Rollup of 18 pull requests

RELEASES.md

@@ -18,8 +18,9 @@ Language
 
 Compiler
 --------
-- [Stabilize `--remap-path-scope` for controlling the scoping of how paths get remapped in the resulting binary](https://github.com/rust-lang/rust/pull/147611)
 
+- [Stabilize `--remap-path-scope` for controlling the scoping of how paths get remapped in the resulting binary](https://github.com/rust-lang/rust/pull/147611)
+- [Apply patches for CVE-2026-6042 and CVE-2026-40200 to vendored musl](https://github.com/rust-lang/rust/pull/155171)
 
 <a id="1.95-Platform-Support"></a>
 
@@ -78,25 +79,31 @@ Stabilized APIs
 - [`<*const T>::as_ref_unchecked`](https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.as_ref_unchecked)
 - [`<*mut T>::as_ref_unchecked`](https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.as_ref_unchecked-1)
 - [`<*mut T>::as_mut_unchecked`](https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.as_mut_unchecked)
-
+- [`Vec::push_mut`](https://doc.rust-lang.org/stable/std/vec/struct.Vec.html#method.push_mut)
+- [`Vec::insert_mut`](https://doc.rust-lang.org/stable/std/vec/struct.Vec.html#method.insert_mut)
+- [`VecDeque::push_front_mut`](https://doc.rust-lang.org/stable/std/collections/struct.VecDeque.html#method.push_front_mut)
+- [`VecDeque::push_back_mut`](https://doc.rust-lang.org/stable/std/collections/struct.VecDeque.html#method.push_back_mut)
+- [`VecDeque::insert_mut`](https://doc.rust-lang.org/stable/std/collections/struct.VecDeque.html#method.insert_mut)
+- [`LinkedList::push_front_mut`](https://doc.rust-lang.org/stable/std/collections/struct.LinkedList.html#method.push_front_mut)
+- [`LinkedList::push_back_mut`](https://doc.rust-lang.org/stable/std/collections/struct.LinkedList.html#method.push_back_mut)
+- [`Layout::dangling_ptr`](https://doc.rust-lang.org/stable/std/alloc/struct.Layout.html#method.dangling_ptr)
+- [`Layout::repeat`](https://doc.rust-lang.org/stable/std/alloc/struct.Layout.html#method.repeat)
+- [`Layout::repeat_packed`](https://doc.rust-lang.org/stable/std/alloc/struct.Layout.html#method.repeat_packed)
+- [`Layout::extend_packed`](https://doc.rust-lang.org/stable/std/alloc/struct.Layout.html#method.extend_packed)
 
 These previously stable APIs are now stable in const contexts:
 
 - [`fmt::from_fn`](https://doc.rust-lang.org/stable/std/fmt/fn.from_fn.html)
 - [`ControlFlow::is_break`](https://doc.rust-lang.org/stable/core/ops/enum.ControlFlow.html#method.is_break)
 - [`ControlFlow::is_continue`](https://doc.rust-lang.org/stable/core/ops/enum.ControlFlow.html#method.is_continue)
 
-
-<a id="1.95-Cargo"></a>
-
-Cargo
------
-- [docs(report): enhance man pages for `cargo report *`](https://github.com/rust-lang/cargo/pull/16430/)<a id="1.95-Rustdoc"></a>
+<a id="1.95-Rustdoc"></a>
 
 Rustdoc
 -----
 - [In search results, rank unstable items lower](https://github.com/rust-lang/rust/pull/149460)
 - [Add new "hide deprecated items" setting in rustdoc](https://github.com/rust-lang/rust/pull/151091)
+
 <a id="1.95-Compatibility-Notes"></a>
 
 Compatibility Notes
@@ -116,7 +123,6 @@ Compatibility Notes
 - [JSON target specs](https://doc.rust-lang.org/rustc/targets/custom.html) have been destabilized and now require `-Z unstable-options` to use. Previously, they could not be used without the standard library, which has no stable build mechanism. In preparation for the `build-std` project adding that support, JSON target specs are being proactively gated to ensure they remain unstable even if `build-std` is stabilized. Cargo now includes the `-Z json-target-spec` CLI flag to automatically pass `-Z unstable-options` to the compiler when needed. See [#150151](https://github.com/rust-lang/rust/pull/150151), [#151534](https://github.com/rust-lang/rust/pull/150151), and [rust-lang/cargo#16557](https://github.com/rust-lang/cargo/pull/16557).
 - [The arguments of `#[feature]` attributes on invalid targets are now checked](https://github.com/rust-lang/rust/issues/153764)
 
-
 <a id="1.95-Internal-Changes"></a>
 
 Internal Changes

compiler/rustc_arena/src/lib.rs

@@ -140,25 +140,19 @@ impl<T> TypedArena<T> {
     /// Allocates an object in the `TypedArena`, returning a reference to it.
     #[inline]
     pub fn alloc(&self, object: T) -> &mut T {
+        assert!(size_of::<T>() != 0);
+
         if self.ptr == self.end {
             self.grow(1)
         }
 
         unsafe {
-            if size_of::<T>() == 0 {
-                self.ptr.set(self.ptr.get().wrapping_byte_add(1));
-                let ptr = ptr::NonNull::<T>::dangling().as_ptr();
-                // Don't drop the object. This `write` is equivalent to `forget`.
-                ptr::write(ptr, object);
-                &mut *ptr
-            } else {
-                let ptr = self.ptr.get();
-                // Advance the pointer.
-                self.ptr.set(self.ptr.get().add(1));
-                // Write into uninitialized memory.
-                ptr::write(ptr, object);
-                &mut *ptr
-            }
+            let ptr = self.ptr.get();
+            // Advance the pointer.
+            self.ptr.set(self.ptr.get().add(1));
+            // Write into uninitialized memory.
+            ptr::write(ptr, object);
+            &mut *ptr
         }
     }
 
@@ -302,16 +296,10 @@ impl<T> TypedArena<T> {
         let end = self.ptr.get().addr();
         // We then calculate the number of elements to be dropped in the last chunk,
         // which is the filled area's length.
-        let diff = if size_of::<T>() == 0 {
-            // `T` is ZST. It can't have a drop flag, so the value here doesn't matter. We get
-            // the number of zero-sized values in the last and only chunk, just out of caution.
-            // Recall that `end` was incremented for each allocated value.
-            end - start
-        } else {
-            // FIXME: this should *likely* use `offset_from`, but more
-            // investigation is needed (including running tests in miri).
-            (end - start) / size_of::<T>()
-        };
+        assert_ne!(size_of::<T>(), 0);
+        // FIXME: this should *likely* use `offset_from`, but more
+        // investigation is needed (including running tests in miri).
+        let diff = (end - start) / size_of::<T>();
         // Pass that to the `destroy` method.
         unsafe {
             last_chunk.destroy(diff);

compiler/rustc_arena/src/tests.rs

@@ -22,7 +22,6 @@ impl<T> TypedArena<T> {
             if let Some(last_chunk) = chunks_borrow.last_mut() {
                 self.clear_last_chunk(last_chunk);
                 let len = chunks_borrow.len();
-                // If `T` is ZST, code below has no effect.
                 for mut chunk in chunks_borrow.drain(..len - 1) {
                     chunk.destroy(chunk.entries);
                 }
@@ -117,18 +116,6 @@ fn test_noncopy() {
     }
 }
 
-#[test]
-fn test_typed_arena_zero_sized() {
-    let arena = TypedArena::default();
-    #[cfg(not(miri))]
-    const N: usize = 100000;
-    #[cfg(miri)]
-    const N: usize = 1000;
-    for _ in 0..N {
-        arena.alloc(());
-    }
-}
-
 #[test]
 fn test_typed_arena_clear() {
     let mut arena = TypedArena::default();
@@ -207,7 +194,8 @@ thread_local! {
     static DROP_COUNTER: Cell<u32> = Cell::new(0)
 }
 
-struct SmallDroppable;
+#[allow(unused)]
+struct SmallDroppable(u8);
 
 impl Drop for SmallDroppable {
     fn drop(&mut self) {
@@ -222,7 +210,7 @@ fn test_typed_arena_drop_small_count() {
         let arena: TypedArena<SmallDroppable> = TypedArena::default();
         for _ in 0..100 {
             // Allocate something with drop glue to make sure it doesn't leak.
-            arena.alloc(SmallDroppable);
+            arena.alloc(SmallDroppable(0));
         }
         // dropping
     };

compiler/rustc_ast_lowering/src/expr.rs

@@ -29,7 +29,7 @@ use super::{
 use crate::errors::{InvalidLegacyConstGenericArg, UseConstGenericArg, YieldInClosure};
 use crate::{AllowReturnTypeNotation, FnDeclKind, ImplTraitPosition, TryBlockScope};
 
-struct WillCreateDefIdsVisitor {}
+pub(super) struct WillCreateDefIdsVisitor;
 
 impl<'v> rustc_ast::visit::Visitor<'v> for WillCreateDefIdsVisitor {
     type Result = ControlFlow<Span>;
@@ -479,18 +479,18 @@ impl<'hir, R: ResolverAstLoweringExt<'hir>> LoweringContext<'_, 'hir, R> {
                     DefPathData::LateAnonConst,
                     f.span,
                 );
-                let mut visitor = WillCreateDefIdsVisitor {};
-                let const_value = if let ControlFlow::Break(span) = visitor.visit_expr(&arg) {
-                    Box::new(Expr {
-                        id: self.next_node_id(),
-                        kind: ExprKind::Err(invalid_expr_error(self.tcx, span)),
-                        span: f.span,
-                        attrs: [].into(),
-                        tokens: None,
-                    })
-                } else {
-                    arg
-                };
+                let const_value =
+                    if let ControlFlow::Break(span) = WillCreateDefIdsVisitor.visit_expr(&arg) {
+                        Box::new(Expr {
+                            id: self.next_node_id(),
+                            kind: ExprKind::Err(invalid_expr_error(self.tcx, span)),
+                            span: f.span,
+                            attrs: [].into(),
+                            tokens: None,
+                        })
+                    } else {
+                        arg
+                    };
 
                 let anon_const = AnonConst {
                     id: node_id,

compiler/rustc_ast_lowering/src/lib.rs

@@ -39,6 +39,7 @@ use std::mem;
 use std::sync::Arc;
 
 use rustc_ast::node_id::NodeMap;
+use rustc_ast::visit::Visitor;
 use rustc_ast::{self as ast, *};
 use rustc_attr_parsing::{AttributeParser, Late, OmitDoc};
 use rustc_data_structures::fingerprint::Fingerprint;
@@ -2219,14 +2220,22 @@ impl<'hir, R: ResolverAstLoweringExt<'hir>> LoweringContext<'_, 'hir, R> {
                 // since later compiler stages cannot handle them (and shouldn't need to be able to).
                 let default = default
                     .as_ref()
-                    .filter(|_| match source {
+                    .filter(|anon_const| match source {
                         hir::GenericParamSource::Generics => true,
                         hir::GenericParamSource::Binder => {
-                            self.dcx().emit_err(errors::GenericParamDefaultInBinder {
-                                span: param.span(),
-                            });
-
-                            false
+                            let err = errors::GenericParamDefaultInBinder { span: param.span() };
+                            if expr::WillCreateDefIdsVisitor
+                                .visit_expr(&anon_const.value)
+                                .is_break()
+                            {
+                                // FIXME(mgca): make this non-fatal once we have a better way
+                                // to handle nested items in anno const from binder
+                                // Issue: https://github.com/rust-lang/rust/issues/123629
+                                self.dcx().emit_fatal(err)
+                            } else {
+                                self.dcx().emit_err(err);
+                                false
+                            }
                         }
                     })
                     .map(|def| self.lower_anon_const_to_const_arg_and_alloc(def));
@@ -2563,12 +2572,17 @@ impl<'hir, R: ResolverAstLoweringExt<'hir>> LoweringContext<'_, 'hir, R> {
         let span = self.lower_span(expr.span);
 
         let overly_complex_const = |this: &mut Self| {
-            let e = this.dcx().struct_span_err(
-                expr.span,
-                "complex const arguments must be placed inside of a `const` block",
-            );
+            let msg = "complex const arguments must be placed inside of a `const` block";
+            let e = if expr::WillCreateDefIdsVisitor.visit_expr(expr).is_break() {
+                // FIXME(mgca): make this non-fatal once we have a better way to handle
+                // nested items in const args
+                // Issue: https://github.com/rust-lang/rust/issues/154539
+                this.dcx().struct_span_fatal(expr.span, msg).emit()
+            } else {
+                this.dcx().struct_span_err(expr.span, msg).emit()
+            };
 
-            ConstArg { hir_id: this.next_id(), kind: hir::ConstArgKind::Error(e.emit()), span }
+            ConstArg { hir_id: this.next_id(), kind: hir::ConstArgKind::Error(e), span }
         };
 
         match &expr.kind {