Auto merge of #91959 - matthiaskrgr:rollup-rhajuvw, r=matthiaskrgr

Rollup of 7 pull requests

Successful merges:

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

Failed merges:

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

10 files changed, 8 insertions, 55 deletions

diff --git a/compiler/rustc_ast_lowering/src/expr.rs b/compiler/rustc_ast_lowering/src/expr.rs
index 75a45a437e7..be67fe72127 100644
--- a/compiler/rustc_ast_lowering/src/expr.rs
+++ b/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![];
 
diff --git a/compiler/rustc_ast_lowering/src/lib.rs b/compiler/rustc_ast_lowering/src/lib.rs
index fee2e7636ea..0077dec889d 100644
--- a/compiler/rustc_ast_lowering/src/lib.rs
+++ b/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
diff --git a/compiler/rustc_ast_passes/src/feature_gate.rs b/compiler/rustc_ast_passes/src/feature_gate.rs
index 1d1539152be..975874b6b2c 100644
--- a/compiler/rustc_ast_passes/src/feature_gate.rs
+++ b/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).
diff --git a/compiler/rustc_expand/src/lib.rs b/compiler/rustc_expand/src/lib.rs
index 60a62ac204c..47a64b457d0 100644
--- a/compiler/rustc_expand/src/lib.rs
+++ b/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)]
diff --git a/compiler/rustc_feature/src/accepted.rs b/compiler/rustc_feature/src/accepted.rs
index 87b08dc5264..32a9d081ed8 100644
--- a/compiler/rustc_feature/src/accepted.rs
+++ b/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.
diff --git a/compiler/rustc_feature/src/active.rs b/compiler/rustc_feature/src/active.rs
index 22f6559d15f..ebd12d6ab4e 100644
--- a/compiler/rustc_feature/src/active.rs
+++ b/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(...))]`.
diff --git a/compiler/rustc_hir/src/hir.rs b/compiler/rustc_hir/src/hir.rs
index f044c187f39..e2358aac1e7 100644
--- a/compiler/rustc_hir/src/hir.rs
+++ b/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,
 }
 
diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index c62ebb271f4..ddb4f2dc25d 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/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;
                 }
diff --git a/compiler/rustc_resolve/src/late/lifetimes.rs b/compiler/rustc_resolve/src/late/lifetimes.rs
index c94c56df75b..05098defead 100644
--- a/compiler/rustc_resolve/src/late/lifetimes.rs
+++ b/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;
                 }
             }
         }
diff --git a/compiler/rustc_typeck/src/check/expr.rs b/compiler/rustc_typeck/src/check/expr.rs
index bc6ad3c9686..6a63feb09a1 100644
--- a/compiler/rustc_typeck/src/check/expr.rs
+++ b/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(_)