Auto merge of rust-lang#104655 - matthiaskrgr:rollup-r5kfffy, r=matthiaskrgr

Rollup of 9 pull requests

Successful merges:

 - rust-lang#101310 (Clarify and restrict when `{Arc,Rc}::get_unchecked_mut` is allowed.)
 - rust-lang#104461 (Fix building of `aarch64-pc-windows-gnullvm`)
 - rust-lang#104487 (update ntapi dep to remove future-incompat warning)
 - rust-lang#104504 (Add a detailed note for missing comma typo w/ FRU syntax)
 - rust-lang#104581 (rustdoc: remove unused JS IIFE from main.js)
 - rust-lang#104632 (avoid non-strict-provenance casts in libcore tests)
 - rust-lang#104634 (move core::arch into separate file)
 - rust-lang#104641 (replace unusual grammar)
 - rust-lang#104643 (add examples to chunks remainder methods. )

Failed merges:

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

Author: bors

compiler/rustc_error_messages/locales/en-US/hir_typeck.ftl

@@ -0,0 +1,8 @@
+hir_typeck_fru_note = this expression may have been misinterpreted as a `..` range expression
+hir_typeck_fru_expr = this expression does not end in a comma...
+hir_typeck_fru_expr2 = ... so this is interpreted as a `..` range expression, instead of functional record update syntax
+hir_typeck_fru_suggestion =
+    to set the remaining fields{$expr ->
+        [NONE]{""}
+        *[other] {" "}from `{$expr}`
+    }, separate the last named field with a comma

compiler/rustc_error_messages/src/lib.rs

@@ -51,6 +51,7 @@ fluent_messages! {
     errors => "../locales/en-US/errors.ftl",
     expand => "../locales/en-US/expand.ftl",
     hir_analysis => "../locales/en-US/hir_analysis.ftl",
+    hir_typeck => "../locales/en-US/hir_typeck.ftl",
     infer => "../locales/en-US/infer.ftl",
     interface => "../locales/en-US/interface.ftl",
     lint => "../locales/en-US/lint.ftl",

compiler/rustc_errors/src/lib.rs

@@ -467,6 +467,9 @@ pub enum StashKey {
     /// When an invalid lifetime e.g. `'2` should be reinterpreted
     /// as a char literal in the parser
     LifetimeIsChar,
+    /// Maybe there was a typo where a comma was forgotten before
+    /// FRU syntax
+    MaybeFruTypo,
 }
 
 fn default_track_diagnostic(_: &Diagnostic) {}

compiler/rustc_hir_typeck/src/errors.rs

@@ -1,4 +1,5 @@
 //! Errors emitted by `rustc_hir_analysis`.
+use rustc_errors::{AddToDiagnostic, Applicability, Diagnostic, MultiSpan, SubdiagnosticMessage};
 use rustc_macros::{Diagnostic, Subdiagnostic};
 use rustc_middle::ty::Ty;
 use rustc_span::{symbol::Ident, Span};
@@ -133,3 +134,41 @@ pub struct OpMethodGenericParams {
     pub span: Span,
     pub method_name: String,
 }
+
+pub struct TypeMismatchFruTypo {
+    /// Span of the LHS of the range
+    pub expr_span: Span,
+    /// Span of the `..RHS` part of the range
+    pub fru_span: Span,
+    /// Rendered expression of the RHS of the range
+    pub expr: Option<String>,
+}
+
+impl AddToDiagnostic for TypeMismatchFruTypo {
+    fn add_to_diagnostic_with<F>(self, diag: &mut Diagnostic, _: F)
+    where
+        F: Fn(&mut Diagnostic, SubdiagnosticMessage) -> SubdiagnosticMessage,
+    {
+        diag.set_arg("expr", self.expr.as_deref().unwrap_or("NONE"));
+
+        // Only explain that `a ..b` is a range if it's split up
+        if self.expr_span.between(self.fru_span).is_empty() {
+            diag.span_note(
+                self.expr_span.to(self.fru_span),
+                rustc_errors::fluent::hir_typeck_fru_note,
+            );
+        } else {
+            let mut multispan: MultiSpan = vec![self.expr_span, self.fru_span].into();
+            multispan.push_span_label(self.expr_span, rustc_errors::fluent::hir_typeck_fru_expr);
+            multispan.push_span_label(self.fru_span, rustc_errors::fluent::hir_typeck_fru_expr2);
+            diag.span_note(multispan, rustc_errors::fluent::hir_typeck_fru_note);
+        }
+
+        diag.span_suggestion(
+            self.expr_span.shrink_to_hi(),
+            rustc_errors::fluent::hir_typeck_fru_suggestion,
+            ", ",
+            Applicability::MaybeIncorrect,
+        );
+    }
+}

compiler/rustc_hir_typeck/src/expr.rs

@@ -5,6 +5,7 @@
 use crate::cast;
 use crate::coercion::CoerceMany;
 use crate::coercion::DynamicCoerceMany;
+use crate::errors::TypeMismatchFruTypo;
 use crate::errors::{AddressOfTemporaryTaken, ReturnStmtOutsideOfFnBody, StructExprNonExhaustive};
 use crate::errors::{
     FieldMultiplySpecifiedInInitializer, FunctionalRecordUpdateOnNonStruct,
@@ -1616,10 +1617,16 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 self.demand_coerce_diag(&field.expr, ty, field_type, None, AllowTwoPhase::No);
 
             if let Some(mut diag) = diag {
-                if idx == ast_fields.len() - 1 && remaining_fields.is_empty() {
-                    self.suggest_fru_from_range(field, variant, substs, &mut diag);
+                if idx == ast_fields.len() - 1 {
+                    if remaining_fields.is_empty() {
+                        self.suggest_fru_from_range(field, variant, substs, &mut diag);
+                        diag.emit();
+                    } else {
+                        diag.stash(field.span, StashKey::MaybeFruTypo);
+                    }
+                } else {
+                    diag.emit();
                 }
-                diag.emit();
             }
         }
 
@@ -1877,19 +1884,39 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 .map(|adt| adt.did())
                 != range_def_id
         {
-            let instead = self
+            // Suppress any range expr type mismatches
+            if let Some(mut diag) = self
+                .tcx
+                .sess
+                .diagnostic()
+                .steal_diagnostic(last_expr_field.span, StashKey::MaybeFruTypo)
+            {
+                diag.delay_as_bug();
+            }
+
+            // Use a (somewhat arbitrary) filtering heuristic to avoid printing
+            // expressions that are either too long, or have control character
+            //such as newlines in them.
+            let expr = self
                 .tcx
                 .sess
                 .source_map()
                 .span_to_snippet(range_end.expr.span)
-                .map(|s| format!(" from `{s}`"))
-                .unwrap_or_default();
-            err.span_suggestion(
-                range_start.span.shrink_to_hi(),
-                &format!("to set the remaining fields{instead}, separate the last named field with a comma"),
-                ",",
-                Applicability::MaybeIncorrect,
-            );
+                .ok()
+                .filter(|s| s.len() < 25 && !s.contains(|c: char| c.is_control()));
+
+            let fru_span = self
+                .tcx
+                .sess
+                .source_map()
+                .span_extend_while(range_start.span, |c| c.is_whitespace())
+                .unwrap_or(range_start.span).shrink_to_hi().to(range_end.span);
+
+            err.subdiagnostic(TypeMismatchFruTypo {
+                expr_span: range_start.span,
+                fru_span,
+                expr,
+            });
         }
     }
 

library/alloc/src/collections/btree/map.rs

@@ -46,8 +46,8 @@ pub(super) const MIN_LEN: usize = node::MIN_LEN_AFTER_SPLIT;
 /// is done is *very* inefficient for modern computer architectures. In particular, every element
 /// is stored in its own individually heap-allocated node. This means that every single insertion
 /// triggers a heap-allocation, and every single comparison should be a cache-miss. Since these
-/// are both notably expensive things to do in practice, we are forced to at very least reconsider
-/// the BST strategy.
+/// are both notably expensive things to do in practice, we are forced to, at the very least,
+/// reconsider the BST strategy.
 ///
 /// A B-Tree instead makes each node contain B-1 to 2B-1 elements in a contiguous array. By doing
 /// this, we reduce the number of allocations by a factor of B, and improve cache efficiency in

library/alloc/src/rc.rs

@@ -1091,10 +1091,11 @@ impl<T: ?Sized> Rc<T> {
     ///
     /// # Safety
     ///
-    /// Any other `Rc` or [`Weak`] pointers to the same allocation must not be dereferenced
-    /// for the duration of the returned borrow.
-    /// This is trivially the case if no such pointers exist,
-    /// for example immediately after `Rc::new`.
+    /// If any other `Rc` or [`Weak`] pointers to the same allocation exist, then
+    /// they must be must not be dereferenced or have active borrows for the duration
+    /// of the returned borrow, and their inner type must be exactly the same as the
+    /// inner type of this Rc (including lifetimes). This is trivially the case if no
+    /// such pointers exist, for example immediately after `Rc::new`.
     ///
     /// # Examples
     ///
@@ -1109,6 +1110,38 @@ impl<T: ?Sized> Rc<T> {
     /// }
     /// assert_eq!(*x, "foo");
     /// ```
+    /// Other `Rc` pointers to the same allocation must be to the same type.
+    /// ```no_run
+    /// #![feature(get_mut_unchecked)]
+    ///
+    /// use std::rc::Rc;
+    ///
+    /// let x: Rc<str> = Rc::from("Hello, world!");
+    /// let mut y: Rc<[u8]> = x.clone().into();
+    /// unsafe {
+    ///     // this is Undefined Behavior, because x's inner type is str, not [u8]
+    ///     Rc::get_mut_unchecked(&mut y).fill(0xff); // 0xff is invalid in UTF-8
+    /// }
+    /// println!("{}", &*x); // Invalid UTF-8 in a str
+    /// ```
+    /// Other `Rc` pointers to the same allocation must be to the exact same type, including lifetimes.
+    /// ```no_run
+    /// #![feature(get_mut_unchecked)]
+    ///
+    /// use std::rc::Rc;
+    ///
+    /// let x: Rc<&str> = Rc::new("Hello, world!");
+    /// {
+    ///     let s = String::from("Oh, no!");
+    ///     let mut y: Rc<&str> = x.clone().into();
+    ///     unsafe {
+    ///         // this is Undefined Behavior, because x's inner type
+    ///         // is &'long str, not &'short str
+    ///         *Rc::get_mut_unchecked(&mut y) = &s;
+    ///     }
+    /// }
+    /// println!("{}", &*x); // Use-after-free
+    /// ```
     #[inline]
     #[unstable(feature = "get_mut_unchecked", issue = "63292")]
     pub unsafe fn get_mut_unchecked(this: &mut Self) -> &mut T {

library/alloc/src/sync.rs

@@ -1587,10 +1587,11 @@ impl<T: ?Sized> Arc<T> {
     ///
     /// # Safety
     ///
-    /// Any other `Arc` or [`Weak`] pointers to the same allocation must not be dereferenced
-    /// for the duration of the returned borrow.
-    /// This is trivially the case if no such pointers exist,
-    /// for example immediately after `Arc::new`.
+    /// If any other `Arc` or [`Weak`] pointers to the same allocation exist, then
+    /// they must be must not be dereferenced or have active borrows for the duration
+    /// of the returned borrow, and their inner type must be exactly the same as the
+    /// inner type of this Rc (including lifetimes). This is trivially the case if no
+    /// such pointers exist, for example immediately after `Arc::new`.
     ///
     /// # Examples
     ///
@@ -1605,6 +1606,38 @@ impl<T: ?Sized> Arc<T> {
     /// }
     /// assert_eq!(*x, "foo");
     /// ```
+    /// Other `Arc` pointers to the same allocation must be to the same type.
+    /// ```no_run
+    /// #![feature(get_mut_unchecked)]
+    ///
+    /// use std::sync::Arc;
+    ///
+    /// let x: Arc<str> = Arc::from("Hello, world!");
+    /// let mut y: Arc<[u8]> = x.clone().into();
+    /// unsafe {
+    ///     // this is Undefined Behavior, because x's inner type is str, not [u8]
+    ///     Arc::get_mut_unchecked(&mut y).fill(0xff); // 0xff is invalid in UTF-8
+    /// }
+    /// println!("{}", &*x); // Invalid UTF-8 in a str
+    /// ```
+    /// Other `Arc` pointers to the same allocation must be to the exact same type, including lifetimes.
+    /// ```no_run
+    /// #![feature(get_mut_unchecked)]
+    ///
+    /// use std::sync::Arc;
+    ///
+    /// let x: Arc<&str> = Arc::new("Hello, world!");
+    /// {
+    ///     let s = String::from("Oh, no!");
+    ///     let mut y: Arc<&str> = x.clone().into();
+    ///     unsafe {
+    ///         // this is Undefined Behavior, because x's inner type
+    ///         // is &'long str, not &'short str
+    ///         *Arc::get_mut_unchecked(&mut y) = &s;
+    ///     }
+    /// }
+    /// println!("{}", &*x); // Use-after-free
+    /// ```
     #[inline]
     #[unstable(feature = "get_mut_unchecked", issue = "63292")]
     pub unsafe fn get_mut_unchecked(this: &mut Self) -> &mut T {

library/core/src/arch.rs

@@ -0,0 +1,30 @@
+#![doc = include_str!("../../stdarch/crates/core_arch/src/core_arch_docs.md")]
+
+#[stable(feature = "simd_arch", since = "1.27.0")]
+pub use crate::core_arch::arch::*;
+
+/// Inline assembly.
+///
+/// Refer to [rust by example] for a usage guide and the [reference] for
+/// detailed information about the syntax and available options.
+///
+/// [rust by example]: https://doc.rust-lang.org/nightly/rust-by-example/unsafe/asm.html
+/// [reference]: https://doc.rust-lang.org/nightly/reference/inline-assembly.html
+#[stable(feature = "asm", since = "1.59.0")]
+#[rustc_builtin_macro]
+pub macro asm("assembly template", $(operands,)* $(options($(option),*))?) {
+    /* compiler built-in */
+}
+
+/// Module-level inline assembly.
+///
+/// Refer to [rust by example] for a usage guide and the [reference] for
+/// detailed information about the syntax and available options.
+///
+/// [rust by example]: https://doc.rust-lang.org/nightly/rust-by-example/unsafe/asm.html
+/// [reference]: https://doc.rust-lang.org/nightly/reference/inline-assembly.html
+#[stable(feature = "global_asm", since = "1.59.0")]
+#[rustc_builtin_macro]
+pub macro global_asm("assembly template", $(operands,)* $(options($(option),*))?) {
+    /* compiler built-in */
+}

library/core/src/lib.rs

@@ -89,6 +89,7 @@
 // Lints:
 #![deny(rust_2021_incompatible_or_patterns)]
 #![deny(unsafe_op_in_unsafe_fn)]
+#![deny(fuzzy_provenance_casts)]
 #![warn(deprecated_in_future)]
 #![warn(missing_debug_implementations)]
 #![warn(missing_docs)]
@@ -162,6 +163,7 @@
 #![feature(slice_ptr_get)]
 #![feature(slice_split_at_unchecked)]
 #![feature(str_internals)]
+#![feature(strict_provenance)]
 #![feature(utf16_extra)]
 #![feature(utf16_extra_const)]
 #![feature(variant_count)]
@@ -392,38 +394,8 @@ pub mod primitive;
 #[unstable(feature = "stdsimd", issue = "48556")]
 mod core_arch;
 
-#[doc = include_str!("../../stdarch/crates/core_arch/src/core_arch_docs.md")]
 #[stable(feature = "simd_arch", since = "1.27.0")]
-pub mod arch {
-    #[stable(feature = "simd_arch", since = "1.27.0")]
-    pub use crate::core_arch::arch::*;
-
-    /// Inline assembly.
-    ///
-    /// Refer to [rust by example] for a usage guide and the [reference] for
-    /// detailed information about the syntax and available options.
-    ///
-    /// [rust by example]: https://doc.rust-lang.org/nightly/rust-by-example/unsafe/asm.html
-    /// [reference]: https://doc.rust-lang.org/nightly/reference/inline-assembly.html
-    #[stable(feature = "asm", since = "1.59.0")]
-    #[rustc_builtin_macro]
-    pub macro asm("assembly template", $(operands,)* $(options($(option),*))?) {
-        /* compiler built-in */
-    }
-
-    /// Module-level inline assembly.
-    ///
-    /// Refer to [rust by example] for a usage guide and the [reference] for
-    /// detailed information about the syntax and available options.
-    ///
-    /// [rust by example]: https://doc.rust-lang.org/nightly/rust-by-example/unsafe/asm.html
-    /// [reference]: https://doc.rust-lang.org/nightly/reference/inline-assembly.html
-    #[stable(feature = "global_asm", since = "1.59.0")]
-    #[rustc_builtin_macro]
-    pub macro global_asm("assembly template", $(operands,)* $(options($(option),*))?) {
-        /* compiler built-in */
-    }
-}
+pub mod arch;
 
 // Pull in the `core_simd` crate directly into libcore. The contents of
 // `core_simd` are in a different repository: rust-lang/portable-simd.

library/core/src/ptr/const_ptr.rs

@@ -140,6 +140,7 @@ impl<T: ?Sized> *const T {
     /// assert_eq!(<*const u8>::from_bits(1), dangling);
     /// ```
     #[unstable(feature = "ptr_to_from_bits", issue = "91126")]
+    #[allow(fuzzy_provenance_casts)] // this is an unstable and semi-deprecated cast function
     pub fn from_bits(bits: usize) -> Self
     where
         T: Sized,

library/core/src/ptr/mod.rs

@@ -616,6 +616,7 @@ pub const fn invalid_mut<T>(addr: usize) -> *mut T {
 #[inline]
 #[unstable(feature = "strict_provenance", issue = "95228")]
 #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
+#[allow(fuzzy_provenance_casts)] // this *is* the strict provenance API one should use instead
 pub fn from_exposed_addr<T>(addr: usize) -> *const T
 where
     T: Sized,
@@ -653,6 +654,7 @@ where
 #[inline]
 #[unstable(feature = "strict_provenance", issue = "95228")]
 #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
+#[allow(fuzzy_provenance_casts)] // this *is* the strict provenance API one should use instead
 pub fn from_exposed_addr_mut<T>(addr: usize) -> *mut T
 where
     T: Sized,

library/core/src/ptr/mut_ptr.rs

@@ -146,6 +146,7 @@ impl<T: ?Sized> *mut T {
     /// assert_eq!(<*mut u8>::from_bits(1), dangling);
     /// ```
     #[unstable(feature = "ptr_to_from_bits", issue = "91126")]
+    #[allow(fuzzy_provenance_casts)] // this is an unstable and semi-deprecated cast function
     pub fn from_bits(bits: usize) -> Self
     where
         T: Sized,