a>(sess: &Session, s: &'a str) -> Option<LLVMFea
         ("riscv32" | "riscv64", "unaligned-scalar-mem") if get_version().0 == 18 => {
             Some(LLVMFeature::new("fast-unaligned-access"))
         }
+        // Filter out features that are not supported by the current LLVM version
+        ("riscv32" | "riscv64", "zaamo") if get_version().0 < 19 => None,
+        ("riscv32" | "riscv64", "zabha") if get_version().0 < 19 => None,
+        ("riscv32" | "riscv64", "zalrsc") if get_version().0 < 19 => None,
         // Enable the evex512 target feature if an avx512 target feature is enabled.
         ("x86", s) if s.starts_with("avx512") => {
             Some(LLVMFeature::with_dependency(s, TargetFeatureFoldStrength::EnableOnly("evex512")))

compiler/rustc_target/src/target_features.rs

@@ -373,7 +373,7 @@ const MIPS_ALLOWED_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[
 
 const RISCV_ALLOWED_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[
     // tidy-alphabetical-start
-    ("a", Stable, &[]),
+    ("a", Stable, &["zaamo", "zalrsc"]),
     ("c", Stable, &[]),
     ("d", Unstable(sym::riscv_target_feature), &["f"]),
     ("e", Unstable(sym::riscv_target_feature), &[]),
@@ -382,6 +382,9 @@ const RISCV_ALLOWED_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[
     ("relax", Unstable(sym::riscv_target_feature), &[]),
     ("unaligned-scalar-mem", Unstable(sym::riscv_target_feature), &[]),
     ("v", Unstable(sym::riscv_target_feature), &[]),
+    ("zaamo", Unstable(sym::riscv_target_feature), &[]),
+    ("zabha", Unstable(sym::riscv_target_feature), &["zaamo"]),
+    ("zalrsc", Unstable(sym::riscv_target_feature), &[]),
     ("zba", Stable, &[]),
     ("zbb", Stable, &[]),
     ("zbc", Stable, &[]),

library/alloc/src/boxed.rs

@@ -228,6 +228,7 @@ mod thin;
 #[lang = "owned_box"]
 #[fundamental]
 #[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_insignificant_dtor]
 // The declaration of the `Box` struct must be kept in sync with the
 // compiler or ICEs will happen.
 pub struct Box<

library/alloc/src/ffi/c_str.rs

@@ -696,6 +696,7 @@ impl CString {
 // memory-unsafe code from working by accident. Inline
 // to prevent LLVM from optimizing it away in debug builds.
 #[stable(feature = "cstring_drop", since = "1.13.0")]
+#[rustc_insignificant_dtor]
 impl Drop for CString {
     #[inline]
     fn drop(&mut self) {

library/alloc/src/sync.rs

@@ -237,6 +237,7 @@ macro_rules! acquire {
 /// [rc_examples]: crate::rc#examples
 #[cfg_attr(not(test), rustc_diagnostic_item = "Arc")]
 #[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_insignificant_dtor]
 pub struct Arc<
     T: ?Sized,
     #[unstable(feature = "allocator_api", issue = "32838")] A: Allocator = Global,

library/core/src/intrinsics.rs

@@ -3165,7 +3165,7 @@ pub const fn type_id<T: ?Sized + 'static>() -> u128 {
 /// change the possible layouts of pointers.
 #[rustc_nounwind]
 #[unstable(feature = "core_intrinsics", issue = "none")]
-#[rustc_const_unstable(feature = "ptr_metadata", issue = "81513")]
+#[rustc_const_stable(feature = "ptr_metadata_const", since = "CURRENT_RUSTC_VERSION")]
 #[rustc_intrinsic]
 #[rustc_intrinsic_must_be_overridden]
 pub const fn aggregate_raw_ptr<P: AggregateRawPtr<D, Metadata = M>, D, M>(_data: D, _meta: M) -> P {
@@ -3190,7 +3190,7 @@ impl<P: ?Sized, T: ptr::Thin> AggregateRawPtr<*mut T> for *mut P {
 /// This is used to implement functions like `ptr::metadata`.
 #[rustc_nounwind]
 #[unstable(feature = "core_intrinsics", issue = "none")]
-#[rustc_const_unstable(feature = "ptr_metadata", issue = "81513")]
+#[rustc_const_stable(feature = "ptr_metadata_const", since = "CURRENT_RUSTC_VERSION")]
 #[rustc_intrinsic]
 #[rustc_intrinsic_must_be_overridden]
 pub const fn ptr_metadata<P: ptr::Pointee<Metadata = M> + ?Sized, M>(_ptr: *const P) -> M {

library/core/src/ptr/const_ptr.rs

@@ -92,7 +92,7 @@ impl<T: ?Sized> *const T {
     /// }
     /// ```
     #[unstable(feature = "set_ptr_value", issue = "75091")]
-    #[rustc_const_unstable(feature = "set_ptr_value", issue = "75091")]
+    #[rustc_const_stable(feature = "ptr_metadata_const", since = "CURRENT_RUSTC_VERSION")]
     #[must_use = "returns a new pointer rather than modifying its argument"]
     #[inline]
     pub const fn with_metadata_of<U>(self, meta: *const U) -> *const U
@@ -412,7 +412,6 @@ impl<T: ?Sized> *const T {
     #[inline(always)]
     #[stable(feature = "pointer_byte_offsets", since = "1.75.0")]
     #[rustc_const_stable(feature = "const_pointer_byte_offsets", since = "1.75.0")]
-    #[rustc_allow_const_fn_unstable(set_ptr_value)]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
     pub const unsafe fn byte_offset(self, count: isize) -> Self {
         // SAFETY: the caller must uphold the safety contract for `offset`.
@@ -495,7 +494,6 @@ impl<T: ?Sized> *const T {
     #[inline(always)]
     #[stable(feature = "pointer_byte_offsets", since = "1.75.0")]
     #[rustc_const_stable(feature = "const_pointer_byte_offsets", since = "1.75.0")]
-    #[rustc_allow_const_fn_unstable(set_ptr_value)]
     pub const fn wrapping_byte_offset(self, count: isize) -> Self {
         self.cast::<u8>().wrapping_offset(count).with_metadata_of(self)
     }
@@ -645,7 +643,6 @@ impl<T: ?Sized> *const T {
     #[inline(always)]
     #[stable(feature = "pointer_byte_offsets", since = "1.75.0")]
     #[rustc_const_stable(feature = "const_pointer_byte_offsets", since = "1.75.0")]
-    #[rustc_allow_const_fn_unstable(set_ptr_value)]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
     pub const unsafe fn byte_offset_from<U: ?Sized>(self, origin: *const U) -> isize {
         // SAFETY: the caller must uphold the safety contract for `offset_from`.
@@ -873,7 +870,6 @@ impl<T: ?Sized> *const T {
     #[inline(always)]
     #[stable(feature = "pointer_byte_offsets", since = "1.75.0")]
     #[rustc_const_stable(feature = "const_pointer_byte_offsets", since = "1.75.0")]
-    #[rustc_allow_const_fn_unstable(set_ptr_value)]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
     pub const unsafe fn byte_add(self, count: usize) -> Self {
         // SAFETY: the caller must uphold the safety contract for `add`.
@@ -956,7 +952,6 @@ impl<T: ?Sized> *const T {
     #[inline(always)]
     #[stable(feature = "pointer_byte_offsets", since = "1.75.0")]
     #[rustc_const_stable(feature = "const_pointer_byte_offsets", since = "1.75.0")]
-    #[rustc_allow_const_fn_unstable(set_ptr_value)]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
     pub const unsafe fn byte_sub(self, count: usize) -> Self {
         // SAFETY: the caller must uphold the safety contract for `sub`.
@@ -1039,7 +1034,6 @@ impl<T: ?Sized> *const T {
     #[inline(always)]
     #[stable(feature = "pointer_byte_offsets", since = "1.75.0")]
     #[rustc_const_stable(feature = "const_pointer_byte_offsets", since = "1.75.0")]
-    #[rustc_allow_const_fn_unstable(set_ptr_value)]
     pub const fn wrapping_byte_add(self, count: usize) -> Self {
         self.cast::<u8>().wrapping_add(count).with_metadata_of(self)
     }
@@ -1120,7 +1114,6 @@ impl<T: ?Sized> *const T {
     #[inline(always)]
     #[stable(feature = "pointer_byte_offsets", since = "1.75.0")]
     #[rustc_const_stable(feature = "const_pointer_byte_offsets", since = "1.75.0")]
-    #[rustc_allow_const_fn_unstable(set_ptr_value)]
     pub const fn wrapping_byte_sub(self, count: usize) -> Self {
         self.cast::<u8>().wrapping_sub(count).with_metadata_of(self)
     }
@@ -1554,7 +1547,6 @@ impl<T> *const [T] {
     #[inline]
     #[stable(feature = "slice_ptr_len", since = "1.79.0")]
     #[rustc_const_stable(feature = "const_slice_ptr_len", since = "1.79.0")]
-    #[rustc_allow_const_fn_unstable(ptr_metadata)]
     pub const fn len(self) -> usize {
         metadata(self)
     }

library/core/src/ptr/metadata.rs

@@ -92,7 +92,7 @@ pub trait Thin = Pointee<Metadata = ()>;
 ///
 /// assert_eq!(std::ptr::metadata("foo"), 3_usize);
 /// ```
-#[rustc_const_unstable(feature = "ptr_metadata", issue = "81513")]
+#[rustc_const_stable(feature = "ptr_metadata_const", since = "CURRENT_RUSTC_VERSION")]
 #[inline]
 pub const fn metadata<T: ?Sized>(ptr: *const T) -> <T as Pointee>::Metadata {
     ptr_metadata(ptr)
@@ -106,7 +106,7 @@ pub const fn metadata<T: ?Sized>(ptr: *const T) -> <T as Pointee>::Metadata {
 ///
 /// [`slice::from_raw_parts`]: crate::slice::from_raw_parts
 #[unstable(feature = "ptr_metadata", issue = "81513")]
-#[rustc_const_unstable(feature = "ptr_metadata", issue = "81513")]
+#[rustc_const_stable(feature = "ptr_metadata_const", since = "CURRENT_RUSTC_VERSION")]
 #[inline]
 pub const fn from_raw_parts<T: ?Sized>(
     data_pointer: *const impl Thin,
@@ -120,7 +120,7 @@ pub const fn from_raw_parts<T: ?Sized>(
 ///
 /// See the documentation of [`from_raw_parts`] for more details.
 #[unstable(feature = "ptr_metadata", issue = "81513")]
-#[rustc_const_unstable(feature = "ptr_metadata", issue = "81513")]
+#[rustc_const_stable(feature = "ptr_metadata_const", since = "CURRENT_RUSTC_VERSION")]
 #[inline]
 pub const fn from_raw_parts_mut<T: ?Sized>(
     data_pointer: *mut impl Thin,

library/core/src/ptr/mod.rs

@@ -599,7 +599,6 @@ pub unsafe fn drop_in_place<T: ?Sized>(to_drop: *mut T) {
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_promotable]
 #[rustc_const_stable(feature = "const_ptr_null", since = "1.24.0")]
-#[rustc_allow_const_fn_unstable(ptr_metadata)]
 #[rustc_diagnostic_item = "ptr_null"]
 pub const fn null<T: ?Sized + Thin>() -> *const T {
     from_raw_parts(without_provenance::<()>(0), ())
@@ -625,7 +624,6 @@ pub const fn null<T: ?Sized + Thin>() -> *const T {
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_promotable]
 #[rustc_const_stable(feature = "const_ptr_null", since = "1.24.0")]
-#[rustc_allow_const_fn_unstable(ptr_metadata)]
 #[rustc_diagnostic_item = "ptr_null_mut"]
 pub const fn null_mut<T: ?Sized + Thin>() -> *mut T {
     from_raw_parts_mut(without_provenance_mut::<()>(0), ())
@@ -949,7 +947,6 @@ pub const fn from_mut<T: ?Sized>(r: &mut T) -> *mut T {
 #[inline]
 #[stable(feature = "slice_from_raw_parts", since = "1.42.0")]
 #[rustc_const_stable(feature = "const_slice_from_raw_parts", since = "1.64.0")]
-#[rustc_allow_const_fn_unstable(ptr_metadata)]
 #[rustc_diagnostic_item = "ptr_slice_from_raw_parts"]
 pub const fn slice_from_raw_parts<T>(data: *const T, len: usize) -> *const [T] {
     from_raw_parts(data, len)

library/core/src/ptr/mut_ptr.rs

@@ -74,7 +74,7 @@ impl<T: ?Sized> *mut T {
     /// }
     /// ```
     #[unstable(feature = "set_ptr_value", issue = "75091")]
-    #[rustc_const_unstable(feature = "set_ptr_value", issue = "75091")]
+    #[rustc_const_stable(feature = "ptr_metadata_const", since = "CURRENT_RUSTC_VERSION")]
     #[must_use = "returns a new pointer rather than modifying its argument"]
     #[inline]
     pub const fn with_metadata_of<U>(self, meta: *const U) -> *mut U
@@ -412,7 +412,6 @@ impl<T: ?Sized> *mut T {
     #[inline(always)]
     #[stable(feature = "pointer_byte_offsets", since = "1.75.0")]
     #[rustc_const_stable(feature = "const_pointer_byte_offsets", since = "1.75.0")]
-    #[rustc_allow_const_fn_unstable(set_ptr_value)]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
     pub const unsafe fn byte_offset(self, count: isize) -> Self {
         // SAFETY: the caller must uphold the safety contract for `offset`.
@@ -492,7 +491,6 @@ impl<T: ?Sized> *mut T {
     #[inline(always)]
     #[stable(feature = "pointer_byte_offsets", since = "1.75.0")]
     #[rustc_const_stable(feature = "const_pointer_byte_offsets", since = "1.75.0")]
-    #[rustc_allow_const_fn_unstable(set_ptr_value)]
     pub const fn wrapping_byte_offset(self, count: isize) -> Self {
         self.cast::<u8>().wrapping_offset(count).with_metadata_of(self)
     }
@@ -808,7 +806,6 @@ impl<T: ?Sized> *mut T {
     #[inline(always)]
     #[stable(feature = "pointer_byte_offsets", since = "1.75.0")]
     #[rustc_const_stable(feature = "const_pointer_byte_offsets", since = "1.75.0")]
-    #[rustc_allow_const_fn_unstable(set_ptr_value)]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
     pub const unsafe fn byte_offset_from<U: ?Sized>(self, origin: *const U) -> isize {
         // SAFETY: the caller must uphold the safety contract for `offset_from`.
@@ -954,7 +951,6 @@ impl<T: ?Sized> *mut T {
     #[inline(always)]
     #[stable(feature = "pointer_byte_offsets", since = "1.75.0")]
     #[rustc_const_stable(feature = "const_pointer_byte_offsets", since = "1.75.0")]
-    #[rustc_allow_const_fn_unstable(set_ptr_value)]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
     pub const unsafe fn byte_add(self, count: usize) -> Self {
         // SAFETY: the caller must uphold the safety contract for `add`.
@@ -1037,7 +1033,6 @@ impl<T: ?Sized> *mut T {
     #[inline(always)]
     #[stable(feature = "pointer_byte_offsets", since = "1.75.0")]
     #[rustc_const_stable(feature = "const_pointer_byte_offsets", since = "1.75.0")]
-    #[rustc_allow_const_fn_unstable(set_ptr_value)]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
     pub const unsafe fn byte_sub(self, count: usize) -> Self {
         // SAFETY: the caller must uphold the safety contract for `sub`.
@@ -1118,7 +1113,6 @@ impl<T: ?Sized> *mut T {
     #[inline(always)]
     #[stable(feature = "pointer_byte_offsets", since = "1.75.0")]
     #[rustc_const_stable(feature = "const_pointer_byte_offsets", since = "1.75.0")]
-    #[rustc_allow_const_fn_unstable(set_ptr_value)]
     pub const fn wrapping_byte_add(self, count: usize) -> Self {
         self.cast::<u8>().wrapping_add(count).with_metadata_of(self)
     }
@@ -1197,7 +1191,6 @@ impl<T: ?Sized> *mut T {
     #[inline(always)]
     #[stable(feature = "pointer_byte_offsets", since = "1.75.0")]
     #[rustc_const_stable(feature = "const_pointer_byte_offsets", since = "1.75.0")]
-    #[rustc_allow_const_fn_unstable(set_ptr_value)]
     pub const fn wrapping_byte_sub(self, count: usize) -> Self {
         self.cast::<u8>().wrapping_sub(count).with_metadata_of(self)
     }
@@ -1804,7 +1797,6 @@ impl<T> *mut [T] {
     #[inline(always)]
     #[stable(feature = "slice_ptr_len", since = "1.79.0")]
     #[rustc_const_stable(feature = "const_slice_ptr_len", since = "1.79.0")]
-    #[rustc_allow_const_fn_unstable(ptr_metadata)]
     pub const fn len(self) -> usize {
         metadata(self)
     }

library/core/src/ptr/non_null.rs

@@ -567,7 +567,6 @@ impl<T: ?Sized> NonNull<T> {
     #[must_use]
     #[inline(always)]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
-    #[rustc_allow_const_fn_unstable(set_ptr_value)]
     #[stable(feature = "non_null_convenience", since = "1.80.0")]
     #[rustc_const_stable(feature = "non_null_convenience", since = "1.80.0")]
     pub const unsafe fn byte_add(self, count: usize) -> Self {
@@ -651,7 +650,6 @@ impl<T: ?Sized> NonNull<T> {
     #[must_use]
     #[inline(always)]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
-    #[rustc_allow_const_fn_unstable(set_ptr_value)]
     #[stable(feature = "non_null_convenience", since = "1.80.0")]
     #[rustc_const_stable(feature = "non_null_convenience", since = "1.80.0")]
     pub const unsafe fn byte_sub(self, count: usize) -> Self {

library/core/src/slice/mod.rs

@@ -111,7 +111,6 @@ impl<T> [T] {
     #[lang = "slice_len_fn"]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_stable(feature = "const_slice_len", since = "1.39.0")]
-    #[rustc_allow_const_fn_unstable(ptr_metadata)]
     #[inline]
     #[must_use]
     pub const fn len(&self) -> usize {

library/std/build.rs

@@ -102,9 +102,6 @@ fn main() {
         ("arm64ec", _) => false,
         // MinGW ABI bugs <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115054>
         ("x86_64", "windows") => false,
-        // Apple has a special ABI for `f16` that we do not yet support
-        // FIXME(builtins): fixed by <https://github.com/rust-lang/compiler-builtins/pull/675>
-        ("x86" | "x86_64", _) if target_vendor == "apple" => false,
         // Infinite recursion <https://github.com/llvm/llvm-project/issues/97981>
         ("csky", _) => false,
         ("hexagon", _) => false,

library/std/src/collections/hash/map/tests.rs

@@ -1018,6 +1018,7 @@ mod test_extract_if {
     }
 
     #[test]
+    #[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")]
     fn drop_panic_leak() {
         static PREDS: AtomicUsize = AtomicUsize::new(0);
         static DROPS: AtomicUsize = AtomicUsize::new(0);
@@ -1047,6 +1048,7 @@ mod test_extract_if {
     }
 
     #[test]
+    #[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")]
     fn pred_panic_leak() {
         static PREDS: AtomicUsize = AtomicUsize::new(0);
         static DROPS: AtomicUsize = AtomicUsize::new(0);
@@ -1076,6 +1078,7 @@ mod test_extract_if {
 
     // Same as above, but attempt to use the iterator again after the panic in the predicate
     #[test]
+    #[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")]
     fn pred_panic_reuse() {
         static PREDS: AtomicUsize = AtomicUsize::new(0);
         static DROPS: AtomicUsize = AtomicUsize::new(0);

library/std/src/collections/hash/set/tests.rs

@@ -429,6 +429,7 @@ fn test_extract_if() {
 }
 
 #[test]
+#[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")]
 fn test_extract_if_drop_panic_leak() {
     static PREDS: AtomicU32 = AtomicU32::new(0);
     static DROPS: AtomicU32 = AtomicU32::new(0);
@@ -459,6 +460,7 @@ fn test_extract_if_drop_panic_leak() {
 }
 
 #[test]
+#[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")]
 fn test_extract_if_pred_panic_leak() {
     static PREDS: AtomicU32 = AtomicU32::new(0);
     static DROPS: AtomicU32 = AtomicU32::new(0);

library/std/src/env/tests.rs

@@ -1,7 +1,7 @@
 use super::*;
 
 #[test]
-#[cfg_attr(any(target_os = "emscripten", target_env = "sgx"), ignore)]
+#[cfg_attr(any(target_os = "emscripten", target_os = "wasi", target_env = "sgx"), ignore)]
 fn test_self_exe_path() {
     let path = current_exe();
     assert!(path.is_ok());

library/std/src/fs.rs

@@ -8,7 +8,15 @@
 #![stable(feature = "rust1", since = "1.0.0")]
 #![deny(unsafe_op_in_unsafe_fn)]
 
-#[cfg(all(test, not(any(target_os = "emscripten", target_env = "sgx", target_os = "xous"))))]
+#[cfg(all(
+    test,
+    not(any(
+        target_os = "emscripten",
+        target_os = "wasi",
+        target_env = "sgx",
+        target_os = "xous"
+    ))
+))]
 mod tests;
 
 use crate::ffi::OsString;

library/std/src/io/buffered/tests.rs

@@ -164,6 +164,7 @@ fn test_buffered_reader_stream_position() {
 }
 
 #[test]
+#[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")]
 fn test_buffered_reader_stream_position_panic() {
     let inner: &[u8] = &[5, 6, 7, 0, 1, 2, 3, 4];
     let mut reader = BufReader::with_capacity(4, io::Cursor::new(inner));
@@ -487,7 +488,7 @@ fn dont_panic_in_drop_on_panicked_flush() {
 }
 
 #[test]
-#[cfg_attr(target_os = "emscripten", ignore)]
+#[cfg_attr(any(target_os = "emscripten", target_os = "wasi"), ignore)] // no threads
 fn panic_in_write_doesnt_flush_in_drop() {
     static WRITES: AtomicUsize = AtomicUsize::new(0);
 

library/std/src/io/error/repr_bitpacked.rs

@@ -124,6 +124,7 @@ const TAG_SIMPLE: usize = 0b11;
 /// is_unwind_safe::<std::io::Error>();
 /// ```
 #[repr(transparent)]
+#[rustc_insignificant_dtor]
 pub(super) struct Repr(NonNull<()>, PhantomData<ErrorData<Box<Custom>>>);
 
 // All the types `Repr` stores internally are Send + Sync, and so is it.

library/std/src/io/stdio/tests.rs

@@ -25,7 +25,7 @@ fn stderrlock_unwind_safe() {
 fn assert_unwind_safe<T: UnwindSafe + RefUnwindSafe>() {}
 
 #[test]
-#[cfg_attr(target_os = "emscripten", ignore)]
+#[cfg_attr(any(target_os = "emscripten", target_os = "wasi"), ignore)] // no threads
 fn panic_doesnt_poison() {
     thread::spawn(|| {
         let _a = stdin();
@@ -48,17 +48,17 @@ fn panic_doesnt_poison() {
 }
 
 #[test]
-#[cfg_attr(target_os = "emscripten", ignore)]
+#[cfg_attr(any(target_os = "emscripten", target_os = "wasi"), ignore)] // no threads
 fn test_lock_stderr() {
     test_lock(stderr, || stderr().lock());
 }
 #[test]
-#[cfg_attr(target_os = "emscripten", ignore)]
+#[cfg_attr(any(target_os = "emscripten", target_os = "wasi"), ignore)] // no threads
 fn test_lock_stdin() {
     test_lock(stdin, || stdin().lock());
 }
 #[test]
-#[cfg_attr(target_os = "emscripten", ignore)]
+#[cfg_attr(any(target_os = "emscripten", target_os = "wasi"), ignore)] // no threads
 fn test_lock_stdout() {
     test_lock(stdout, || stdout().lock());
 }

library/std/src/net/ip_addr.rs

@@ -1,5 +1,5 @@
 // Tests for this module
-#[cfg(all(test, not(target_os = "emscripten")))]
+#[cfg(all(test, not(any(target_os = "emscripten", all(target_os = "wasi", target_env = "p1")))))]
 mod tests;
 
 #[stable(feature = "ip_addr", since = "1.7.0")]

library/std/src/net/socket_addr.rs

@@ -1,5 +1,5 @@
 // Tests for this module
-#[cfg(all(test, not(target_os = "emscripten")))]
+#[cfg(all(test, not(any(target_os = "emscripten", all(target_os = "wasi", target_env = "p1")))))]
 mod tests;
 
 #[stable(feature = "rust1", since = "1.0.0")]

library/std/src/net/tcp.rs

@@ -1,6 +1,13 @@
 #![deny(unsafe_op_in_unsafe_fn)]
 
-#[cfg(all(test, not(any(target_os = "emscripten", target_os = "xous"))))]
+#[cfg(all(
+    test,
+    not(any(
+        target_os = "emscripten",
+        all(target_os = "wasi", target_env = "p1"),
+        target_os = "xous"
+    ))
+))]
 mod tests;
 
 use crate::fmt;

library/std/src/net/tcp/tests.rs

@@ -57,6 +57,7 @@ fn connect_timeout_error() {
 }
 
 #[test]
+#[cfg_attr(target_os = "wasi", ignore)] // no threads
 fn listen_localhost() {
     let socket_addr = next_test_ip4();
     let listener = t!(TcpListener::bind(&socket_addr));
@@ -73,6 +74,7 @@ fn listen_localhost() {
 }
 
 #[test]
+#[cfg_attr(target_os = "wasi", ignore)] // no threads
 fn connect_loopback() {
     each_ip(&mut |addr| {
         let acceptor = t!(TcpListener::bind(&addr));
@@ -94,6 +96,7 @@ fn connect_loopback() {
 }
 
 #[test]
+#[cfg_attr(target_os = "wasi", ignore)] // no threads
 fn smoke_test() {
     each_ip(&mut |addr| {
         let acceptor = t!(TcpListener::bind(&addr));
@@ -114,6 +117,7 @@ fn smoke_test() {
 }
 
 #[test]
+#[cfg_attr(target_os = "wasi", ignore)] // no threads
 fn read_eof() {
     each_ip(&mut |addr| {
         let acceptor = t!(TcpListener::bind(&addr));
@@ -133,6 +137,7 @@ fn read_eof() {
 }
 
 #[test]
+#[cfg_attr(target_os = "wasi", ignore)] // no threads
 fn write_close() {
     each_ip(&mut |addr| {
         let acceptor = t!(TcpListener::bind(&addr));
@@ -161,6 +166,7 @@ fn write_close() {
 }
 
 #[test]
+#[cfg_attr(target_os = "wasi", ignore)] // no threads
 fn multiple_connect_serial() {
     each_ip(&mut |addr| {
         let max = 10;
@@ -183,6 +189,7 @@ fn multiple_connect_serial() {
 }
 
 #[test]
+#[cfg_attr(target_os = "wasi", ignore)] // no threads
 fn multiple_connect_interleaved_greedy_schedule() {
     const MAX: usize = 10;
     each_ip(&mut |addr| {
@@ -220,6 +227,7 @@ fn multiple_connect_interleaved_greedy_schedule() {
 }
 
 #[test]
+#[cfg_attr(target_os = "wasi", ignore)] // no threads
 fn multiple_connect_interleaved_lazy_schedule() {
     const MAX: usize = 10;
     each_ip(&mut |addr| {
@@ -255,6 +263,7 @@ fn multiple_connect_interleaved_lazy_schedule() {
 }
 
 #[test]
+#[cfg_attr(target_os = "wasi", ignore)] // no threads
 fn socket_and_peer_name() {
     each_ip(&mut |addr| {
         let listener = t!(TcpListener::bind(&addr));
@@ -270,6 +279,7 @@ fn socket_and_peer_name() {
 }
 
 #[test]
+#[cfg_attr(target_os = "wasi", ignore)] // no threads
 fn partial_read() {
     each_ip(&mut |addr| {
         let (tx, rx) = channel();
@@ -291,6 +301,7 @@ fn partial_read() {
 }
 
 #[test]
+#[cfg_attr(target_os = "wasi", ignore)] // no threads
 fn read_buf() {
     each_ip(&mut |addr| {
         let srv = t!(TcpListener::bind(&addr));
@@ -389,6 +400,7 @@ fn double_bind() {
 }
 
 #[test]
+#[cfg_attr(target_os = "wasi", ignore)] // no threads
 fn tcp_clone_smoke() {
     each_ip(&mut |addr| {
         let acceptor = t!(TcpListener::bind(&addr));
@@ -420,6 +432,7 @@ fn tcp_clone_smoke() {
 }
 
 #[test]
+#[cfg_attr(target_os = "wasi", ignore)] // no threads
 fn tcp_clone_two_read() {
     each_ip(&mut |addr| {
         let acceptor = t!(TcpListener::bind(&addr));
@@ -454,6 +467,7 @@ fn tcp_clone_two_read() {
 }
 
 #[test]
+#[cfg_attr(target_os = "wasi", ignore)] // no threads
 fn tcp_clone_two_write() {
     each_ip(&mut |addr| {
         let acceptor = t!(TcpListener::bind(&addr));
@@ -483,6 +497,7 @@ fn tcp_clone_two_write() {
 #[test]
 // FIXME: https://github.com/fortanix/rust-sgx/issues/110
 #[cfg_attr(target_env = "sgx", ignore)]
+#[cfg_attr(target_os = "wasi", ignore)] // no threads
 fn shutdown_smoke() {
     each_ip(&mut |addr| {
         let a = t!(TcpListener::bind(&addr));
@@ -505,6 +520,7 @@ fn shutdown_smoke() {
 #[test]
 // FIXME: https://github.com/fortanix/rust-sgx/issues/110
 #[cfg_attr(target_env = "sgx", ignore)]
+#[cfg_attr(target_os = "wasi", ignore)] // no threads
 fn close_readwrite_smoke() {
     each_ip(&mut |addr| {
         let a = t!(TcpListener::bind(&addr));
@@ -547,6 +563,7 @@ fn close_readwrite_smoke() {
 #[cfg_attr(target_env = "sgx", ignore)]
 // On windows, shutdown will not wake up blocking I/O operations.
 #[cfg_attr(windows, ignore)]
+#[cfg_attr(target_os = "wasi", ignore)] // no threads
 fn close_read_wakes_up() {
     each_ip(&mut |addr| {
         let listener = t!(TcpListener::bind(&addr));
@@ -574,6 +591,7 @@ fn close_read_wakes_up() {
 }
 
 #[test]
+#[cfg_attr(target_os = "wasi", ignore)] // no threads
 fn clone_while_reading() {
     each_ip(&mut |addr| {
         let accept = t!(TcpListener::bind(&addr));
@@ -614,6 +632,7 @@ fn clone_while_reading() {
 }
 
 #[test]
+#[cfg_attr(target_os = "wasi", ignore)] // no threads
 fn clone_accept_smoke() {
     each_ip(&mut |addr| {
         let a = t!(TcpListener::bind(&addr));
@@ -632,6 +651,7 @@ fn clone_accept_smoke() {
 }
 
 #[test]
+#[cfg_attr(target_os = "wasi", ignore)] // no threads
 fn clone_accept_concurrent() {
     each_ip(&mut |addr| {
         let a = t!(TcpListener::bind(&addr));
@@ -670,10 +690,10 @@ fn debug() {
         addr.to_string()
     }
 
+    #[cfg(any(unix, target_os = "wasi"))]
+    use crate::os::fd::AsRawFd;
     #[cfg(target_env = "sgx")]
     use crate::os::fortanix_sgx::io::AsRawFd;
-    #[cfg(unix)]
-    use crate::os::unix::io::AsRawFd;
     #[cfg(not(windows))]
     fn render_inner(addr: &dyn AsRawFd) -> impl fmt::Debug {
         addr.as_raw_fd()
@@ -714,6 +734,7 @@ fn debug() {
     ignore
 )]
 #[cfg_attr(target_env = "sgx", ignore)] // FIXME: https://github.com/fortanix/rust-sgx/issues/31
+#[cfg_attr(target_os = "wasi", ignore)] // timeout not supported
 #[test]
 fn timeouts() {
     let addr = next_test_ip4();
@@ -742,6 +763,7 @@ fn timeouts() {
 
 #[test]
 #[cfg_attr(target_env = "sgx", ignore)] // FIXME: https://github.com/fortanix/rust-sgx/issues/31
+#[cfg_attr(target_os = "wasi", ignore)] // timeout not supported
 fn test_read_timeout() {
     let addr = next_test_ip4();
     let listener = t!(TcpListener::bind(&addr));
@@ -763,6 +785,7 @@ fn test_read_timeout() {
 
 #[test]
 #[cfg_attr(target_env = "sgx", ignore)] // FIXME: https://github.com/fortanix/rust-sgx/issues/31
+#[cfg_attr(target_os = "wasi", ignore)] // timeout not supported
 fn test_read_with_timeout() {
     let addr = next_test_ip4();
     let listener = t!(TcpListener::bind(&addr));
@@ -810,6 +833,7 @@ fn test_timeout_zero_duration() {
 
 #[test]
 #[cfg_attr(target_env = "sgx", ignore)]
+#[cfg_attr(target_os = "wasi", ignore)] // linger not supported
 fn linger() {
     let addr = next_test_ip4();
     let _listener = t!(TcpListener::bind(&addr));
@@ -879,6 +903,7 @@ fn set_nonblocking() {
 
 #[test]
 #[cfg_attr(target_env = "sgx", ignore)] // FIXME: https://github.com/fortanix/rust-sgx/issues/31
+#[cfg_attr(target_os = "wasi", ignore)] // no threads
 fn peek() {
     each_ip(&mut |addr| {
         let (txdone, rxdone) = channel();

library/std/src/net/udp.rs

@@ -1,4 +1,12 @@
-#[cfg(all(test, not(any(target_os = "emscripten", target_env = "sgx", target_os = "xous"))))]
+#[cfg(all(
+    test,
+    not(any(
+        target_os = "emscripten",
+        all(target_os = "wasi", target_env = "p1"),
+        target_env = "sgx",
+        target_os = "xous"
+    ))
+))]
 mod tests;
 
 use crate::fmt;

library/std/src/net/udp/tests.rs

@@ -27,6 +27,7 @@ fn bind_error() {
 }
 
 #[test]
+#[cfg_attr(target_os = "wasi", ignore)] // no threads
 fn socket_smoke_test_ip4() {
     each_ip(&mut |server_ip, client_ip| {
         let (tx1, rx1) = channel();
@@ -69,6 +70,7 @@ fn socket_peer() {
 }
 
 #[test]
+#[cfg_attr(target_os = "wasi", ignore)] // no threads
 fn udp_clone_smoke() {
     each_ip(&mut |addr1, addr2| {
         let sock1 = t!(UdpSocket::bind(&addr1));
@@ -98,6 +100,7 @@ fn udp_clone_smoke() {
 }
 
 #[test]
+#[cfg_attr(target_os = "wasi", ignore)] // no threads
 fn udp_clone_two_read() {
     each_ip(&mut |addr1, addr2| {
         let sock1 = t!(UdpSocket::bind(&addr1));
@@ -130,6 +133,7 @@ fn udp_clone_two_read() {
 }
 
 #[test]
+#[cfg_attr(target_os = "wasi", ignore)] // no threads
 fn udp_clone_two_write() {
     each_ip(&mut |addr1, addr2| {
         let sock1 = t!(UdpSocket::bind(&addr1));
@@ -183,6 +187,7 @@ fn debug() {
     any(target_os = "netbsd", target_os = "openbsd", target_os = "vxworks", target_os = "nto"),
     ignore
 )]
+#[cfg_attr(target_os = "wasi", ignore)] // timeout not supported
 #[test]
 fn timeouts() {
     let addr = next_test_ip4();
@@ -208,6 +213,7 @@ fn timeouts() {
 }
 
 #[test]
+#[cfg_attr(target_os = "wasi", ignore)] // timeout not supported
 fn test_read_timeout() {
     let addr = next_test_ip4();
 
@@ -232,6 +238,7 @@ fn test_read_timeout() {
 }
 
 #[test]
+#[cfg_attr(target_os = "wasi", ignore)] // timeout not supported
 fn test_read_with_timeout() {
     let addr = next_test_ip4();
 
@@ -291,6 +298,7 @@ fn connect_send_recv() {
 }
 
 #[test]
+#[cfg_attr(target_os = "wasi", ignore)] // peek not supported
 fn connect_send_peek_recv() {
     each_ip(&mut |addr, _| {
         let socket = t!(UdpSocket::bind(&addr));
@@ -313,6 +321,7 @@ fn connect_send_peek_recv() {
 }
 
 #[test]
+#[cfg_attr(target_os = "wasi", ignore)] // peek_from not supported
 fn peek_from() {
     each_ip(&mut |addr, _| {
         let socket = t!(UdpSocket::bind(&addr));

library/std/src/path/tests.rs

@@ -139,7 +139,7 @@ fn test_pathbuf_leak() {
 }
 
 #[test]
-#[cfg(unix)]
+#[cfg(any(unix, target_os = "wasi"))]
 pub fn test_decompositions_unix() {
     t!("",
     iter: [],
@@ -1201,7 +1201,10 @@ pub fn test_push() {
         });
     );
 
-    if cfg!(unix) || cfg!(all(target_env = "sgx", target_vendor = "fortanix")) {
+    if cfg!(unix)
+        || cfg!(target_os = "wasi")
+        || cfg!(all(target_env = "sgx", target_vendor = "fortanix"))
+    {
         tp!("", "foo", "foo");
         tp!("foo", "bar", "foo/bar");
         tp!("foo/", "bar", "foo/bar");
@@ -1358,7 +1361,10 @@ pub fn test_set_file_name() {
     tfn!("foo", "bar", "bar");
     tfn!("foo", "", "");
     tfn!("", "foo", "foo");
-    if cfg!(unix) || cfg!(all(target_env = "sgx", target_vendor = "fortanix")) {
+    if cfg!(unix)
+        || cfg!(target_os = "wasi")
+        || cfg!(all(target_env = "sgx", target_vendor = "fortanix"))
+    {
         tfn!(".", "foo", "./foo");
         tfn!("foo/", "bar", "bar");
         tfn!("foo/.", "bar", "bar");
@@ -1758,7 +1764,7 @@ fn test_components_debug() {
     assert_eq!(expected, actual);
 }
 
-#[cfg(unix)]
+#[cfg(any(unix, target_os = "wasi"))]
 #[test]
 fn test_iter_debug() {
     let path = Path::new("/tmp");
@@ -1859,7 +1865,7 @@ fn test_ord() {
 }
 
 #[test]
-#[cfg(unix)]
+#[cfg(any(unix, target_os = "wasi"))]
 fn test_unix_absolute() {
     use crate::path::absolute;
 

library/std/src/process.rs

@@ -148,7 +148,15 @@
 #![stable(feature = "process", since = "1.0.0")]
 #![deny(unsafe_op_in_unsafe_fn)]
 
-#[cfg(all(test, not(any(target_os = "emscripten", target_env = "sgx", target_os = "xous"))))]
+#[cfg(all(
+    test,
+    not(any(
+        target_os = "emscripten",
+        target_os = "wasi",
+        target_env = "sgx",
+        target_os = "xous"
+    ))
+))]
 mod tests;
 
 use crate::convert::Infallible;

library/std/src/sync/barrier/tests.rs

@@ -3,7 +3,7 @@ use crate::sync::{Arc, Barrier};
 use crate::thread;
 
 #[test]
-#[cfg_attr(target_os = "emscripten", ignore)]
+#[cfg_attr(any(target_os = "emscripten", target_os = "wasi"), ignore)] // no threads
 fn test_barrier() {
     const N: usize = 10;
 

library/std/src/sync/condvar/tests.rs

@@ -12,7 +12,7 @@ fn smoke() {
 }
 
 #[test]
-#[cfg_attr(target_os = "emscripten", ignore)]
+#[cfg_attr(any(target_os = "emscripten", target_os = "wasi"), ignore)] // no threads
 fn notify_one() {
     let m = Arc::new(Mutex::new(()));
     let m2 = m.clone();
@@ -29,7 +29,7 @@ fn notify_one() {
 }
 
 #[test]
-#[cfg_attr(target_os = "emscripten", ignore)]
+#[cfg_attr(any(target_os = "emscripten", target_os = "wasi"), ignore)] // no threads
 fn notify_all() {
     const N: usize = 10;
 
@@ -66,7 +66,7 @@ fn notify_all() {
 }
 
 #[test]
-#[cfg_attr(target_os = "emscripten", ignore)]
+#[cfg_attr(any(target_os = "emscripten", target_os = "wasi"), ignore)] // no threads
 fn wait_while() {
     let pair = Arc::new((Mutex::new(false), Condvar::new()));
     let pair2 = pair.clone();
@@ -87,7 +87,7 @@ fn wait_while() {
 }
 
 #[test]
-#[cfg_attr(target_os = "emscripten", ignore)]
+#[cfg_attr(any(target_os = "emscripten", target_os = "wasi"), ignore)] // condvar wait not supported
 fn wait_timeout_wait() {
     let m = Arc::new(Mutex::new(()));
     let c = Arc::new(Condvar::new());
@@ -106,7 +106,7 @@ fn wait_timeout_wait() {
 }
 
 #[test]
-#[cfg_attr(target_os = "emscripten", ignore)]
+#[cfg_attr(any(target_os = "emscripten", target_os = "wasi"), ignore)] // condvar wait not supported
 fn wait_timeout_while_wait() {
     let m = Arc::new(Mutex::new(()));
     let c = Arc::new(Condvar::new());
@@ -118,7 +118,7 @@ fn wait_timeout_while_wait() {
 }
 
 #[test]
-#[cfg_attr(target_os = "emscripten", ignore)]
+#[cfg_attr(any(target_os = "emscripten", target_os = "wasi"), ignore)] // condvar wait not supported
 fn wait_timeout_while_instant_satisfy() {
     let m = Arc::new(Mutex::new(()));
     let c = Arc::new(Condvar::new());
@@ -130,7 +130,7 @@ fn wait_timeout_while_instant_satisfy() {
 }
 
 #[test]
-#[cfg_attr(target_os = "emscripten", ignore)]
+#[cfg_attr(any(target_os = "emscripten", target_os = "wasi"), ignore)] // no threads
 fn wait_timeout_while_wake() {
     let pair = Arc::new((Mutex::new(false), Condvar::new()));
     let pair_copy = pair.clone();
@@ -153,7 +153,7 @@ fn wait_timeout_while_wake() {
 }
 
 #[test]
-#[cfg_attr(target_os = "emscripten", ignore)]
+#[cfg_attr(any(target_os = "emscripten", target_os = "wasi"), ignore)] // no threads
 fn wait_timeout_wake() {
     let m = Arc::new(Mutex::new(()));
     let c = Arc::new(Condvar::new());

library/std/src/sync/lazy_lock/tests.rs

@@ -34,6 +34,7 @@ fn lazy_default() {
 }
 
 #[test]
+#[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")]
 fn lazy_poisoning() {
     let x: LazyCell<String> = LazyCell::new(|| panic!("kaboom"));
     for _ in 0..2 {
@@ -43,7 +44,7 @@ fn lazy_poisoning() {
 }
 
 #[test]
-#[cfg_attr(target_os = "emscripten", ignore)]
+#[cfg_attr(any(target_os = "emscripten", target_os = "wasi"), ignore)] // no threads
 fn sync_lazy_new() {
     static CALLED: AtomicUsize = AtomicUsize::new(0);
     static SYNC_LAZY: LazyLock<i32> = LazyLock::new(|| {
@@ -90,7 +91,7 @@ fn sync_lazy_default() {
 }
 
 #[test]
-#[cfg_attr(target_os = "emscripten", ignore)]
+#[cfg_attr(any(target_os = "emscripten", target_os = "wasi"), ignore)] // no threads
 fn static_sync_lazy() {
     static XS: LazyLock<Vec<i32>> = LazyLock::new(|| {
         let mut xs = Vec::new();
@@ -123,6 +124,7 @@ fn static_sync_lazy_via_fn() {
 }
 
 #[test]
+#[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")]
 fn sync_lazy_poisoning() {
     let x: LazyLock<String> = LazyLock::new(|| panic!("kaboom"));
     for _ in 0..2 {

library/std/src/sync/mpsc/mod.rs

@@ -137,10 +137,10 @@
 
 #![stable(feature = "rust1", since = "1.0.0")]
 
-#[cfg(all(test, not(target_os = "emscripten")))]
+#[cfg(all(test, not(any(target_os = "emscripten", target_os = "wasi"))))]
 mod tests;
 
-#[cfg(all(test, not(target_os = "emscripten")))]
+#[cfg(all(test, not(any(target_os = "emscripten", target_os = "wasi"))))]
 mod sync_tests;
 
 // MPSC channels are built as a wrapper around MPMC channels, which

library/std/src/sync/mutex.rs

@@ -1,4 +1,4 @@
-#[cfg(all(test, not(target_os = "emscripten")))]
+#[cfg(all(test, not(any(target_os = "emscripten", target_os = "wasi"))))]
 mod tests;
 
 use crate::cell::UnsafeCell;

library/std/src/sync/once.rs

@@ -3,7 +3,7 @@
 //! This primitive is meant to be used to run one-time initialization. An
 //! example use case would be for initializing an FFI library.
 
-#[cfg(all(test, not(target_os = "emscripten")))]
+#[cfg(all(test, not(any(target_os = "emscripten", target_os = "wasi"))))]
 mod tests;
 
 use crate::fmt;

library/std/src/sync/once_lock/tests.rs

@@ -9,7 +9,7 @@ fn spawn_and_wait<R: Send + 'static>(f: impl FnOnce() -> R + Send + 'static) ->
 }
 
 #[test]
-#[cfg_attr(target_os = "emscripten", ignore)]
+#[cfg_attr(any(target_os = "emscripten", target_os = "wasi"), ignore)] // no threads
 fn sync_once_cell() {
     static ONCE_CELL: OnceLock<i32> = OnceLock::new();
 
@@ -43,7 +43,7 @@ fn sync_once_cell_get_unchecked() {
 }
 
 #[test]
-#[cfg_attr(target_os = "emscripten", ignore)]
+#[cfg_attr(any(target_os = "emscripten", target_os = "wasi"), ignore)] // no threads
 fn sync_once_cell_drop() {
     static DROP_CNT: AtomicUsize = AtomicUsize::new(0);
     struct Dropper;
@@ -81,6 +81,7 @@ fn clone() {
 }
 
 #[test]
+#[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")]
 fn get_or_try_init() {
     let cell: OnceLock<String> = OnceLock::new();
     assert!(cell.get().is_none());
@@ -154,7 +155,7 @@ fn eval_once_macro() {
 }
 
 #[test]
-#[cfg_attr(target_os = "emscripten", ignore)]
+#[cfg_attr(any(target_os = "emscripten", target_os = "wasi"), ignore)] // no threads
 fn sync_once_cell_does_not_leak_partially_constructed_boxes() {
     static ONCE_CELL: OnceLock<String> = OnceLock::new();
 

library/std/src/sync/reentrant_lock.rs

@@ -1,4 +1,4 @@
-#[cfg(all(test, not(target_os = "emscripten")))]
+#[cfg(all(test, not(any(target_os = "emscripten", target_os = "wasi"))))]
 mod tests;
 
 use cfg_if::cfg_if;

library/std/src/sync/rwlock.rs

@@ -1,4 +1,4 @@
-#[cfg(all(test, not(target_os = "emscripten")))]
+#[cfg(all(test, not(any(target_os = "emscripten", target_os = "wasi"))))]
 mod tests;
 
 use crate::cell::UnsafeCell;

library/std/src/sys/pal/wasip2/mod.rs

@@ -20,7 +20,6 @@ pub mod futex;
 #[path = "../wasi/io.rs"]
 pub mod io;
 
-#[path = "../wasi/net.rs"]
 pub mod net;
 #[path = "../wasi/os.rs"]
 pub mod os;

library/std/src/sys/pal/wasip2/net.rs

@@ -0,0 +1,379 @@
+#![deny(unsafe_op_in_unsafe_fn)]
+
+use libc::{c_int, c_void, size_t};
+
+use super::fd::WasiFd;
+use crate::ffi::CStr;
+use crate::io::{self, BorrowedBuf, BorrowedCursor, IoSlice, IoSliceMut};
+use crate::net::{Shutdown, SocketAddr};
+use crate::os::wasi::io::{AsFd, AsRawFd, BorrowedFd, FromRawFd, IntoRawFd, RawFd};
+use crate::sys::unsupported;
+use crate::sys_common::net::{TcpListener, getsockopt, setsockopt, sockaddr_to_addr};
+use crate::sys_common::{AsInner, FromInner, IntoInner};
+use crate::time::{Duration, Instant};
+use crate::{cmp, mem, str};
+
+pub extern crate libc as netc;
+
+#[allow(non_camel_case_types)]
+pub type wrlen_t = size_t;
+
+#[doc(hidden)]
+pub trait IsMinusOne {
+    fn is_minus_one(&self) -> bool;
+}
+
+macro_rules! impl_is_minus_one {
+    ($($t:ident)*) => ($(impl IsMinusOne for $t {
+        fn is_minus_one(&self) -> bool {
+            *self == -1
+        }
+    })*)
+}
+
+impl_is_minus_one! { i8 i16 i32 i64 isize }
+
+pub fn cvt<T: IsMinusOne>(t: T) -> crate::io::Result<T> {
+    if t.is_minus_one() { Err(crate::io::Error::last_os_error()) } else { Ok(t) }
+}
+
+pub fn cvt_r<T, F>(mut f: F) -> crate::io::Result<T>
+where
+    T: IsMinusOne,
+    F: FnMut() -> T,
+{
+    loop {
+        match cvt(f()) {
+            Err(ref e) if e.is_interrupted() => {}
+            other => return other,
+        }
+    }
+}
+
+pub fn cvt_gai(err: c_int) -> io::Result<()> {
+    if err == 0 {
+        return Ok(());
+    }
+
+    if err == netc::EAI_SYSTEM {
+        return Err(io::Error::last_os_error());
+    }
+
+    let detail = unsafe {
+        str::from_utf8(CStr::from_ptr(netc::gai_strerror(err)).to_bytes()).unwrap().to_owned()
+    };
+
+    Err(io::Error::new(
+        io::ErrorKind::Uncategorized,
+        &format!("failed to lookup address information: {detail}")[..],
+    ))
+}
+
+pub fn init() {}
+
+pub struct Socket(WasiFd);
+
+impl Socket {
+    pub fn new(addr: &SocketAddr, ty: c_int) -> io::Result<Socket> {
+        let fam = match *addr {
+            SocketAddr::V4(..) => netc::AF_INET,
+            SocketAddr::V6(..) => netc::AF_INET6,
+        };
+        Socket::new_raw(fam, ty)
+    }
+
+    pub fn new_raw(fam: c_int, ty: c_int) -> io::Result<Socket> {
+        let fd = cvt(unsafe { netc::socket(fam, ty, 0) })?;
+        Ok(unsafe { Self::from_raw_fd(fd) })
+    }
+
+    pub fn connect(&self, addr: &SocketAddr) -> io::Result<()> {
+        let (addr, len) = addr.into_inner();
+        cvt_r(|| unsafe { netc::connect(self.as_raw_fd(), addr.as_ptr(), len) })?;
+        Ok(())
+    }
+
+    pub fn connect_timeout(&self, addr: &SocketAddr, timeout: Duration) -> io::Result<()> {
+        self.set_nonblocking(true)?;
+        let r = self.connect(addr);
+        self.set_nonblocking(false)?;
+
+        match r {
+            Ok(_) => return Ok(()),
+            // there's no ErrorKind for EINPROGRESS
+            Err(ref e) if e.raw_os_error() == Some(netc::EINPROGRESS) => {}
+            Err(e) => return Err(e),
+        }
+
+        let mut pollfd = netc::pollfd { fd: self.as_raw_fd(), events: netc::POLLOUT, revents: 0 };
+
+        if timeout.as_secs() == 0 && timeout.subsec_nanos() == 0 {
+            return Err(io::Error::ZERO_TIMEOUT);
+        }
+
+        let start = Instant::now();
+
+        loop {
+            let elapsed = start.elapsed();
+            if elapsed >= timeout {
+                return Err(io::const_io_error!(io::ErrorKind::TimedOut, "connection timed out"));
+            }
+
+            let timeout = timeout - elapsed;
+            let mut timeout = timeout
+                .as_secs()
+                .saturating_mul(1_000)
+                .saturating_add(timeout.subsec_nanos() as u64 / 1_000_000);
+            if timeout == 0 {
+                timeout = 1;
+            }
+
+            let timeout = cmp::min(timeout, c_int::MAX as u64) as c_int;
+
+            match unsafe { netc::poll(&mut pollfd, 1, timeout) } {
+                -1 => {
+                    let err = io::Error::last_os_error();
+                    if !err.is_interrupted() {
+                        return Err(err);
+                    }
+                }
+                0 => {}
+                _ => {
+                    // WASI poll does not return  POLLHUP or POLLERR in revents. Check if the
+                    // connnection actually succeeded and return ok only when the socket is
+                    // ready and no errors were found.
+                    if let Some(e) = self.take_error()? {
+                        return Err(e);
+                    }
+
+                    return Ok(());
+                }
+            }
+        }
+    }
+
+    pub fn accept(
+        &self,
+        storage: *mut netc::sockaddr,
+        len: *mut netc::socklen_t,
+    ) -> io::Result<Socket> {
+        let fd = cvt_r(|| unsafe { netc::accept(self.as_raw_fd(), storage, len) })?;
+        Ok(unsafe { Self::from_raw_fd(fd) })
+    }
+
+    pub fn duplicate(&self) -> io::Result<Socket> {
+        unsupported()
+    }
+
+    fn recv_with_flags(&self, mut buf: BorrowedCursor<'_>, flags: c_int) -> io::Result<()> {
+        let ret = cvt(unsafe {
+            netc::recv(
+                self.as_raw_fd(),
+                buf.as_mut().as_mut_ptr() as *mut c_void,
+                buf.capacity(),
+                flags,
+            )
+        })?;
+        unsafe {
+            buf.advance_unchecked(ret as usize);
+        }
+        Ok(())
+    }
+
+    pub fn read(&self, buf: &mut [u8]) -> io::Result<usize> {
+        let mut buf = BorrowedBuf::from(buf);
+        self.recv_with_flags(buf.unfilled(), 0)?;
+        Ok(buf.len())
+    }
+
+    pub fn peek(&self, buf: &mut [u8]) -> io::Result<usize> {
+        let mut buf = BorrowedBuf::from(buf);
+        self.recv_with_flags(buf.unfilled(), netc::MSG_PEEK)?;
+        Ok(buf.len())
+    }
+
+    pub fn read_buf(&self, buf: BorrowedCursor<'_>) -> io::Result<()> {
+        self.recv_with_flags(buf, 0)
+    }
+
+    pub fn read_vectored(&self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
+        io::default_read_vectored(|b| self.read(b), bufs)
+    }
+
+    #[inline]
+    pub fn is_read_vectored(&self) -> bool {
+        false
+    }
+
+    fn recv_from_with_flags(
+        &self,
+        buf: &mut [u8],
+        flags: c_int,
+    ) -> io::Result<(usize, SocketAddr)> {
+        let mut storage: netc::sockaddr_storage = unsafe { mem::zeroed() };
+        let mut addrlen = mem::size_of_val(&storage) as netc::socklen_t;
+
+        let n = cvt(unsafe {
+            netc::recvfrom(
+                self.as_raw_fd(),
+                buf.as_mut_ptr() as *mut c_void,
+                buf.len(),
+                flags,
+                core::ptr::addr_of_mut!(storage) as *mut _,
+                &mut addrlen,
+            )
+        })?;
+        Ok((n as usize, sockaddr_to_addr(&storage, addrlen as usize)?))
+    }
+
+    pub fn recv_from(&self, buf: &mut [u8]) -> io::Result<(usize, SocketAddr)> {
+        self.recv_from_with_flags(buf, 0)
+    }
+
+    pub fn peek_from(&self, buf: &mut [u8]) -> io::Result<(usize, SocketAddr)> {
+        self.recv_from_with_flags(buf, netc::MSG_PEEK)
+    }
+
+    fn write(&self, buf: &[u8]) -> io::Result<usize> {
+        let len = cmp::min(buf.len(), <wrlen_t>::MAX as usize) as wrlen_t;
+        let ret = cvt(unsafe {
+            netc::send(self.as_raw(), buf.as_ptr() as *const c_void, len, netc::MSG_NOSIGNAL)
+        })?;
+        Ok(ret as usize)
+    }
+
+    pub fn write_vectored(&self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
+        io::default_write_vectored(|b| self.write(b), bufs)
+    }
+
+    #[inline]
+    pub fn is_write_vectored(&self) -> bool {
+        false
+    }
+
+    pub fn set_timeout(&self, dur: Option<Duration>, kind: c_int) -> io::Result<()> {
+        let timeout = match dur {
+            Some(dur) => {
+                if dur.as_secs() == 0 && dur.subsec_nanos() == 0 {
+                    return Err(io::Error::ZERO_TIMEOUT);
+                }
+
+                let secs = dur.as_secs().try_into().unwrap_or(netc::time_t::MAX);
+                let mut timeout = netc::timeval {
+                    tv_sec: secs,
+                    tv_usec: dur.subsec_micros() as netc::suseconds_t,
+                };
+                if timeout.tv_sec == 0 && timeout.tv_usec == 0 {
+                    timeout.tv_usec = 1;
+                }
+                timeout
+            }
+            None => netc::timeval { tv_sec: 0, tv_usec: 0 },
+        };
+        setsockopt(self, netc::SOL_SOCKET, kind, timeout)
+    }
+
+    pub fn timeout(&self, kind: c_int) -> io::Result<Option<Duration>> {
+        let raw: netc::timeval = getsockopt(self, netc::SOL_SOCKET, kind)?;
+        if raw.tv_sec == 0 && raw.tv_usec == 0 {
+            Ok(None)
+        } else {
+            let sec = raw.tv_sec as u64;
+            let nsec = (raw.tv_usec as u32) * 1000;
+            Ok(Some(Duration::new(sec, nsec)))
+        }
+    }
+
+    pub fn shutdown(&self, how: Shutdown) -> io::Result<()> {
+        let how = match how {
+            Shutdown::Write => netc::SHUT_WR,
+            Shutdown::Read => netc::SHUT_RD,
+            Shutdown::Both => netc::SHUT_RDWR,
+        };
+        cvt(unsafe { netc::shutdown(self.as_raw_fd(), how) })?;
+        Ok(())
+    }
+
+    pub fn set_linger(&self, _linger: Option<Duration>) -> io::Result<()> {
+        unsupported()
+    }
+
+    pub fn linger(&self) -> io::Result<Option<Duration>> {
+        unsupported()
+    }
+
+    pub fn set_nodelay(&self, nodelay: bool) -> io::Result<()> {
+        setsockopt(self, netc::IPPROTO_TCP, netc::TCP_NODELAY, nodelay as c_int)
+    }
+
+    pub fn nodelay(&self) -> io::Result<bool> {
+        let raw: c_int = getsockopt(self, netc::IPPROTO_TCP, netc::TCP_NODELAY)?;
+        Ok(raw != 0)
+    }
+
+    pub fn set_nonblocking(&self, nonblocking: bool) -> io::Result<()> {
+        let mut nonblocking = nonblocking as c_int;
+        cvt(unsafe { netc::ioctl(self.as_raw_fd(), netc::FIONBIO, &mut nonblocking) }).map(drop)
+    }
+
+    pub fn take_error(&self) -> io::Result<Option<io::Error>> {
+        let raw: c_int = getsockopt(self, netc::SOL_SOCKET, netc::SO_ERROR)?;
+        if raw == 0 { Ok(None) } else { Ok(Some(io::Error::from_raw_os_error(raw as i32))) }
+    }
+
+    // This is used by sys_common code to abstract over Windows and Unix.
+    pub fn as_raw(&self) -> RawFd {
+        self.as_raw_fd()
+    }
+}
+
+impl AsInner<WasiFd> for Socket {
+    #[inline]
+    fn as_inner(&self) -> &WasiFd {
+        &self.0
+    }
+}
+
+impl IntoInner<WasiFd> for Socket {
+    fn into_inner(self) -> WasiFd {
+        self.0
+    }
+}
+
+impl FromInner<WasiFd> for Socket {
+    fn from_inner(inner: WasiFd) -> Socket {
+        Socket(inner)
+    }
+}
+
+impl AsFd for Socket {
+    fn as_fd(&self) -> BorrowedFd<'_> {
+        self.0.as_fd()
+    }
+}
+
+impl AsRawFd for Socket {
+    #[inline]
+    fn as_raw_fd(&self) -> RawFd {
+        self.0.as_raw_fd()
+    }
+}
+
+impl IntoRawFd for Socket {
+    fn into_raw_fd(self) -> RawFd {
+        self.0.into_raw_fd()
+    }
+}
+
+impl FromRawFd for Socket {
+    unsafe fn from_raw_fd(raw_fd: RawFd) -> Self {
+        unsafe { Self(FromRawFd::from_raw_fd(raw_fd)) }
+    }
+}
+
+impl AsInner<Socket> for TcpListener {
+    #[inline]
+    fn as_inner(&self) -> &Socket {
+        &self.socket()
+    }
+}

library/std/src/sys_common/io.rs

@@ -3,7 +3,7 @@
 pub const DEFAULT_BUF_SIZE: usize = if cfg!(target_os = "espidf") { 512 } else { 8 * 1024 };
 
 #[cfg(test)]
-#[allow(dead_code)] // not used on emscripten
+#[allow(dead_code)] // not used on emscripten and wasi
 pub mod test {
     use rand::RngCore;
 

library/std/src/sys_common/mod.rs

@@ -32,7 +32,8 @@ cfg_if::cfg_if! {
         all(unix, not(target_os = "l4re")),
         windows,
         target_os = "hermit",
-        target_os = "solid_asp3"
+        target_os = "solid_asp3",
+        all(target_os = "wasi", target_env = "p2")
     ))] {
         pub mod net;
     } else {

library/std/src/thread/local.rs

@@ -2,7 +2,7 @@
 
 #![unstable(feature = "thread_local_internals", issue = "none")]
 
-#[cfg(all(test, not(target_os = "emscripten")))]
+#[cfg(all(test, not(any(target_os = "emscripten", target_os = "wasi"))))]
 mod tests;
 
 #[cfg(test)]

library/std/src/thread/mod.rs

@@ -155,7 +155,7 @@
 // Under `test`, `__FastLocalKeyInner` seems unused.
 #![cfg_attr(test, allow(dead_code))]
 
-#[cfg(all(test, not(target_os = "emscripten")))]
+#[cfg(all(test, not(any(target_os = "emscripten", target_os = "wasi"))))]
 mod tests;
 
 use crate::any::Any;

library/std/tests/create_dir_all_bare.rs

@@ -1,4 +1,4 @@
-#![cfg(all(test, not(any(target_os = "emscripten", target_env = "sgx"))))]
+#![cfg(all(test, not(any(target_os = "emscripten", target_os = "wasi", target_env = "sgx"))))]
 
 //! Note that this test changes the current directory so
 //! should not be in the same process as other tests.

library/std/tests/process_spawning.rs

@@ -5,7 +5,7 @@ use std::{env, fs, process, str};
 mod common;
 
 #[test]
-#[cfg_attr(miri, ignore)] // Process spawning not supported by Miri
+#[cfg_attr(any(miri, target_os = "wasi"), ignore)] // Process spawning not supported by Miri and wasi
 fn issue_15149() {
     // If we're the parent, copy our own binary to a new directory.
     let my_path = env::current_exe().unwrap();

library/std/tests/thread.rs

@@ -4,7 +4,7 @@ use std::thread;
 use std::time::Duration;
 
 #[test]
-#[cfg_attr(target_os = "emscripten", ignore)]
+#[cfg_attr(any(target_os = "emscripten", target_os = "wasi"), ignore)] // no threads
 #[cfg_attr(miri, ignore)] // Miri does not like the thread leak
 fn sleep_very_long() {
     let finished = Arc::new(Mutex::new(false));

src/bootstrap/src/lib.rs

@@ -1370,7 +1370,7 @@ Executed at: {executed_at}"#,
         }
 
         if target.starts_with("wasm") && target.contains("wasi") {
-            self.default_wasi_runner()
+            self.default_wasi_runner(target)
         } else {
             None
         }
@@ -1379,7 +1379,7 @@ Executed at: {executed_at}"#,
     /// When a `runner` configuration is not provided and a WASI-looking target
     /// is being tested this is consulted to prove the environment to see if
     /// there's a runtime already lying around that seems reasonable to use.
-    fn default_wasi_runner(&self) -> Option<String> {
+    fn default_wasi_runner(&self, target: TargetSelection) -> Option<String> {
         let mut finder = crate::core::sanity::Finder::new();
 
         // Look for Wasmtime, and for its default options be sure to disable
@@ -1395,6 +1395,11 @@ Executed at: {executed_at}"#,
                 // inherit the entire environment rather than just this single
                 // environment variable.
                 path.push_str(" --env RUSTC_BOOTSTRAP");
+
+                if target.contains("wasip2") {
+                    path.push_str(" --wasi inherit-network --wasi allow-ip-name-lookup");
+                }
+
                 return Some(path);
             }
         }

tests/ui/check-cfg/mix.stderr

@@ -251,7 +251,7 @@ warning: unexpected `cfg` condition value: `zebra`
 LL |     cfg!(target_feature = "zebra");
    |          ^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: expected values for `target_feature` are: `10e60`, `2e3`, `3e3r1`, `3e3r2`, `3e3r3`, `3e7`, `7e10`, `a`, `aclass`, `adx`, `aes`, `altivec`, `alu32`, `amx-bf16`, `amx-complex`, `amx-fp16`, `amx-int8`, `amx-tile`, `atomics`, `avx`, `avx2`, `avx512bf16`, `avx512bitalg`, `avx512bw`, `avx512cd`, `avx512dq`, `avx512f`, `avx512fp16`, `avx512ifma`, `avx512vbmi`, `avx512vbmi2`, `avx512vl`, `avx512vnni`, `avx512vp2intersect`, and `avx512vpopcntdq` and 241 more
+   = note: expected values for `target_feature` are: `10e60`, `2e3`, `3e3r1`, `3e3r2`, `3e3r3`, `3e7`, `7e10`, `a`, `aclass`, `adx`, `aes`, `altivec`, `alu32`, `amx-bf16`, `amx-complex`, `amx-fp16`, `amx-int8`, `amx-tile`, `atomics`, `avx`, `avx2`, `avx512bf16`, `avx512bitalg`, `avx512bw`, `avx512cd`, `avx512dq`, `avx512f`, `avx512fp16`, `avx512ifma`, `avx512vbmi`, `avx512vbmi2`, `avx512vl`, `avx512vnni`, `avx512vp2intersect`, and `avx512vpopcntdq` and 244 more
    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
 
 warning: 27 warnings emitted

tests/ui/check-cfg/well-known-values.stderr

@@ -174,7 +174,7 @@ warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
 LL |     target_feature = "_UNEXPECTED_VALUE",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: expected values for `target_feature` are: `10e60`, `2e3`, `3e3r1`, `3e3r2`, `3e3r3`, `3e7`, `7e10`, `a`, `aclass`, `adx`, `aes`, `altivec`, `alu32`, `amx-bf16`, `amx-complex`, `amx-fp16`, `amx-int8`, `amx-tile`, `atomics`, `avx`, `avx2`, `avx512bf16`, `avx512bitalg`, `avx512bw`, `avx512cd`, `avx512dq`, `avx512f`, `avx512fp16`, `avx512ifma`, `avx512vbmi`, `avx512vbmi2`, `avx512vl`, `avx512vnni`, `avx512vp2intersect`, `avx512vpopcntdq`, `avxifma`, `avxneconvert`, `avxvnni`, `avxvnniint16`, `avxvnniint8`, `backchain`, `bf16`, `bmi1`, `bmi2`, `bti`, `bulk-memory`, `c`, `cache`, `cmpxchg16b`, `crc`, `crt-static`, `cssc`, `d`, `d32`, `dit`, `doloop`, `dotprod`, `dpb`, `dpb2`, `dsp`, `dsp1e2`, `dspe60`, `e`, `e1`, `e2`, `ecv`, `edsp`, `elrw`, `ermsb`, `exception-handling`, `extended-const`, `f`, `f16c`, `f32mm`, `f64mm`, `faminmax`, `fcma`, `fdivdu`, `fhm`, `flagm`, `flagm2`, `float1e2`, `float1e3`, `float3e4`, `float7e60`, `floate1`, `fma`, `fp-armv8`, `fp16`, `fp64`, `fp8`, `fp8dot2`, `fp8dot4`, `fp8fma`, `fpuv2_df`, `fpuv2_sf`, `fpuv3_df`, `fpuv3_hf`, `fpuv3_hi`, `fpuv3_sf`, `frecipe`, `frintts`, `fxsr`, `gfni`, `hard-float`, `hard-float-abi`, `hard-tp`, `hbc`, `high-registers`, `hvx`, `hvx-length128b`, `hwdiv`, `i8mm`, `jsconv`, `lahfsahf`, `lasx`, `lbt`, `lor`, `lse`, `lse128`, `lse2`, `lsx`, `lut`, `lvz`, `lzcnt`, `m`, `mclass`, `mops`, `movbe`, `mp`, `mp1e2`, `msa`, `mte`, `multivalue`, `mutable-globals`, `neon`, `nontrapping-fptoint`, `nvic`, `paca`, `pacg`, `pan`, `partword-atomics`, `pclmulqdq`, `pmuv3`, `popcnt`, `power10-vector`, `power8-altivec`, `power8-vector`, `power9-altivec`, `power9-vector`, `prfchw`, `quadword-atomics`, `rand`, `ras`, `rclass`, `rcpc`, `rcpc2`, `rcpc3`, `rdm`, `rdrand`, `rdseed`, `reference-types`, `relax`, `relaxed-simd`, `rtm`, `sb`, `sha`, `sha2`, `sha3`, `sha512`, `sign-ext`, `simd128`, `sm3`, `sm4`, `sme`, `sme-f16f16`, `sme-f64f64`, `sme-f8f16`, `sme-f8f32`, `sme-fa64`, `sme-i16i64`, `sme-lutv2`, `sme2`, `sme2p1`, `spe`, `ssbs`, `sse`, `sse2`, `sse3`, `sse4.1`, `sse4.2`, `sse4a`, `ssse3`, `ssve-fp8dot2`, `ssve-fp8dot4`, `ssve-fp8fma`, `sve`, `sve-b16b16`, `sve2`, `sve2-aes`, `sve2-bitperm`, `sve2-sha3`, `sve2-sm4`, `sve2p1`, `tbm`, `thumb-mode`, `thumb2`, `tme`, `trust`, `trustzone`, `ual`, `unaligned-scalar-mem`, `v`, `v5te`, `v6`, `v6k`, `v6t2`, `v7`, `v8`, `v8.1a`, `v8.2a`, `v8.3a`, `v8.4a`, `v8.5a`, `v8.6a`, `v8.7a`, `v8.8a`, `v8.9a`, `v9.1a`, `v9.2a`, `v9.3a`, `v9.4a`, `v9.5a`, `v9a`, `vaes`, `vdsp2e60f`, `vdspv1`, `vdspv2`, `vector`, `vfp2`, `vfp3`, `vfp4`, `vh`, `virt`, `virtualization`, `vpclmulqdq`, `vsx`, `wfxt`, `xop`, `xsave`, `xsavec`, `xsaveopt`, `xsaves`, `zba`, `zbb`, `zbc`, `zbkb`, `zbkc`, `zbkx`, `zbs`, `zdinx`, `zfh`, `zfhmin`, `zfinx`, `zhinx`, `zhinxmin`, `zk`, `zkn`, `zknd`, `zkne`, `zknh`, `zkr`, `zks`, `zksed`, `zksh`, and `zkt`
+   = note: expected values for `target_feature` are: `10e60`, `2e3`, `3e3r1`, `3e3r2`, `3e3r3`, `3e7`, `7e10`, `a`, `aclass`, `adx`, `aes`, `altivec`, `alu32`, `amx-bf16`, `amx-complex`, `amx-fp16`, `amx-int8`, `amx-tile`, `atomics`, `avx`, `avx2`, `avx512bf16`, `avx512bitalg`, `avx512bw`, `avx512cd`, `avx512dq`, `avx512f`, `avx512fp16`, `avx512ifma`, `avx512vbmi`, `avx512vbmi2`, `avx512vl`, `avx512vnni`, `avx512vp2intersect`, `avx512vpopcntdq`, `avxifma`, `avxneconvert`, `avxvnni`, `avxvnniint16`, `avxvnniint8`, `backchain`, `bf16`, `bmi1`, `bmi2`, `bti`, `bulk-memory`, `c`, `cache`, `cmpxchg16b`, `crc`, `crt-static`, `cssc`, `d`, `d32`, `dit`, `doloop`, `dotprod`, `dpb`, `dpb2`, `dsp`, `dsp1e2`, `dspe60`, `e`, `e1`, `e2`, `ecv`, `edsp`, `elrw`, `ermsb`, `exception-handling`, `extended-const`, `f`, `f16c`, `f32mm`, `f64mm`, `faminmax`, `fcma`, `fdivdu`, `fhm`, `flagm`, `flagm2`, `float1e2`, `float1e3`, `float3e4`, `float7e60`, `floate1`, `fma`, `fp-armv8`, `fp16`, `fp64`, `fp8`, `fp8dot2`, `fp8dot4`, `fp8fma`, `fpuv2_df`, `fpuv2_sf`, `fpuv3_df`, `fpuv3_hf`, `fpuv3_hi`, `fpuv3_sf`, `frecipe`, `frintts`, `fxsr`, `gfni`, `hard-float`, `hard-float-abi`, `hard-tp`, `hbc`, `high-registers`, `hvx`, `hvx-length128b`, `hwdiv`, `i8mm`, `jsconv`, `lahfsahf`, `lasx`, `lbt`, `lor`, `lse`, `lse128`, `lse2`, `lsx`, `lut`, `lvz`, `lzcnt`, `m`, `mclass`, `mops`, `movbe`, `mp`, `mp1e2`, `msa`, `mte`, `multivalue`, `mutable-globals`, `neon`, `nontrapping-fptoint`, `nvic`, `paca`, `pacg`, `pan`, `partword-atomics`, `pclmulqdq`, `pmuv3`, `popcnt`, `power10-vector`, `power8-altivec`, `power8-vector`, `power9-altivec`, `power9-vector`, `prfchw`, `quadword-atomics`, `rand`, `ras`, `rclass`, `rcpc`, `rcpc2`, `rcpc3`, `rdm`, `rdrand`, `rdseed`, `reference-types`, `relax`, `relaxed-simd`, `rtm`, `sb`, `sha`, `sha2`, `sha3`, `sha512`, `sign-ext`, `simd128`, `sm3`, `sm4`, `sme`, `sme-f16f16`, `sme-f64f64`, `sme-f8f16`, `sme-f8f32`, `sme-fa64`, `sme-i16i64`, `sme-lutv2`, `sme2`, `sme2p1`, `spe`, `ssbs`, `sse`, `sse2`, `sse3`, `sse4.1`, `sse4.2`, `sse4a`, `ssse3`, `ssve-fp8dot2`, `ssve-fp8dot4`, `ssve-fp8fma`, `sve`, `sve-b16b16`, `sve2`, `sve2-aes`, `sve2-bitperm`, `sve2-sha3`, `sve2-sm4`, `sve2p1`, `tbm`, `thumb-mode`, `thumb2`, `tme`, `trust`, `trustzone`, `ual`, `unaligned-scalar-mem`, `v`, `v5te`, `v6`, `v6k`, `v6t2`, `v7`, `v8`, `v8.1a`, `v8.2a`, `v8.3a`, `v8.4a`, `v8.5a`, `v8.6a`, `v8.7a`, `v8.8a`, `v8.9a`, `v9.1a`, `v9.2a`, `v9.3a`, `v9.4a`, `v9.5a`, `v9a`, `vaes`, `vdsp2e60f`, `vdspv1`, `vdspv2`, `vector`, `vfp2`, `vfp3`, `vfp4`, `vh`, `virt`, `virtualization`, `vpclmulqdq`, `vsx`, `wfxt`, `xop`, `xsave`, `xsavec`, `xsaveopt`, `xsaves`, `zaamo`, `zabha`, `zalrsc`, `zba`, `zbb`, `zbc`, `zbkb`, `zbkc`, `zbkx`, `zbs`, `zdinx`, `zfh`, `zfhmin`, `zfinx`, `zhinx`, `zhinxmin`, `zk`, `zkn`, `zknd`, `zkne`, `zknh`, `zkr`, `zks`, `zksed`, `zksh`, and `zkt`
    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`

tests/ui/consts/auxiliary/unstable_but_const_stable.rs

@@ -0,0 +1,13 @@
+#![feature(staged_api, rustc_attrs, intrinsics)]
+#![stable(since="1.0.0", feature = "stable")]
+
+extern "rust-intrinsic" {
+    #[unstable(feature = "unstable", issue = "42")]
+    #[rustc_const_stable(feature = "stable", since = "1.0.0")]
+    #[rustc_nounwind]
+    pub fn write_bytes<T>(dst: *mut T, val: u8, count: usize);
+}
+
+#[unstable(feature = "unstable", issue = "42")]
+#[rustc_const_stable(feature = "stable", since = "1.0.0")]
+pub const fn some_unstable_fn() {}

tests/ui/consts/unstable-const-stable.rs

@@ -0,0 +1,14 @@
+//@ aux-build:unstable_but_const_stable.rs
+
+extern crate unstable_but_const_stable;
+use unstable_but_const_stable::*;
+
+fn main() {
+    some_unstable_fn(); //~ERROR use of unstable library feature
+    unsafe { write_bytes(4 as *mut u8, 0, 0) }; //~ERROR use of unstable library feature
+}
+
+const fn const_main() {
+    some_unstable_fn(); //~ERROR use of unstable library feature
+    unsafe { write_bytes(4 as *mut u8, 0, 0) }; //~ERROR use of unstable library feature
+}

tests/ui/consts/unstable-const-stable.stderr

@@ -0,0 +1,43 @@
+error[E0658]: use of unstable library feature 'unstable'
+  --> $DIR/unstable-const-stable.rs:7:5
+   |
+LL |     some_unstable_fn();
+   |     ^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #42 <https://github.com/rust-lang/rust/issues/42> for more information
+   = help: add `#![feature(unstable)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error[E0658]: use of unstable library feature 'unstable'
+  --> $DIR/unstable-const-stable.rs:8:14
+   |
+LL |     unsafe { write_bytes(4 as *mut u8, 0, 0) };
+   |              ^^^^^^^^^^^
+   |
+   = note: see issue #42 <https://github.com/rust-lang/rust/issues/42> for more information
+   = help: add `#![feature(unstable)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error[E0658]: use of unstable library feature 'unstable'
+  --> $DIR/unstable-const-stable.rs:12:5
+   |
+LL |     some_unstable_fn();
+   |     ^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #42 <https://github.com/rust-lang/rust/issues/42> for more information
+   = help: add `#![feature(unstable)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error[E0658]: use of unstable library feature 'unstable'
+  --> $DIR/unstable-const-stable.rs:13:14
+   |
+LL |     unsafe { write_bytes(4 as *mut u8, 0, 0) };
+   |              ^^^^^^^^^^^
+   |
+   = note: see issue #42 <https://github.com/rust-lang/rust/issues/42> for more information
+   = help: add `#![feature(unstable)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0658`.