diff --git a/compiler/rustc_ast/src/ast.rs b/compiler/rustc_ast/src/ast.rs
index 09f376a480050..6c514c75a500c 100644
--- a/compiler/rustc_ast/src/ast.rs
+++ b/compiler/rustc_ast/src/ast.rs
@@ -2088,15 +2088,15 @@ pub enum InlineAsmRegOrRegClass {
 bitflags::bitflags! {
     #[derive(Encodable, Decodable, HashStable_Generic)]
     pub struct InlineAsmOptions: u16 {
-        const PURE = 1 << 0;
-        const NOMEM = 1 << 1;
-        const READONLY = 1 << 2;
+        const PURE            = 1 << 0;
+        const NOMEM           = 1 << 1;
+        const READONLY        = 1 << 2;
         const PRESERVES_FLAGS = 1 << 3;
-        const NORETURN = 1 << 4;
-        const NOSTACK = 1 << 5;
-        const ATT_SYNTAX = 1 << 6;
-        const RAW = 1 << 7;
-        const MAY_UNWIND = 1 << 8;
+        const NORETURN        = 1 << 4;
+        const NOSTACK         = 1 << 5;
+        const ATT_SYNTAX      = 1 << 6;
+        const RAW             = 1 << 7;
+        const MAY_UNWIND      = 1 << 8;
     }
 }
 
diff --git a/compiler/rustc_ast/src/lib.rs b/compiler/rustc_ast/src/lib.rs
index 4d3620ee8b0f0..bd7a85b07a09e 100644
--- a/compiler/rustc_ast/src/lib.rs
+++ b/compiler/rustc_ast/src/lib.rs
@@ -15,7 +15,7 @@
 #![feature(if_let_guard)]
 #![cfg_attr(bootstrap, feature(label_break_value))]
 #![feature(let_chains)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(min_specialization)]
 #![feature(negative_impls)]
 #![feature(slice_internals)]
diff --git a/compiler/rustc_ast/src/util/parser.rs b/compiler/rustc_ast/src/util/parser.rs
index 5edeb54be5f0f..b40ad6f700e82 100644
--- a/compiler/rustc_ast/src/util/parser.rs
+++ b/compiler/rustc_ast/src/util/parser.rs
@@ -297,11 +297,11 @@ impl ExprPrecedence {
         match self {
             ExprPrecedence::Closure => PREC_CLOSURE,
 
-            ExprPrecedence::Break |
-            ExprPrecedence::Continue |
-            ExprPrecedence::Ret |
-            ExprPrecedence::Yield |
-            ExprPrecedence::Yeet => PREC_JUMP,
+            ExprPrecedence::Break
+            | ExprPrecedence::Continue
+            | ExprPrecedence::Ret
+            | ExprPrecedence::Yield
+            | ExprPrecedence::Yeet => PREC_JUMP,
 
             // `Range` claims to have higher precedence than `Assign`, but `x .. x = x` fails to
             // parse, instead of parsing as `(x .. x) = x`.  Giving `Range` a lower precedence
@@ -318,43 +318,43 @@ impl ExprPrecedence {
             ExprPrecedence::AssignOp => AssocOp::Assign.precedence() as i8,
 
             // Unary, prefix
-            ExprPrecedence::Box |
-            ExprPrecedence::AddrOf |
+            ExprPrecedence::Box
+            | ExprPrecedence::AddrOf
             // Here `let pats = expr` has `let pats =` as a "unary" prefix of `expr`.
             // However, this is not exactly right. When `let _ = a` is the LHS of a binop we
             // need parens sometimes. E.g. we can print `(let _ = a) && b` as `let _ = a && b`
             // but we need to print `(let _ = a) < b` as-is with parens.
-            ExprPrecedence::Let |
-            ExprPrecedence::Unary => PREC_PREFIX,
+            | ExprPrecedence::Let
+            | ExprPrecedence::Unary => PREC_PREFIX,
 
             // Unary, postfix
-            ExprPrecedence::Await |
-            ExprPrecedence::Call |
-            ExprPrecedence::MethodCall |
-            ExprPrecedence::Field |
-            ExprPrecedence::Index |
-            ExprPrecedence::Try |
-            ExprPrecedence::InlineAsm |
-            ExprPrecedence::Mac => PREC_POSTFIX,
+            ExprPrecedence::Await
+            | ExprPrecedence::Call
+            | ExprPrecedence::MethodCall
+            | ExprPrecedence::Field
+            | ExprPrecedence::Index
+            | ExprPrecedence::Try
+            | ExprPrecedence::InlineAsm
+            | ExprPrecedence::Mac => PREC_POSTFIX,
 
             // Never need parens
-            ExprPrecedence::Array |
-            ExprPrecedence::Repeat |
-            ExprPrecedence::Tup |
-            ExprPrecedence::Lit |
-            ExprPrecedence::Path |
-            ExprPrecedence::Paren |
-            ExprPrecedence::If |
-            ExprPrecedence::While |
-            ExprPrecedence::ForLoop |
-            ExprPrecedence::Loop |
-            ExprPrecedence::Match |
-            ExprPrecedence::ConstBlock |
-            ExprPrecedence::Block |
-            ExprPrecedence::TryBlock |
-            ExprPrecedence::Async |
-            ExprPrecedence::Struct |
-            ExprPrecedence::Err => PREC_PAREN,
+            ExprPrecedence::Array
+            | ExprPrecedence::Repeat
+            | ExprPrecedence::Tup
+            | ExprPrecedence::Lit
+            | ExprPrecedence::Path
+            | ExprPrecedence::Paren
+            | ExprPrecedence::If
+            | ExprPrecedence::While
+            | ExprPrecedence::ForLoop
+            | ExprPrecedence::Loop
+            | ExprPrecedence::Match
+            | ExprPrecedence::ConstBlock
+            | ExprPrecedence::Block
+            | ExprPrecedence::TryBlock
+            | ExprPrecedence::Async
+            | ExprPrecedence::Struct
+            | ExprPrecedence::Err => PREC_PAREN,
         }
     }
 }
diff --git a/compiler/rustc_ast_lowering/src/block.rs b/compiler/rustc_ast_lowering/src/block.rs
index e0869bb1063d9..12a0cc0d25508 100644
--- a/compiler/rustc_ast_lowering/src/block.rs
+++ b/compiler/rustc_ast_lowering/src/block.rs
@@ -1,8 +1,6 @@
 use crate::{ImplTraitContext, ImplTraitPosition, LoweringContext};
 use rustc_ast::{Block, BlockCheckMode, Local, LocalKind, Stmt, StmtKind};
 use rustc_hir as hir;
-use rustc_session::parse::feature_err;
-use rustc_span::sym;
 
 use smallvec::SmallVec;
 
@@ -92,15 +90,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         let hir_id = self.lower_node_id(l.id);
         let pat = self.lower_pat(&l.pat);
         let els = if let LocalKind::InitElse(_, els) = &l.kind {
-            if !self.tcx.features().let_else {
-                feature_err(
-                    &self.tcx.sess.parse_sess,
-                    sym::let_else,
-                    l.span,
-                    "`let...else` statements are unstable",
-                )
-                .emit();
-            }
             Some(self.lower_block(els, false))
         } else {
             None
diff --git a/compiler/rustc_ast_lowering/src/lib.rs b/compiler/rustc_ast_lowering/src/lib.rs
index cb6bf0863b387..d2ce6bdb08e58 100644
--- a/compiler/rustc_ast_lowering/src/lib.rs
+++ b/compiler/rustc_ast_lowering/src/lib.rs
@@ -32,7 +32,7 @@
 
 #![feature(box_patterns)]
 #![feature(let_chains)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(never_type)]
 #![recursion_limit = "256"]
 #![allow(rustc::potential_query_instability)]
diff --git a/compiler/rustc_ast_passes/src/lib.rs b/compiler/rustc_ast_passes/src/lib.rs
index af25982e2887b..8aa9d57f046a9 100644
--- a/compiler/rustc_ast_passes/src/lib.rs
+++ b/compiler/rustc_ast_passes/src/lib.rs
@@ -9,7 +9,7 @@
 #![feature(if_let_guard)]
 #![feature(iter_is_partitioned)]
 #![feature(let_chains)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![recursion_limit = "256"]
 
 #[macro_use]
diff --git a/compiler/rustc_attr/src/lib.rs b/compiler/rustc_attr/src/lib.rs
index 053f848aacbf7..52e65a9c7743d 100644
--- a/compiler/rustc_attr/src/lib.rs
+++ b/compiler/rustc_attr/src/lib.rs
@@ -5,7 +5,7 @@
 //! to this crate.
 
 #![feature(let_chains)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![deny(rustc::untranslatable_diagnostic)]
 #![deny(rustc::diagnostic_outside_of_impl)]
 
diff --git a/compiler/rustc_borrowck/src/lib.rs b/compiler/rustc_borrowck/src/lib.rs
index ec652f852179a..86da87d060313 100644
--- a/compiler/rustc_borrowck/src/lib.rs
+++ b/compiler/rustc_borrowck/src/lib.rs
@@ -3,7 +3,7 @@
 #![allow(rustc::potential_query_instability)]
 #![feature(box_patterns)]
 #![feature(let_chains)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(min_specialization)]
 #![feature(never_type)]
 #![feature(rustc_attrs)]
diff --git a/compiler/rustc_builtin_macros/src/lib.rs b/compiler/rustc_builtin_macros/src/lib.rs
index 280fa70451141..8aeb3b82a9cd0 100644
--- a/compiler/rustc_builtin_macros/src/lib.rs
+++ b/compiler/rustc_builtin_macros/src/lib.rs
@@ -9,7 +9,7 @@
 #![feature(if_let_guard)]
 #![feature(is_sorted)]
 #![feature(let_chains)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(proc_macro_internals)]
 #![feature(proc_macro_quote)]
 #![recursion_limit = "256"]
diff --git a/compiler/rustc_codegen_llvm/src/intrinsic.rs b/compiler/rustc_codegen_llvm/src/intrinsic.rs
index 3d789904707c0..a640de42a6a86 100644
--- a/compiler/rustc_codegen_llvm/src/intrinsic.rs
+++ b/compiler/rustc_codegen_llvm/src/intrinsic.rs
@@ -1705,6 +1705,97 @@ unsupported {} from `{}` with element `{}` of size `{}` to `{}`"#,
     bitwise_red!(simd_reduce_all: vector_reduce_and, true);
     bitwise_red!(simd_reduce_any: vector_reduce_or, true);
 
+    if name == sym::simd_cast_ptr {
+        require_simd!(ret_ty, "return");
+        let (out_len, out_elem) = ret_ty.simd_size_and_type(bx.tcx());
+        require!(
+            in_len == out_len,
+            "expected return type with length {} (same as input type `{}`), \
+                  found `{}` with length {}",
+            in_len,
+            in_ty,
+            ret_ty,
+            out_len
+        );
+
+        match in_elem.kind() {
+            ty::RawPtr(p) => {
+                let (metadata, check_sized) = p.ty.ptr_metadata_ty(bx.tcx, |ty| {
+                    bx.tcx.normalize_erasing_regions(ty::ParamEnv::reveal_all(), ty)
+                });
+                assert!(!check_sized); // we are in codegen, so we shouldn't see these types
+                require!(metadata.is_unit(), "cannot cast fat pointer `{}`", in_elem)
+            }
+            _ => return_error!("expected pointer, got `{}`", in_elem),
+        }
+        match out_elem.kind() {
+            ty::RawPtr(p) => {
+                let (metadata, check_sized) = p.ty.ptr_metadata_ty(bx.tcx, |ty| {
+                    bx.tcx.normalize_erasing_regions(ty::ParamEnv::reveal_all(), ty)
+                });
+                assert!(!check_sized); // we are in codegen, so we shouldn't see these types
+                require!(metadata.is_unit(), "cannot cast to fat pointer `{}`", out_elem)
+            }
+            _ => return_error!("expected pointer, got `{}`", out_elem),
+        }
+
+        if in_elem == out_elem {
+            return Ok(args[0].immediate());
+        } else {
+            return Ok(bx.pointercast(args[0].immediate(), llret_ty));
+        }
+    }
+
+    if name == sym::simd_expose_addr {
+        require_simd!(ret_ty, "return");
+        let (out_len, out_elem) = ret_ty.simd_size_and_type(bx.tcx());
+        require!(
+            in_len == out_len,
+            "expected return type with length {} (same as input type `{}`), \
+                  found `{}` with length {}",
+            in_len,
+            in_ty,
+            ret_ty,
+            out_len
+        );
+
+        match in_elem.kind() {
+            ty::RawPtr(_) => {}
+            _ => return_error!("expected pointer, got `{}`", in_elem),
+        }
+        match out_elem.kind() {
+            ty::Uint(ty::UintTy::Usize) => {}
+            _ => return_error!("expected `usize`, got `{}`", out_elem),
+        }
+
+        return Ok(bx.ptrtoint(args[0].immediate(), llret_ty));
+    }
+
+    if name == sym::simd_from_exposed_addr {
+        require_simd!(ret_ty, "return");
+        let (out_len, out_elem) = ret_ty.simd_size_and_type(bx.tcx());
+        require!(
+            in_len == out_len,
+            "expected return type with length {} (same as input type `{}`), \
+                  found `{}` with length {}",
+            in_len,
+            in_ty,
+            ret_ty,
+            out_len
+        );
+
+        match in_elem.kind() {
+            ty::Uint(ty::UintTy::Usize) => {}
+            _ => return_error!("expected `usize`, got `{}`", in_elem),
+        }
+        match out_elem.kind() {
+            ty::RawPtr(_) => {}
+            _ => return_error!("expected pointer, got `{}`", out_elem),
+        }
+
+        return Ok(bx.inttoptr(args[0].immediate(), llret_ty));
+    }
+
     if name == sym::simd_cast || name == sym::simd_as {
         require_simd!(ret_ty, "return");
         let (out_len, out_elem) = ret_ty.simd_size_and_type(bx.tcx());
diff --git a/compiler/rustc_codegen_llvm/src/lib.rs b/compiler/rustc_codegen_llvm/src/lib.rs
index 334425ae55b43..42c65e04e3b6b 100644
--- a/compiler/rustc_codegen_llvm/src/lib.rs
+++ b/compiler/rustc_codegen_llvm/src/lib.rs
@@ -7,7 +7,7 @@
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(hash_raw_entry)]
 #![feature(let_chains)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(extern_types)]
 #![feature(once_cell)]
 #![feature(iter_intersperse)]
diff --git a/compiler/rustc_codegen_ssa/src/lib.rs b/compiler/rustc_codegen_ssa/src/lib.rs
index 4ea75dba47120..e736b2aba9c14 100644
--- a/compiler/rustc_codegen_ssa/src/lib.rs
+++ b/compiler/rustc_codegen_ssa/src/lib.rs
@@ -1,7 +1,7 @@
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(box_patterns)]
 #![feature(try_blocks)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(once_cell)]
 #![feature(associated_type_bounds)]
 #![feature(strict_provenance)]
diff --git a/compiler/rustc_const_eval/src/lib.rs b/compiler/rustc_const_eval/src/lib.rs
index 72ac6af685dc4..9f47d302a0c3d 100644
--- a/compiler/rustc_const_eval/src/lib.rs
+++ b/compiler/rustc_const_eval/src/lib.rs
@@ -10,7 +10,7 @@ Rust MIR: a lowered representation of Rust.
 #![feature(decl_macro)]
 #![feature(exact_size_is_empty)]
 #![feature(let_chains)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(map_try_insert)]
 #![feature(min_specialization)]
 #![feature(slice_ptr_get)]
diff --git a/compiler/rustc_data_structures/src/lib.rs b/compiler/rustc_data_structures/src/lib.rs
index a7429ed008fb8..56f7823efe0c2 100644
--- a/compiler/rustc_data_structures/src/lib.rs
+++ b/compiler/rustc_data_structures/src/lib.rs
@@ -13,7 +13,7 @@
 #![feature(cell_leak)]
 #![feature(control_flow_enum)]
 #![feature(extend_one)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(hash_raw_entry)]
 #![feature(hasher_prefixfree_extras)]
 #![feature(maybe_uninit_uninit_array)]
diff --git a/compiler/rustc_driver/src/lib.rs b/compiler/rustc_driver/src/lib.rs
index d6f51d7eee1af..8fb9508194b68 100644
--- a/compiler/rustc_driver/src/lib.rs
+++ b/compiler/rustc_driver/src/lib.rs
@@ -5,7 +5,7 @@
 //! This API is completely unstable and subject to change.
 
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(once_cell)]
 #![recursion_limit = "256"]
 #![allow(rustc::potential_query_instability)]
diff --git a/compiler/rustc_error_messages/locales/en-US/privacy.ftl b/compiler/rustc_error_messages/locales/en-US/privacy.ftl
index da987152ff660..a26d1b2b381e8 100644
--- a/compiler/rustc_error_messages/locales/en-US/privacy.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/privacy.ftl
@@ -11,7 +11,7 @@ privacy_in_public_interface = {$vis_descr} {$kind} `{$descr}` in public interfac
     .label = can't leak {$vis_descr} {$kind}
     .visibility_label = `{$descr}` declared as {$vis_descr}
 
-privacy_report_access_level = {$descr}
+privacy_report_effective_visibility = {$descr}
 
 privacy_from_private_dep_in_public_interface =
     {$kind} `{$descr}` from private dependency '{$krate}' in public interface
diff --git a/compiler/rustc_errors/src/lib.rs b/compiler/rustc_errors/src/lib.rs
index 1b24f07e689bb..c3e7820961256 100644
--- a/compiler/rustc_errors/src/lib.rs
+++ b/compiler/rustc_errors/src/lib.rs
@@ -7,7 +7,7 @@
 #![feature(if_let_guard)]
 #![feature(adt_const_params)]
 #![feature(let_chains)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(never_type)]
 #![feature(result_option_inspect)]
 #![feature(rustc_attrs)]
diff --git a/compiler/rustc_expand/src/lib.rs b/compiler/rustc_expand/src/lib.rs
index ac0e200b1b73e..ffc9abe64d2ea 100644
--- a/compiler/rustc_expand/src/lib.rs
+++ b/compiler/rustc_expand/src/lib.rs
@@ -3,7 +3,7 @@
 #![feature(associated_type_defaults)]
 #![feature(if_let_guard)]
 #![feature(let_chains)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(macro_metavar_expr)]
 #![feature(proc_macro_diagnostic)]
 #![feature(proc_macro_internals)]
diff --git a/compiler/rustc_feature/src/accepted.rs b/compiler/rustc_feature/src/accepted.rs
index 100000f4cd629..5f7de94e72657 100644
--- a/compiler/rustc_feature/src/accepted.rs
+++ b/compiler/rustc_feature/src/accepted.rs
@@ -190,6 +190,8 @@ declare_features! (
     (accepted, item_like_imports, "1.15.0", Some(35120), None),
     /// Allows `'a: { break 'a; }`.
     (accepted, label_break_value, "CURRENT_RUSTC_VERSION", Some(48594), None),
+    /// Allows `let...else` statements.
+    (accepted, let_else, "CURRENT_RUSTC_VERSION", Some(87335), None),
     /// Allows `break {expr}` with a value inside `loop`s.
     (accepted, loop_break_value, "1.19.0", Some(37339), None),
     /// Allows use of `?` as the Kleene "at most one" operator in macros.
diff --git a/compiler/rustc_feature/src/active.rs b/compiler/rustc_feature/src/active.rs
index c28fa654a6c52..ad28595ca82b3 100644
--- a/compiler/rustc_feature/src/active.rs
+++ b/compiler/rustc_feature/src/active.rs
@@ -430,8 +430,6 @@ declare_features! (
     (active, large_assignments, "1.52.0", Some(83518), None),
     /// Allows `if/while p && let q = r && ...` chains.
     (active, let_chains, "1.37.0", Some(53667), None),
-    /// Allows `let...else` statements.
-    (active, let_else, "1.56.0", Some(87335), None),
     /// Allows `#[link(..., cfg(..))]`.
     (active, link_cfg, "1.14.0", Some(37406), None),
     /// Allows using `reason` in lint attributes and the `#[expect(lint)]` lint check.
diff --git a/compiler/rustc_feature/src/builtin_attrs.rs b/compiler/rustc_feature/src/builtin_attrs.rs
index b50c972e6f6c0..0f6d7ed9edc16 100644
--- a/compiler/rustc_feature/src/builtin_attrs.rs
+++ b/compiler/rustc_feature/src/builtin_attrs.rs
@@ -762,7 +762,7 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
     // Internal attributes, Testing:
     // ==========================================================================
 
-    rustc_attr!(TEST, rustc_access_level, Normal, template!(Word), WarnFollowing),
+    rustc_attr!(TEST, rustc_effective_visibility, Normal, template!(Word), WarnFollowing),
     rustc_attr!(TEST, rustc_outlives, Normal, template!(Word), WarnFollowing),
     rustc_attr!(TEST, rustc_capture_analysis, Normal, template!(Word), WarnFollowing),
     rustc_attr!(TEST, rustc_insignificant_dtor, Normal, template!(Word), WarnFollowing),
diff --git a/compiler/rustc_hir/src/hir.rs b/compiler/rustc_hir/src/hir.rs
index 037cbc1be9adf..a8436ea64f8d7 100644
--- a/compiler/rustc_hir/src/hir.rs
+++ b/compiler/rustc_hir/src/hir.rs
@@ -139,11 +139,10 @@ impl LifetimeName {
         match self {
             LifetimeName::ImplicitObjectLifetimeDefault | LifetimeName::Infer => true,
 
-            // It might seem surprising that `Fresh` counts as
-            // *not* elided -- but this is because, as far as the code
-            // in the compiler is concerned -- `Fresh` variants act
-            // equivalently to "some fresh name". They correspond to
-            // early-bound regions on an impl, in other words.
+            // It might seem surprising that `Fresh` counts as not *elided*
+            // -- but this is because, as far as the code in the compiler is
+            // concerned -- `Fresh` variants act equivalently to "some fresh name".
+            // They correspond to early-bound regions on an impl, in other words.
             LifetimeName::Error | LifetimeName::Param(..) | LifetimeName::Static => false,
         }
     }
diff --git a/compiler/rustc_hir/src/lib.rs b/compiler/rustc_hir/src/lib.rs
index 1b33cb9c2da9c..946da9265ba09 100644
--- a/compiler/rustc_hir/src/lib.rs
+++ b/compiler/rustc_hir/src/lib.rs
@@ -5,7 +5,7 @@
 #![feature(associated_type_defaults)]
 #![feature(closure_track_caller)]
 #![feature(const_btree_new)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(once_cell)]
 #![feature(min_specialization)]
 #![feature(never_type)]
diff --git a/compiler/rustc_incremental/src/lib.rs b/compiler/rustc_incremental/src/lib.rs
index 1e88e8091c373..2c9e21f769fb1 100644
--- a/compiler/rustc_incremental/src/lib.rs
+++ b/compiler/rustc_incremental/src/lib.rs
@@ -2,7 +2,7 @@
 
 #![deny(missing_docs)]
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![recursion_limit = "256"]
 #![allow(rustc::potential_query_instability)]
 
diff --git a/compiler/rustc_index/src/lib.rs b/compiler/rustc_index/src/lib.rs
index aa34673de81d7..a00d7bd680147 100644
--- a/compiler/rustc_index/src/lib.rs
+++ b/compiler/rustc_index/src/lib.rs
@@ -3,7 +3,7 @@
 #![feature(allow_internal_unstable)]
 #![feature(bench_black_box)]
 #![feature(extend_one)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(min_specialization)]
 #![feature(new_uninit)]
 #![feature(step_trait)]
diff --git a/compiler/rustc_infer/src/lib.rs b/compiler/rustc_infer/src/lib.rs
index 931ebca7d0145..ef60d2c918845 100644
--- a/compiler/rustc_infer/src/lib.rs
+++ b/compiler/rustc_infer/src/lib.rs
@@ -19,7 +19,7 @@
 #![feature(extend_one)]
 #![cfg_attr(bootstrap, feature(label_break_value))]
 #![feature(let_chains)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(min_specialization)]
 #![feature(never_type)]
 #![feature(try_blocks)]
diff --git a/compiler/rustc_interface/src/lib.rs b/compiler/rustc_interface/src/lib.rs
index 1a8d619fafb62..41cd7b0e9b1d6 100644
--- a/compiler/rustc_interface/src/lib.rs
+++ b/compiler/rustc_interface/src/lib.rs
@@ -1,5 +1,5 @@
 #![feature(box_patterns)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(internal_output_capture)]
 #![feature(thread_spawn_unchecked)]
 #![feature(once_cell)]
diff --git a/compiler/rustc_lint/src/lib.rs b/compiler/rustc_lint/src/lib.rs
index 2a22a6e5be1ba..c760e435699c6 100644
--- a/compiler/rustc_lint/src/lib.rs
+++ b/compiler/rustc_lint/src/lib.rs
@@ -34,7 +34,7 @@
 #![feature(iter_intersperse)]
 #![feature(iter_order_by)]
 #![feature(let_chains)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(min_specialization)]
 #![feature(never_type)]
 #![recursion_limit = "256"]
diff --git a/compiler/rustc_macros/src/lib.rs b/compiler/rustc_macros/src/lib.rs
index 20ee5dfc72798..2c027d754da4d 100644
--- a/compiler/rustc_macros/src/lib.rs
+++ b/compiler/rustc_macros/src/lib.rs
@@ -1,5 +1,5 @@
 #![feature(allow_internal_unstable)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(never_type)]
 #![feature(proc_macro_diagnostic)]
 #![feature(proc_macro_span)]
diff --git a/compiler/rustc_metadata/src/lib.rs b/compiler/rustc_metadata/src/lib.rs
index ba6f1e4a3a5ca..6f5604b7e11f0 100644
--- a/compiler/rustc_metadata/src/lib.rs
+++ b/compiler/rustc_metadata/src/lib.rs
@@ -5,7 +5,7 @@
 #![cfg_attr(bootstrap, feature(generic_associated_types))]
 #![feature(iter_from_generator)]
 #![feature(let_chains)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(once_cell)]
 #![feature(proc_macro_internals)]
 #![feature(macro_metavar_expr)]
diff --git a/compiler/rustc_middle/src/lib.rs b/compiler/rustc_middle/src/lib.rs
index ea08879cb53cc..01b9277b98362 100644
--- a/compiler/rustc_middle/src/lib.rs
+++ b/compiler/rustc_middle/src/lib.rs
@@ -40,7 +40,7 @@
 #![feature(new_uninit)]
 #![feature(once_cell)]
 #![feature(let_chains)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(min_specialization)]
 #![feature(trusted_len)]
 #![feature(type_alias_impl_trait)]
diff --git a/compiler/rustc_middle/src/middle/privacy.rs b/compiler/rustc_middle/src/middle/privacy.rs
index 751c7f4648225..c595fbec0dd5c 100644
--- a/compiler/rustc_middle/src/middle/privacy.rs
+++ b/compiler/rustc_middle/src/middle/privacy.rs
@@ -1,7 +1,7 @@
 //! A pass that checks to make sure private fields and methods aren't used
 //! outside their scopes. This pass will also generate a set of exported items
 //! which are available for use externally when compiled as a library.
-
+use crate::ty::Visibility;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_macros::HashStable;
@@ -27,26 +27,107 @@ pub enum AccessLevel {
     Public,
 }
 
+#[derive(Clone, Copy, PartialEq, Eq, Debug, HashStable, Default)]
+pub struct EffectiveVisibility {
+    public: Option<Visibility>,
+    exported: Option<Visibility>,
+    reachable: Option<Visibility>,
+    reachable_from_impl_trait: Option<Visibility>,
+}
+
+impl EffectiveVisibility {
+    pub fn get(&self, tag: AccessLevel) -> Option<&Visibility> {
+        match tag {
+            AccessLevel::Public => &self.public,
+            AccessLevel::Exported => &self.exported,
+            AccessLevel::Reachable => &self.reachable,
+            AccessLevel::ReachableFromImplTrait => &self.reachable_from_impl_trait,
+        }
+        .as_ref()
+    }
+
+    fn get_mut(&mut self, tag: AccessLevel) -> &mut Option<Visibility> {
+        match tag {
+            AccessLevel::Public => &mut self.public,
+            AccessLevel::Exported => &mut self.exported,
+            AccessLevel::Reachable => &mut self.reachable,
+            AccessLevel::ReachableFromImplTrait => &mut self.reachable_from_impl_trait,
+        }
+    }
+
+    pub fn is_public_at_level(&self, tag: AccessLevel) -> bool {
+        self.get(tag).map_or(false, |vis| vis.is_public())
+    }
+}
+
 /// Holds a map of accessibility levels for reachable HIR nodes.
 #[derive(Debug, Clone)]
 pub struct AccessLevels<Id = LocalDefId> {
-    pub map: FxHashMap<Id, AccessLevel>,
+    map: FxHashMap<Id, EffectiveVisibility>,
 }
 
-impl<Id: Hash + Eq> AccessLevels<Id> {
+impl<Id: Hash + Eq + Copy> AccessLevels<Id> {
+    pub fn is_public_at_level(&self, id: Id, tag: AccessLevel) -> bool {
+        self.get_effective_vis(id)
+            .map_or(false, |effective_vis| effective_vis.is_public_at_level(tag))
+    }
+
     /// See `AccessLevel::Reachable`.
     pub fn is_reachable(&self, id: Id) -> bool {
-        self.map.get(&id) >= Some(&AccessLevel::Reachable)
+        self.is_public_at_level(id, AccessLevel::Reachable)
     }
 
     /// See `AccessLevel::Exported`.
     pub fn is_exported(&self, id: Id) -> bool {
-        self.map.get(&id) >= Some(&AccessLevel::Exported)
+        self.is_public_at_level(id, AccessLevel::Exported)
     }
 
     /// See `AccessLevel::Public`.
     pub fn is_public(&self, id: Id) -> bool {
-        self.map.get(&id) >= Some(&AccessLevel::Public)
+        self.is_public_at_level(id, AccessLevel::Public)
+    }
+
+    pub fn get_access_level(&self, id: Id) -> Option<AccessLevel> {
+        self.get_effective_vis(id).and_then(|effective_vis| {
+            for level in [
+                AccessLevel::Public,
+                AccessLevel::Exported,
+                AccessLevel::Reachable,
+                AccessLevel::ReachableFromImplTrait,
+            ] {
+                if effective_vis.is_public_at_level(level) {
+                    return Some(level);
+                }
+            }
+            None
+        })
+    }
+
+    pub fn set_access_level(&mut self, id: Id, tag: AccessLevel) {
+        let mut effective_vis = self.get_effective_vis(id).copied().unwrap_or_default();
+        for level in [
+            AccessLevel::Public,
+            AccessLevel::Exported,
+            AccessLevel::Reachable,
+            AccessLevel::ReachableFromImplTrait,
+        ] {
+            if level <= tag {
+                *effective_vis.get_mut(level) = Some(Visibility::Public);
+            }
+        }
+        self.map.insert(id, effective_vis);
+    }
+
+    pub fn get_effective_vis(&self, id: Id) -> Option<&EffectiveVisibility> {
+        self.map.get(&id)
+    }
+
+    pub fn iter(&self) -> impl Iterator<Item = (&Id, &EffectiveVisibility)> {
+        self.map.iter()
+    }
+
+    pub fn map_id<OutId: Hash + Eq + Copy>(&self, f: impl Fn(Id) -> OutId) -> AccessLevels<OutId> {
+        AccessLevels { map: self.map.iter().map(|(k, v)| (f(*k), *v)).collect() }
     }
 }
 
diff --git a/compiler/rustc_mir_build/src/lib.rs b/compiler/rustc_mir_build/src/lib.rs
index 11cd2a9aa4dea..0c0a2fe9c9ed6 100644
--- a/compiler/rustc_mir_build/src/lib.rs
+++ b/compiler/rustc_mir_build/src/lib.rs
@@ -6,7 +6,7 @@
 #![feature(control_flow_enum)]
 #![feature(if_let_guard)]
 #![feature(let_chains)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(min_specialization)]
 #![feature(once_cell)]
 #![recursion_limit = "256"]
diff --git a/compiler/rustc_mir_build/src/thir/pattern/check_match.rs b/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
index 69a8c98b27a3d..d45b886903bbf 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
@@ -491,8 +491,8 @@ impl<'p, 'tcx> MatchVisitor<'_, 'p, 'tcx> {
                     err.span_suggestion_verbose(
                         semi_span.shrink_to_lo(),
                         &format!(
-                            "alternatively, on nightly, you might want to use \
-                             `#![feature(let_else)]` to handle the variant{} that {} matched",
+                            "alternatively, you might want to use \
+                             let else to handle the variant{} that {} matched",
                             pluralize!(witnesses.len()),
                             match witnesses.len() {
                                 1 => "isn't",
diff --git a/compiler/rustc_mir_dataflow/src/lib.rs b/compiler/rustc_mir_dataflow/src/lib.rs
index 62b712f7b8dbd..b45c32ee986b6 100644
--- a/compiler/rustc_mir_dataflow/src/lib.rs
+++ b/compiler/rustc_mir_dataflow/src/lib.rs
@@ -1,7 +1,7 @@
 #![feature(associated_type_defaults)]
 #![feature(box_patterns)]
 #![feature(exact_size_is_empty)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(min_specialization)]
 #![feature(once_cell)]
 #![feature(stmt_expr_attributes)]
diff --git a/compiler/rustc_mir_transform/src/lib.rs b/compiler/rustc_mir_transform/src/lib.rs
index 162f7d969b181..e6fc85595714b 100644
--- a/compiler/rustc_mir_transform/src/lib.rs
+++ b/compiler/rustc_mir_transform/src/lib.rs
@@ -1,7 +1,7 @@
 #![allow(rustc::potential_query_instability)]
 #![feature(box_patterns)]
 #![feature(let_chains)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(map_try_insert)]
 #![feature(min_specialization)]
 #![feature(never_type)]
diff --git a/compiler/rustc_monomorphize/src/lib.rs b/compiler/rustc_monomorphize/src/lib.rs
index 3afff7bcabf7d..ba6ce9fd40f63 100644
--- a/compiler/rustc_monomorphize/src/lib.rs
+++ b/compiler/rustc_monomorphize/src/lib.rs
@@ -1,6 +1,6 @@
 #![feature(array_windows)]
 #![feature(control_flow_enum)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![recursion_limit = "256"]
 #![allow(rustc::potential_query_instability)]
 #![deny(rustc::untranslatable_diagnostic)]
diff --git a/compiler/rustc_parse/src/lib.rs b/compiler/rustc_parse/src/lib.rs
index 3c88e1ef377e2..a37327f42942a 100644
--- a/compiler/rustc_parse/src/lib.rs
+++ b/compiler/rustc_parse/src/lib.rs
@@ -4,7 +4,7 @@
 #![feature(box_patterns)]
 #![feature(if_let_guard)]
 #![feature(let_chains)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(never_type)]
 #![feature(rustc_attrs)]
 #![recursion_limit = "256"]
diff --git a/compiler/rustc_passes/src/check_attr.rs b/compiler/rustc_passes/src/check_attr.rs
index ebe4d2e9dd0bd..b3f15ba7cbf25 100644
--- a/compiler/rustc_passes/src/check_attr.rs
+++ b/compiler/rustc_passes/src/check_attr.rs
@@ -1666,7 +1666,8 @@ impl CheckAttrVisitor<'_> {
                         E0552,
                         "unrecognized representation hint"
                     )
-                    .help("valid reprs are `C`, `align`, `packed`, `transparent`, `simd`, `i8`, `u8`, `i16`, `u16`, `i32`, `u32`, `i64`, `u64`, `i128`, `u128`, `isize`, `usize`")
+                    .help("valid reprs are `C`, `align`, `packed`, `transparent`, `simd`, `i8`, `u8`, \
+                          `i16`, `u16`, `i32`, `u32`, `i64`, `u64`, `i128`, `u128`, `isize`, `usize`")
                     .emit();
 
                     continue;
diff --git a/compiler/rustc_passes/src/dead.rs b/compiler/rustc_passes/src/dead.rs
index f141d7beeb921..57f7c379d0490 100644
--- a/compiler/rustc_passes/src/dead.rs
+++ b/compiler/rustc_passes/src/dead.rs
@@ -11,7 +11,7 @@ use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::{Node, PatKind, TyKind};
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
-use rustc_middle::middle::privacy;
+use rustc_middle::middle::privacy::AccessLevel;
 use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::{self, DefIdTree, TyCtxt};
 use rustc_session::lint;
@@ -619,13 +619,10 @@ fn create_and_seed_worklist<'tcx>(
     // see `MarkSymbolVisitor::struct_constructors`
     let mut struct_constructors = Default::default();
     let mut worklist = access_levels
-        .map
         .iter()
-        .filter_map(
-            |(&id, &level)| {
-                if level >= privacy::AccessLevel::Reachable { Some(id) } else { None }
-            },
-        )
+        .filter_map(|(&id, effective_vis)| {
+            effective_vis.is_public_at_level(AccessLevel::Reachable).then_some(id)
+        })
         // Seed entry point
         .chain(tcx.entry_fn(()).and_then(|(def_id, _)| def_id.as_local()))
         .collect::<Vec<_>>();
diff --git a/compiler/rustc_passes/src/lib.rs b/compiler/rustc_passes/src/lib.rs
index 7b2f83958af85..39ebb8db21cbc 100644
--- a/compiler/rustc_passes/src/lib.rs
+++ b/compiler/rustc_passes/src/lib.rs
@@ -8,7 +8,7 @@
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(iter_intersperse)]
 #![feature(let_chains)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(map_try_insert)]
 #![feature(min_specialization)]
 #![feature(try_blocks)]
diff --git a/compiler/rustc_passes/src/reachable.rs b/compiler/rustc_passes/src/reachable.rs
index f7e3fac6b2e20..75244124e20ef 100644
--- a/compiler/rustc_passes/src/reachable.rs
+++ b/compiler/rustc_passes/src/reachable.rs
@@ -12,7 +12,7 @@ use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::Node;
 use rustc_middle::middle::codegen_fn_attrs::{CodegenFnAttrFlags, CodegenFnAttrs};
-use rustc_middle::middle::privacy;
+use rustc_middle::middle::privacy::{self, AccessLevel};
 use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::{self, DefIdTree, TyCtxt};
 use rustc_session::config::CrateType;
@@ -373,7 +373,13 @@ fn reachable_set<'tcx>(tcx: TyCtxt<'tcx>, (): ()) -> FxHashSet<LocalDefId> {
     //         If other crates link to us, they're going to expect to be able to
     //         use the lang items, so we need to be sure to mark them as
     //         exported.
-    reachable_context.worklist.extend(access_levels.map.keys());
+    reachable_context.worklist = access_levels
+        .iter()
+        .filter_map(|(&id, effective_vis)| {
+            effective_vis.is_public_at_level(AccessLevel::ReachableFromImplTrait).then_some(id)
+        })
+        .collect::<Vec<_>>();
+
     for item in tcx.lang_items().items().iter() {
         if let Some(def_id) = *item {
             if let Some(def_id) = def_id.as_local() {
diff --git a/compiler/rustc_privacy/src/errors.rs b/compiler/rustc_privacy/src/errors.rs
index 63f83f8965ec5..705ad567aa779 100644
--- a/compiler/rustc_privacy/src/errors.rs
+++ b/compiler/rustc_privacy/src/errors.rs
@@ -76,8 +76,8 @@ pub struct InPublicInterface<'a> {
 }
 
 #[derive(SessionDiagnostic)]
-#[diag(privacy::report_access_level)]
-pub struct ReportAccessLevel {
+#[diag(privacy::report_effective_visibility)]
+pub struct ReportEffectiveVisibility {
     #[primary_span]
     pub span: Span,
     pub descr: String,
diff --git a/compiler/rustc_privacy/src/lib.rs b/compiler/rustc_privacy/src/lib.rs
index 92ef61fe64c37..8f5ee51e6cfbb 100644
--- a/compiler/rustc_privacy/src/lib.rs
+++ b/compiler/rustc_privacy/src/lib.rs
@@ -1,7 +1,7 @@
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(associated_type_defaults)]
 #![feature(control_flow_enum)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(rustc_private)]
 #![feature(try_blocks)]
 #![recursion_limit = "256"]
@@ -42,7 +42,7 @@ use std::{cmp, fmt, mem};
 
 use errors::{
     FieldIsPrivate, FieldIsPrivateLabel, FromPrivateDependencyInPublicInterface, InPublicInterface,
-    InPublicInterfaceTraits, ItemIsPrivate, PrivateInPublicLint, ReportAccessLevel,
+    InPublicInterfaceTraits, ItemIsPrivate, PrivateInPublicLint, ReportEffectiveVisibility,
     UnnamedItemIsPrivate,
 };
 
@@ -376,7 +376,7 @@ impl VisibilityLike for Option<AccessLevel> {
     // (which require reaching the `DefId`s in them).
     const SHALLOW: bool = true;
     fn new_min(find: &FindMin<'_, '_, Self>, def_id: LocalDefId) -> Self {
-        cmp::min(find.access_levels.map.get(&def_id).copied(), find.min)
+        cmp::min(find.access_levels.get_access_level(def_id), find.min)
     }
 }
 
@@ -416,7 +416,7 @@ struct ReachEverythingInTheInterfaceVisitor<'a, 'tcx> {
 
 impl<'tcx> EmbargoVisitor<'tcx> {
     fn get(&self, def_id: LocalDefId) -> Option<AccessLevel> {
-        self.access_levels.map.get(&def_id).copied()
+        self.access_levels.get_access_level(def_id)
     }
 
     fn update_with_hir_id(
@@ -433,7 +433,7 @@ impl<'tcx> EmbargoVisitor<'tcx> {
         let old_level = self.get(def_id);
         // Accessibility levels can only grow.
         if level > old_level {
-            self.access_levels.map.insert(def_id, level.unwrap());
+            self.access_levels.set_access_level(def_id, level.unwrap());
             self.changed = true;
             level
         } else {
@@ -914,10 +914,31 @@ pub struct TestReachabilityVisitor<'tcx, 'a> {
 
 impl<'tcx, 'a> TestReachabilityVisitor<'tcx, 'a> {
     fn access_level_diagnostic(&mut self, def_id: LocalDefId) {
-        if self.tcx.has_attr(def_id.to_def_id(), sym::rustc_access_level) {
-            let access_level = format!("{:?}", self.access_levels.map.get(&def_id));
-            let span = self.tcx.def_span(def_id.to_def_id());
-            self.tcx.sess.emit_err(ReportAccessLevel { span, descr: access_level });
+        let span = self.tcx.def_span(def_id.to_def_id());
+        if self.tcx.has_attr(def_id.to_def_id(), sym::rustc_effective_visibility) {
+            let mut error_msg = String::new();
+
+            let effective_vis =
+                self.access_levels.get_effective_vis(def_id).copied().unwrap_or_default();
+            for level in [
+                AccessLevel::Public,
+                AccessLevel::Exported,
+                AccessLevel::Reachable,
+                AccessLevel::ReachableFromImplTrait,
+            ] {
+                let vis_str = match effective_vis.get(level) {
+                    Some(ty::Visibility::Restricted(restricted_id)) => {
+                        format!("pub({})", self.tcx.item_name(restricted_id.to_def_id()))
+                    }
+                    Some(ty::Visibility::Public) => "pub".to_string(),
+                    None => "pub(self)".to_string(),
+                };
+                if level != AccessLevel::Public {
+                    error_msg.push_str(", ");
+                }
+                error_msg.push_str(&format!("{:?}: {}", level, vis_str));
+            }
+            self.tcx.sess.emit_err(ReportEffectiveVisibility { span, descr: error_msg });
         }
     }
 }
diff --git a/compiler/rustc_query_system/src/lib.rs b/compiler/rustc_query_system/src/lib.rs
index 8a88b5c334078..f92c3831f2689 100644
--- a/compiler/rustc_query_system/src/lib.rs
+++ b/compiler/rustc_query_system/src/lib.rs
@@ -1,7 +1,7 @@
 #![feature(assert_matches)]
 #![feature(core_intrinsics)]
 #![feature(hash_raw_entry)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(min_specialization)]
 #![feature(extern_types)]
 #![allow(rustc::potential_query_instability)]
diff --git a/compiler/rustc_resolve/src/access_levels.rs b/compiler/rustc_resolve/src/access_levels.rs
index 0a3add2e0f532..9b1111c02c73f 100644
--- a/compiler/rustc_resolve/src/access_levels.rs
+++ b/compiler/rustc_resolve/src/access_levels.rs
@@ -46,7 +46,7 @@ impl<'r, 'a> AccessLevelsVisitor<'r, 'a> {
     /// This will also follow `use` chains (see PrivacyVisitor::set_import_binding_access_level).
     fn set_bindings_access_level(&mut self, module_id: LocalDefId) {
         assert!(self.r.module_map.contains_key(&&module_id.to_def_id()));
-        let module_level = self.r.access_levels.map.get(&module_id).copied();
+        let module_level = self.r.access_levels.get_access_level(module_id);
         if !module_level.is_some() {
             return;
         }
@@ -103,9 +103,9 @@ impl<'r, 'a> AccessLevelsVisitor<'r, 'a> {
         def_id: LocalDefId,
         access_level: Option<AccessLevel>,
     ) -> Option<AccessLevel> {
-        let old_level = self.r.access_levels.map.get(&def_id).copied();
+        let old_level = self.r.access_levels.get_access_level(def_id);
         if old_level < access_level {
-            self.r.access_levels.map.insert(def_id, access_level.unwrap());
+            self.r.access_levels.set_access_level(def_id, access_level.unwrap());
             self.changed = true;
             access_level
         } else {
@@ -131,7 +131,7 @@ impl<'r, 'ast> Visitor<'ast> for AccessLevelsVisitor<'ast, 'r> {
             // Foreign modules inherit level from parents.
             ast::ItemKind::ForeignMod(..) => {
                 let parent_level =
-                    self.r.access_levels.map.get(&self.r.local_parent(def_id)).copied();
+                    self.r.access_levels.get_access_level(self.r.local_parent(def_id));
                 self.set_access_level(item.id, parent_level);
             }
 
@@ -151,7 +151,7 @@ impl<'r, 'ast> Visitor<'ast> for AccessLevelsVisitor<'ast, 'r> {
                 self.set_bindings_access_level(def_id);
                 for variant in variants {
                     let variant_def_id = self.r.local_def_id(variant.id);
-                    let variant_level = self.r.access_levels.map.get(&variant_def_id).copied();
+                    let variant_level = self.r.access_levels.get_access_level(variant_def_id);
                     for field in variant.data.fields() {
                         self.set_access_level(field.id, variant_level);
                     }
@@ -159,7 +159,7 @@ impl<'r, 'ast> Visitor<'ast> for AccessLevelsVisitor<'ast, 'r> {
             }
 
             ast::ItemKind::Struct(ref def, _) | ast::ItemKind::Union(ref def, _) => {
-                let inherited_level = self.r.access_levels.map.get(&def_id).copied();
+                let inherited_level = self.r.access_levels.get_access_level(def_id);
                 for field in def.fields() {
                     if field.vis.kind.is_pub() {
                         self.set_access_level(field.id, inherited_level);
diff --git a/compiler/rustc_resolve/src/lib.rs b/compiler/rustc_resolve/src/lib.rs
index 749a78a7552ed..54a7f416ce64c 100644
--- a/compiler/rustc_resolve/src/lib.rs
+++ b/compiler/rustc_resolve/src/lib.rs
@@ -12,7 +12,7 @@
 #![feature(if_let_guard)]
 #![feature(iter_intersperse)]
 #![feature(let_chains)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(never_type)]
 #![recursion_limit = "256"]
 #![allow(rustdoc::private_intra_doc_links)]
diff --git a/compiler/rustc_save_analysis/src/lib.rs b/compiler/rustc_save_analysis/src/lib.rs
index ebe44a56449d3..ce03c2a8ad05f 100644
--- a/compiler/rustc_save_analysis/src/lib.rs
+++ b/compiler/rustc_save_analysis/src/lib.rs
@@ -1,6 +1,6 @@
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(if_let_guard)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![recursion_limit = "256"]
 #![allow(rustc::potential_query_instability)]
 #![feature(never_type)]
diff --git a/compiler/rustc_serialize/src/lib.rs b/compiler/rustc_serialize/src/lib.rs
index 91f4cfaf5acaa..fa9c7bd54c395 100644
--- a/compiler/rustc_serialize/src/lib.rs
+++ b/compiler/rustc_serialize/src/lib.rs
@@ -14,7 +14,7 @@ Core encoding and decoding interfaces.
 #![feature(min_specialization)]
 #![feature(core_intrinsics)]
 #![feature(maybe_uninit_slice)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(new_uninit)]
 #![feature(allocator_api)]
 #![cfg_attr(test, feature(test))]
diff --git a/compiler/rustc_session/src/lib.rs b/compiler/rustc_session/src/lib.rs
index b9b243f6f0840..f6bab775e76b3 100644
--- a/compiler/rustc_session/src/lib.rs
+++ b/compiler/rustc_session/src/lib.rs
@@ -1,6 +1,6 @@
 #![feature(if_let_guard)]
 #![feature(let_chains)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(min_specialization)]
 #![feature(never_type)]
 #![feature(once_cell)]
diff --git a/compiler/rustc_span/src/lib.rs b/compiler/rustc_span/src/lib.rs
index 26b4ebeab1b39..ada3bae61502f 100644
--- a/compiler/rustc_span/src/lib.rs
+++ b/compiler/rustc_span/src/lib.rs
@@ -15,7 +15,7 @@
 
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(array_windows)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(if_let_guard)]
 #![feature(negative_impls)]
 #![feature(min_specialization)]
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index fcc22e22cc18c..562360130e92f 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -1214,7 +1214,6 @@ symbols! {
         rust_eh_unregister_frames,
         rust_oom,
         rustc,
-        rustc_access_level,
         rustc_allocator,
         rustc_allocator_nounwind,
         rustc_allocator_zeroed,
@@ -1242,6 +1241,7 @@ symbols! {
         rustc_dump_program_clauses,
         rustc_dump_user_substs,
         rustc_dump_vtable,
+        rustc_effective_visibility,
         rustc_error,
         rustc_evaluate_where_clauses,
         rustc_expected_cgu_reuse,
@@ -1322,9 +1322,11 @@ symbols! {
         simd_as,
         simd_bitmask,
         simd_cast,
+        simd_cast_ptr,
         simd_ceil,
         simd_div,
         simd_eq,
+        simd_expose_addr,
         simd_extract,
         simd_fabs,
         simd_fcos,
@@ -1340,6 +1342,7 @@ symbols! {
         simd_fmin,
         simd_fpow,
         simd_fpowi,
+        simd_from_exposed_addr,
         simd_fsin,
         simd_fsqrt,
         simd_gather,
diff --git a/compiler/rustc_target/src/lib.rs b/compiler/rustc_target/src/lib.rs
index 9c9e297849ed5..a7deab9d2efc8 100644
--- a/compiler/rustc_target/src/lib.rs
+++ b/compiler/rustc_target/src/lib.rs
@@ -11,7 +11,7 @@
 #![feature(assert_matches)]
 #![feature(associated_type_bounds)]
 #![feature(exhaustive_patterns)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(min_specialization)]
 #![feature(never_type)]
 #![feature(rustc_attrs)]
diff --git a/compiler/rustc_trait_selection/src/lib.rs b/compiler/rustc_trait_selection/src/lib.rs
index f039b1fca1817..d35f74974fdd9 100644
--- a/compiler/rustc_trait_selection/src/lib.rs
+++ b/compiler/rustc_trait_selection/src/lib.rs
@@ -18,7 +18,7 @@
 #![feature(hash_drain_filter)]
 #![cfg_attr(bootstrap, feature(label_break_value))]
 #![feature(let_chains)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(if_let_guard)]
 #![feature(never_type)]
 #![feature(type_alias_impl_trait)]
diff --git a/compiler/rustc_traits/src/lib.rs b/compiler/rustc_traits/src/lib.rs
index 318e76c79f18b..2d39e973ed9bb 100644
--- a/compiler/rustc_traits/src/lib.rs
+++ b/compiler/rustc_traits/src/lib.rs
@@ -3,7 +3,7 @@
 
 #![deny(rustc::untranslatable_diagnostic)]
 #![deny(rustc::diagnostic_outside_of_impl)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![recursion_limit = "256"]
 
 #[macro_use]
diff --git a/compiler/rustc_ty_utils/src/lib.rs b/compiler/rustc_ty_utils/src/lib.rs
index 6931b15b1ba57..8524e57cb58a3 100644
--- a/compiler/rustc_ty_utils/src/lib.rs
+++ b/compiler/rustc_ty_utils/src/lib.rs
@@ -6,7 +6,7 @@
 
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(control_flow_enum)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(never_type)]
 #![feature(box_patterns)]
 #![recursion_limit = "256"]
diff --git a/compiler/rustc_typeck/src/check/intrinsic.rs b/compiler/rustc_typeck/src/check/intrinsic.rs
index 4fa33da50c9e0..c7425ff7865f7 100644
--- a/compiler/rustc_typeck/src/check/intrinsic.rs
+++ b/compiler/rustc_typeck/src/check/intrinsic.rs
@@ -477,7 +477,11 @@ pub fn check_platform_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>)
         sym::simd_scatter => (3, vec![param(0), param(1), param(2)], tcx.mk_unit()),
         sym::simd_insert => (2, vec![param(0), tcx.types.u32, param(1)], param(0)),
         sym::simd_extract => (2, vec![param(0), tcx.types.u32], param(1)),
-        sym::simd_cast | sym::simd_as => (2, vec![param(0)], param(1)),
+        sym::simd_cast
+        | sym::simd_as
+        | sym::simd_cast_ptr
+        | sym::simd_expose_addr
+        | sym::simd_from_exposed_addr => (2, vec![param(0)], param(1)),
         sym::simd_bitmask => (2, vec![param(0)], param(1)),
         sym::simd_select | sym::simd_select_bitmask => {
             (2, vec![param(0), param(1), param(1)], param(1))
diff --git a/compiler/rustc_typeck/src/collect.rs b/compiler/rustc_typeck/src/collect.rs
index fe74ed28aa5cc..60bd91c867e7a 100644
--- a/compiler/rustc_typeck/src/collect.rs
+++ b/compiler/rustc_typeck/src/collect.rs
@@ -1604,6 +1604,13 @@ fn generics_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::Generics {
         _ => None,
     };
 
+    enum Defaults {
+        Allowed,
+        // See #36887
+        FutureCompatDisallowed,
+        Deny,
+    }
+
     let no_generics = hir::Generics::empty();
     let ast_generics = node.generics().unwrap_or(&no_generics);
     let (opt_self, allow_defaults) = match node {
@@ -1625,17 +1632,26 @@ fn generics_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::Generics {
                         },
                     });
 
-                    (opt_self, true)
+                    (opt_self, Defaults::Allowed)
                 }
                 ItemKind::TyAlias(..)
                 | ItemKind::Enum(..)
                 | ItemKind::Struct(..)
                 | ItemKind::OpaqueTy(..)
-                | ItemKind::Union(..) => (None, true),
-                _ => (None, false),
+                | ItemKind::Union(..) => (None, Defaults::Allowed),
+                _ => (None, Defaults::FutureCompatDisallowed),
             }
         }
-        _ => (None, false),
+
+        // GATs
+        Node::TraitItem(item) if matches!(item.kind, TraitItemKind::Type(..)) => {
+            (None, Defaults::Deny)
+        }
+        Node::ImplItem(item) if matches!(item.kind, ImplItemKind::TyAlias(..)) => {
+            (None, Defaults::Deny)
+        }
+
+        _ => (None, Defaults::FutureCompatDisallowed),
     };
 
     let has_self = opt_self.is_some();
@@ -1668,23 +1684,30 @@ fn generics_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::Generics {
     let type_start = own_start - has_self as u32 + params.len() as u32;
     let mut i = 0;
 
+    const TYPE_DEFAULT_NOT_ALLOWED: &'static str = "defaults for type parameters are only allowed in \
+    `struct`, `enum`, `type`, or `trait` definitions";
+
     params.extend(ast_generics.params.iter().filter_map(|param| match param.kind {
         GenericParamKind::Lifetime { .. } => None,
         GenericParamKind::Type { ref default, synthetic, .. } => {
-            if !allow_defaults && default.is_some() {
-                if !tcx.features().default_type_parameter_fallback {
-                    tcx.struct_span_lint_hir(
-                        lint::builtin::INVALID_TYPE_PARAM_DEFAULT,
-                        param.hir_id,
-                        param.span,
-                        |lint| {
-                            lint.build(
-                                "defaults for type parameters are only allowed in \
-                                 `struct`, `enum`, `type`, or `trait` definitions",
-                            )
-                            .emit();
-                        },
-                    );
+            if default.is_some() {
+                match allow_defaults {
+                    Defaults::Allowed => {}
+                    Defaults::FutureCompatDisallowed
+                        if tcx.features().default_type_parameter_fallback => {}
+                    Defaults::FutureCompatDisallowed => {
+                        tcx.struct_span_lint_hir(
+                            lint::builtin::INVALID_TYPE_PARAM_DEFAULT,
+                            param.hir_id,
+                            param.span,
+                            |lint| {
+                                lint.build(TYPE_DEFAULT_NOT_ALLOWED).emit();
+                            },
+                        );
+                    }
+                    Defaults::Deny => {
+                        tcx.sess.span_err(param.span, TYPE_DEFAULT_NOT_ALLOWED);
+                    }
                 }
             }
 
@@ -1701,7 +1724,7 @@ fn generics_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::Generics {
             Some(param_def)
         }
         GenericParamKind::Const { default, .. } => {
-            if !allow_defaults && default.is_some() {
+            if !matches!(allow_defaults, Defaults::Allowed) && default.is_some() {
                 tcx.sess.span_err(
                     param.span,
                     "defaults for const parameters are only allowed in \
diff --git a/compiler/rustc_typeck/src/lib.rs b/compiler/rustc_typeck/src/lib.rs
index ac66819d2836f..b1ce972e1d682 100644
--- a/compiler/rustc_typeck/src/lib.rs
+++ b/compiler/rustc_typeck/src/lib.rs
@@ -66,7 +66,7 @@ This API is completely unstable and subject to change.
 #![feature(iter_intersperse)]
 #![cfg_attr(bootstrap, feature(label_break_value))]
 #![feature(let_chains)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(min_specialization)]
 #![feature(never_type)]
 #![feature(once_cell)]
diff --git a/library/alloc/src/lib.rs b/library/alloc/src/lib.rs
index e5cf9033c8603..8619467c2d928 100644
--- a/library/alloc/src/lib.rs
+++ b/library/alloc/src/lib.rs
@@ -169,7 +169,7 @@
 #![cfg_attr(not(test), feature(generator_trait))]
 #![feature(hashmap_internals)]
 #![feature(lang_items)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(min_specialization)]
 #![feature(negative_impls)]
 #![feature(never_type)]
diff --git a/library/std/src/lib.rs b/library/std/src/lib.rs
index f13500de01431..bc4f1b27c2aaa 100644
--- a/library/std/src/lib.rs
+++ b/library/std/src/lib.rs
@@ -255,7 +255,7 @@
 #![cfg_attr(bootstrap, feature(label_break_value))]
 #![feature(lang_items)]
 #![feature(let_chains)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(linkage)]
 #![feature(link_cfg)]
 #![feature(min_specialization)]
diff --git a/src/bootstrap/builder.rs b/src/bootstrap/builder.rs
index 14e8ebd6876b4..3d5933f1f1400 100644
--- a/src/bootstrap/builder.rs
+++ b/src/bootstrap/builder.rs
@@ -708,6 +708,7 @@ impl<'a> Builder<'a> {
             Kind::Dist => describe!(
                 dist::Docs,
                 dist::RustcDocs,
+                dist::JsonDocs,
                 dist::Mingw,
                 dist::Rustc,
                 dist::Std,
diff --git a/src/bootstrap/builder/tests.rs b/src/bootstrap/builder/tests.rs
index 280eba75f0c19..88bbcc93d072c 100644
--- a/src/bootstrap/builder/tests.rs
+++ b/src/bootstrap/builder/tests.rs
@@ -236,7 +236,7 @@ mod defaults {
     fn doc_default() {
         let mut config = configure("doc", &["A"], &["A"]);
         config.compiler_docs = true;
-        config.cmd = Subcommand::Doc { paths: Vec::new(), open: false };
+        config.cmd = Subcommand::Doc { paths: Vec::new(), open: false, json: false };
         let mut cache = run_build(&[], config);
         let a = TargetSelection::from_user("A");
 
@@ -587,7 +587,7 @@ mod dist {
     fn doc_ci() {
         let mut config = configure(&["A"], &["A"]);
         config.compiler_docs = true;
-        config.cmd = Subcommand::Doc { paths: Vec::new(), open: false };
+        config.cmd = Subcommand::Doc { paths: Vec::new(), open: false, json: false };
         let build = Build::new(config);
         let mut builder = Builder::new(&build);
         builder.run_step_descriptions(&Builder::get_step_descriptions(Kind::Doc), &[]);
diff --git a/src/bootstrap/dist.rs b/src/bootstrap/dist.rs
index 1a59b3958f106..c9ee3c1c7d65d 100644
--- a/src/bootstrap/dist.rs
+++ b/src/bootstrap/dist.rs
@@ -87,6 +87,45 @@ impl Step for Docs {
     }
 }
 
+#[derive(Debug, PartialOrd, Ord, Copy, Clone, Hash, PartialEq, Eq)]
+pub struct JsonDocs {
+    pub host: TargetSelection,
+}
+
+impl Step for JsonDocs {
+    type Output = Option<GeneratedTarball>;
+    const DEFAULT: bool = true;
+
+    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
+        let default = run.builder.config.docs;
+        run.alias("rust-json-docs").default_condition(default)
+    }
+
+    fn make_run(run: RunConfig<'_>) {
+        run.builder.ensure(JsonDocs { host: run.target });
+    }
+
+    /// Builds the `rust-json-docs` installer component.
+    fn run(self, builder: &Builder<'_>) -> Option<GeneratedTarball> {
+        // This prevents JSON docs from being built for "dist" or "install"
+        // on the stable/beta channels. The JSON format is not stable yet and
+        // should not be included in stable/beta toolchains.
+        if !builder.build.unstable_features() {
+            return None;
+        }
+
+        let host = self.host;
+        builder.ensure(crate::doc::JsonStd { stage: builder.top_stage, target: host });
+
+        let dest = "share/doc/rust/json";
+
+        let mut tarball = Tarball::new(builder, "rust-json-docs", &host.triple);
+        tarball.set_product_name("Rust Documentation In JSON Format");
+        tarball.add_bulk_dir(&builder.json_doc_out(host), dest);
+        Some(tarball.generate())
+    }
+}
+
 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
 pub struct RustcDocs {
     pub host: TargetSelection,
diff --git a/src/bootstrap/doc.rs b/src/bootstrap/doc.rs
index f909ecc0ab858..8de41c806807b 100644
--- a/src/bootstrap/doc.rs
+++ b/src/bootstrap/doc.rs
@@ -7,6 +7,7 @@
 //! Everything here is basically just a shim around calling either `rustbook` or
 //! `rustdoc`.
 
+use std::ffi::OsStr;
 use std::fs;
 use std::io;
 use std::path::{Path, PathBuf};
@@ -432,48 +433,24 @@ impl Step for Std {
         let stage = self.stage;
         let target = self.target;
         builder.info(&format!("Documenting stage{} std ({})", stage, target));
-        if builder.no_std(target) == Some(true) {
-            panic!(
-                "building std documentation for no_std target {target} is not supported\n\
-                 Set `docs = false` in the config to disable documentation."
-            );
-        }
         let out = builder.doc_out(target);
         t!(fs::create_dir_all(&out));
-        let compiler = builder.compiler(stage, builder.config.build);
-
-        let out_dir = builder.stage_out(compiler, Mode::Std).join(target.triple).join("doc");
-
         t!(fs::copy(builder.src.join("src/doc/rust.css"), out.join("rust.css")));
 
-        let run_cargo_rustdoc_for = |package: &str| {
-            let mut cargo =
-                builder.cargo(compiler, Mode::Std, SourceType::InTree, target, "rustdoc");
-            compile::std_cargo(builder, target, compiler.stage, &mut cargo);
-
-            cargo
-                .arg("-p")
-                .arg(package)
-                .arg("-Zskip-rustdoc-fingerprint")
-                .arg("--")
-                .arg("--markdown-css")
-                .arg("rust.css")
-                .arg("--markdown-no-toc")
-                .arg("-Z")
-                .arg("unstable-options")
-                .arg("--resource-suffix")
-                .arg(&builder.version)
-                .arg("--index-page")
-                .arg(&builder.src.join("src/doc/index.md"));
-
-            if !builder.config.docs_minification {
-                cargo.arg("--disable-minification");
-            }
-
-            builder.run(&mut cargo.into());
-        };
+        let index_page = builder.src.join("src/doc/index.md").into_os_string();
+        let mut extra_args = vec![
+            OsStr::new("--markdown-css"),
+            OsStr::new("rust.css"),
+            OsStr::new("--markdown-no-toc"),
+            OsStr::new("--index-page"),
+            &index_page,
+        ];
+
+        if !builder.config.docs_minification {
+            extra_args.push(OsStr::new("--disable-minification"));
+        }
 
-        let paths = builder
+        let requested_crates = builder
             .paths
             .iter()
             .map(components_simplified)
@@ -491,30 +468,20 @@ impl Step for Std {
             })
             .collect::<Vec<_>>();
 
-        // Only build the following crates. While we could just iterate over the
-        // folder structure, that would also build internal crates that we do
-        // not want to show in documentation. These crates will later be visited
-        // by the rustc step, so internal documentation will show them.
-        //
-        // Note that the order here is important! The crates need to be
-        // processed starting from the leaves, otherwise rustdoc will not
-        // create correct links between crates because rustdoc depends on the
-        // existence of the output directories to know if it should be a local
-        // or remote link.
-        let krates = ["core", "alloc", "std", "proc_macro", "test"];
-        for krate in &krates {
-            run_cargo_rustdoc_for(krate);
-            if paths.iter().any(|p| p == krate) {
-                // No need to document more of the libraries if we have the one we want.
-                break;
-            }
-        }
-        builder.cp_r(&out_dir, &out);
+        doc_std(
+            builder,
+            DocumentationFormat::HTML,
+            stage,
+            target,
+            &out,
+            &extra_args,
+            &requested_crates,
+        );
 
         // Look for library/std, library/core etc in the `x.py doc` arguments and
         // open the corresponding rendered docs.
-        for requested_crate in paths {
-            if krates.iter().any(|k| *k == requested_crate.as_str()) {
+        for requested_crate in requested_crates {
+            if STD_PUBLIC_CRATES.iter().any(|k| *k == requested_crate.as_str()) {
                 let index = out.join(requested_crate).join("index.html");
                 open(builder, &index);
             }
@@ -522,6 +489,132 @@ impl Step for Std {
     }
 }
 
+#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
+pub struct JsonStd {
+    pub stage: u32,
+    pub target: TargetSelection,
+}
+
+impl Step for JsonStd {
+    type Output = ();
+    const DEFAULT: bool = false;
+
+    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
+        let default = run.builder.config.docs && run.builder.config.cmd.json();
+        run.all_krates("test").path("library").default_condition(default)
+    }
+
+    fn make_run(run: RunConfig<'_>) {
+        run.builder.ensure(Std { stage: run.builder.top_stage, target: run.target });
+    }
+
+    /// Build JSON documentation for the standard library crates.
+    ///
+    /// This is largely just a wrapper around `cargo doc`.
+    fn run(self, builder: &Builder<'_>) {
+        let stage = self.stage;
+        let target = self.target;
+        let out = builder.json_doc_out(target);
+        t!(fs::create_dir_all(&out));
+        let extra_args = [OsStr::new("--output-format"), OsStr::new("json")];
+        doc_std(builder, DocumentationFormat::JSON, stage, target, &out, &extra_args, &[])
+    }
+}
+
+/// Name of the crates that are visible to consumers of the standard library.
+/// Documentation for internal crates is handled by the rustc step, so internal crates will show
+/// up there.
+///
+/// Order here is important!
+/// Crates need to be processed starting from the leaves, otherwise rustdoc will not
+/// create correct links between crates because rustdoc depends on the
+/// existence of the output directories to know if it should be a local
+/// or remote link.
+const STD_PUBLIC_CRATES: [&str; 5] = ["core", "alloc", "std", "proc_macro", "test"];
+
+#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
+enum DocumentationFormat {
+    HTML,
+    JSON,
+}
+
+impl DocumentationFormat {
+    fn as_str(&self) -> &str {
+        match self {
+            DocumentationFormat::HTML => "HTML",
+            DocumentationFormat::JSON => "JSON",
+        }
+    }
+}
+
+/// Build the documentation for public standard library crates.
+///
+/// `requested_crates` can be used to build only a subset of the crates. If empty, all crates will
+/// be built.
+fn doc_std(
+    builder: &Builder<'_>,
+    format: DocumentationFormat,
+    stage: u32,
+    target: TargetSelection,
+    out: &Path,
+    extra_args: &[&OsStr],
+    requested_crates: &[String],
+) {
+    builder.info(&format!(
+        "Documenting stage{} std ({}) in {} format",
+        stage,
+        target,
+        format.as_str()
+    ));
+    if builder.no_std(target) == Some(true) {
+        panic!(
+            "building std documentation for no_std target {target} is not supported\n\
+             Set `docs = false` in the config to disable documentation."
+        );
+    }
+    let compiler = builder.compiler(stage, builder.config.build);
+    // This is directory where the compiler will place the output of the command.
+    // We will then copy the files from this directory into the final `out` directory, the specified
+    // as a function parameter.
+    let out_dir = builder.stage_out(compiler, Mode::Std).join(target.triple).join("doc");
+    // `cargo` uses the same directory for both JSON docs and HTML docs.
+    // This could lead to cross-contamination when copying files into the specified `out` directory.
+    // For example:
+    // ```bash
+    // x doc std
+    // x doc std --json
+    // ```
+    // could lead to HTML docs being copied into the JSON docs output directory.
+    // To avoid this issue, we clean the doc folder before invoking `cargo`.
+    builder.remove_dir(&out_dir);
+
+    let run_cargo_rustdoc_for = |package: &str| {
+        let mut cargo = builder.cargo(compiler, Mode::Std, SourceType::InTree, target, "rustdoc");
+        compile::std_cargo(builder, target, compiler.stage, &mut cargo);
+        cargo
+            .arg("-p")
+            .arg(package)
+            .arg("-Zskip-rustdoc-fingerprint")
+            .arg("--")
+            .arg("-Z")
+            .arg("unstable-options")
+            .arg("--resource-suffix")
+            .arg(&builder.version)
+            .args(extra_args);
+        builder.run(&mut cargo.into());
+    };
+
+    for krate in STD_PUBLIC_CRATES {
+        run_cargo_rustdoc_for(krate);
+        if requested_crates.iter().any(|p| p == krate) {
+            // No need to document more of the libraries if we have the one we want.
+            break;
+        }
+    }
+
+    builder.cp_r(&out_dir, &out);
+}
+
 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
 pub struct Rustc {
     pub stage: u32,
diff --git a/src/bootstrap/flags.rs b/src/bootstrap/flags.rs
index 789da74810035..802b49d748ac6 100644
--- a/src/bootstrap/flags.rs
+++ b/src/bootstrap/flags.rs
@@ -107,6 +107,7 @@ pub enum Subcommand {
     Doc {
         paths: Vec<PathBuf>,
         open: bool,
+        json: bool,
     },
     Test {
         paths: Vec<PathBuf>,
@@ -325,6 +326,11 @@ To learn more about a subcommand, run `./x.py <subcommand> -h`",
             }
             Kind::Doc => {
                 opts.optflag("", "open", "open the docs in a browser");
+                opts.optflag(
+                    "",
+                    "json",
+                    "render the documentation in JSON format in addition to the usual HTML format",
+                );
             }
             Kind::Clean => {
                 opts.optflag("", "all", "clean all build artifacts");
@@ -493,6 +499,7 @@ Arguments:
         ./x.py doc src/doc/book
         ./x.py doc src/doc/nomicon
         ./x.py doc src/doc/book library/std
+        ./x.py doc library/std --json
         ./x.py doc library/std --open
 
     If no arguments are passed then everything is documented:
@@ -581,7 +588,11 @@ Arguments:
                 },
             },
             Kind::Bench => Subcommand::Bench { paths, test_args: matches.opt_strs("test-args") },
-            Kind::Doc => Subcommand::Doc { paths, open: matches.opt_present("open") },
+            Kind::Doc => Subcommand::Doc {
+                paths,
+                open: matches.opt_present("open"),
+                json: matches.opt_present("json"),
+            },
             Kind::Clean => {
                 if !paths.is_empty() {
                     println!("\nclean does not take a path argument\n");
@@ -787,6 +798,13 @@ impl Subcommand {
             _ => false,
         }
     }
+
+    pub fn json(&self) -> bool {
+        match *self {
+            Subcommand::Doc { json, .. } => json,
+            _ => false,
+        }
+    }
 }
 
 fn split(s: &[String]) -> Vec<String> {
diff --git a/src/bootstrap/lib.rs b/src/bootstrap/lib.rs
index cc0cf12bd187a..868ec10bc15d8 100644
--- a/src/bootstrap/lib.rs
+++ b/src/bootstrap/lib.rs
@@ -825,6 +825,11 @@ impl Build {
         self.out.join(&*target.triple).join("doc")
     }
 
+    /// Output directory for all JSON-formatted documentation for a target
+    fn json_doc_out(&self, target: TargetSelection) -> PathBuf {
+        self.out.join(&*target.triple).join("json-doc")
+    }
+
     fn test_out(&self, target: TargetSelection) -> PathBuf {
         self.out.join(&*target.triple).join("test")
     }
diff --git a/src/librustdoc/core.rs b/src/librustdoc/core.rs
index c48b25aea4a37..76562d26a5502 100644
--- a/src/librustdoc/core.rs
+++ b/src/librustdoc/core.rs
@@ -10,7 +10,6 @@ use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::{HirId, Path, TraitCandidate};
 use rustc_interface::interface;
 use rustc_middle::hir::nested_filter;
-use rustc_middle::middle::privacy::AccessLevels;
 use rustc_middle::ty::{ParamEnv, Ty, TyCtxt};
 use rustc_resolve as resolve;
 use rustc_session::config::{self, CrateType, ErrorOutputType};
@@ -364,9 +363,7 @@ pub(crate) fn run_global_ctxt(
         .copied()
         .filter(|&trait_def_id| tcx.trait_is_auto(trait_def_id))
         .collect();
-    let access_levels = AccessLevels {
-        map: tcx.privacy_access_levels(()).map.iter().map(|(k, v)| (k.to_def_id(), *v)).collect(),
-    };
+    let access_levels = tcx.privacy_access_levels(()).map_id(Into::into);
 
     let mut ctxt = DocContext {
         tcx,
diff --git a/src/librustdoc/html/static/css/themes/ayu.css b/src/librustdoc/html/static/css/themes/ayu.css
index 74de113495c2e..c292a8a7ef70b 100644
--- a/src/librustdoc/html/static/css/themes/ayu.css
+++ b/src/librustdoc/html/static/css/themes/ayu.css
@@ -118,8 +118,7 @@ pre, .rustdoc.source .example-wrap {
 .content span.primitive, .content a.primitive { color: #ffa0a5; }
 .content span.traitalias, .content a.traitalias { color: #39AFD7; }
 .content span.keyword, .content a.keyword { color: #39AFD7; }
-
-.content span.externcrate, .content span.mod, .content a.mod {
+.content span.mod, .content a.mod {
 	color: #39AFD7;
 }
 .content span.struct, .content a.struct {
@@ -131,20 +130,10 @@ pre, .rustdoc.source .example-wrap {
 .content span.trait, .content a.trait {
 	color: #39AFD7;
 }
-.content span.type, .content a.type {
-	color: #39AFD7;
-}
-.content span.type,
-.content a.type,
-.block a.current.type { color: #39AFD7; }
-.content span.associatedtype,
-.content a.associatedtype,
-.block a.current.associatedtype { color: #39AFD7; }
-.content span.fn, .content a.fn, .content span.method,
-.content a.method, .content span.tymethod,
-.content a.tymethod, .content .fnname {
-	color: #fdd687;
-}
+.content span.type, .content a.type { color: #39AFD7; }
+.content span.associatedtype, .content a.associatedtype { color: #39AFD7; }
+.content span.fn, .content a.fn,
+.content .fnname { color: #fdd687; }
 .content span.attr, .content a.attr, .content span.derive,
 .content a.derive, .content span.macro, .content a.macro {
 	color: #a37acc;
@@ -152,7 +141,6 @@ pre, .rustdoc.source .example-wrap {
 
 .sidebar a { color: #53b1db; }
 .sidebar a.current.type { color: #53b1db; }
-.sidebar a.current.associatedtype { color: #53b1db; }
 
 pre.rust .comment { color: #788797; }
 pre.rust .doccomment { color: #a1ac88; }
@@ -290,34 +278,11 @@ individually rather than as a group) */
 /* FIXME: these rules should be at the bottom of the file but currently must be
 above the `@media (max-width: 700px)` rules due to a bug in the css checker */
 /* see https://github.com/rust-lang/rust/pull/71237#issuecomment-618170143 */
-.content span.attr,.content a.attr,.block a.current.attr,.content span.derive,.content a.derive,
-.block a.current.derive,.content span.macro,.content a.macro,.block a.current.macro {}
-.content span.struct,.content a.struct,.block a.current.struct {}
-#titles>button:hover,#titles>button.selected {}
-.content span.typedef,.content a.typedef,.block a.current.typedef {}
-.content span.union,.content a.union,.block a.current.union {}
 pre.rust .lifetime {}
-.stab.unstable {}
-h2,
-h3:not(.impl):not(.method):not(.type):not(.tymethod), h4:not(.method):not(.type):not(.tymethod) {}
-.content span.enum,.content a.enum,.block a.current.enum {}
-.content span.constant,.content a.constant,.block a.current.constant,.content span.static,
-.content a.static, .block a.current.static {}
-.content span.keyword,.content a.keyword,.block a.current.keyword {}
-.content span.traitalias,.content a.traitalias,.block a.current.traitalias {}
-.content span.fn,.content a.fn,.block a.current.fn,.content span.method,.content a.method,
-.block a.current.method,.content span.tymethod,.content a.tymethod,.block a.current.tymethod,
-.content .fnname {}
 pre.rust .kw {}
-pre.rust .self,pre.rust .bool-val,pre.rust .prelude-val,pre.rust .attribute {}
-.content span.foreigntype,.content a.foreigntype,.block a.current.foreigntype {}
-.stab.deprecated {}
-.content a.attr,.content a.derive,.content a.macro {}
-.stab.portability {}
-.content span.primitive,.content a.primitive,.block a.current.primitive {}
-.content span.externcrate,.content span.mod,.content a.mod,.block a.current.mod {}
-pre.rust .kw-2,pre.rust .prelude-ty {}
-.content span.trait,.content a.trait,.block a.current.trait {}
+#titles > button:hover, #titles > button.selected {}
+pre.rust .self, pre.rust .bool-val, pre.rust .prelude-val, pre.rust .attribute {}
+pre.rust .kw-2, pre.rust .prelude-ty {}
 
 .search-results a:focus span {}
 a.result-trait:focus {}
@@ -353,13 +318,9 @@ a.result-keyword:focus {}
 .sidebar a.current.constant
 .sidebar a.current.static {}
 .sidebar a.current.primitive {}
-.sidebar a.current.externcrate
-.sidebar a.current.mod {}
 .sidebar a.current.trait {}
 .sidebar a.current.traitalias {}
-.sidebar a.current.fn,
-.sidebar a.current.method,
-.sidebar a.current.tymethod {}
+.sidebar a.current.fn {}
 .sidebar a.current.keyword {}
 
 kbd {
diff --git a/src/librustdoc/html/static/css/themes/dark.css b/src/librustdoc/html/static/css/themes/dark.css
index 153b40f05d8de..68542d3305ca0 100644
--- a/src/librustdoc/html/static/css/themes/dark.css
+++ b/src/librustdoc/html/static/css/themes/dark.css
@@ -83,35 +83,29 @@ a.result-keyword:focus { background-color: #884719; }
 
 .content .item-info::before { color: #ccc; }
 
-.content span.enum, .content a.enum, .block a.current.enum { color: #2dbfb8; }
-.content span.struct, .content a.struct, .block a.current.struct { color: #2dbfb8; }
-.content span.type, .content a.type, .block a.current.type { color: #2dbfb8; }
-.content span.associatedtype,
-.content a.associatedtype,
-.block a.current.associatedtype { color: #D2991D; }
-.content span.foreigntype, .content a.foreigntype, .block a.current.foreigntype { color: #2dbfb8; }
-.content span.attr, .content a.attr, .block a.current.attr,
-.content span.derive, .content a.derive, .block a.current.derive,
-.content span.macro, .content a.macro, .block a.current.macro { color: #09bd00; }
-.content span.union, .content a.union, .block a.current.union { color: #2dbfb8; }
-.content span.constant, .content a.constant, .block a.current.constant,
-.content span.static, .content a.static, .block a.current.static { color: #D2991D; }
-.content span.primitive, .content a.primitive, .block a.current.primitive { color: #2dbfb8; }
-.content span.externcrate,
-.content span.mod, .content a.mod, .block a.current.mod { color: #D2991D; }
-.content span.trait, .content a.trait, .block a.current.trait { color: #b78cf2; }
-.content span.traitalias, .content a.traitalias, .block a.current.traitalias { color: #b78cf2; }
-.content span.fn, .content a.fn, .block a.current.fn,
-.content span.method, .content a.method, .block a.current.method,
-.content span.tymethod, .content a.tymethod, .block a.current.tymethod,
-.content .fnname{ color: #2BAB63; }
-.content span.keyword, .content a.keyword, .block a.current.keyword { color: #D2991D; }
+.content span.enum, .content a.enum { color: #2dbfb8; }
+.content span.struct, .content a.struct { color: #2dbfb8; }
+.content span.type, .content a.type { color: #2dbfb8; }
+.content span.associatedtype, .content a.associatedtype { color: #D2991D; }
+.content span.foreigntype, .content a.foreigntype { color: #2dbfb8; }
+.content span.attr, .content a.attr,
+.content span.derive, .content a.derive,
+.content span.macro, .content a.macro { color: #09bd00; }
+.content span.union, .content a.union { color: #2dbfb8; }
+.content span.constant, .content a.constant,
+.content span.static, .content a.static { color: #D2991D; }
+.content span.primitive, .content a.primitive { color: #2dbfb8; }
+.content span.mod, .content a.mod { color: #D2991D; }
+.content span.trait, .content a.trait { color: #b78cf2; }
+.content span.traitalias, .content a.traitalias { color: #b78cf2; }
+.content span.fn, .content a.fn,
+.content .fnname { color: #2BAB63; }
+.content span.keyword, .content a.keyword { color: #D2991D; }
 
 .sidebar a { color: #fdbf35; }
 .sidebar a.current.enum { color: #12ece2; }
 .sidebar a.current.struct { color: #12ece2; }
 .sidebar a.current.type { color: #12ece2; }
-.sidebar a.current.associatedtype { color: #fdbf35; }
 .sidebar a.current.foreigntype { color: #12ece2; }
 .sidebar a.current.attr,
 .sidebar a.current.derive,
@@ -120,13 +114,9 @@ a.result-keyword:focus { background-color: #884719; }
 .sidebar a.current.constant
 .sidebar a.current.static { color: #fdbf35; }
 .sidebar a.current.primitive { color: #12ece2; }
-.sidebar a.current.externcrate
-.sidebar a.current.mod { color: #fdbf35; }
 .sidebar a.current.trait { color: #cca7ff; }
 .sidebar a.current.traitalias { color: #cca7ff; }
-.sidebar a.current.fn,
-.sidebar a.current.method,
-.sidebar a.current.tymethod { color: #32d479; }
+.sidebar a.current.fn { color: #32d479; }
 .sidebar a.current.keyword { color: #fdbf35; }
 
 pre.rust .comment { color: #8d8d8b; }
diff --git a/src/librustdoc/html/static/css/themes/light.css b/src/librustdoc/html/static/css/themes/light.css
index 9ced9e7b5ce32..0b7d1600e7aa4 100644
--- a/src/librustdoc/html/static/css/themes/light.css
+++ b/src/librustdoc/html/static/css/themes/light.css
@@ -82,35 +82,29 @@ a.result-keyword:focus { background-color: #afc6e4; }
 
 .content .item-info::before { color: #ccc; }
 
-.content span.enum, .content a.enum, .block a.current.enum { color: #AD378A; }
-.content span.struct, .content a.struct, .block a.current.struct { color: #AD378A; }
-.content span.type, .content a.type, .block a.current.type { color:  #AD378A; }
-.content span.foreigntype, .content a.foreigntype, .block a.current.foreigntype { color: #3873AD; }
-.content span.associatedtype,
-.content a.associatedtype,
-.block a.current.associatedtype { color: #3873AD; }
-.content span.attr, .content a.attr, .block a.current.attr,
-.content span.derive, .content a.derive, .block a.current.derive,
-.content span.macro, .content a.macro, .block a.current.macro { color: #068000; }
-.content span.union, .content a.union, .block a.current.union { color: #AD378A; }
-.content span.constant, .content a.constant, .block a.current.constant,
-.content span.static, .content a.static, .block a.current.static { color: #3873AD; }
-.content span.primitive, .content a.primitive, .block a.current.primitive { color: #AD378A; }
-.content span.externcrate,
-.content span.mod, .content a.mod, .block a.current.mod { color: #3873AD; }
-.content span.trait, .content a.trait, .block a.current.trait { color: #6E4FC9; }
-.content span.traitalias, .content a.traitalias, .block a.current.traitalias { color: #5137AD; }
-.content span.fn, .content a.fn, .block a.current.fn,
-.content span.method, .content a.method, .block a.current.method,
-.content span.tymethod, .content a.tymethod, .block a.current.tymethod,
+.content span.enum, .content a.enum { color: #AD378A; }
+.content span.struct, .content a.struct { color: #AD378A; }
+.content span.type, .content a.type { color:  #AD378A; }
+.content span.associatedtype, .content a.associatedtype { color: #3873AD; }
+.content span.foreigntype, .content a.foreigntype { color: #3873AD; }
+.content span.attr, .content a.attr,
+.content span.derive, .content a.derive,
+.content span.macro, .content a.macro { color: #068000; }
+.content span.union, .content a.union { color: #AD378A; }
+.content span.constant, .content a.constant,
+.content span.static, .content a.static { color: #3873AD; }
+.content span.primitive, .content a.primitive { color: #AD378A; }
+.content span.mod, .content a.mod { color: #3873AD; }
+.content span.trait, .content a.trait { color: #6E4FC9; }
+.content span.traitalias, .content a.traitalias { color: #5137AD; }
+.content span.fn, .content a.fn,
 .content .fnname { color: #AD7C37; }
-.content span.keyword, .content a.keyword, .block a.current.keyword { color: #3873AD; }
+.content span.keyword, .content a.keyword { color: #3873AD; }
 
 .sidebar a { color: #356da4; }
 .sidebar a.current.enum { color: #a63283; }
 .sidebar a.current.struct { color: #a63283; }
 .sidebar a.current.type { color: #a63283; }
-.sidebar a.current.associatedtype { color: #356da4; }
 .sidebar a.current.foreigntype { color: #356da4; }
 .sidebar a.current.attr,
 .sidebar a.current.derive,
@@ -119,13 +113,9 @@ a.result-keyword:focus { background-color: #afc6e4; }
 .sidebar a.current.constant
 .sidebar a.current.static { color: #356da4; }
 .sidebar a.current.primitive { color: #a63283; }
-.sidebar a.current.externcrate
-.sidebar a.current.mod { color: #356da4; }
 .sidebar a.current.trait { color: #6849c3; }
 .sidebar a.current.traitalias { color: #4b349e; }
-.sidebar a.current.fn,
-.sidebar a.current.method,
-.sidebar a.current.tymethod { color: #a67736; }
+.sidebar a.current.fn { color: #a67736; }
 .sidebar a.current.keyword { color: #356da4; }
 
 a {
diff --git a/src/librustdoc/lib.rs b/src/librustdoc/lib.rs
index f6c648140b856..14d695582b0f8 100644
--- a/src/librustdoc/lib.rs
+++ b/src/librustdoc/lib.rs
@@ -9,7 +9,7 @@
 #![feature(control_flow_enum)]
 #![feature(drain_filter)]
 #![feature(let_chains)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(test)]
 #![feature(never_type)]
 #![feature(once_cell)]
diff --git a/src/librustdoc/visit_ast.rs b/src/librustdoc/visit_ast.rs
index c27ac0ac40e1d..e6cef4a326ac0 100644
--- a/src/librustdoc/visit_ast.rs
+++ b/src/librustdoc/visit_ast.rs
@@ -230,7 +230,7 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
                     } else {
                         // All items need to be handled here in case someone wishes to link
                         // to them with intra-doc links
-                        self.cx.cache.access_levels.map.insert(did, AccessLevel::Public);
+                        self.cx.cache.access_levels.set_access_level(did, AccessLevel::Public);
                     }
                 }
             }
diff --git a/src/librustdoc/visit_lib.rs b/src/librustdoc/visit_lib.rs
index f01ec38665c01..8221e0998d79a 100644
--- a/src/librustdoc/visit_lib.rs
+++ b/src/librustdoc/visit_lib.rs
@@ -38,10 +38,10 @@ impl<'a, 'tcx> LibEmbargoVisitor<'a, 'tcx> {
     fn update(&mut self, did: DefId, level: Option<AccessLevel>) -> Option<AccessLevel> {
         let is_hidden = self.tcx.is_doc_hidden(did);
 
-        let old_level = self.access_levels.map.get(&did).cloned();
+        let old_level = self.access_levels.get_access_level(did);
         // Accessibility levels can only grow
         if level > old_level && !is_hidden {
-            self.access_levels.map.insert(did, level.unwrap());
+            self.access_levels.set_access_level(did, level.unwrap());
             level
         } else {
             old_level
diff --git a/src/test/ui/async-await/async-await-let-else.rs b/src/test/ui/async-await/async-await-let-else.rs
index 4b287159d13e7..3fb2142b9e5d8 100644
--- a/src/test/ui/async-await/async-await-let-else.rs
+++ b/src/test/ui/async-await/async-await-let-else.rs
@@ -2,7 +2,7 @@
 // revisions: drop-tracking no-drop-tracking
 // [drop-tracking] compile-flags: -Zdrop-tracking=yes
 // [no-drop-tracking] compile-flags: -Zdrop-tracking=no
-#![feature(let_else)]
+
 use std::rc::Rc;
 
 async fn foo(x: Option<bool>) {
diff --git a/src/test/ui/empty/empty-never-array.stderr b/src/test/ui/empty/empty-never-array.stderr
index 8c80b05ee3aea..adf7827436805 100644
--- a/src/test/ui/empty/empty-never-array.stderr
+++ b/src/test/ui/empty/empty-never-array.stderr
@@ -18,7 +18,7 @@ help: you might want to use `if let` to ignore the variant that isn't matched
    |
 LL |     let u = if let Helper::U(u) = Helper::T(t, []) { u } else { todo!() };
    |     ++++++++++                                     ++++++++++++++++++++++
-help: alternatively, on nightly, you might want to use `#![feature(let_else)]` to handle the variant that isn't matched
+help: alternatively, you might want to use let else to handle the variant that isn't matched
    |
 LL |     let Helper::U(u) = Helper::T(t, []) else { todo!() };
    |                                         ++++++++++++++++
diff --git a/src/test/ui/error-codes/E0005.stderr b/src/test/ui/error-codes/E0005.stderr
index f01a77bd374b6..de8e6bac486c1 100644
--- a/src/test/ui/error-codes/E0005.stderr
+++ b/src/test/ui/error-codes/E0005.stderr
@@ -19,7 +19,7 @@ help: you might want to use `if let` to ignore the variant that isn't matched
    |
 LL |     let y = if let Some(y) = x { y } else { todo!() };
    |     ++++++++++                 ++++++++++++++++++++++
-help: alternatively, on nightly, you might want to use `#![feature(let_else)]` to handle the variant that isn't matched
+help: alternatively, you might want to use let else to handle the variant that isn't matched
    |
 LL |     let Some(y) = x else { todo!() };
    |                     ++++++++++++++++
diff --git a/src/test/ui/feature-gates/feature-gate-exhaustive-patterns.stderr b/src/test/ui/feature-gates/feature-gate-exhaustive-patterns.stderr
index f8349391a0fe7..5ced344f13f38 100644
--- a/src/test/ui/feature-gates/feature-gate-exhaustive-patterns.stderr
+++ b/src/test/ui/feature-gates/feature-gate-exhaustive-patterns.stderr
@@ -19,7 +19,7 @@ help: you might want to use `if let` to ignore the variant that isn't matched
    |
 LL |     let _x = if let Ok(_x) = foo() { _x } else { todo!() };
    |     +++++++++++                    +++++++++++++++++++++++
-help: alternatively, on nightly, you might want to use `#![feature(let_else)]` to handle the variant that isn't matched
+help: alternatively, you might want to use let else to handle the variant that isn't matched
    |
 LL |     let Ok(_x) = foo() else { todo!() };
    |                        ++++++++++++++++
diff --git a/src/test/ui/feature-gates/feature-gate-let_else.rs b/src/test/ui/feature-gates/feature-gate-let_else.rs
deleted file mode 100644
index 3f04a9dabfd1f..0000000000000
--- a/src/test/ui/feature-gates/feature-gate-let_else.rs
+++ /dev/null
@@ -1,5 +0,0 @@
-fn main() {
-    let Some(x) = Some(1) else { //~ ERROR `let...else` statements are unstable
-        return;
-    };
-}
diff --git a/src/test/ui/feature-gates/feature-gate-let_else.stderr b/src/test/ui/feature-gates/feature-gate-let_else.stderr
deleted file mode 100644
index 8625260415467..0000000000000
--- a/src/test/ui/feature-gates/feature-gate-let_else.stderr
+++ /dev/null
@@ -1,14 +0,0 @@
-error[E0658]: `let...else` statements are unstable
-  --> $DIR/feature-gate-let_else.rs:2:5
-   |
-LL | /     let Some(x) = Some(1) else {
-LL | |         return;
-LL | |     };
-   | |______^
-   |
-   = note: see issue #87335 <https://github.com/rust-lang/rust/issues/87335> for more information
-   = help: add `#![feature(let_else)]` to the crate attributes to enable
-
-error: aborting due to previous error
-
-For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/generic-associated-types/type-param-defaults.rs b/src/test/ui/generic-associated-types/type-param-defaults.rs
new file mode 100644
index 0000000000000..f034076b01093
--- /dev/null
+++ b/src/test/ui/generic-associated-types/type-param-defaults.rs
@@ -0,0 +1,34 @@
+// Check that we disallow GAT param defaults, even with `invalid_type_param_default` allowed
+
+#![allow(invalid_type_param_default)]
+
+trait Trait {
+    type Assoc<T = u32>;
+    //~^ defaults for type parameters are only allowed
+}
+
+impl Trait for () {
+    type Assoc<T = u32> = u64;
+    //~^ defaults for type parameters are only allowed
+}
+
+impl Trait for u32 {
+    type Assoc<T = u32> = T;
+    //~^ defaults for type parameters are only allowed
+}
+
+trait Other {}
+impl Other for u32 {}
+
+fn foo<T>()
+where
+    T: Trait<Assoc = u32>,
+    T::Assoc: Other {
+    }
+
+fn main() {
+    // errors
+    foo::<()>();
+    // works
+    foo::<u32>();
+}
diff --git a/src/test/ui/generic-associated-types/type-param-defaults.stderr b/src/test/ui/generic-associated-types/type-param-defaults.stderr
new file mode 100644
index 0000000000000..85ccaba0e69e7
--- /dev/null
+++ b/src/test/ui/generic-associated-types/type-param-defaults.stderr
@@ -0,0 +1,20 @@
+error: defaults for type parameters are only allowed in `struct`, `enum`, `type`, or `trait` definitions
+  --> $DIR/type-param-defaults.rs:6:16
+   |
+LL |     type Assoc<T = u32>;
+   |                ^^^^^^^
+
+error: defaults for type parameters are only allowed in `struct`, `enum`, `type`, or `trait` definitions
+  --> $DIR/type-param-defaults.rs:11:16
+   |
+LL |     type Assoc<T = u32> = u64;
+   |                ^^^^^^^
+
+error: defaults for type parameters are only allowed in `struct`, `enum`, `type`, or `trait` definitions
+  --> $DIR/type-param-defaults.rs:16:16
+   |
+LL |     type Assoc<T = u32> = T;
+   |                ^^^^^^^
+
+error: aborting due to 3 previous errors
+
diff --git a/src/test/ui/let-else/issue-100103.rs b/src/test/ui/let-else/issue-100103.rs
index e393deab764f3..f5f9b2f5f0634 100644
--- a/src/test/ui/let-else/issue-100103.rs
+++ b/src/test/ui/let-else/issue-100103.rs
@@ -2,7 +2,7 @@
 // check-pass
 
 #![feature(try_blocks)]
-#![feature(let_else)]
+
 
 fn main() {
     let _: Result<i32, i32> = try {
diff --git a/src/test/ui/let-else/issue-94176.rs b/src/test/ui/let-else/issue-94176.rs
index e35bbd8883062..f76dfc15bc15d 100644
--- a/src/test/ui/let-else/issue-94176.rs
+++ b/src/test/ui/let-else/issue-94176.rs
@@ -1,6 +1,6 @@
 // Issue #94176: wrong span for the error message of a mismatched type error,
 // if the function uses a `let else` construct.
-#![feature(let_else)]
+
 
 pub fn test(a: Option<u32>) -> Option<u32> { //~ ERROR mismatched types
     let Some(_) = a else { return None; };
diff --git a/src/test/ui/let-else/issue-99975.rs b/src/test/ui/let-else/issue-99975.rs
index 80f6355619412..5b164f347e7dd 100644
--- a/src/test/ui/let-else/issue-99975.rs
+++ b/src/test/ui/let-else/issue-99975.rs
@@ -1,7 +1,7 @@
 // run-pass
 // compile-flags: -C opt-level=3 -Zvalidate-mir
 
-#![feature(let_else)]
+
 
 fn return_result() -> Option<String> {
     Some("ok".to_string())
diff --git a/src/test/ui/let-else/let-else-allow-in-expr.rs b/src/test/ui/let-else/let-else-allow-in-expr.rs
index 39f4c9060fea5..33acb6c6a29c5 100644
--- a/src/test/ui/let-else/let-else-allow-in-expr.rs
+++ b/src/test/ui/let-else/let-else-allow-in-expr.rs
@@ -1,5 +1,3 @@
-#![feature(let_else)]
-
 #![deny(unused_variables)]
 
 fn main() {
diff --git a/src/test/ui/let-else/let-else-allow-in-expr.stderr b/src/test/ui/let-else/let-else-allow-in-expr.stderr
index e86bcbc850029..3b2b9066c90d6 100644
--- a/src/test/ui/let-else/let-else-allow-in-expr.stderr
+++ b/src/test/ui/let-else/let-else-allow-in-expr.stderr
@@ -1,17 +1,17 @@
 error: unused variable: `x`
-  --> $DIR/let-else-allow-in-expr.rs:7:13
+  --> $DIR/let-else-allow-in-expr.rs:5:13
    |
 LL |         let x = 1;
    |             ^ help: if this is intentional, prefix it with an underscore: `_x`
    |
 note: the lint level is defined here
-  --> $DIR/let-else-allow-in-expr.rs:3:9
+  --> $DIR/let-else-allow-in-expr.rs:1:9
    |
 LL | #![deny(unused_variables)]
    |         ^^^^^^^^^^^^^^^^
 
 error: unused variable: `x`
-  --> $DIR/let-else-allow-in-expr.rs:29:9
+  --> $DIR/let-else-allow-in-expr.rs:27:9
    |
 LL |     let x = 1;
    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
diff --git a/src/test/ui/let-else/let-else-allow-unused.rs b/src/test/ui/let-else/let-else-allow-unused.rs
index 86ebacfa7b7d1..bbb1c7beaf8d3 100644
--- a/src/test/ui/let-else/let-else-allow-unused.rs
+++ b/src/test/ui/let-else/let-else-allow-unused.rs
@@ -1,6 +1,6 @@
 // issue #89807
 
-#![feature(let_else)]
+
 
 #[deny(unused_variables)]
 
diff --git a/src/test/ui/let-else/let-else-binding-explicit-mut-annotated.rs b/src/test/ui/let-else/let-else-binding-explicit-mut-annotated.rs
index b65fa13c1de1e..955f33ee134d2 100644
--- a/src/test/ui/let-else/let-else-binding-explicit-mut-annotated.rs
+++ b/src/test/ui/let-else/let-else-binding-explicit-mut-annotated.rs
@@ -1,6 +1,6 @@
 // from rfc2005 test suite
 
-#![feature(let_else)]
+
 
 // Verify the binding mode shifts - only when no `&` are auto-dereferenced is the
 // final default binding mode mutable.
diff --git a/src/test/ui/let-else/let-else-binding-explicit-mut-borrow.rs b/src/test/ui/let-else/let-else-binding-explicit-mut-borrow.rs
index 63b35df76aa04..1524d01023331 100644
--- a/src/test/ui/let-else/let-else-binding-explicit-mut-borrow.rs
+++ b/src/test/ui/let-else/let-else-binding-explicit-mut-borrow.rs
@@ -1,8 +1,8 @@
-#![feature(let_else)]
-
 // Slightly different from explicit-mut-annotated -- this won't show an error until borrowck.
 // Should it show a type error instead?
 
+
+
 fn main() {
     let Some(n): &mut Option<i32> = &mut &Some(5i32) else {
         //~^ ERROR cannot borrow data in a `&` reference as mutable
diff --git a/src/test/ui/let-else/let-else-binding-explicit-mut-pass.rs b/src/test/ui/let-else/let-else-binding-explicit-mut-pass.rs
index 305be92219214..b0a6264a10d45 100644
--- a/src/test/ui/let-else/let-else-binding-explicit-mut-pass.rs
+++ b/src/test/ui/let-else/let-else-binding-explicit-mut-pass.rs
@@ -1,6 +1,6 @@
 // check-pass
 
-#![feature(let_else)]
+
 
 fn main() {
     let Some(n) = &mut &mut Some(5i32) else { return; };
diff --git a/src/test/ui/let-else/let-else-binding-explicit-mut.rs b/src/test/ui/let-else/let-else-binding-explicit-mut.rs
index dbe4715b1a975..a153b3af0de1c 100644
--- a/src/test/ui/let-else/let-else-binding-explicit-mut.rs
+++ b/src/test/ui/let-else/let-else-binding-explicit-mut.rs
@@ -1,6 +1,6 @@
 // from rfc2005 test suite
 
-#![feature(let_else)]
+
 
 // Verify the binding mode shifts - only when no `&` are auto-dereferenced is the
 // final default binding mode mutable.
diff --git a/src/test/ui/let-else/let-else-binding-immutable.rs b/src/test/ui/let-else/let-else-binding-immutable.rs
index 96de0ffe26e6b..ff2d9f240a094 100644
--- a/src/test/ui/let-else/let-else-binding-immutable.rs
+++ b/src/test/ui/let-else/let-else-binding-immutable.rs
@@ -1,6 +1,6 @@
 // from rfc2005 test suite
 
-#![feature(let_else)]
+
 
 pub fn main() {
     let Some(x) = &Some(3) else {
diff --git a/src/test/ui/let-else/let-else-bindings.rs b/src/test/ui/let-else/let-else-bindings.rs
index d5121e744dad3..7d2cad978fc02 100644
--- a/src/test/ui/let-else/let-else-bindings.rs
+++ b/src/test/ui/let-else/let-else-bindings.rs
@@ -1,6 +1,6 @@
 // run-pass
 // adapted from src/test/ui/binding/if-let.rs
-#![feature(let_else)]
+
 #![allow(dead_code)]
 
 fn none() -> bool {
diff --git a/src/test/ui/let-else/let-else-bool-binop-init.fixed b/src/test/ui/let-else/let-else-bool-binop-init.fixed
index e47f7f23d7e07..20e558ca909cf 100644
--- a/src/test/ui/let-else/let-else-bool-binop-init.fixed
+++ b/src/test/ui/let-else/let-else-bool-binop-init.fixed
@@ -1,6 +1,6 @@
 // run-rustfix
 
-#![feature(let_else)]
+
 
 fn main() {
     let true = (true && false) else { return }; //~ ERROR a `&&` expression cannot be directly assigned in `let...else`
diff --git a/src/test/ui/let-else/let-else-bool-binop-init.rs b/src/test/ui/let-else/let-else-bool-binop-init.rs
index e443fb0d6a376..f88179a940b5d 100644
--- a/src/test/ui/let-else/let-else-bool-binop-init.rs
+++ b/src/test/ui/let-else/let-else-bool-binop-init.rs
@@ -1,6 +1,6 @@
 // run-rustfix
 
-#![feature(let_else)]
+
 
 fn main() {
     let true = true && false else { return }; //~ ERROR a `&&` expression cannot be directly assigned in `let...else`
diff --git a/src/test/ui/let-else/let-else-brace-before-else.fixed b/src/test/ui/let-else/let-else-brace-before-else.fixed
index fb4fd77791e03..a75c770ddf299 100644
--- a/src/test/ui/let-else/let-else-brace-before-else.fixed
+++ b/src/test/ui/let-else/let-else-brace-before-else.fixed
@@ -1,6 +1,6 @@
 // run-rustfix
 
-#![feature(let_else)]
+
 
 fn main() {
     let Some(1) = ({ Some(1) }) else {
diff --git a/src/test/ui/let-else/let-else-brace-before-else.rs b/src/test/ui/let-else/let-else-brace-before-else.rs
index c4c5a1ca28bbe..5603b946f3883 100644
--- a/src/test/ui/let-else/let-else-brace-before-else.rs
+++ b/src/test/ui/let-else/let-else-brace-before-else.rs
@@ -1,6 +1,6 @@
 // run-rustfix
 
-#![feature(let_else)]
+
 
 fn main() {
     let Some(1) = { Some(1) } else {
diff --git a/src/test/ui/let-else/let-else-check.rs b/src/test/ui/let-else/let-else-check.rs
index 9e32cbef742a2..713fd986e9792 100644
--- a/src/test/ui/let-else/let-else-check.rs
+++ b/src/test/ui/let-else/let-else-check.rs
@@ -1,5 +1,3 @@
-#![feature(let_else)]
-
 #![deny(unused_variables)]
 
 fn main() {
diff --git a/src/test/ui/let-else/let-else-check.stderr b/src/test/ui/let-else/let-else-check.stderr
index 3d647a4c05d86..bdecbf708f9d2 100644
--- a/src/test/ui/let-else/let-else-check.stderr
+++ b/src/test/ui/let-else/let-else-check.stderr
@@ -1,17 +1,17 @@
 error: unused variable: `x`
-  --> $DIR/let-else-check.rs:14:13
+  --> $DIR/let-else-check.rs:12:13
    |
 LL |         let x = 1;
    |             ^ help: if this is intentional, prefix it with an underscore: `_x`
    |
 note: the lint level is defined here
-  --> $DIR/let-else-check.rs:3:9
+  --> $DIR/let-else-check.rs:1:9
    |
 LL | #![deny(unused_variables)]
    |         ^^^^^^^^^^^^^^^^
 
 error: unused variable: `x`
-  --> $DIR/let-else-check.rs:18:9
+  --> $DIR/let-else-check.rs:16:9
    |
 LL |     let x = 1;
    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
diff --git a/src/test/ui/let-else/let-else-deref-coercion-annotated.rs b/src/test/ui/let-else/let-else-deref-coercion-annotated.rs
index 65d88a6d82827..60fdf825a336a 100644
--- a/src/test/ui/let-else/let-else-deref-coercion-annotated.rs
+++ b/src/test/ui/let-else/let-else-deref-coercion-annotated.rs
@@ -6,7 +6,7 @@
 // Deref/DerefMut to Bar. You can do this with an irrefutable binding, so it should work with
 // let-else too.
 
-#![feature(let_else)]
+
 use std::ops::{Deref, DerefMut};
 
 struct Foo(Bar);
diff --git a/src/test/ui/let-else/let-else-deref-coercion.rs b/src/test/ui/let-else/let-else-deref-coercion.rs
index 87489d84bbf3d..052a5a8c73cc4 100644
--- a/src/test/ui/let-else/let-else-deref-coercion.rs
+++ b/src/test/ui/let-else/let-else-deref-coercion.rs
@@ -3,7 +3,7 @@
 // We attempt to `let Bar::Present(_) = foo else { ... }` where foo is meant to Deref/DerefMut to
 // Bar. This fails, you must add a type annotation like `let _: &mut Bar = _ else { ... }`
 
-#![feature(let_else)]
+
 use std::ops::{Deref, DerefMut};
 
 struct Foo(Bar);
diff --git a/src/test/ui/let-else/let-else-destructuring.rs b/src/test/ui/let-else/let-else-destructuring.rs
index 9a09c414ac80f..d1f1a69bfc254 100644
--- a/src/test/ui/let-else/let-else-destructuring.rs
+++ b/src/test/ui/let-else/let-else-destructuring.rs
@@ -1,4 +1,3 @@
-#![feature(let_else)]
 #[derive(Debug)]
 enum Foo {
     Done,
diff --git a/src/test/ui/let-else/let-else-destructuring.stderr b/src/test/ui/let-else/let-else-destructuring.stderr
index 95efb7116829e..7d6cb2386440d 100644
--- a/src/test/ui/let-else/let-else-destructuring.stderr
+++ b/src/test/ui/let-else/let-else-destructuring.stderr
@@ -1,11 +1,11 @@
 error: <assignment> ... else { ... } is not allowed
-  --> $DIR/let-else-destructuring.rs:11:9
+  --> $DIR/let-else-destructuring.rs:10:9
    |
 LL |         &Foo::Nested(Some(value)) = value else { break };
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0070]: invalid left-hand side of assignment
-  --> $DIR/let-else-destructuring.rs:11:35
+  --> $DIR/let-else-destructuring.rs:10:35
    |
 LL |         &Foo::Nested(Some(value)) = value else { break };
    |         ------------------------- ^
diff --git a/src/test/ui/let-else/let-else-drop-order.rs b/src/test/ui/let-else/let-else-drop-order.rs
index 0054f3d4182ec..e91e5de84e4bd 100644
--- a/src/test/ui/let-else/let-else-drop-order.rs
+++ b/src/test/ui/let-else/let-else-drop-order.rs
@@ -16,7 +16,7 @@
 // This is important as it's easy to update the stdout file
 // with a --bless and miss the impact of that change.
 
-#![feature(let_else)]
+
 #![allow(irrefutable_let_patterns)]
 
 use std::cell::RefCell;
diff --git a/src/test/ui/let-else/let-else-if.rs b/src/test/ui/let-else/let-else-if.rs
index c3a17330d6e2f..e8c54ca7ab293 100644
--- a/src/test/ui/let-else/let-else-if.rs
+++ b/src/test/ui/let-else/let-else-if.rs
@@ -1,5 +1,3 @@
-#![feature(let_else)]
-
 fn main() {
     let Some(_) = Some(()) else if true {
         //~^ ERROR conditional `else if` is not supported for `let...else`
diff --git a/src/test/ui/let-else/let-else-if.stderr b/src/test/ui/let-else/let-else-if.stderr
index 746738bbd939b..c63fd61c5dec9 100644
--- a/src/test/ui/let-else/let-else-if.stderr
+++ b/src/test/ui/let-else/let-else-if.stderr
@@ -1,5 +1,5 @@
 error: conditional `else if` is not supported for `let...else`
-  --> $DIR/let-else-if.rs:4:33
+  --> $DIR/let-else-if.rs:2:33
    |
 LL |     let Some(_) = Some(()) else if true {
    |                                 ^^ expected `{`
diff --git a/src/test/ui/let-else/let-else-irrefutable.rs b/src/test/ui/let-else/let-else-irrefutable.rs
index b1e09a1248ff7..1cb68ecb8a6bf 100644
--- a/src/test/ui/let-else/let-else-irrefutable.rs
+++ b/src/test/ui/let-else/let-else-irrefutable.rs
@@ -1,6 +1,6 @@
 // check-pass
 
-#![feature(let_else)]
+
 
 fn main() {
     let x = 1 else { return }; //~ WARN irrefutable `let...else` pattern
diff --git a/src/test/ui/let-else/let-else-missing-semicolon.rs b/src/test/ui/let-else/let-else-missing-semicolon.rs
index ed9d79f1ebde9..d87ac90c1a772 100644
--- a/src/test/ui/let-else/let-else-missing-semicolon.rs
+++ b/src/test/ui/let-else/let-else-missing-semicolon.rs
@@ -1,5 +1,3 @@
-#![feature(let_else)]
-
 fn main() {
     let Some(x) = Some(1) else {
         return;
diff --git a/src/test/ui/let-else/let-else-missing-semicolon.stderr b/src/test/ui/let-else/let-else-missing-semicolon.stderr
index 1818a0b126348..99029ff33fe0c 100644
--- a/src/test/ui/let-else/let-else-missing-semicolon.stderr
+++ b/src/test/ui/let-else/let-else-missing-semicolon.stderr
@@ -1,5 +1,5 @@
 error: expected `;`, found keyword `let`
-  --> $DIR/let-else-missing-semicolon.rs:6:6
+  --> $DIR/let-else-missing-semicolon.rs:4:6
    |
 LL |     }
    |      ^ help: add `;` here
@@ -7,7 +7,7 @@ LL |     let _ = "";
    |     --- unexpected token
 
 error: expected `;`, found `}`
-  --> $DIR/let-else-missing-semicolon.rs:10:6
+  --> $DIR/let-else-missing-semicolon.rs:8:6
    |
 LL |     }
    |      ^ help: add `;` here
diff --git a/src/test/ui/let-else/let-else-no-double-error.rs b/src/test/ui/let-else/let-else-no-double-error.rs
index 35dcdd3f6be3c..91fcc5d7e91e8 100644
--- a/src/test/ui/let-else/let-else-no-double-error.rs
+++ b/src/test/ui/let-else/let-else-no-double-error.rs
@@ -1,6 +1,6 @@
 // from rfc2005 test suite
 
-#![feature(let_else)]
+
 
 // Without caching type lookups in FnCtxt.resolve_ty_and_def_ufcs
 // the error below would be reported twice (once when checking
diff --git a/src/test/ui/let-else/let-else-non-copy.rs b/src/test/ui/let-else/let-else-non-copy.rs
index 79ed82dd124bd..08c07dd1a43ac 100644
--- a/src/test/ui/let-else/let-else-non-copy.rs
+++ b/src/test/ui/let-else/let-else-non-copy.rs
@@ -10,7 +10,7 @@
 //
 // The move was due to mir::Place being Copy, but mir::VarDebugInfoContents not being Copy.
 
-#![feature(let_else)]
+
 
 #[derive(Copy, Clone)]
 struct Copyable;
diff --git a/src/test/ui/let-else/let-else-non-diverging.rs b/src/test/ui/let-else/let-else-non-diverging.rs
index a1cee335aeeba..b5bd91ceb9e75 100644
--- a/src/test/ui/let-else/let-else-non-diverging.rs
+++ b/src/test/ui/let-else/let-else-non-diverging.rs
@@ -1,5 +1,3 @@
-#![feature(let_else)]
-
 fn main() {
     let Some(x) = Some(1) else { //~ ERROR does not diverge
         Some(2)
diff --git a/src/test/ui/let-else/let-else-non-diverging.stderr b/src/test/ui/let-else/let-else-non-diverging.stderr
index 05e45f689890d..c999a54952560 100644
--- a/src/test/ui/let-else/let-else-non-diverging.stderr
+++ b/src/test/ui/let-else/let-else-non-diverging.stderr
@@ -1,5 +1,5 @@
 error[E0308]: `else` clause of `let...else` does not diverge
-  --> $DIR/let-else-non-diverging.rs:4:32
+  --> $DIR/let-else-non-diverging.rs:2:32
    |
 LL |       let Some(x) = Some(1) else {
    |  ________________________________^
@@ -13,7 +13,7 @@ LL | |     };
    = help: ...or use `match` instead of `let...else`
 
 error[E0308]: `else` clause of `let...else` does not diverge
-  --> $DIR/let-else-non-diverging.rs:7:32
+  --> $DIR/let-else-non-diverging.rs:5:32
    |
 LL |       let Some(x) = Some(1) else {
    |  ________________________________^
@@ -29,7 +29,7 @@ LL | |     };
    = help: ...or use `match` instead of `let...else`
 
 error[E0308]: `else` clause of `let...else` does not diverge
-  --> $DIR/let-else-non-diverging.rs:12:32
+  --> $DIR/let-else-non-diverging.rs:10:32
    |
 LL |     let Some(x) = Some(1) else { Some(2) };
    |                                ^^^^^^^^^^^ expected `!`, found enum `Option`
diff --git a/src/test/ui/let-else/let-else-ref-bindings-pass.rs b/src/test/ui/let-else/let-else-ref-bindings-pass.rs
index f4abd6cc2df25..62fc65731cd2f 100644
--- a/src/test/ui/let-else/let-else-ref-bindings-pass.rs
+++ b/src/test/ui/let-else/let-else-ref-bindings-pass.rs
@@ -1,6 +1,6 @@
 // check-pass
 
-#![feature(let_else)]
+
 #![allow(unused_variables)]
 
 fn ref_() {
diff --git a/src/test/ui/let-else/let-else-ref-bindings.rs b/src/test/ui/let-else/let-else-ref-bindings.rs
index a4cd8e8c47d46..687e235d47e78 100644
--- a/src/test/ui/let-else/let-else-ref-bindings.rs
+++ b/src/test/ui/let-else/let-else-ref-bindings.rs
@@ -1,6 +1,6 @@
-#![feature(let_else)]
 #![allow(unused_variables)]
 
+
 fn ref_() {
     let bytes: Vec<u8> = b"Hello"[..].to_vec();
     let some = Some(bytes);
diff --git a/src/test/ui/let-else/let-else-run-pass.rs b/src/test/ui/let-else/let-else-run-pass.rs
index 5d96623236dab..a0fb6c683f8ce 100644
--- a/src/test/ui/let-else/let-else-run-pass.rs
+++ b/src/test/ui/let-else/let-else-run-pass.rs
@@ -1,6 +1,6 @@
 // run-pass
 
-#![feature(let_else)]
+
 
 fn main() {
     #[allow(dead_code)]
diff --git a/src/test/ui/let-else/let-else-scope.rs b/src/test/ui/let-else/let-else-scope.rs
index f17682db4c3bd..78a67769ef284 100644
--- a/src/test/ui/let-else/let-else-scope.rs
+++ b/src/test/ui/let-else/let-else-scope.rs
@@ -1,5 +1,3 @@
-#![feature(let_else)]
-
 fn main() {
     let Some(x) = Some(2) else {
         panic!("{}", x); //~ ERROR cannot find value `x` in this scope
diff --git a/src/test/ui/let-else/let-else-scope.stderr b/src/test/ui/let-else/let-else-scope.stderr
index 4b3936eac4bd5..3b4f0982940e8 100644
--- a/src/test/ui/let-else/let-else-scope.stderr
+++ b/src/test/ui/let-else/let-else-scope.stderr
@@ -1,5 +1,5 @@
 error[E0425]: cannot find value `x` in this scope
-  --> $DIR/let-else-scope.rs:5:22
+  --> $DIR/let-else-scope.rs:3:22
    |
 LL |         panic!("{}", x);
    |                      ^ not found in this scope
diff --git a/src/test/ui/let-else/let-else-slicing-error.rs b/src/test/ui/let-else/let-else-slicing-error.rs
index 4022656a8f53d..25770094bce99 100644
--- a/src/test/ui/let-else/let-else-slicing-error.rs
+++ b/src/test/ui/let-else/let-else-slicing-error.rs
@@ -1,5 +1,5 @@
 // issue #92069
-#![feature(let_else)]
+
 
 fn main() {
     let nums = vec![5, 4, 3, 2, 1];
diff --git a/src/test/ui/let-else/let-else-source-expr-nomove-pass.rs b/src/test/ui/let-else/let-else-source-expr-nomove-pass.rs
index 2aa17ae8ceb1a..ee378abcf2bad 100644
--- a/src/test/ui/let-else/let-else-source-expr-nomove-pass.rs
+++ b/src/test/ui/let-else/let-else-source-expr-nomove-pass.rs
@@ -1,7 +1,7 @@
 // run-pass
 // issue #89688
 
-#![feature(let_else)]
+
 
 fn example_let_else(value: Option<String>) {
     let Some(inner) = value else {
diff --git a/src/test/ui/let-else/let-else-temp-borrowck.rs b/src/test/ui/let-else/let-else-temp-borrowck.rs
index 3910d35e77676..6b4642d2f9852 100644
--- a/src/test/ui/let-else/let-else-temp-borrowck.rs
+++ b/src/test/ui/let-else/let-else-temp-borrowck.rs
@@ -3,7 +3,7 @@
 // from issue #93951, where borrowck complained the temporary that `foo(&x)` was stored in was to
 // be dropped sometime after `x` was. It then suggested adding a semicolon that was already there.
 
-#![feature(let_else)]
+
 use std::fmt::Debug;
 
 fn foo<'a>(x: &'a str) -> Result<impl Debug + 'a, ()> {
diff --git a/src/test/ui/let-else/let-else-temporary-lifetime.rs b/src/test/ui/let-else/let-else-temporary-lifetime.rs
index 8542c3496b045..c23eaa997fe4d 100644
--- a/src/test/ui/let-else/let-else-temporary-lifetime.rs
+++ b/src/test/ui/let-else/let-else-temporary-lifetime.rs
@@ -1,6 +1,5 @@
 // run-pass
 // compile-flags: -Zvalidate-mir
-#![feature(let_else)]
 
 use std::fmt::Display;
 use std::rc::Rc;
diff --git a/src/test/ui/let-else/let-else-then-diverge.rs b/src/test/ui/let-else/let-else-then-diverge.rs
index 49633d943beea..1c8f7d758e8a6 100644
--- a/src/test/ui/let-else/let-else-then-diverge.rs
+++ b/src/test/ui/let-else/let-else-then-diverge.rs
@@ -2,7 +2,7 @@
 // popped up in in #94012, where an alternative desugaring was
 // causing unreachable code errors
 
-#![feature(let_else)]
+
 #![deny(unused_variables)]
 #![deny(unreachable_code)]
 
diff --git a/src/test/ui/let-else/let-else.rs b/src/test/ui/let-else/let-else.rs
new file mode 100644
index 0000000000000..3505533e63f14
--- /dev/null
+++ b/src/test/ui/let-else/let-else.rs
@@ -0,0 +1,8 @@
+// run-pass
+
+fn main() {
+    let Some(x) = Some(1) else {
+        return;
+    };
+    assert_eq!(x, 1);
+}
diff --git a/src/test/ui/pattern/usefulness/issue-31561.stderr b/src/test/ui/pattern/usefulness/issue-31561.stderr
index 46aebccc5ffff..20f2f09500aa2 100644
--- a/src/test/ui/pattern/usefulness/issue-31561.stderr
+++ b/src/test/ui/pattern/usefulness/issue-31561.stderr
@@ -21,7 +21,7 @@ help: you might want to use `if let` to ignore the variants that aren't matched
    |
 LL |     let y = if let Thing::Foo(y) = Thing::Foo(1) { y } else { todo!() };
    |     ++++++++++                                   ++++++++++++++++++++++
-help: alternatively, on nightly, you might want to use `#![feature(let_else)]` to handle the variants that aren't matched
+help: alternatively, you might want to use let else to handle the variants that aren't matched
    |
 LL |     let Thing::Foo(y) = Thing::Foo(1) else { todo!() };
    |                                       ++++++++++++++++
diff --git a/src/test/ui/pattern/usefulness/non-exhaustive-defined-here.stderr b/src/test/ui/pattern/usefulness/non-exhaustive-defined-here.stderr
index ac2a9713e7d24..678c9b2ab58c3 100644
--- a/src/test/ui/pattern/usefulness/non-exhaustive-defined-here.stderr
+++ b/src/test/ui/pattern/usefulness/non-exhaustive-defined-here.stderr
@@ -187,7 +187,7 @@ help: you might want to use `if let` to ignore the variant that isn't matched
    |
 LL |     let _x = if let Opt::Some(ref _x) = e { _x } else { todo!() };
    |     +++++++++++                           +++++++++++++++++++++++
-help: alternatively, on nightly, you might want to use `#![feature(let_else)]` to handle the variant that isn't matched
+help: alternatively, you might want to use let else to handle the variant that isn't matched
    |
 LL |     let Opt::Some(ref _x) = e else { todo!() };
    |                               ++++++++++++++++
diff --git a/src/test/ui/pattern/usefulness/top-level-alternation.rs b/src/test/ui/pattern/usefulness/top-level-alternation.rs
index 076de846129e6..e8cd12ea4a2c4 100644
--- a/src/test/ui/pattern/usefulness/top-level-alternation.rs
+++ b/src/test/ui/pattern/usefulness/top-level-alternation.rs
@@ -1,5 +1,3 @@
-#![feature(let_else)]
-
 #![deny(unreachable_patterns)]
 
 fn main() {
diff --git a/src/test/ui/pattern/usefulness/top-level-alternation.stderr b/src/test/ui/pattern/usefulness/top-level-alternation.stderr
index dd5936fdcc429..17fa951c53905 100644
--- a/src/test/ui/pattern/usefulness/top-level-alternation.stderr
+++ b/src/test/ui/pattern/usefulness/top-level-alternation.stderr
@@ -1,71 +1,71 @@
 error: unreachable pattern
-  --> $DIR/top-level-alternation.rs:6:23
+  --> $DIR/top-level-alternation.rs:4:23
    |
 LL |     while let 0..=2 | 1 = 0 {}
    |                       ^
    |
 note: the lint level is defined here
-  --> $DIR/top-level-alternation.rs:3:9
+  --> $DIR/top-level-alternation.rs:1:9
    |
 LL | #![deny(unreachable_patterns)]
    |         ^^^^^^^^^^^^^^^^^^^^
 
 error: unreachable pattern
-  --> $DIR/top-level-alternation.rs:7:20
+  --> $DIR/top-level-alternation.rs:5:20
    |
 LL |     if let 0..=2 | 1 = 0 {}
    |                    ^
 
 error: unreachable pattern
-  --> $DIR/top-level-alternation.rs:11:15
+  --> $DIR/top-level-alternation.rs:9:15
    |
 LL |             | 0 => {}
    |               ^
 
 error: unreachable pattern
-  --> $DIR/top-level-alternation.rs:16:15
+  --> $DIR/top-level-alternation.rs:14:15
    |
 LL |             | Some(0) => {}
    |               ^^^^^^^
 
 error: unreachable pattern
-  --> $DIR/top-level-alternation.rs:21:9
+  --> $DIR/top-level-alternation.rs:19:9
    |
 LL |         (0, 0) => {}
    |         ^^^^^^
 
 error: unreachable pattern
-  --> $DIR/top-level-alternation.rs:41:9
+  --> $DIR/top-level-alternation.rs:39:9
    |
 LL |         _ => {}
    |         ^
 
 error: unreachable pattern
-  --> $DIR/top-level-alternation.rs:45:9
+  --> $DIR/top-level-alternation.rs:43:9
    |
 LL |         Some(_) => {}
    |         ^^^^^^^
 
 error: unreachable pattern
-  --> $DIR/top-level-alternation.rs:46:9
+  --> $DIR/top-level-alternation.rs:44:9
    |
 LL |         None => {}
    |         ^^^^
 
 error: unreachable pattern
-  --> $DIR/top-level-alternation.rs:51:9
+  --> $DIR/top-level-alternation.rs:49:9
    |
 LL |         None | Some(_) => {}
    |         ^^^^^^^^^^^^^^
 
 error: unreachable pattern
-  --> $DIR/top-level-alternation.rs:55:9
+  --> $DIR/top-level-alternation.rs:53:9
    |
 LL |         1..=2 => {},
    |         ^^^^^
 
 error: unreachable pattern
-  --> $DIR/top-level-alternation.rs:58:14
+  --> $DIR/top-level-alternation.rs:56:14
    |
 LL |     let (0 | 0) = 0 else { return };
    |              ^
diff --git a/src/test/ui/privacy/access_levels.rs b/src/test/ui/privacy/access_levels.rs
index d51d2b57267b6..aa718ab9254df 100644
--- a/src/test/ui/privacy/access_levels.rs
+++ b/src/test/ui/privacy/access_levels.rs
@@ -1,49 +1,62 @@
 #![feature(rustc_attrs)]
 
-#[rustc_access_level] mod outer { //~ ERROR None
-    #[rustc_access_level] pub mod inner { //~ ERROR Some(Exported)
-        #[rustc_access_level]
-        extern "C" { //~ ERROR Some(Exported)
-            #[rustc_access_level] static a: u8; //~ ERROR None
-            #[rustc_access_level] pub fn b(); //~ ERROR Some(Exported)
-        }
-        #[rustc_access_level]
-        pub trait Trait { //~ ERROR Some(Exported)
-            #[rustc_access_level] const A: i32; //~ ERROR Some(Exported)
-            #[rustc_access_level] type B; //~ ERROR Some(Exported)
+#[rustc_effective_visibility]
+mod outer { //~ ERROR Public: pub(self), Exported: pub(self), Reachable: pub(self), ReachableFromImplTrait: pub(self)
+    #[rustc_effective_visibility]
+    pub mod inner1 { //~ ERROR Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+
+        #[rustc_effective_visibility]
+        extern "C" {} //~ ERROR Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+
+        #[rustc_effective_visibility]
+        pub trait PubTrait { //~ ERROR Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+            #[rustc_effective_visibility]
+            const A: i32; //~ ERROR Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+            #[rustc_effective_visibility]
+            type B; //~ ERROR Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
         }
 
-        #[rustc_access_level]
-        pub struct Struct { //~ ERROR Some(Exported)
-            #[rustc_access_level] a: u8, //~ ERROR None
-            #[rustc_access_level] pub b: u8, //~ ERROR Some(Exported)
-        }
+        #[rustc_effective_visibility]
+        struct PrivStruct; //~ ERROR Public: pub(self), Exported: pub(self), Reachable: pub(self), ReachableFromImplTrait: pub(self)
 
-        #[rustc_access_level]
-        pub union Union { //~ ERROR Some(Exported)
-            #[rustc_access_level] a: u8, //~ ERROR None
-            #[rustc_access_level] pub b: u8, //~ ERROR Some(Exported)
+        #[rustc_effective_visibility]
+        pub union PubUnion { //~ ERROR Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+            #[rustc_effective_visibility]
+            a: u8, //~ ERROR Public: pub(self), Exported: pub(self), Reachable: pub(self), ReachableFromImplTrait: pub(self)
+            #[rustc_effective_visibility]
+            pub b: u8, //~ ERROR Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
         }
 
-        #[rustc_access_level]
-        pub enum Enum { //~ ERROR Some(Exported)
-            #[rustc_access_level] A( //~ ERROR Some(Exported)
-                #[rustc_access_level] Struct, //~ ERROR Some(Exported)
-                #[rustc_access_level] Union,  //~ ERROR Some(Exported)
+        #[rustc_effective_visibility]
+        pub enum Enum { //~ ERROR Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+            #[rustc_effective_visibility]
+            A( //~ ERROR Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+                #[rustc_effective_visibility]
+                PubUnion,  //~ ERROR Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
             ),
         }
     }
 
-    #[rustc_access_level] macro_rules! none_macro { //~ ERROR None
+    #[rustc_effective_visibility]
+    macro_rules! none_macro { //~ Public: pub(self), Exported: pub(self), Reachable: pub(self), ReachableFromImplTrait: pub(self)
         () => {};
     }
 
     #[macro_export]
-    #[rustc_access_level] macro_rules! public_macro { //~ ERROR Some(Public)
+    #[rustc_effective_visibility]
+    macro_rules! public_macro { //~ Public: pub, Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
         () => {};
     }
+
+    #[rustc_effective_visibility]
+    pub struct ReachableStruct { //~ ERROR Public: pub(self), Exported: pub(self), Reachable: pub, ReachableFromImplTrait: pub
+        #[rustc_effective_visibility]
+        pub a: u8, //~ ERROR Public: pub(self), Exported: pub(self), Reachable: pub, ReachableFromImplTrait: pub
+    }
 }
 
-pub use outer::inner;
+pub use outer::inner1;
+
+pub fn foo() -> outer::ReachableStruct { outer::ReachableStruct {a: 0} }
 
 fn main() {}
diff --git a/src/test/ui/privacy/access_levels.stderr b/src/test/ui/privacy/access_levels.stderr
index f326293c384a5..2ed6c330a2f97 100644
--- a/src/test/ui/privacy/access_levels.stderr
+++ b/src/test/ui/privacy/access_levels.stderr
@@ -1,125 +1,104 @@
-error: None
-  --> $DIR/access_levels.rs:3:23
+error: Public: pub(self), Exported: pub(self), Reachable: pub(self), ReachableFromImplTrait: pub(self)
+  --> $DIR/access_levels.rs:4:1
    |
-LL | #[rustc_access_level] mod outer {
-   |                       ^^^^^^^^^
+LL | mod outer {
+   | ^^^^^^^^^
 
-error: Some(Exported)
-  --> $DIR/access_levels.rs:4:27
+error: Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+  --> $DIR/access_levels.rs:6:5
    |
-LL |     #[rustc_access_level] pub mod inner {
-   |                           ^^^^^^^^^^^^^
+LL |     pub mod inner1 {
+   |     ^^^^^^^^^^^^^^
 
-error: Some(Exported)
-  --> $DIR/access_levels.rs:6:9
+error: Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+  --> $DIR/access_levels.rs:9:9
    |
-LL | /         extern "C" {
-LL | |             #[rustc_access_level] static a: u8;
-LL | |             #[rustc_access_level] pub fn b();
-LL | |         }
-   | |_________^
+LL |         extern "C" {}
+   |         ^^^^^^^^^^^^^
 
-error: Some(Exported)
-  --> $DIR/access_levels.rs:11:9
+error: Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+  --> $DIR/access_levels.rs:12:9
    |
-LL |         pub trait Trait {
-   |         ^^^^^^^^^^^^^^^
+LL |         pub trait PubTrait {
+   |         ^^^^^^^^^^^^^^^^^^
 
-error: Some(Exported)
-  --> $DIR/access_levels.rs:17:9
+error: Public: pub(self), Exported: pub(self), Reachable: pub(self), ReachableFromImplTrait: pub(self)
+  --> $DIR/access_levels.rs:20:9
    |
-LL |         pub struct Struct {
+LL |         struct PrivStruct;
    |         ^^^^^^^^^^^^^^^^^
 
-error: None
-  --> $DIR/access_levels.rs:18:35
-   |
-LL |             #[rustc_access_level] a: u8,
-   |                                   ^^^^^
-
-error: Some(Exported)
-  --> $DIR/access_levels.rs:19:35
-   |
-LL |             #[rustc_access_level] pub b: u8,
-   |                                   ^^^^^^^^^
-
-error: Some(Exported)
+error: Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
   --> $DIR/access_levels.rs:23:9
    |
-LL |         pub union Union {
-   |         ^^^^^^^^^^^^^^^
+LL |         pub union PubUnion {
+   |         ^^^^^^^^^^^^^^^^^^
 
-error: None
-  --> $DIR/access_levels.rs:24:35
+error: Public: pub(self), Exported: pub(self), Reachable: pub(self), ReachableFromImplTrait: pub(self)
+  --> $DIR/access_levels.rs:25:13
    |
-LL |             #[rustc_access_level] a: u8,
-   |                                   ^^^^^
+LL |             a: u8,
+   |             ^^^^^
 
-error: Some(Exported)
-  --> $DIR/access_levels.rs:25:35
+error: Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+  --> $DIR/access_levels.rs:27:13
    |
-LL |             #[rustc_access_level] pub b: u8,
-   |                                   ^^^^^^^^^
+LL |             pub b: u8,
+   |             ^^^^^^^^^
 
-error: Some(Exported)
-  --> $DIR/access_levels.rs:29:9
+error: Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+  --> $DIR/access_levels.rs:31:9
    |
 LL |         pub enum Enum {
    |         ^^^^^^^^^^^^^
 
-error: Some(Exported)
-  --> $DIR/access_levels.rs:30:35
-   |
-LL |             #[rustc_access_level] A(
-   |                                   ^
-
-error: Some(Exported)
-  --> $DIR/access_levels.rs:31:39
+error: Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+  --> $DIR/access_levels.rs:33:13
    |
-LL |                 #[rustc_access_level] Struct,
-   |                                       ^^^^^^
+LL |             A(
+   |             ^
 
-error: Some(Exported)
-  --> $DIR/access_levels.rs:32:39
+error: Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+  --> $DIR/access_levels.rs:35:17
    |
-LL |                 #[rustc_access_level] Union,
-   |                                       ^^^^^
+LL |                 PubUnion,
+   |                 ^^^^^^^^
 
-error: None
-  --> $DIR/access_levels.rs:37:27
+error: Public: pub(self), Exported: pub(self), Reachable: pub(self), ReachableFromImplTrait: pub(self)
+  --> $DIR/access_levels.rs:41:5
    |
-LL |     #[rustc_access_level] macro_rules! none_macro {
-   |                           ^^^^^^^^^^^^^^^^^^^^^^^
+LL |     macro_rules! none_macro {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^
 
-error: Some(Public)
-  --> $DIR/access_levels.rs:42:27
+error: Public: pub, Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+  --> $DIR/access_levels.rs:47:5
    |
-LL |     #[rustc_access_level] macro_rules! public_macro {
-   |                           ^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |     macro_rules! public_macro {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error: Some(Exported)
-  --> $DIR/access_levels.rs:12:35
+error: Public: pub(self), Exported: pub(self), Reachable: pub, ReachableFromImplTrait: pub
+  --> $DIR/access_levels.rs:52:5
    |
-LL |             #[rustc_access_level] const A: i32;
-   |                                   ^^^^^^^^^^^^
+LL |     pub struct ReachableStruct {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error: Some(Exported)
-  --> $DIR/access_levels.rs:13:35
+error: Public: pub(self), Exported: pub(self), Reachable: pub, ReachableFromImplTrait: pub
+  --> $DIR/access_levels.rs:54:9
    |
-LL |             #[rustc_access_level] type B;
-   |                                   ^^^^^^
+LL |         pub a: u8,
+   |         ^^^^^^^^^
 
-error: None
-  --> $DIR/access_levels.rs:7:35
+error: Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+  --> $DIR/access_levels.rs:14:13
    |
-LL |             #[rustc_access_level] static a: u8;
-   |                                   ^^^^^^^^^^^^
+LL |             const A: i32;
+   |             ^^^^^^^^^^^^
 
-error: Some(Exported)
-  --> $DIR/access_levels.rs:8:35
+error: Public: pub(self), Exported: pub, Reachable: pub, ReachableFromImplTrait: pub
+  --> $DIR/access_levels.rs:16:13
    |
-LL |             #[rustc_access_level] pub fn b();
-   |                                   ^^^^^^^^^^
+LL |             type B;
+   |             ^^^^^^
 
-error: aborting due to 20 previous errors
+error: aborting due to 17 previous errors
 
diff --git a/src/test/ui/recursion/recursive-types-are-not-uninhabited.stderr b/src/test/ui/recursion/recursive-types-are-not-uninhabited.stderr
index acbd0d05984f1..321ee0a36942e 100644
--- a/src/test/ui/recursion/recursive-types-are-not-uninhabited.stderr
+++ b/src/test/ui/recursion/recursive-types-are-not-uninhabited.stderr
@@ -19,7 +19,7 @@ help: you might want to use `if let` to ignore the variant that isn't matched
    |
 LL |     let x = if let Ok(x) = res { x } else { todo!() };
    |     ++++++++++                 ++++++++++++++++++++++
-help: alternatively, on nightly, you might want to use `#![feature(let_else)]` to handle the variant that isn't matched
+help: alternatively, you might want to use let else to handle the variant that isn't matched
    |
 LL |     let Ok(x) = res else { todo!() };
    |                     ++++++++++++++++
diff --git a/src/test/ui/rfc-2497-if-let-chains/ensure-that-let-else-does-not-interact-with-let-chains.rs b/src/test/ui/rfc-2497-if-let-chains/ensure-that-let-else-does-not-interact-with-let-chains.rs
index 12befc637c787..2a6c144350a7a 100644
--- a/src/test/ui/rfc-2497-if-let-chains/ensure-that-let-else-does-not-interact-with-let-chains.rs
+++ b/src/test/ui/rfc-2497-if-let-chains/ensure-that-let-else-does-not-interact-with-let-chains.rs
@@ -1,4 +1,4 @@
-#![feature(let_chains, let_else)]
+#![feature(let_chains)]
 
 fn main() {
     let opt = Some(1i32);
diff --git a/src/test/ui/simd/intrinsic/ptr-cast.rs b/src/test/ui/simd/intrinsic/ptr-cast.rs
new file mode 100644
index 0000000000000..1d13720bcd31e
--- /dev/null
+++ b/src/test/ui/simd/intrinsic/ptr-cast.rs
@@ -0,0 +1,33 @@
+// run-pass
+
+#![feature(repr_simd, platform_intrinsics)]
+
+extern "platform-intrinsic" {
+    fn simd_cast_ptr<T, U>(x: T) -> U;
+    fn simd_expose_addr<T, U>(x: T) -> U;
+    fn simd_from_exposed_addr<T, U>(x: T) -> U;
+}
+
+#[derive(Copy, Clone)]
+#[repr(simd)]
+struct V<T>([T; 2]);
+
+fn main() {
+    unsafe {
+        let mut foo = 4i8;
+        let ptr = &mut foo as *mut i8;
+
+        let ptrs = V::<*mut i8>([ptr, core::ptr::null_mut()]);
+
+        // change constness and type
+        let const_ptrs: V<*const u8> = simd_cast_ptr(ptrs);
+
+        let exposed_addr: V<usize> = simd_expose_addr(const_ptrs);
+
+        let from_exposed_addr: V<*mut i8> = simd_from_exposed_addr(exposed_addr);
+
+        assert!(const_ptrs.0 == [ptr as *const u8, core::ptr::null()]);
+        assert!(exposed_addr.0 == [ptr as usize, 0]);
+        assert!(from_exposed_addr.0 == ptrs.0);
+    }
+}
diff --git a/src/test/ui/uninhabited/uninhabited-irrefutable.stderr b/src/test/ui/uninhabited/uninhabited-irrefutable.stderr
index feeaa89e76f11..32f287a18188c 100644
--- a/src/test/ui/uninhabited/uninhabited-irrefutable.stderr
+++ b/src/test/ui/uninhabited/uninhabited-irrefutable.stderr
@@ -18,7 +18,7 @@ help: you might want to use `if let` to ignore the variant that isn't matched
    |
 LL |     let (_y, _z) = if let Foo::D(_y, _z) = x { (_y, _z) } else { todo!() };
    |     +++++++++++++++++                        +++++++++++++++++++++++++++++
-help: alternatively, on nightly, you might want to use `#![feature(let_else)]` to handle the variant that isn't matched
+help: alternatively, you might want to use let else to handle the variant that isn't matched
    |
 LL |     let Foo::D(_y, _z) = x else { todo!() };
    |                            ++++++++++++++++
diff --git a/src/test/ui/uninhabited/uninhabited-matches-feature-gated.stderr b/src/test/ui/uninhabited/uninhabited-matches-feature-gated.stderr
index 2c107b1f7a47b..c7882963407f7 100644
--- a/src/test/ui/uninhabited/uninhabited-matches-feature-gated.stderr
+++ b/src/test/ui/uninhabited/uninhabited-matches-feature-gated.stderr
@@ -122,7 +122,7 @@ help: you might want to use `if let` to ignore the variant that isn't matched
    |
 LL |     let x = if let Ok(x) = x { x } else { todo!() };
    |     ++++++++++               ++++++++++++++++++++++
-help: alternatively, on nightly, you might want to use `#![feature(let_else)]` to handle the variant that isn't matched
+help: alternatively, you might want to use let else to handle the variant that isn't matched
    |
 LL |     let Ok(x) = x else { todo!() };
    |                   ++++++++++++++++
diff --git a/src/test/ui/unpretty/pretty-let-else.rs b/src/test/ui/unpretty/pretty-let-else.rs
index 5abfa2523b74e..b5ae529699da2 100644
--- a/src/test/ui/unpretty/pretty-let-else.rs
+++ b/src/test/ui/unpretty/pretty-let-else.rs
@@ -1,7 +1,7 @@
 // compile-flags: -Zunpretty=hir
 // check-pass
 
-#![feature(let_else)]
+
 
 fn foo(x: Option<u32>) {
     let Some(_) = x else { panic!() };
diff --git a/src/test/ui/unpretty/pretty-let-else.stdout b/src/test/ui/unpretty/pretty-let-else.stdout
index ffe1d1657aa15..35ad1cd1b1812 100644
--- a/src/test/ui/unpretty/pretty-let-else.stdout
+++ b/src/test/ui/unpretty/pretty-let-else.stdout
@@ -1,11 +1,11 @@
-// compile-flags: -Zunpretty=hir
-// check-pass
-
-#![feature(let_else)]
 #[prelude_import]
 use ::std::prelude::rust_2015::*;
 #[macro_use]
 extern crate std;
+// compile-flags: -Zunpretty=hir
+// check-pass
+
+
 
 fn foo(x:
         Option<u32>) {
diff --git a/src/tools/clippy/clippy_dev/src/lib.rs b/src/tools/clippy/clippy_dev/src/lib.rs
index 82574a8e64b0a..54c7456a2a3b0 100644
--- a/src/tools/clippy/clippy_dev/src/lib.rs
+++ b/src/tools/clippy/clippy_dev/src/lib.rs
@@ -1,5 +1,5 @@
 #![feature(let_chains)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(once_cell)]
 #![feature(rustc_private)]
 #![cfg_attr(feature = "deny-warnings", deny(warnings))]
diff --git a/src/tools/clippy/clippy_lints/src/lib.rs b/src/tools/clippy/clippy_lints/src/lib.rs
index e984254bf2919..ceaaf5c6d6ed6 100644
--- a/src/tools/clippy/clippy_lints/src/lib.rs
+++ b/src/tools/clippy/clippy_lints/src/lib.rs
@@ -5,7 +5,7 @@
 #![feature(drain_filter)]
 #![feature(iter_intersperse)]
 #![feature(let_chains)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(lint_reasons)]
 #![feature(never_type)]
 #![feature(once_cell)]
diff --git a/src/tools/clippy/clippy_utils/src/lib.rs b/src/tools/clippy/clippy_utils/src/lib.rs
index 23b51ec2d0849..62da850a15e70 100644
--- a/src/tools/clippy/clippy_utils/src/lib.rs
+++ b/src/tools/clippy/clippy_utils/src/lib.rs
@@ -1,9 +1,9 @@
 #![feature(array_chunks)]
 #![feature(box_patterns)]
 #![feature(control_flow_enum)]
-#![feature(let_else)]
 #![feature(let_chains)]
 #![feature(lint_reasons)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(once_cell)]
 #![feature(rustc_private)]
 #![recursion_limit = "512"]
diff --git a/src/tools/clippy/tests/ui/needless_return.fixed b/src/tools/clippy/tests/ui/needless_return.fixed
index 87c8fc03b3c36..695883e8dff77 100644
--- a/src/tools/clippy/tests/ui/needless_return.fixed
+++ b/src/tools/clippy/tests/ui/needless_return.fixed
@@ -1,7 +1,6 @@
 // run-rustfix
 
 #![feature(lint_reasons)]
-#![feature(let_else)]
 #![allow(unused)]
 #![allow(
     clippy::if_same_then_else,
diff --git a/src/tools/clippy/tests/ui/needless_return.rs b/src/tools/clippy/tests/ui/needless_return.rs
index 5a86e656255dd..63d9fe9ecdf8e 100644
--- a/src/tools/clippy/tests/ui/needless_return.rs
+++ b/src/tools/clippy/tests/ui/needless_return.rs
@@ -1,7 +1,6 @@
 // run-rustfix
 
 #![feature(lint_reasons)]
-#![feature(let_else)]
 #![allow(unused)]
 #![allow(
     clippy::if_same_then_else,
diff --git a/src/tools/clippy/tests/ui/needless_return.stderr b/src/tools/clippy/tests/ui/needless_return.stderr
index 83ff07638693c..cadee6e00dff2 100644
--- a/src/tools/clippy/tests/ui/needless_return.stderr
+++ b/src/tools/clippy/tests/ui/needless_return.stderr
@@ -1,5 +1,5 @@
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:27:5
+  --> $DIR/needless_return.rs:26:5
    |
 LL |     return true;
    |     ^^^^^^^^^^^^ help: remove `return`: `true`
@@ -7,217 +7,217 @@ LL |     return true;
    = note: `-D clippy::needless-return` implied by `-D warnings`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:31:5
+  --> $DIR/needless_return.rs:30:5
    |
 LL |     return true;
    |     ^^^^^^^^^^^^ help: remove `return`: `true`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:36:9
+  --> $DIR/needless_return.rs:35:9
    |
 LL |         return true;
    |         ^^^^^^^^^^^^ help: remove `return`: `true`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:38:9
+  --> $DIR/needless_return.rs:37:9
    |
 LL |         return false;
    |         ^^^^^^^^^^^^^ help: remove `return`: `false`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:44:17
+  --> $DIR/needless_return.rs:43:17
    |
 LL |         true => return false,
    |                 ^^^^^^^^^^^^ help: remove `return`: `false`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:46:13
+  --> $DIR/needless_return.rs:45:13
    |
 LL |             return true;
    |             ^^^^^^^^^^^^ help: remove `return`: `true`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:53:9
+  --> $DIR/needless_return.rs:52:9
    |
 LL |         return true;
    |         ^^^^^^^^^^^^ help: remove `return`: `true`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:55:16
+  --> $DIR/needless_return.rs:54:16
    |
 LL |     let _ = || return true;
    |                ^^^^^^^^^^^ help: remove `return`: `true`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:59:5
+  --> $DIR/needless_return.rs:58:5
    |
 LL |     return the_answer!();
    |     ^^^^^^^^^^^^^^^^^^^^^ help: remove `return`: `the_answer!()`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:63:5
+  --> $DIR/needless_return.rs:62:5
    |
 LL |     return;
    |     ^^^^^^^ help: remove `return`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:68:9
+  --> $DIR/needless_return.rs:67:9
    |
 LL |         return;
    |         ^^^^^^^ help: remove `return`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:70:9
+  --> $DIR/needless_return.rs:69:9
    |
 LL |         return;
    |         ^^^^^^^ help: remove `return`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:77:14
+  --> $DIR/needless_return.rs:76:14
    |
 LL |         _ => return,
    |              ^^^^^^ help: replace `return` with a unit value: `()`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:86:13
+  --> $DIR/needless_return.rs:85:13
    |
 LL |             return;
    |             ^^^^^^^ help: remove `return`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:88:14
+  --> $DIR/needless_return.rs:87:14
    |
 LL |         _ => return,
    |              ^^^^^^ help: replace `return` with a unit value: `()`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:101:9
+  --> $DIR/needless_return.rs:100:9
    |
 LL |         return String::from("test");
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove `return`: `String::from("test")`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:103:9
+  --> $DIR/needless_return.rs:102:9
    |
 LL |         return String::new();
    |         ^^^^^^^^^^^^^^^^^^^^^ help: remove `return`: `String::new()`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:125:32
+  --> $DIR/needless_return.rs:124:32
    |
 LL |         bar.unwrap_or_else(|_| return)
    |                                ^^^^^^ help: replace `return` with an empty block: `{}`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:130:13
+  --> $DIR/needless_return.rs:129:13
    |
 LL |             return;
    |             ^^^^^^^ help: remove `return`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:132:20
+  --> $DIR/needless_return.rs:131:20
    |
 LL |         let _ = || return;
    |                    ^^^^^^ help: replace `return` with an empty block: `{}`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:138:32
+  --> $DIR/needless_return.rs:137:32
    |
 LL |         res.unwrap_or_else(|_| return Foo)
    |                                ^^^^^^^^^^ help: remove `return`: `Foo`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:147:5
+  --> $DIR/needless_return.rs:146:5
    |
 LL |     return true;
    |     ^^^^^^^^^^^^ help: remove `return`: `true`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:151:5
+  --> $DIR/needless_return.rs:150:5
    |
 LL |     return true;
    |     ^^^^^^^^^^^^ help: remove `return`: `true`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:156:9
+  --> $DIR/needless_return.rs:155:9
    |
 LL |         return true;
    |         ^^^^^^^^^^^^ help: remove `return`: `true`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:158:9
+  --> $DIR/needless_return.rs:157:9
    |
 LL |         return false;
    |         ^^^^^^^^^^^^^ help: remove `return`: `false`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:164:17
+  --> $DIR/needless_return.rs:163:17
    |
 LL |         true => return false,
    |                 ^^^^^^^^^^^^ help: remove `return`: `false`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:166:13
+  --> $DIR/needless_return.rs:165:13
    |
 LL |             return true;
    |             ^^^^^^^^^^^^ help: remove `return`: `true`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:173:9
+  --> $DIR/needless_return.rs:172:9
    |
 LL |         return true;
    |         ^^^^^^^^^^^^ help: remove `return`: `true`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:175:16
+  --> $DIR/needless_return.rs:174:16
    |
 LL |     let _ = || return true;
    |                ^^^^^^^^^^^ help: remove `return`: `true`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:179:5
+  --> $DIR/needless_return.rs:178:5
    |
 LL |     return the_answer!();
    |     ^^^^^^^^^^^^^^^^^^^^^ help: remove `return`: `the_answer!()`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:183:5
+  --> $DIR/needless_return.rs:182:5
    |
 LL |     return;
    |     ^^^^^^^ help: remove `return`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:188:9
+  --> $DIR/needless_return.rs:187:9
    |
 LL |         return;
    |         ^^^^^^^ help: remove `return`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:190:9
+  --> $DIR/needless_return.rs:189:9
    |
 LL |         return;
    |         ^^^^^^^ help: remove `return`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:197:14
+  --> $DIR/needless_return.rs:196:14
    |
 LL |         _ => return,
    |              ^^^^^^ help: replace `return` with a unit value: `()`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:210:9
+  --> $DIR/needless_return.rs:209:9
    |
 LL |         return String::from("test");
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove `return`: `String::from("test")`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:212:9
+  --> $DIR/needless_return.rs:211:9
    |
 LL |         return String::new();
    |         ^^^^^^^^^^^^^^^^^^^^^ help: remove `return`: `String::new()`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:228:5
+  --> $DIR/needless_return.rs:227:5
    |
 LL |     return format!("Hello {}", "world!");
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove `return`: `format!("Hello {}", "world!")`
diff --git a/src/tools/clippy/tests/ui/semicolon_if_nothing_returned.rs b/src/tools/clippy/tests/ui/semicolon_if_nothing_returned.rs
index c3235f06779b3..c4dfbd9210e0d 100644
--- a/src/tools/clippy/tests/ui/semicolon_if_nothing_returned.rs
+++ b/src/tools/clippy/tests/ui/semicolon_if_nothing_returned.rs
@@ -1,6 +1,5 @@
 #![warn(clippy::semicolon_if_nothing_returned)]
 #![allow(clippy::redundant_closure)]
-#![feature(let_else)]
 
 fn get_unit() {}
 
diff --git a/src/tools/clippy/tests/ui/semicolon_if_nothing_returned.stderr b/src/tools/clippy/tests/ui/semicolon_if_nothing_returned.stderr
index 78813e7cc1c39..8d9a67585cf12 100644
--- a/src/tools/clippy/tests/ui/semicolon_if_nothing_returned.stderr
+++ b/src/tools/clippy/tests/ui/semicolon_if_nothing_returned.stderr
@@ -1,5 +1,5 @@
 error: consider adding a `;` to the last statement for consistent formatting
-  --> $DIR/semicolon_if_nothing_returned.rs:9:5
+  --> $DIR/semicolon_if_nothing_returned.rs:8:5
    |
 LL |     println!("Hello")
    |     ^^^^^^^^^^^^^^^^^ help: add a `;` here: `println!("Hello");`
@@ -7,25 +7,25 @@ LL |     println!("Hello")
    = note: `-D clippy::semicolon-if-nothing-returned` implied by `-D warnings`
 
 error: consider adding a `;` to the last statement for consistent formatting
-  --> $DIR/semicolon_if_nothing_returned.rs:13:5
+  --> $DIR/semicolon_if_nothing_returned.rs:12:5
    |
 LL |     get_unit()
    |     ^^^^^^^^^^ help: add a `;` here: `get_unit();`
 
 error: consider adding a `;` to the last statement for consistent formatting
-  --> $DIR/semicolon_if_nothing_returned.rs:18:5
+  --> $DIR/semicolon_if_nothing_returned.rs:17:5
    |
 LL |     y = x + 1
    |     ^^^^^^^^^ help: add a `;` here: `y = x + 1;`
 
 error: consider adding a `;` to the last statement for consistent formatting
-  --> $DIR/semicolon_if_nothing_returned.rs:24:9
+  --> $DIR/semicolon_if_nothing_returned.rs:23:9
    |
 LL |         hello()
    |         ^^^^^^^ help: add a `;` here: `hello();`
 
 error: consider adding a `;` to the last statement for consistent formatting
-  --> $DIR/semicolon_if_nothing_returned.rs:35:9
+  --> $DIR/semicolon_if_nothing_returned.rs:34:9
    |
 LL |         ptr::drop_in_place(s.as_mut_ptr())
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: add a `;` here: `ptr::drop_in_place(s.as_mut_ptr());`