Auto merge of #104083 - JohnTitor:rollup-lo3wbzs, r=JohnTitor

Rollup of 9 pull requests

Successful merges:

 - #103885 (rustdoc: various cross-crate reexport fixes)
 - #103914 (Make underscore_literal_suffix a hard error.)
 - #104045 (Add type_array to BaseTypeMethods)
 - #104056 (Vec: IntoIterator signature consistency)
 - #104059 (Fix typo in `rustc_middle/lint.rs`)
 - #104062 (rustdoc: remove unused CSS `#sidebar-filler`)
 - #104065 (Migrate rust logo filter to CSS variables)
 - #104066 (LLVM 16: Update RISCV data layout)
 - #104074 (rustdoc: Add an example for round that is different from truncate)

Failed merges:

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

37 files changed, 242 insertions, 144 deletions

diff --git a/compiler/rustc_codegen_gcc/src/type_.rs b/compiler/rustc_codegen_gcc/src/type_.rs
index 68bdb8d4e55..862ed62c68b 100644
--- a/compiler/rustc_codegen_gcc/src/type_.rs
+++ b/compiler/rustc_codegen_gcc/src/type_.rs
@@ -201,6 +201,27 @@ impl<'gcc, 'tcx> BaseTypeMethods<'tcx> for CodegenCx<'gcc, 'tcx> {
     fn val_ty(&self, value: RValue<'gcc>) -> Type<'gcc> {
         value.get_type()
     }
+
+    fn type_array(&self, ty: Type<'gcc>, mut len: u64) -> Type<'gcc> {
+        if let Some(struct_type) = ty.is_struct() {
+            if struct_type.get_field_count() == 0 {
+                // NOTE: since gccjit only supports i32 for the array size and libcore's tests uses a
+                // size of usize::MAX in test_binary_search, we workaround this by setting the size to
+                // zero for ZSTs.
+                // FIXME(antoyo): fix gccjit API.
+                len = 0;
+            }
+        }
+
+        // NOTE: see note above. Some other test uses usize::MAX.
+        if len == u64::MAX {
+            len = 0;
+        }
+
+        let len: i32 = len.try_into().expect("array len");
+
+        self.context.new_array_type(None, ty, len)
+    }
 }
 
 impl<'gcc, 'tcx> CodegenCx<'gcc, 'tcx> {
@@ -227,27 +248,6 @@ impl<'gcc, 'tcx> CodegenCx<'gcc, 'tcx> {
         self.context.new_opaque_struct_type(None, name)
     }
 
-    pub fn type_array(&self, ty: Type<'gcc>, mut len: u64) -> Type<'gcc> {
-        if let Some(struct_type) = ty.is_struct() {
-            if struct_type.get_field_count() == 0 {
-                // NOTE: since gccjit only supports i32 for the array size and libcore's tests uses a
-                // size of usize::MAX in test_binary_search, we workaround this by setting the size to
-                // zero for ZSTs.
-                // FIXME(antoyo): fix gccjit API.
-                len = 0;
-            }
-        }
-
-        // NOTE: see note above. Some other test uses usize::MAX.
-        if len == u64::MAX {
-            len = 0;
-        }
-
-        let len: i32 = len.try_into().expect("array len");
-
-        self.context.new_array_type(None, ty, len)
-    }
-
     pub fn type_bool(&self) -> Type<'gcc> {
         self.context.new_type::<bool>()
     }
diff --git a/compiler/rustc_codegen_llvm/src/context.rs b/compiler/rustc_codegen_llvm/src/context.rs
index 79ddfd884df..c22ec128dac 100644
--- a/compiler/rustc_codegen_llvm/src/context.rs
+++ b/compiler/rustc_codegen_llvm/src/context.rs
@@ -158,6 +158,10 @@ pub unsafe fn create_module<'ll>(
         if sess.target.arch == "s390x" {
             target_data_layout = target_data_layout.replace("-v128:64", "");
         }
+
+        if sess.target.arch == "riscv64" {
+            target_data_layout = target_data_layout.replace("-n32:64-", "-n64-");
+        }
     }
 
     // Ensure the data-layout values hardcoded remain the defaults.
diff --git a/compiler/rustc_codegen_llvm/src/type_.rs b/compiler/rustc_codegen_llvm/src/type_.rs
index eeb38d4ecf5..5eec7dc6130 100644
--- a/compiler/rustc_codegen_llvm/src/type_.rs
+++ b/compiler/rustc_codegen_llvm/src/type_.rs
@@ -127,10 +127,6 @@ impl<'ll> CodegenCx<'ll, '_> {
     pub(crate) fn type_variadic_func(&self, args: &[&'ll Type], ret: &'ll Type) -> &'ll Type {
         unsafe { llvm::LLVMFunctionType(ret, args.as_ptr(), args.len() as c_uint, True) }
     }
-
-    pub(crate) fn type_array(&self, ty: &'ll Type, len: u64) -> &'ll Type {
-        unsafe { llvm::LLVMRustArrayType(ty, len) }
-    }
 }
 
 impl<'ll, 'tcx> BaseTypeMethods<'tcx> for CodegenCx<'ll, 'tcx> {
@@ -231,6 +227,10 @@ impl<'ll, 'tcx> BaseTypeMethods<'tcx> for CodegenCx<'ll, 'tcx> {
     fn val_ty(&self, v: &'ll Value) -> &'ll Type {
         common::val_ty(v)
     }
+
+    fn type_array(&self, ty: &'ll Type, len: u64) -> &'ll Type {
+        unsafe { llvm::LLVMRustArrayType(ty, len) }
+    }
 }
 
 impl Type {
diff --git a/compiler/rustc_codegen_ssa/src/traits/type_.rs b/compiler/rustc_codegen_ssa/src/traits/type_.rs
index bdc6a91cf6a..86481d5d758 100644
--- a/compiler/rustc_codegen_ssa/src/traits/type_.rs
+++ b/compiler/rustc_codegen_ssa/src/traits/type_.rs
@@ -22,6 +22,7 @@ pub trait BaseTypeMethods<'tcx>: Backend<'tcx> {
     fn type_f32(&self) -> Self::Type;
     fn type_f64(&self) -> Self::Type;
 
+    fn type_array(&self, ty: Self::Type, len: u64) -> Self::Type;
     fn type_func(&self, args: &[Self::Type], ret: Self::Type) -> Self::Type;
     fn type_struct(&self, els: &[Self::Type], packed: bool) -> Self::Type;
     fn type_kind(&self, ty: Self::Type) -> TypeKind;
diff --git a/compiler/rustc_lexer/src/lib.rs b/compiler/rustc_lexer/src/lib.rs
index 51515976e4e..dd2c09cae02 100644
--- a/compiler/rustc_lexer/src/lib.rs
+++ b/compiler/rustc_lexer/src/lib.rs
@@ -88,7 +88,9 @@ pub enum TokenKind {
     /// tokens.
     UnknownPrefix,
 
-    /// Examples: `"12_u8"`, `"1.0e-40"`, `b"123`.
+    /// Examples: `12u8`, `1.0e-40`, `b"123"`. Note that `_` is an invalid
+    /// suffix, but may be present here on string and float literals. Users of
+    /// this type will need to check for and reject that case.
     ///
     /// See [LiteralKind] for more details.
     Literal { kind: LiteralKind, suffix_start: u32 },
@@ -840,12 +842,13 @@ impl Cursor<'_> {
         self.eat_decimal_digits()
     }
 
-    // Eats the suffix of the literal, e.g. "_u8".
+    // Eats the suffix of the literal, e.g. "u8".
     fn eat_literal_suffix(&mut self) {
         self.eat_identifier();
     }
 
-    // Eats the identifier.
+    // Eats the identifier. Note: succeeds on `_`, which isn't a valid
+    // identifer.
     fn eat_identifier(&mut self) {
         if !is_id_start(self.first()) {
             return;
diff --git a/compiler/rustc_middle/src/lint.rs b/compiler/rustc_middle/src/lint.rs
index 79522bd0b2b..51df42f6d14 100644
--- a/compiler/rustc_middle/src/lint.rs
+++ b/compiler/rustc_middle/src/lint.rs
@@ -276,7 +276,7 @@ pub fn explain_lint_level_source(
 
 /// The innermost function for emitting lints.
 ///
-/// If you are loocking to implement a lint, look for higher level functions,
+/// If you are looking to implement a lint, look for higher level functions,
 /// for example:
 /// - [`TyCtxt::emit_spanned_lint`]
 /// - [`TyCtxt::struct_span_lint_hir`]
diff --git a/compiler/rustc_parse/src/lexer/mod.rs b/compiler/rustc_parse/src/lexer/mod.rs
index 462bce16ad7..de8f1c00c12 100644
--- a/compiler/rustc_parse/src/lexer/mod.rs
+++ b/compiler/rustc_parse/src/lexer/mod.rs
@@ -175,20 +175,10 @@ impl<'a> StringReader<'a> {
                         if string == "_" {
                             self.sess
                                 .span_diagnostic
-                                .struct_span_warn(
+                                .struct_span_err(
                                     self.mk_sp(suffix_start, self.pos),
                                     "underscore literal suffix is not allowed",
                                 )
-                                .warn(
-                                    "this was previously accepted by the compiler but is \
-                                       being phased out; it will become a hard error in \
-                                       a future release!",
-                                )
-                                .note(
-                                    "see issue #42326 \
-                                     <https://github.com/rust-lang/rust/issues/42326> \
-                                     for more information",
-                                )
                                 .emit();
                             None
                         } else {
diff --git a/compiler/rustc_target/src/spec/riscv64gc_unknown_freebsd.rs b/compiler/rustc_target/src/spec/riscv64gc_unknown_freebsd.rs
index 0539eca6c1f..8281bac10f8 100644
--- a/compiler/rustc_target/src/spec/riscv64gc_unknown_freebsd.rs
+++ b/compiler/rustc_target/src/spec/riscv64gc_unknown_freebsd.rs
@@ -4,7 +4,7 @@ pub fn target() -> Target {
     Target {
         llvm_target: "riscv64-unknown-freebsd".into(),
         pointer_width: 64,
-        data_layout: "e-m:e-p:64:64-i64:64-i128:128-n64-S128".into(),
+        data_layout: "e-m:e-p:64:64-i64:64-i128:128-n32:64-S128".into(),
         arch: "riscv64".into(),
         options: TargetOptions {
             code_model: Some(CodeModel::Medium),
diff --git a/compiler/rustc_target/src/spec/riscv64gc_unknown_linux_gnu.rs b/compiler/rustc_target/src/spec/riscv64gc_unknown_linux_gnu.rs
index 7d1bf228c37..90dccb28063 100644
--- a/compiler/rustc_target/src/spec/riscv64gc_unknown_linux_gnu.rs
+++ b/compiler/rustc_target/src/spec/riscv64gc_unknown_linux_gnu.rs
@@ -4,7 +4,7 @@ pub fn target() -> Target {
     Target {
         llvm_target: "riscv64-unknown-linux-gnu".into(),
         pointer_width: 64,
-        data_layout: "e-m:e-p:64:64-i64:64-i128:128-n64-S128".into(),
+        data_layout: "e-m:e-p:64:64-i64:64-i128:128-n32:64-S128".into(),
         arch: "riscv64".into(),
         options: TargetOptions {
             code_model: Some(CodeModel::Medium),
diff --git a/compiler/rustc_target/src/spec/riscv64gc_unknown_linux_musl.rs b/compiler/rustc_target/src/spec/riscv64gc_unknown_linux_musl.rs
index f04f8a48bc8..1a56c78e685 100644
--- a/compiler/rustc_target/src/spec/riscv64gc_unknown_linux_musl.rs
+++ b/compiler/rustc_target/src/spec/riscv64gc_unknown_linux_musl.rs
@@ -4,7 +4,7 @@ pub fn target() -> Target {
     Target {
         llvm_target: "riscv64-unknown-linux-musl".into(),
         pointer_width: 64,
-        data_layout: "e-m:e-p:64:64-i64:64-i128:128-n64-S128".into(),
+        data_layout: "e-m:e-p:64:64-i64:64-i128:128-n32:64-S128".into(),
         arch: "riscv64".into(),
         options: TargetOptions {
             code_model: Some(CodeModel::Medium),
diff --git a/compiler/rustc_target/src/spec/riscv64gc_unknown_none_elf.rs b/compiler/rustc_target/src/spec/riscv64gc_unknown_none_elf.rs
index 67806d578c8..409b0b26961 100644
--- a/compiler/rustc_target/src/spec/riscv64gc_unknown_none_elf.rs
+++ b/compiler/rustc_target/src/spec/riscv64gc_unknown_none_elf.rs
@@ -3,7 +3,7 @@ use crate::spec::{RelocModel, Target, TargetOptions};
 
 pub fn target() -> Target {
     Target {
-        data_layout: "e-m:e-p:64:64-i64:64-i128:128-n64-S128".into(),
+        data_layout: "e-m:e-p:64:64-i64:64-i128:128-n32:64-S128".into(),
         llvm_target: "riscv64".into(),
         pointer_width: 64,
         arch: "riscv64".into(),
diff --git a/compiler/rustc_target/src/spec/riscv64gc_unknown_openbsd.rs b/compiler/rustc_target/src/spec/riscv64gc_unknown_openbsd.rs
index cd10f3afaac..ade9d77624b 100644
--- a/compiler/rustc_target/src/spec/riscv64gc_unknown_openbsd.rs
+++ b/compiler/rustc_target/src/spec/riscv64gc_unknown_openbsd.rs
@@ -4,7 +4,7 @@ pub fn target() -> Target {
     Target {
         llvm_target: "riscv64-unknown-openbsd".into(),
         pointer_width: 64,
-        data_layout: "e-m:e-p:64:64-i64:64-i128:128-n64-S128".into(),
+        data_layout: "e-m:e-p:64:64-i64:64-i128:128-n32:64-S128".into(),
         arch: "riscv64".into(),
         options: TargetOptions {
             code_model: Some(CodeModel::Medium),
diff --git a/compiler/rustc_target/src/spec/riscv64imac_unknown_none_elf.rs b/compiler/rustc_target/src/spec/riscv64imac_unknown_none_elf.rs
index f371e09bed7..87aba9171b4 100644
--- a/compiler/rustc_target/src/spec/riscv64imac_unknown_none_elf.rs
+++ b/compiler/rustc_target/src/spec/riscv64imac_unknown_none_elf.rs
@@ -3,7 +3,7 @@ use crate::spec::{RelocModel, Target, TargetOptions};
 
 pub fn target() -> Target {
     Target {
-        data_layout: "e-m:e-p:64:64-i64:64-i128:128-n64-S128".into(),
+        data_layout: "e-m:e-p:64:64-i64:64-i128:128-n32:64-S128".into(),
         llvm_target: "riscv64".into(),
         pointer_width: 64,
         arch: "riscv64".into(),
diff --git a/library/alloc/src/vec/mod.rs b/library/alloc/src/vec/mod.rs
index 834c8f58cb2..766006939fa 100644
--- a/library/alloc/src/vec/mod.rs
+++ b/library/alloc/src/vec/mod.rs
@@ -2780,7 +2780,7 @@ impl<T, A: Allocator> IntoIterator for Vec<T, A> {
     /// assert_eq!(v_iter.next(), None);
     /// ```
     #[inline]
-    fn into_iter(self) -> IntoIter<T, A> {
+    fn into_iter(self) -> Self::IntoIter {
         unsafe {
             let mut me = ManuallyDrop::new(self);
             let alloc = ManuallyDrop::new(ptr::read(me.allocator()));
@@ -2808,7 +2808,7 @@ impl<'a, T, A: Allocator> IntoIterator for &'a Vec<T, A> {
     type Item = &'a T;
     type IntoIter = slice::Iter<'a, T>;
 
-    fn into_iter(self) -> slice::Iter<'a, T> {
+    fn into_iter(self) -> Self::IntoIter {
         self.iter()
     }
 }
@@ -2818,7 +2818,7 @@ impl<'a, T, A: Allocator> IntoIterator for &'a mut Vec<T, A> {
     type Item = &'a mut T;
     type IntoIter = slice::IterMut<'a, T>;
 
-    fn into_iter(self) -> slice::IterMut<'a, T> {
+    fn into_iter(self) -> Self::IntoIter {
         self.iter_mut()
     }
 }
diff --git a/library/std/src/f32.rs b/library/std/src/f32.rs
index dafcd876744..4127c4056f2 100644
--- a/library/std/src/f32.rs
+++ b/library/std/src/f32.rs
@@ -77,9 +77,11 @@ impl f32 {
     /// ```
     /// let f = 3.3_f32;
     /// let g = -3.3_f32;
+    /// let h = -3.7_f32;
     ///
     /// assert_eq!(f.round(), 3.0);
     /// assert_eq!(g.round(), -3.0);
+    /// assert_eq!(h.round(), -4.0);
     /// ```
     #[rustc_allow_incoherent_impl]
     #[must_use = "method returns a new number and does not mutate the original value"]
diff --git a/library/std/src/f64.rs b/library/std/src/f64.rs
index 77048f9a28f..cc64258da60 100644
--- a/library/std/src/f64.rs
+++ b/library/std/src/f64.rs
@@ -77,9 +77,11 @@ impl f64 {
     /// ```
     /// let f = 3.3_f64;
     /// let g = -3.3_f64;
+    /// let h = -3.7_f64;
     ///
     /// assert_eq!(f.round(), 3.0);
     /// assert_eq!(g.round(), -3.0);
+    /// assert_eq!(h.round(), -4.0);
     /// ```
     #[rustc_allow_incoherent_impl]
     #[must_use = "method returns a new number and does not mutate the original value"]
diff --git a/src/librustdoc/clean/auto_trait.rs b/src/librustdoc/clean/auto_trait.rs
index 84e77e69ecf..85bd8446640 100644
--- a/src/librustdoc/clean/auto_trait.rs
+++ b/src/librustdoc/clean/auto_trait.rs
@@ -336,10 +336,7 @@ where
                 match br {
                     // We only care about named late bound regions, as we need to add them
                     // to the 'for<>' section
-                    ty::BrNamed(_, name) => Some(GenericParamDef {
-                        name,
-                        kind: GenericParamDefKind::Lifetime { outlives: vec![] },
-                    }),
+                    ty::BrNamed(_, name) => Some(GenericParamDef::lifetime(name)),
                     _ => None,
                 }
             })
diff --git a/src/librustdoc/clean/inline.rs b/src/librustdoc/clean/inline.rs
index 841c4f9d530..8a5463c10f2 100644
--- a/src/librustdoc/clean/inline.rs
+++ b/src/librustdoc/clean/inline.rs
@@ -243,10 +243,19 @@ pub(crate) fn build_external_trait(cx: &mut DocContext<'_>, did: DefId) -> clean
 fn build_external_function<'tcx>(cx: &mut DocContext<'tcx>, did: DefId) -> Box<clean::Function> {
     let sig = cx.tcx.fn_sig(did);
 
-    let predicates = cx.tcx.predicates_of(did);
+    let late_bound_regions = sig.bound_vars().into_iter().filter_map(|var| match var {
+        ty::BoundVariableKind::Region(ty::BrNamed(_, name)) if name != kw::UnderscoreLifetime => {
+            Some(clean::GenericParamDef::lifetime(name))
+        }
+        _ => None,
+    });
+
+    let predicates = cx.tcx.explicit_predicates_of(did);
     let (generics, decl) = clean::enter_impl_trait(cx, |cx| {
         // NOTE: generics need to be cleaned before the decl!
-        let generics = clean_ty_generics(cx, cx.tcx.generics_of(did), predicates);
+        let mut generics = clean_ty_generics(cx, cx.tcx.generics_of(did), predicates);
+        // FIXME: This does not place parameters in source order (late-bound ones come last)
+        generics.params.extend(late_bound_regions);
         let decl = clean_fn_decl_from_did_and_sig(cx, Some(did), sig);
         (generics, decl)
     });
diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index 16e2d9a3cfc..19276b9b187 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -12,7 +12,7 @@ pub(crate) mod utils;
 
 use rustc_ast as ast;
 use rustc_attr as attr;
-use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexSet};
 use rustc_hir as hir;
 use rustc_hir::def::{CtorKind, DefKind, Res};
 use rustc_hir::def_id::{DefId, LOCAL_CRATE};
@@ -182,10 +182,9 @@ fn clean_poly_trait_ref_with_bindings<'tcx>(
         .collect_referenced_late_bound_regions(&poly_trait_ref)
         .into_iter()
         .filter_map(|br| match br {
-            ty::BrNamed(_, name) if name != kw::UnderscoreLifetime => Some(GenericParamDef {
-                name,
-                kind: GenericParamDefKind::Lifetime { outlives: vec![] },
-            }),
+            ty::BrNamed(_, name) if name != kw::UnderscoreLifetime => {
+                Some(GenericParamDef::lifetime(name))
+            }
             _ => None,
         })
         .collect();
@@ -741,10 +740,7 @@ fn clean_ty_generics<'tcx>(
                             p.get_bound_params()
                                 .into_iter()
                                 .flatten()
-                                .map(|param| GenericParamDef {
-                                    name: param.0,
-                                    kind: GenericParamDefKind::Lifetime { outlives: Vec::new() },
-                                })
+                                .map(|param| GenericParamDef::lifetime(param.0))
                                 .collect(),
                         ));
                     }
@@ -957,12 +953,14 @@ fn clean_args_from_types_and_names<'tcx>(
         values: types
             .iter()
             .enumerate()
-            .map(|(i, ty)| {
-                let mut name = names.get(i).map_or(kw::Empty, |ident| ident.name);
-                if name.is_empty() {
-                    name = kw::Underscore;
-                }
-                Argument { name, type_: clean_ty(ty, cx), is_const: false }
+            .map(|(i, ty)| Argument {
+                type_: clean_ty(ty, cx),
+                name: names
+                    .get(i)
+                    .map(|ident| ident.name)
+                    .filter(|ident| !ident.is_empty())
+                    .unwrap_or(kw::Underscore),
+                is_const: false,
             })
             .collect(),
     }
@@ -1024,7 +1022,11 @@ fn clean_fn_decl_from_did_and_sig<'tcx>(
                 .iter()
                 .map(|t| Argument {
                     type_: clean_middle_ty(*t, cx, None),
-                    name: names.next().map_or(kw::Empty, |i| i.name),
+                    name: names
+                        .next()
+                        .map(|i| i.name)
+                        .filter(|i| !i.is_empty())
+                        .unwrap_or(kw::Underscore),
                     is_const: false,
                 })
                 .collect(),
@@ -1144,12 +1146,25 @@ pub(crate) fn clean_middle_assoc_item<'tcx>(
             }
         }
         ty::AssocKind::Fn => {
-            let generics = clean_ty_generics(
+            let sig = tcx.fn_sig(assoc_item.def_id);
+
+            let late_bound_regions = sig.bound_vars().into_iter().filter_map(|var| match var {
+                ty::BoundVariableKind::Region(ty::BrNamed(_, name))
+                    if name != kw::UnderscoreLifetime =>
+                {
+                    Some(GenericParamDef::lifetime(name))
+                }
+                _ => None,
+            });
+
+            let mut generics = clean_ty_generics(
                 cx,
                 tcx.generics_of(assoc_item.def_id),
                 tcx.explicit_predicates_of(assoc_item.def_id),
             );
-            let sig = tcx.fn_sig(assoc_item.def_id);
+            // FIXME: This does not place parameters in source order (late-bound ones come last)
+            generics.params.extend(late_bound_regions);
+
             let mut decl = clean_fn_decl_from_did_and_sig(cx, Some(assoc_item.def_id), sig);
 
             if assoc_item.fn_has_self_parameter {
@@ -1281,7 +1296,16 @@ pub(crate) fn clean_middle_assoc_item<'tcx>(
                         ..
                     }) = generics.params.iter_mut().find(|param| &param.name == arg)
                     {
-                        param_bounds.extend(mem::take(bounds));
+                        param_bounds.append(bounds);
+                    } else if let WherePredicate::RegionPredicate { lifetime: Lifetime(arg), bounds } = &mut pred
+                    && let Some(GenericParamDef {
+                        kind: GenericParamDefKind::Lifetime { outlives: param_bounds },
+                        ..
+                    }) = generics.params.iter_mut().find(|param| &param.name == arg) {
+                        param_bounds.extend(bounds.drain(..).map(|bound| match bound {
+                            GenericBound::Outlives(lifetime) => lifetime,
+                            _ => unreachable!(),
+                        }));
                     } else {
                         where_predicates.push(pred);
                     }
@@ -1653,6 +1677,9 @@ pub(crate) fn clean_middle_ty<'tcx>(
 
             inline::record_extern_fqn(cx, did, ItemType::Trait);
 
+            // FIXME(fmease): Hide the trait-object lifetime bound if it coincides with its default
+            // to partially address #44306. Follow the rules outlined at
+            // https://doc.rust-lang.org/reference/lifetime-elision.html#default-trait-object-lifetimes
             let lifetime = clean_middle_region(*reg);
             let mut bounds = dids
                 .map(|did| {
@@ -1680,8 +1707,22 @@ pub(crate) fn clean_middle_ty<'tcx>(
                 })
                 .collect();
 
+            let late_bound_regions: FxIndexSet<_> = obj
+                .iter()
+                .flat_map(|pb| pb.bound_vars())
+                .filter_map(|br| match br {
+                    ty::BoundVariableKind::Region(ty::BrNamed(_, name))
+                        if name != kw::UnderscoreLifetime =>
+                    {
+                        Some(GenericParamDef::lifetime(name))
+                    }
+                    _ => None,
+                })
+                .collect();
+            let late_bound_regions = late_bound_regions.into_iter().collect();
+
             let path = external_path(cx, did, false, bindings, substs);
-            bounds.insert(0, PolyTrait { trait_: path, generic_params: Vec::new() });
+            bounds.insert(0, PolyTrait { trait_: path, generic_params: late_bound_regions });
 
             DynTrait(bounds, lifetime)
         }
diff --git a/src/librustdoc/clean/simplify.rs b/src/librustdoc/clean/simplify.rs
index 1c184f9b269..7d97d2994e4 100644
--- a/src/librustdoc/clean/simplify.rs
+++ b/src/librustdoc/clean/simplify.rs
@@ -51,10 +51,7 @@ pub(crate) fn where_clauses(cx: &DocContext<'_>, clauses: Vec<WP>) -> ThinVec<WP
         let Some((bounds, _)) = tybounds.get_mut(ty) else { return true };
         let bound_params = bound_params
             .into_iter()
-            .map(|param| clean::GenericParamDef {
-                name: param.0,
-                kind: clean::GenericParamDefKind::Lifetime { outlives: Vec::new() },
-            })
+            .map(|param| clean::GenericParamDef::lifetime(param.0))
             .collect();
         merge_bounds(cx, bounds, bound_params, trait_did, name, rhs)
     });
@@ -99,9 +96,8 @@ pub(crate) fn merge_bounds(
         let last = trait_ref.trait_.segments.last_mut().expect("segments were empty");
 
         trait_ref.generic_params.append(&mut bound_params);
-        // Since the parameters (probably) originate from `tcx.collect_*_late_bound_regions` which
-        // returns a hash set, sort them alphabetically to guarantee a stable and deterministic
-        // output (and to fully deduplicate them).
+        // Sort parameters (likely) originating from a hashset alphabetically to
+        // produce predictable output (and to allow for full deduplication).
         trait_ref.generic_params.sort_unstable_by(|p, q| p.name.as_str().cmp(q.name.as_str()));
         trait_ref.generic_params.dedup_by_key(|p| p.name);
 
diff --git a/src/librustdoc/clean/types.rs b/src/librustdoc/clean/types.rs
index fea3690e50a..bbedfdd0eaf 100644
--- a/src/librustdoc/clean/types.rs
+++ b/src/librustdoc/clean/types.rs
@@ -1437,6 +1437,10 @@ pub(crate) struct GenericParamDef {
 }
 
 impl GenericParamDef {
+    pub(crate) fn lifetime(name: Symbol) -> Self {
+        Self { name, kind: GenericParamDefKind::Lifetime { outlives: Vec::new() } }
+    }
+
     pub(crate) fn is_synthetic_type_param(&self) -> bool {
         match self.kind {
             GenericParamDefKind::Lifetime { .. } | GenericParamDefKind::Const { .. } => false,
diff --git a/src/librustdoc/clean/utils.rs b/src/librustdoc/clean/utils.rs
index df20dc3fc3f..824d98113c8 100644
--- a/src/librustdoc/clean/utils.rs
+++ b/src/librustdoc/clean/utils.rs
@@ -4,7 +4,7 @@ use crate::clean::render_macro_matchers::render_macro_matcher;
 use crate::clean::{
     clean_doc_module, clean_middle_const, clean_middle_region, clean_middle_ty, inline, Crate,
     ExternalCrate, Generic, GenericArg, GenericArgs, ImportSource, Item, ItemKind, Lifetime, Path,
-    PathSegment, Primitive, PrimitiveType, Type, TypeBinding,
+    PathSegment, Primitive, PrimitiveType, Term, Type, TypeBinding, TypeBindingKind,
 };
 use crate::core::DocContext;
 use crate::html::format::visibility_to_src_with_space;
@@ -113,12 +113,12 @@ fn external_generic_args<'tcx>(
                 ty::Tuple(tys) => tys.iter().map(|t| clean_middle_ty(t, cx, None)).collect::<Vec<_>>().into(),
                 _ => return GenericArgs::AngleBracketed { args: args.into(), bindings },
             };
-        let output = None;
-        // FIXME(#20299) return type comes from a projection now
-        // match types[1].kind {
-        //     ty::Tuple(ref v) if v.is_empty() => None, // -> ()
-        //     _ => Some(types[1].clean(cx))
-        // };
+        let output = bindings.into_iter().next().and_then(|binding| match binding.kind {
+            TypeBindingKind::Equality { term: Term::Type(ty) } if ty != Type::Tuple(Vec::new()) => {
+                Some(Box::new(ty))
+            }
+            _ => None,
+        });
         GenericArgs::Parenthesized { inputs, output }
     } else {
         GenericArgs::AngleBracketed { args: args.into(), bindings: bindings.into() }
diff --git a/src/librustdoc/html/format.rs b/src/librustdoc/html/format.rs
index 06db3fb0ec4..a5c3d35b1b5 100644
--- a/src/librustdoc/html/format.rs
+++ b/src/librustdoc/html/format.rs
@@ -1232,9 +1232,8 @@ impl clean::Arguments {
     ) -> impl fmt::Display + 'a + Captures<'tcx> {
         display_fn(move |f| {
             for (i, input) in self.values.iter().enumerate() {
-                if !input.name.is_empty() {
-                    write!(f, "{}: ", input.name)?;
-                }
+                write!(f, "{}: ", input.name)?;
+
                 if f.alternate() {
                     write!(f, "{:#}", input.type_.print(cx))?;
                 } else {
@@ -1367,10 +1366,8 @@ impl clean::FnDecl {
                     args.push_str("const ");
                     args_plain.push_str("const ");
                 }
-                if !input.name.is_empty() {
-                    write!(args, "{}: ", input.name);
-                    write!(args_plain, "{}: ", input.name);
-                }
+                write!(args, "{}: ", input.name);
+                write!(args_plain, "{}: ", input.name);
 
                 if f.alternate() {
                     write!(args, "{:#}", input.type_.print(cx));
diff --git a/src/librustdoc/html/static/css/rustdoc.css b/src/librustdoc/html/static/css/rustdoc.css
index 66e48ba8cf1..a38c0e42ab4 100644
--- a/src/librustdoc/html/static/css/rustdoc.css
+++ b/src/librustdoc/html/static/css/rustdoc.css
@@ -378,6 +378,10 @@ img {
 	object-fit: contain;
 }
 
+.rust-logo {
+	filter: var(--rust-logo-filter);
+}
+
 .sidebar, .mobile-topbar, .sidebar-menu-toggle {
 	background-color: var(--sidebar-background-color);
 }
@@ -1804,21 +1808,6 @@ in storage.js
 		display: block;
 	}
 
-	/* Because of ios, we need to actually have a full height sidebar title so the
-	 * actual sidebar can show up. But then we need to make it transparent so we don't
-	 * hide content. The filler just allows to create the background for the sidebar
-	 * title. But because of the absolute position, I had to lower the z-index.
-	 */
-	#sidebar-filler {
-		position: fixed;
-		left: 45px;
-		width: calc(100% - 45px);
-		top: 0;
-		height: 45px;
-		z-index: -1;
-		border-bottom: 1px solid;
-	}
-
 	#main-content > details.rustdoc-toggle > summary::before,
 	#main-content > div > details.rustdoc-toggle > summary::before {
 		left: -11px;
diff --git a/src/librustdoc/html/static/css/themes/ayu.css b/src/librustdoc/html/static/css/themes/ayu.css
index 4b88c42f2df..bf8a60affaa 100644
--- a/src/librustdoc/html/static/css/themes/ayu.css
+++ b/src/librustdoc/html/static/css/themes/ayu.css
@@ -63,6 +63,10 @@ Original by Dempfi (https://github.com/dempfi/ayu)
 	--test-arrow-background-color: rgba(57, 175, 215, 0.09);
 	--test-arrow-hover-color: #c5c5c5;
 	--test-arrow-hover-background-color: rgba(57, 175, 215, 0.368);
+	--rust-logo-filter: drop-shadow(1px 0 0px #fff)
+		drop-shadow(0 1px 0 #fff)
+		drop-shadow(-1px 0 0 #fff)
+		drop-shadow(0 -1px 0 #fff);
 }
 
 .slider {
@@ -104,13 +108,6 @@ pre, .rustdoc.source .example-wrap {
 	color: #e6e1cf;
 }
 
-.rust-logo {
-	filter: drop-shadow(1px 0 0px #fff)
-		drop-shadow(0 1px 0 #fff)
-		drop-shadow(-1px 0 0 #fff)
-		drop-shadow(0 -1px 0 #fff);
-}
-
 .sidebar .current,
 .sidebar a:hover {
 	color: #ffb44c;
diff --git a/src/librustdoc/html/static/css/themes/dark.css b/src/librustdoc/html/static/css/themes/dark.css
index 8edd8fee78d..ac6e527848f 100644
--- a/src/librustdoc/html/static/css/themes/dark.css
+++ b/src/librustdoc/html/static/css/themes/dark.css
@@ -58,6 +58,10 @@
 	--test-arrow-background-color: rgba(78, 139, 202, 0.2);
 	--test-arrow-hover-color: #dedede;
 	--test-arrow-hover-background-color: #4e8bca;
+	--rust-logo-filter: drop-shadow(1px 0 0px #fff)
+		drop-shadow(0 1px 0 #fff)
+		drop-shadow(-1px 0 0 #fff)
+		drop-shadow(0 -1px 0 #fff);
 }
 
 .slider {
@@ -70,13 +74,6 @@ input:focus + .slider {
 	box-shadow: 0 0 0 2px #0a84ff, 0 0 0 6px rgba(10, 132, 255, 0.3);
 }
 
-.rust-logo {
-	filter: drop-shadow(1px 0 0px #fff)
-		drop-shadow(0 1px 0 #fff)
-		drop-shadow(-1px 0 0 #fff)
-		drop-shadow(0 -1px 0 #fff)
-}
-
 .content .item-info::before { color: #ccc; }
 
 body.source .example-wrap pre.rust a {
diff --git a/src/librustdoc/html/static/css/themes/light.css b/src/librustdoc/html/static/css/themes/light.css
index 797be8754f8..608fc5aba7f 100644
--- a/src/librustdoc/html/static/css/themes/light.css
+++ b/src/librustdoc/html/static/css/themes/light.css
@@ -58,6 +58,7 @@
 	--test-arrow-background-color: rgba(78, 139, 202, 0.2);
 	--test-arrow-hover-color: #f5f5f5;
 	--test-arrow-hover-background-color: #4e8bca;
+	--rust-logo-filter: initial;
 }
 
 .slider {
@@ -70,12 +71,6 @@ input:focus + .slider {
 	box-shadow: 0 0 0 2px #0a84ff, 0 0 0 6px rgba(10, 132, 255, 0.3);
 }
 
-.rust-logo {
-	/* This rule exists to force other themes to explicitly style the logo.
-	 * Rustdoc has a custom linter for this purpose.
-	 */
-}
-
 .content .item-info::before { color: #ccc; }
 
 body.source .example-wrap pre.rust a {
diff --git a/src/test/rustdoc-gui/rust-logo.goml b/src/test/rustdoc-gui/rust-logo.goml
index 6c8dc859419..816cc9abd69 100644
--- a/src/test/rustdoc-gui/rust-logo.goml
+++ b/src/test/rustdoc-gui/rust-logo.goml
@@ -17,6 +17,15 @@ define-function: (
         ("local-storage", {"rustdoc-theme": |theme|, "rustdoc-use-system-theme": "false"}),
         ("reload"),
         ("assert-css", (".rust-logo", {"filter": |filter|})),
+        // Now we check that the non-rust logos don't have a CSS filter set.
+        ("goto", "file://" + |DOC_PATH| + "/huge_logo/index.html"),
+        // Changing theme on the new page (again...).
+        ("local-storage", {"rustdoc-theme": |theme|, "rustdoc-use-system-theme": "false"}),
+        ("reload"),
+        // Check there is no rust logo
+        ("assert-false", ".rust-logo"),
+        // Check there is no filter.
+        ("assert-css", (".sidebar .logo-container img", {"filter": "none"})),
     ],
 )
 
diff --git a/src/test/rustdoc/assoc-consts.rs b/src/test/rustdoc/assoc-consts.rs
index a3e10ee5555..3da19a13e53 100644
--- a/src/test/rustdoc/assoc-consts.rs
+++ b/src/test/rustdoc/assoc-consts.rs
@@ -46,6 +46,7 @@ pub fn f(_: &(ToString + 'static)) {}
 impl Bar {
     // @has assoc_consts/struct.Bar.html '//*[@id="associatedconstant.F"]' \
     //      "const F: fn(_: &(dyn ToString + 'static))"
+    // FIXME(fmease): Hide default lifetime, render "const F: fn(_: &dyn ToString)"
     pub const F: fn(_: &(ToString + 'static)) = f;
 }
 
diff --git a/src/test/rustdoc/inline_cross/assoc_item_trait_bounds.rs b/src/test/rustdoc/inline_cross/assoc_item_trait_bounds.rs
index 5f4712aab5b..db2491b87b4 100644
--- a/src/test/rustdoc/inline_cross/assoc_item_trait_bounds.rs
+++ b/src/test/rustdoc/inline_cross/assoc_item_trait_bounds.rs
@@ -33,8 +33,12 @@ extern crate assoc_item_trait_bounds as aux;
 // @snapshot out9 - '//*[@id="associatedtype.Out9"]/*[@class="code-header"]'
 //
 // @has - '//*[@id="tymethod.make"]' \
-// "fn make<F>(F, impl FnMut(&str) -> bool)\
+// "fn make<F>(_: F, _: impl FnMut(&str) -> bool)\
 // where \
 //     F: FnOnce(u32) -> String, \
 //     Self::Out2<()>: Protocol<u8, Q0 = Self::Item, Q1 = ()>"
 pub use aux::Main;
+
+// @has main/trait.Aid.html
+// @has - '//*[@id="associatedtype.Result"]' "type Result<'inter: 'src>"
+pub use aux::Aid;
diff --git a/src/test/rustdoc/inline_cross/auxiliary/assoc_item_trait_bounds.rs b/src/test/rustdoc/inline_cross/auxiliary/assoc_item_trait_bounds.rs
index d326e61daea..6644c8e4147 100644
--- a/src/test/rustdoc/inline_cross/auxiliary/assoc_item_trait_bounds.rs
+++ b/src/test/rustdoc/inline_cross/auxiliary/assoc_item_trait_bounds.rs
@@ -42,5 +42,5 @@ pub trait Helper {
 }
 
 pub trait Aid<'src> {
-    type Result<'inter>;
+    type Result<'inter: 'src>;
 }
diff --git a/src/test/rustdoc/inline_cross/auxiliary/dyn_trait.rs b/src/test/rustdoc/inline_cross/auxiliary/dyn_trait.rs
new file mode 100644
index 00000000000..9ac2e3d96de
--- /dev/null
+++ b/src/test/rustdoc/inline_cross/auxiliary/dyn_trait.rs
@@ -0,0 +1,17 @@
+pub type Ty0 = dyn for<'any> FnOnce(&'any str) -> bool;
+
+pub type Ty1<'obj> = dyn std::fmt::Display + 'obj;
+
+pub type Ty2 = dyn for<'a, 'r> Container<'r, Item<'a, 'static> = ()>;
+
+pub type Ty3<'s> = &'s dyn ToString;
+
+pub fn func0(_: &(dyn Fn() + '_)) {}
+
+pub fn func1<'func>(_: &(dyn Fn() + 'func)) {}
+
+pub trait Container<'r> {
+    type Item<'a, 'ctx>;
+}
+
+pub trait Shape<'a> {}
diff --git a/src/test/rustdoc/inline_cross/dyn_trait.rs b/src/test/rustdoc/inline_cross/dyn_trait.rs
new file mode 100644
index 00000000000..fa760540e43
--- /dev/null
+++ b/src/test/rustdoc/inline_cross/dyn_trait.rs
@@ -0,0 +1,31 @@
+#![crate_name = "user"]
+
+// aux-crate:dyn_trait=dyn_trait.rs
+// edition:2021
+
+// @has user/type.Ty0.html
+// @has - '//*[@class="item-decl"]//code' "dyn for<'any> FnOnce(&'any str) -> bool + 'static"
+// FIXME(fmease): Hide default lifetime bound `'static`
+pub use dyn_trait::Ty0;
+
+// @has user/type.Ty1.html
+// @has - '//*[@class="item-decl"]//code' "dyn Display + 'obj"
+pub use dyn_trait::Ty1;
+
+// @has user/type.Ty2.html
+// @has - '//*[@class="item-decl"]//code' "dyn for<'a, 'r> Container<'r, Item<'a, 'static> = ()>"
+pub use dyn_trait::Ty2;
+
+// @has user/type.Ty3.html
+// @has - '//*[@class="item-decl"]//code' "&'s (dyn ToString + 's)"
+// FIXME(fmease): Hide default lifetime bound, render "&'s dyn ToString"
+pub use dyn_trait::Ty3;
+
+// @has user/fn.func0.html
+// @has - '//pre[@class="rust fn"]' "func0(_: &dyn Fn())"
+// FIXME(fmease): Show placeholder-lifetime bound, render "func0(_: &(dyn Fn() + '_))"
+pub use dyn_trait::func0;
+
+// @has user/fn.func1.html
+// @has - '//pre[@class="rust fn"]' "func1<'func>(_: &(dyn Fn() + 'func))"
+pub use dyn_trait::func1;
diff --git a/src/test/rustdoc/inline_cross/impl_trait.rs b/src/test/rustdoc/inline_cross/impl_trait.rs
index 6c1cf8252a9..9c4f6465920 100644
--- a/src/test/rustdoc/inline_cross/impl_trait.rs
+++ b/src/test/rustdoc/inline_cross/impl_trait.rs
@@ -29,7 +29,7 @@ pub use impl_trait_aux::func4;
 // @has impl_trait/fn.func5.html
 // @has - '//pre[@class="rust fn"]' "func5("
 // @has - '//pre[@class="rust fn"]' "_f: impl for<'any> Fn(&'any str, &'any str) -> bool + for<'r> Other<T<'r> = ()>,"
-// @has - '//pre[@class="rust fn"]' "_a: impl for<'alpha, 'beta> Auxiliary<'alpha, Item<'beta> = fn(&'beta ())>"
+// @has - '//pre[@class="rust fn"]' "_a: impl for<'alpha, 'beta> Auxiliary<'alpha, Item<'beta> = fn(_: &'beta ())>"
 // @!has - '//pre[@class="rust fn"]' 'where'
 pub use impl_trait_aux::func5;
 
diff --git a/src/test/rustdoc/issue-20727.rs b/src/test/rustdoc/issue-20727.rs
index f7acffcb4e5..c1a98cd57da 100644
--- a/src/test/rustdoc/issue-20727.rs
+++ b/src/test/rustdoc/issue-20727.rs
@@ -19,6 +19,6 @@ pub mod reexport {
     // @has - '//*[@class="rust trait"]' 'trait Deref {'
     // @has - '//*[@class="rust trait"]' 'type Target: ?Sized;'
     // @has - '//*[@class="rust trait"]' \
-    //      "fn deref(&'a self) -> &'a Self::Target;"
+    //      "fn deref<'a>(&'a self) -> &'a Self::Target;"
     pub use issue_20727::Deref;
 }
diff --git a/src/test/ui/parser/underscore-suffix-for-string.rs b/src/test/ui/parser/underscore-suffix-for-string.rs
index 2e0ebe2cfa4..bd260752e04 100644
--- a/src/test/ui/parser/underscore-suffix-for-string.rs
+++ b/src/test/ui/parser/underscore-suffix-for-string.rs
@@ -1,8 +1,17 @@
-// check-pass
+macro_rules! sink {
+    ($tt:tt) => {()}
+}
 
 fn main() {
     let _ = "Foo"_;
-    //~^ WARNING underscore literal suffix is not allowed
-    //~| WARNING this was previously accepted
-    //~| NOTE issue #42326
+    //~^ ERROR underscore literal suffix is not allowed
+
+    // This is ok, because `__` is a valid identifier and the macro consumes it
+    // before proper parsing happens.
+    let _ = sink!("Foo"__);
+
+    // This is not ok, even as an input to a macro, because the `_` suffix is
+    // never allowed.
+    sink!("Foo"_);
+    //~^ ERROR underscore literal suffix is not allowed
 }
diff --git a/src/test/ui/parser/underscore-suffix-for-string.stderr b/src/test/ui/parser/underscore-suffix-for-string.stderr
index 00c7657f17b..2fe2c130eb2 100644
--- a/src/test/ui/parser/underscore-suffix-for-string.stderr
+++ b/src/test/ui/parser/underscore-suffix-for-string.stderr
@@ -1,11 +1,14 @@
-warning: underscore literal suffix is not allowed
-  --> $DIR/underscore-suffix-for-string.rs:4:18
+error: underscore literal suffix is not allowed
+  --> $DIR/underscore-suffix-for-string.rs:6:18
    |
 LL |     let _ = "Foo"_;
    |                  ^
+
+error: underscore literal suffix is not allowed
+  --> $DIR/underscore-suffix-for-string.rs:15:16
    |
-   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: see issue #42326 <https://github.com/rust-lang/rust/issues/42326> for more information
+LL |     sink!("Foo"_);
+   |                ^
 
-warning: 1 warning emitted
+error: aborting due to 2 previous errors