Rollup of 7 pull requests

Cargo.lock

@@ -2226,9 +2226,12 @@ dependencies = [
 
 [[package]]
 name = "minifier"
-version = "0.3.0"
+version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "95bbbf96b9ac3482c2a25450b67a15ed851319bc5fabf3b40742ea9066e84282"
+checksum = "9aa3f302fe0f8de065d4a2d1ed64f60204623cac58b80cd3c2a83a25d5a7d437"
+dependencies = [
+ "clap",
+]
 
 [[package]]
 name = "minimal-lexical"

compiler/rustc_feature/src/builtin_attrs.rs

@@ -641,6 +641,11 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
         ErrorFollowing, EncodeCrossCrate::Yes,
         "rustc_deprecated_safe_2024 is supposed to be used in libstd only",
     ),
+    rustc_attr!(
+        rustc_pub_transparent, Normal, template!(Word),
+        WarnFollowing, EncodeCrossCrate::Yes,
+        "used internally to mark types with a `transparent` representation when it is guaranteed by the documentation",
+    ),
 
 
     // ==========================================================================

compiler/rustc_hir_analysis/src/check/check.rs

@@ -1259,7 +1259,8 @@ pub(super) fn check_transparent<'tcx>(tcx: TyCtxt<'tcx>, adt: ty::AdtDef<'tcx>)
                 ty::Tuple(list) => list.iter().try_for_each(|t| check_non_exhaustive(tcx, t)),
                 ty::Array(ty, _) => check_non_exhaustive(tcx, *ty),
                 ty::Adt(def, args) => {
-                    if !def.did().is_local() {
+                    if !def.did().is_local() && !tcx.has_attr(def.did(), sym::rustc_pub_transparent)
+                    {
                         let non_exhaustive = def.is_variant_list_non_exhaustive()
                             || def
                                 .variants()

compiler/rustc_index/src/lib.rs

@@ -2,6 +2,7 @@
 #![cfg_attr(all(feature = "nightly", test), feature(stmt_expr_attributes))]
 #![cfg_attr(feature = "nightly", allow(internal_features))]
 #![cfg_attr(feature = "nightly", feature(extend_one, new_uninit, step_trait, test))]
+#![cfg_attr(feature = "nightly", feature(new_zeroed_alloc))]
 // tidy-alphabetical-end
 
 pub mod bit_set;

compiler/rustc_middle/src/lib.rs

@@ -34,6 +34,7 @@
 #![feature(allocator_api)]
 #![feature(array_windows)]
 #![feature(assert_matches)]
+#![feature(box_as_ptr)]
 #![feature(box_patterns)]
 #![feature(closure_track_caller)]
 #![feature(const_option)]

compiler/rustc_middle/src/mir/interpret/allocation.rs

@@ -62,13 +62,11 @@ impl AllocBytes for Box<[u8]> {
     }
 
     fn as_mut_ptr(&mut self) -> *mut u8 {
-        // Carefully avoiding any intermediate references.
-        ptr::addr_of_mut!(**self).cast()
+        Box::as_mut_ptr(self).cast()
     }
 
     fn as_ptr(&self) -> *const u8 {
-        // Carefully avoiding any intermediate references.
-        ptr::addr_of!(**self).cast()
+        Box::as_ptr(self).cast()
     }
 }
 

compiler/rustc_passes/messages.ftl

@@ -657,6 +657,10 @@ passes_rustc_lint_opt_ty =
     `#[rustc_lint_opt_ty]` should be applied to a struct
     .label = not a struct
 
+passes_rustc_pub_transparent =
+    attribute should be applied to `#[repr(transparent)]` types
+    .label = not a `#[repr(transparent)]` type
+
 passes_rustc_safe_intrinsic =
     attribute should be applied to intrinsic functions
     .label = not an intrinsic function

compiler/rustc_passes/src/check_attr.rs

@@ -245,6 +245,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                     self.check_coroutine(attr, target);
                 }
                 [sym::linkage, ..] => self.check_linkage(attr, span, target),
+                [sym::rustc_pub_transparent, ..] => self.check_rustc_pub_transparent( attr.span, span, attrs),
                 [
                     // ok
                     sym::allow
@@ -2381,6 +2382,18 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
             }
         }
     }
+
+    fn check_rustc_pub_transparent(&self, attr_span: Span, span: Span, attrs: &[Attribute]) {
+        if !attrs
+            .iter()
+            .filter(|attr| attr.has_name(sym::repr))
+            .filter_map(|attr| attr.meta_item_list())
+            .flatten()
+            .any(|nmi| nmi.has_name(sym::transparent))
+        {
+            self.dcx().emit_err(errors::RustcPubTransparent { span, attr_span });
+        }
+    }
 }
 
 impl<'tcx> Visitor<'tcx> for CheckAttrVisitor<'tcx> {

compiler/rustc_passes/src/errors.rs

@@ -622,6 +622,15 @@ pub struct RustcStdInternalSymbol {
     pub span: Span,
 }
 
+#[derive(Diagnostic)]
+#[diag(passes_rustc_pub_transparent)]
+pub struct RustcPubTransparent {
+    #[primary_span]
+    pub attr_span: Span,
+    #[label]
+    pub span: Span,
+}
+
 #[derive(Diagnostic)]
 #[diag(passes_link_ordinal)]
 pub struct LinkOrdinal {

compiler/rustc_span/src/symbol.rs

@@ -1674,6 +1674,7 @@ symbols! {
         rustc_private,
         rustc_proc_macro_decls,
         rustc_promotable,
+        rustc_pub_transparent,
         rustc_reallocator,
         rustc_regions,
         rustc_reservation_impl,

compiler/rustc_type_ir/Cargo.toml

@@ -31,3 +31,6 @@ nightly = [
     "rustc_index/nightly",
     "rustc_ast_ir/nightly"
 ]
+
+[lints.rust]
+unexpected_cfgs = { level = "warn", check-cfg = ['cfg(bootstrap)'] }

compiler/rustc_type_ir/src/elaborate.rs

@@ -237,7 +237,7 @@ pub fn supertrait_def_ids<I: Interner>(
     cx: I,
     trait_def_id: I::DefId,
 ) -> impl Iterator<Item = I::DefId> {
-    let mut set = HashSet::default();
+    let mut set: HashSet<I::DefId> = HashSet::default();
     let mut stack = vec![trait_def_id];
 
     set.insert(trait_def_id);

compiler/rustc_type_ir/src/outlives.rs

@@ -68,6 +68,9 @@ struct OutlivesCollector<'a, I: Interner> {
 }
 
 impl<I: Interner> TypeVisitor<I> for OutlivesCollector<'_, I> {
+    #[cfg(not(feature = "nightly"))]
+    type Result = ();
+
     fn visit_ty(&mut self, ty: I::Ty) -> Self::Result {
         if !self.visited.insert(ty) {
             return;

compiler/rustc_type_ir/src/search_graph/mod.rs

@@ -287,7 +287,7 @@ impl<X: Cx> NestedGoals<X> {
         }
     }
 
-    #[rustc_lint_query_instability]
+    #[cfg_attr(feature = "nightly", rustc_lint_query_instability)]
     #[allow(rustc::potential_query_instability)]
     fn iter(&self) -> impl Iterator<Item = (X::Input, UsageKind)> + '_ {
         self.nested_goals.iter().map(|(i, p)| (*i, *p))

library/alloc/src/boxed.rs

@@ -293,6 +293,7 @@ impl<T> Box<T> {
     ///
     /// ```
     /// #![feature(new_uninit)]
+    /// #![feature(new_zeroed_alloc)]
     ///
     /// let zero = Box::<u32>::new_zeroed();
     /// let zero = unsafe { zero.assume_init() };
@@ -303,7 +304,7 @@ impl<T> Box<T> {
     /// [zeroed]: mem::MaybeUninit::zeroed
     #[cfg(not(no_global_oom_handling))]
     #[inline]
-    #[unstable(feature = "new_uninit", issue = "63291")]
+    #[unstable(feature = "new_zeroed_alloc", issue = "129396")]
     #[must_use]
     pub fn new_zeroed() -> Box<mem::MaybeUninit<T>> {
         Self::new_zeroed_in(Global)
@@ -684,6 +685,7 @@ impl<T> Box<[T]> {
     /// # Examples
     ///
     /// ```
+    /// #![feature(new_zeroed_alloc)]
     /// #![feature(new_uninit)]
     ///
     /// let values = Box::<[u32]>::new_zeroed_slice(3);
@@ -694,7 +696,7 @@ impl<T> Box<[T]> {
     ///
     /// [zeroed]: mem::MaybeUninit::zeroed
     #[cfg(not(no_global_oom_handling))]
-    #[unstable(feature = "new_uninit", issue = "63291")]
+    #[unstable(feature = "new_zeroed_alloc", issue = "129396")]
     #[must_use]
     pub fn new_zeroed_slice(len: usize) -> Box<[mem::MaybeUninit<T>]> {
         unsafe { RawVec::with_capacity_zeroed(len).into_box(len) }
@@ -955,6 +957,7 @@ impl<T, A: Allocator> Box<mem::MaybeUninit<T>, A> {
     /// # Examples
     ///
     /// ```
+    /// #![feature(box_uninit_write)]
     /// #![feature(new_uninit)]
     ///
     /// let big_box = Box::<[usize; 1024]>::new_uninit();
@@ -972,7 +975,7 @@ impl<T, A: Allocator> Box<mem::MaybeUninit<T>, A> {
     ///     assert_eq!(*x, i);
     /// }
     /// ```
-    #[unstable(feature = "new_uninit", issue = "63291")]
+    #[unstable(feature = "box_uninit_write", issue = "129397")]
     #[inline]
     pub fn write(mut boxed: Self, value: T) -> Box<T, A> {
         unsafe {
@@ -1254,6 +1257,95 @@ impl<T: ?Sized, A: Allocator> Box<T, A> {
         unsafe { (Unique::from(&mut *ptr), alloc) }
     }
 
+    /// Returns a raw mutable pointer to the `Box`'s contents.
+    ///
+    /// The caller must ensure that the `Box` outlives the pointer this
+    /// function returns, or else it will end up dangling.
+    ///
+    /// This method guarantees that for the purpose of the aliasing model, this method
+    /// does not materialize a reference to the underlying memory, and thus the returned pointer
+    /// will remain valid when mixed with other calls to [`as_ptr`] and [`as_mut_ptr`].
+    /// Note that calling other methods that materialize references to the memory
+    /// may still invalidate this pointer.
+    /// See the example below for how this guarantee can be used.
+    ///
+    /// # Examples
+    ///
+    /// Due to the aliasing guarantee, the following code is legal:
+    ///
+    /// ```rust
+    /// #![feature(box_as_ptr)]
+    ///
+    /// unsafe {
+    ///     let mut b = Box::new(0);
+    ///     let ptr1 = Box::as_mut_ptr(&mut b);
+    ///     ptr1.write(1);
+    ///     let ptr2 = Box::as_mut_ptr(&mut b);
+    ///     ptr2.write(2);
+    ///     // Notably, the write to `ptr2` did *not* invalidate `ptr1`:
+    ///     ptr1.write(3);
+    /// }
+    /// ```
+    ///
+    /// [`as_mut_ptr`]: Self::as_mut_ptr
+    /// [`as_ptr`]: Self::as_ptr
+    #[unstable(feature = "box_as_ptr", issue = "129090")]
+    #[rustc_never_returns_null_ptr]
+    #[inline]
+    pub fn as_mut_ptr(b: &mut Self) -> *mut T {
+        // This is a primitive deref, not going through `DerefMut`, and therefore not materializing
+        // any references.
+        ptr::addr_of_mut!(**b)
+    }
+
+    /// Returns a raw pointer to the `Box`'s contents.
+    ///
+    /// The caller must ensure that the `Box` outlives the pointer this
+    /// function returns, or else it will end up dangling.
+    ///
+    /// The caller must also ensure that the memory the pointer (non-transitively) points to
+    /// is never written to (except inside an `UnsafeCell`) using this pointer or any pointer
+    /// derived from it. If you need to mutate the contents of the `Box`, use [`as_mut_ptr`].
+    ///
+    /// This method guarantees that for the purpose of the aliasing model, this method
+    /// does not materialize a reference to the underlying memory, and thus the returned pointer
+    /// will remain valid when mixed with other calls to [`as_ptr`] and [`as_mut_ptr`].
+    /// Note that calling other methods that materialize mutable references to the memory,
+    /// as well as writing to this memory, may still invalidate this pointer.
+    /// See the example below for how this guarantee can be used.
+    ///
+    /// # Examples
+    ///
+    /// Due to the aliasing guarantee, the following code is legal:
+    ///
+    /// ```rust
+    /// #![feature(box_as_ptr)]
+    ///
+    /// unsafe {
+    ///     let mut v = Box::new(0);
+    ///     let ptr1 = Box::as_ptr(&v);
+    ///     let ptr2 = Box::as_mut_ptr(&mut v);
+    ///     let _val = ptr2.read();
+    ///     // No write to this memory has happened yet, so `ptr1` is still valid.
+    ///     let _val = ptr1.read();
+    ///     // However, once we do a write...
+    ///     ptr2.write(1);
+    ///     // ... `ptr1` is no longer valid.
+    ///     // This would be UB: let _val = ptr1.read();
+    /// }
+    /// ```
+    ///
+    /// [`as_mut_ptr`]: Self::as_mut_ptr
+    /// [`as_ptr`]: Self::as_ptr
+    #[unstable(feature = "box_as_ptr", issue = "129090")]
+    #[rustc_never_returns_null_ptr]
+    #[inline]
+    pub fn as_ptr(b: &Self) -> *const T {
+        // This is a primitive deref, not going through `DerefMut`, and therefore not materializing
+        // any references.
+        ptr::addr_of!(**b)
+    }
+
     /// Returns a reference to the underlying allocator.
     ///
     /// Note: this is an associated function, which means that you have

library/alloc/src/rc.rs

@@ -539,6 +539,7 @@ impl<T> Rc<T> {
     /// # Examples
     ///
     /// ```
+    /// #![feature(new_zeroed_alloc)]
     /// #![feature(new_uninit)]
     ///
     /// use std::rc::Rc;
@@ -551,7 +552,7 @@ impl<T> Rc<T> {
     ///
     /// [zeroed]: mem::MaybeUninit::zeroed
     #[cfg(not(no_global_oom_handling))]
-    #[unstable(feature = "new_uninit", issue = "63291")]
+    #[unstable(feature = "new_zeroed_alloc", issue = "129396")]
     #[must_use]
     pub fn new_zeroed() -> Rc<mem::MaybeUninit<T>> {
         unsafe {
@@ -1000,6 +1001,7 @@ impl<T> Rc<[T]> {
     ///
     /// ```
     /// #![feature(new_uninit)]
+    /// #![feature(new_zeroed_alloc)]
     ///
     /// use std::rc::Rc;
     ///
@@ -1011,7 +1013,7 @@ impl<T> Rc<[T]> {
     ///
     /// [zeroed]: mem::MaybeUninit::zeroed
     #[cfg(not(no_global_oom_handling))]
-    #[unstable(feature = "new_uninit", issue = "63291")]
+    #[unstable(feature = "new_zeroed_alloc", issue = "129396")]
     #[must_use]
     pub fn new_zeroed_slice(len: usize) -> Rc<[mem::MaybeUninit<T>]> {
         unsafe {

library/alloc/src/sync.rs

@@ -542,6 +542,7 @@ impl<T> Arc<T> {
     /// # Examples
     ///
     /// ```
+    /// #![feature(new_zeroed_alloc)]
     /// #![feature(new_uninit)]
     ///
     /// use std::sync::Arc;
@@ -555,7 +556,7 @@ impl<T> Arc<T> {
     /// [zeroed]: mem::MaybeUninit::zeroed
     #[cfg(not(no_global_oom_handling))]
     #[inline]
-    #[unstable(feature = "new_uninit", issue = "63291")]
+    #[unstable(feature = "new_zeroed_alloc", issue = "129396")]
     #[must_use]
     pub fn new_zeroed() -> Arc<mem::MaybeUninit<T>> {
         unsafe {
@@ -1134,6 +1135,7 @@ impl<T> Arc<[T]> {
     /// # Examples
     ///
     /// ```
+    /// #![feature(new_zeroed_alloc)]
     /// #![feature(new_uninit)]
     ///
     /// use std::sync::Arc;
@@ -1147,7 +1149,7 @@ impl<T> Arc<[T]> {
     /// [zeroed]: mem::MaybeUninit::zeroed
     #[cfg(not(no_global_oom_handling))]
     #[inline]
-    #[unstable(feature = "new_uninit", issue = "63291")]
+    #[unstable(feature = "new_zeroed_alloc", issue = "129396")]
     #[must_use]
     pub fn new_zeroed_slice(len: usize) -> Arc<[mem::MaybeUninit<T>]> {
         unsafe {
@@ -1191,7 +1193,7 @@ impl<T, A: Allocator> Arc<[T], A> {
     /// assert_eq!(*values, [1, 2, 3])
     /// ```
     #[cfg(not(no_global_oom_handling))]
-    #[unstable(feature = "new_uninit", issue = "63291")]
+    #[unstable(feature = "allocator_api", issue = "32838")]
     #[inline]
     pub fn new_uninit_slice_in(len: usize, alloc: A) -> Arc<[mem::MaybeUninit<T>], A> {
         unsafe { Arc::from_ptr_in(Arc::allocate_for_slice_in(len, &alloc), alloc) }
@@ -1220,7 +1222,7 @@ impl<T, A: Allocator> Arc<[T], A> {
     ///
     /// [zeroed]: mem::MaybeUninit::zeroed
     #[cfg(not(no_global_oom_handling))]
-    #[unstable(feature = "new_uninit", issue = "63291")]
+    #[unstable(feature = "allocator_api", issue = "32838")]
     #[inline]
     pub fn new_zeroed_slice_in(len: usize, alloc: A) -> Arc<[mem::MaybeUninit<T>], A> {
         unsafe {