Auto merge of rust-lang#91959 - matthiaskrgr:rollup-rhajuvw, r=matthi…

…askrgr

Rollup of 7 pull requests

Successful merges:

 - rust-lang#90521 (Stabilize `destructuring_assignment`)
 - rust-lang#91479 (Add `[T]::as_simd(_mut)`)
 - rust-lang#91584 (Improve code for rustdoc-gui tester)
 - rust-lang#91886 (core: minor `Option` doc correction)
 - rust-lang#91888 (Handle unordered const/ty generics for object lifetime defaults)
 - rust-lang#91905 (Fix source code page sidebar on mobile)
 - rust-lang#91906 (Removed `in_band_lifetimes` from `library\proc_macro`)

Failed merges:

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

compiler/rustc_ast_lowering/src/expr.rs

@@ -9,7 +9,6 @@ use rustc_errors::struct_span_err;
 use rustc_hir as hir;
 use rustc_hir::def::Res;
 use rustc_hir::definitions::DefPathData;
-use rustc_session::parse::feature_err;
 use rustc_span::hygiene::ExpnId;
 use rustc_span::source_map::{respan, DesugaringKind, Span, Spanned};
 use rustc_span::symbol::{sym, Ident, Symbol};
@@ -962,24 +961,6 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 self.lower_span(eq_sign_span),
             );
         }
-        if !self.sess.features_untracked().destructuring_assignment {
-            let mut err = feature_err(
-                &self.sess.parse_sess,
-                sym::destructuring_assignment,
-                eq_sign_span,
-                "destructuring assignments are unstable",
-            );
-            err.span_label(lhs.span, "cannot assign to this expression");
-            if self.is_in_loop_condition {
-                err.span_suggestion_verbose(
-                    lhs.span.shrink_to_lo(),
-                    "you might have meant to use pattern destructuring",
-                    "let ".to_string(),
-                    rustc_errors::Applicability::MachineApplicable,
-                );
-            }
-            err.emit();
-        }
 
         let mut assignments = vec![];
 

compiler/rustc_ast_lowering/src/lib.rs

@@ -52,7 +52,7 @@ use rustc_hir::def::{DefKind, Namespace, PartialRes, PerNS, Res};
 use rustc_hir::def_id::{DefId, DefPathHash, LocalDefId, CRATE_DEF_ID};
 use rustc_hir::definitions::{DefKey, DefPathData, Definitions};
 use rustc_hir::intravisit;
-use rustc_hir::{ConstArg, GenericArg, InferKind, ParamName};
+use rustc_hir::{ConstArg, GenericArg, ParamName};
 use rustc_index::vec::{Idx, IndexVec};
 use rustc_query_system::ich::StableHashingContext;
 use rustc_session::lint::builtin::BARE_TRAIT_OBJECTS;
@@ -1113,7 +1113,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                         return GenericArg::Infer(hir::InferArg {
                             hir_id: self.lower_node_id(ty.id),
                             span: self.lower_span(ty.span),
-                            kind: InferKind::Type,
                         });
                     }
                     // We parse const arguments as path types as we cannot distinguish them during

compiler/rustc_ast_passes/src/feature_gate.rs

@@ -724,11 +724,6 @@ pub fn check_crate(krate: &ast::Crate, sess: &Session) {
     gate_all!(half_open_range_patterns, "half-open range patterns are unstable");
     gate_all!(inline_const, "inline-const is experimental");
     gate_all!(inline_const_pat, "inline-const in pattern position is experimental");
-    if sess.parse_sess.span_diagnostic.err_count() == 0 {
-        // Errors for `destructuring_assignment` can get quite noisy, especially where `_` is
-        // involved, so we only emit errors where there are no other parsing errors.
-        gate_all!(destructuring_assignment, "destructuring assignments are unstable");
-    }
 
     // All uses of `gate_all!` below this point were added in #65742,
     // and subsequently disabled (with the non-early gating readded).

compiler/rustc_expand/src/lib.rs

@@ -1,6 +1,6 @@
 #![feature(crate_visibility_modifier)]
 #![feature(decl_macro)]
-#![feature(destructuring_assignment)]
+#![cfg_attr(bootstrap, feature(destructuring_assignment))]
 #![feature(if_let_guard)]
 #![feature(let_else)]
 #![feature(proc_macro_diagnostic)]

compiler/rustc_feature/src/accepted.rs

@@ -114,6 +114,8 @@ declare_features! (
     (accepted, default_type_params, "1.0.0", None, None),
     /// Allows `#[deprecated]` attribute.
     (accepted, deprecated, "1.9.0", Some(29935), None),
+    /// Allows the use of destructuring assignments.
+    (accepted, destructuring_assignment, "1.59.0", Some(71126), None),
     /// Allows `#[doc(alias = "...")]`.
     (accepted, doc_alias, "1.48.0", Some(50146), None),
     /// Allows `..` in tuple (struct) patterns.

compiler/rustc_feature/src/active.rs

@@ -356,8 +356,6 @@ declare_features! (
     (active, default_type_parameter_fallback, "1.3.0", Some(27336), None),
     /// Allows `#[derive(Default)]` and `#[default]` on enums.
     (active, derive_default_enum, "1.56.0", Some(86985), None),
-    /// Allows the use of destructuring assignments.
-    (active, destructuring_assignment, "1.49.0", Some(71126), None),
     /// Tells rustdoc to automatically generate `#[doc(cfg(...))]`.
     (active, doc_auto_cfg, "1.58.0", Some(43781), None),
     /// Allows `#[doc(cfg(...))]`.

compiler/rustc_hir/src/hir.rs

@@ -255,23 +255,9 @@ pub struct ConstArg {
     pub span: Span,
 }
 
-#[derive(Copy, Clone, Encodable, Debug, HashStable_Generic)]
-pub enum InferKind {
-    Const,
-    Type,
-}
-
-impl InferKind {
-    #[inline]
-    pub fn is_type(self) -> bool {
-        matches!(self, InferKind::Type)
-    }
-}
-
 #[derive(Encodable, Debug, HashStable_Generic)]
 pub struct InferArg {
     pub hir_id: HirId,
-    pub kind: InferKind,
     pub span: Span,
 }
 

compiler/rustc_parse/src/parser/expr.rs

@@ -1297,7 +1297,6 @@ impl<'a> Parser<'a> {
         } else if self.eat_keyword(kw::Let) {
             self.parse_let_expr(attrs)
         } else if self.eat_keyword(kw::Underscore) {
-            self.sess.gated_spans.gate(sym::destructuring_assignment, self.prev_token.span);
             Ok(self.mk_expr(self.prev_token.span, ExprKind::Underscore, attrs))
         } else if !self.unclosed_delims.is_empty() && self.check(&token::Semi) {
             // Don't complain about bare semicolons after unclosed braces
@@ -2620,7 +2619,6 @@ impl<'a> Parser<'a> {
                 let exp_span = self.prev_token.span;
                 // We permit `.. }` on the left-hand side of a destructuring assignment.
                 if self.check(&token::CloseDelim(close_delim)) {
-                    self.sess.gated_spans.gate(sym::destructuring_assignment, self.prev_token.span);
                     base = ast::StructRest::Rest(self.prev_token.span.shrink_to_hi());
                     break;
                 }

compiler/rustc_resolve/src/late/lifetimes.rs

@@ -2541,8 +2541,8 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
                                 GenericParamDefKind::Type { object_lifetime_default, .. } => {
                                     Some(object_lifetime_default)
                                 }
-                                GenericParamDefKind::Lifetime
-                                | GenericParamDefKind::Const { .. } => None,
+                                GenericParamDefKind::Const { .. } => Some(Set1::Empty),
+                                GenericParamDefKind::Lifetime => None,
                             })
                             .collect()
                     })
@@ -2569,12 +2569,11 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
                 }
                 GenericArg::Const(ct) => {
                     self.visit_anon_const(&ct.value);
+                    i += 1;
                 }
                 GenericArg::Infer(inf) => {
                     self.visit_id(inf.hir_id);
-                    if inf.kind.is_type() {
-                        i += 1;
-                    }
+                    i += 1;
                 }
             }
         }

compiler/rustc_typeck/src/check/expr.rs

@@ -878,11 +878,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         "let ".to_string(),
                         Applicability::MachineApplicable,
                     );
-                    if !self.sess().features_untracked().destructuring_assignment {
-                        // We already emit an E0658 with a suggestion for `while let`, this is
-                        // redundant output.
-                        err.delay_as_bug();
-                    }
                     break;
                 }
                 hir::Node::Item(_)

library/alloc/src/lib.rs

@@ -136,7 +136,7 @@
 #![feature(cfg_target_has_atomic)]
 #![feature(const_fn_trait_bound)]
 #![feature(const_trait_impl)]
-#![feature(destructuring_assignment)]
+#![cfg_attr(bootstrap, feature(destructuring_assignment))]
 #![feature(dropck_eyepatch)]
 #![feature(exclusive_range_pattern)]
 #![feature(fundamental)]

library/core/src/option.rs

@@ -512,11 +512,11 @@ use crate::{
 #[rustc_diagnostic_item = "Option"]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub enum Option<T> {
-    /// No value
+    /// No value.
     #[lang = "None"]
     #[stable(feature = "rust1", since = "1.0.0")]
     None,
-    /// Some value `T`
+    /// Some value of type `T`.
     #[lang = "Some"]
     #[stable(feature = "rust1", since = "1.0.0")]
     Some(#[stable(feature = "rust1", since = "1.0.0")] T),

library/core/src/slice/mod.rs

@@ -16,6 +16,8 @@ use crate::option::Option::{None, Some};
 use crate::ptr;
 use crate::result::Result;
 use crate::result::Result::{Err, Ok};
+#[cfg(not(miri))] // Miri does not support all SIMD intrinsics
+use crate::simd::{self, Simd};
 use crate::slice;
 
 #[unstable(
@@ -3512,6 +3514,123 @@ impl<T> [T] {
         }
     }
 
+    /// Split a slice into a prefix, a middle of aligned SIMD types, and a suffix.
+    ///
+    /// This is a safe wrapper around [`slice::align_to`], so has the same weak
+    /// postconditions as that method.  You're only assured that
+    /// `self.len() == prefix.len() + middle.len() * LANES + suffix.len()`.
+    ///
+    /// Notably, all of the following are possible:
+    /// - `prefix.len() >= LANES`.
+    /// - `middle.is_empty()` despite `self.len() >= 3 * LANES`.
+    /// - `suffix.len() >= LANES`.
+    ///
+    /// That said, this is a safe method, so if you're only writing safe code,
+    /// then this can at most cause incorrect logic, not unsoundness.
+    ///
+    /// # Panics
+    ///
+    /// This will panic if the size of the SIMD type is different from
+    /// `LANES` times that of the scalar.
+    ///
+    /// At the time of writing, the trait restrictions on `Simd<T, LANES>` keeps
+    /// that from ever happening, as only power-of-two numbers of lanes are
+    /// supported.  It's possible that, in the future, those restrictions might
+    /// be lifted in a way that would make it possible to see panics from this
+    /// method for something like `LANES == 3`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(portable_simd)]
+    ///
+    /// let short = &[1, 2, 3];
+    /// let (prefix, middle, suffix) = short.as_simd::<4>();
+    /// assert_eq!(middle, []); // Not enough elements for anything in the middle
+    ///
+    /// // They might be split in any possible way between prefix and suffix
+    /// let it = prefix.iter().chain(suffix).copied();
+    /// assert_eq!(it.collect::<Vec<_>>(), vec![1, 2, 3]);
+    ///
+    /// fn basic_simd_sum(x: &[f32]) -> f32 {
+    ///     use std::ops::Add;
+    ///     use std::simd::f32x4;
+    ///     let (prefix, middle, suffix) = x.as_simd();
+    ///     let sums = f32x4::from_array([
+    ///         prefix.iter().copied().sum(),
+    ///         0.0,
+    ///         0.0,
+    ///         suffix.iter().copied().sum(),
+    ///     ]);
+    ///     let sums = middle.iter().copied().fold(sums, f32x4::add);
+    ///     sums.horizontal_sum()
+    /// }
+    ///
+    /// let numbers: Vec<f32> = (1..101).map(|x| x as _).collect();
+    /// assert_eq!(basic_simd_sum(&numbers[1..99]), 4949.0);
+    /// ```
+    #[unstable(feature = "portable_simd", issue = "86656")]
+    #[cfg(not(miri))] // Miri does not support all SIMD intrinsics
+    pub fn as_simd<const LANES: usize>(&self) -> (&[T], &[Simd<T, LANES>], &[T])
+    where
+        Simd<T, LANES>: AsRef<[T; LANES]>,
+        T: simd::SimdElement,
+        simd::LaneCount<LANES>: simd::SupportedLaneCount,
+    {
+        // These are expected to always match, as vector types are laid out like
+        // arrays per <https://llvm.org/docs/LangRef.html#vector-type>, but we
+        // might as well double-check since it'll optimize away anyhow.
+        assert_eq!(mem::size_of::<Simd<T, LANES>>(), mem::size_of::<[T; LANES]>());
+
+        // SAFETY: The simd types have the same layout as arrays, just with
+        // potentially-higher alignment, so the de-facto transmutes are sound.
+        unsafe { self.align_to() }
+    }
+
+    /// Split a slice into a prefix, a middle of aligned SIMD types, and a suffix.
+    ///
+    /// This is a safe wrapper around [`slice::align_to_mut`], so has the same weak
+    /// postconditions as that method.  You're only assured that
+    /// `self.len() == prefix.len() + middle.len() * LANES + suffix.len()`.
+    ///
+    /// Notably, all of the following are possible:
+    /// - `prefix.len() >= LANES`.
+    /// - `middle.is_empty()` despite `self.len() >= 3 * LANES`.
+    /// - `suffix.len() >= LANES`.
+    ///
+    /// That said, this is a safe method, so if you're only writing safe code,
+    /// then this can at most cause incorrect logic, not unsoundness.
+    ///
+    /// This is the mutable version of [`slice::as_simd`]; see that for examples.
+    ///
+    /// # Panics
+    ///
+    /// This will panic if the size of the SIMD type is different from
+    /// `LANES` times that of the scalar.
+    ///
+    /// At the time of writing, the trait restrictions on `Simd<T, LANES>` keeps
+    /// that from ever happening, as only power-of-two numbers of lanes are
+    /// supported.  It's possible that, in the future, those restrictions might
+    /// be lifted in a way that would make it possible to see panics from this
+    /// method for something like `LANES == 3`.
+    #[unstable(feature = "portable_simd", issue = "86656")]
+    #[cfg(not(miri))] // Miri does not support all SIMD intrinsics
+    pub fn as_simd_mut<const LANES: usize>(&mut self) -> (&mut [T], &mut [Simd<T, LANES>], &mut [T])
+    where
+        Simd<T, LANES>: AsMut<[T; LANES]>,
+        T: simd::SimdElement,
+        simd::LaneCount<LANES>: simd::SupportedLaneCount,
+    {
+        // These are expected to always match, as vector types are laid out like
+        // arrays per <https://llvm.org/docs/LangRef.html#vector-type>, but we
+        // might as well double-check since it'll optimize away anyhow.
+        assert_eq!(mem::size_of::<Simd<T, LANES>>(), mem::size_of::<[T; LANES]>());
+
+        // SAFETY: The simd types have the same layout as arrays, just with
+        // potentially-higher alignment, so the de-facto transmutes are sound.
+        unsafe { self.align_to_mut() }
+    }
+
     /// Checks if the elements of this slice are sorted.
     ///
     /// That is, for each element `a` and its following element `b`, `a <= b` must hold. If the

library/proc_macro/src/bridge/client.rs

@@ -78,7 +78,7 @@ macro_rules! define_handles {
                 }
             }
 
-            impl<S: server::Types> Decode<'_, 's, HandleStore<server::MarkedTypes<S>>>
+            impl<'s, S: server::Types> Decode<'_, 's, HandleStore<server::MarkedTypes<S>>>
                 for &'s Marked<S::$oty, $oty>
             {
                 fn decode(r: &mut Reader<'_>, s: &'s HandleStore<server::MarkedTypes<S>>) -> Self {
@@ -92,7 +92,7 @@ macro_rules! define_handles {
                 }
             }
 
-            impl<S: server::Types> DecodeMut<'_, 's, HandleStore<server::MarkedTypes<S>>>
+            impl<'s, S: server::Types> DecodeMut<'_, 's, HandleStore<server::MarkedTypes<S>>>
                 for &'s mut Marked<S::$oty, $oty>
             {
                 fn decode(

library/proc_macro/src/bridge/mod.rs

@@ -295,13 +295,13 @@ impl<T, M> Unmark for Marked<T, M> {
         self.value
     }
 }
-impl<T, M> Unmark for &'a Marked<T, M> {
+impl<'a, T, M> Unmark for &'a Marked<T, M> {
     type Unmarked = &'a T;
     fn unmark(self) -> Self::Unmarked {
         &self.value
     }
 }
-impl<T, M> Unmark for &'a mut Marked<T, M> {
+impl<'a, T, M> Unmark for &'a mut Marked<T, M> {
     type Unmarked = &'a mut T;
     fn unmark(self) -> Self::Unmarked {
         &mut self.value
@@ -356,8 +356,8 @@ mark_noop! {
     (),
     bool,
     char,
-    &'a [u8],
-    &'a str,
+    &'_ [u8],
+    &'_ str,
     String,
     usize,
     Delimiter,