diff --git a/compiler/rustc_ast_lowering/src/errors.rs b/compiler/rustc_ast_lowering/src/errors.rs
index c6c85ffa84dd7..17ca1aa7fe170 100644
--- a/compiler/rustc_ast_lowering/src/errors.rs
+++ b/compiler/rustc_ast_lowering/src/errors.rs
@@ -1,7 +1,4 @@
-use rustc_errors::{
-    fluent, AddToDiagnostic, Applicability, Diagnostic, DiagnosticArgFromDisplay,
-    SubdiagnosticMessage,
-};
+use rustc_errors::DiagnosticArgFromDisplay;
 use rustc_macros::{Diagnostic, Subdiagnostic};
 use rustc_span::{symbol::Ident, Span, Symbol};
 
@@ -15,25 +12,15 @@ pub struct GenericTypeWithParentheses {
     pub sub: Option<UseAngleBrackets>,
 }
 
-#[derive(Clone, Copy)]
+#[derive(Clone, Copy, Subdiagnostic)]
+#[multipart_suggestion(ast_lowering::use_angle_brackets, applicability = "maybe-incorrect")]
 pub struct UseAngleBrackets {
+    #[suggestion_part(code = "<")]
     pub open_param: Span,
+    #[suggestion_part(code = ">")]
     pub close_param: Span,
 }
 
-impl AddToDiagnostic for UseAngleBrackets {
-    fn add_to_diagnostic_with<F>(self, diag: &mut Diagnostic, _: F)
-    where
-        F: Fn(&mut Diagnostic, SubdiagnosticMessage) -> SubdiagnosticMessage,
-    {
-        diag.multipart_suggestion(
-            fluent::ast_lowering::use_angle_brackets,
-            vec![(self.open_param, String::from("<")), (self.close_param, String::from(">"))],
-            Applicability::MaybeIncorrect,
-        );
-    }
-}
-
 #[derive(Diagnostic)]
 #[diag(ast_lowering::invalid_abi, code = "E0703")]
 #[note]
@@ -68,30 +55,20 @@ pub struct AssocTyParentheses {
     pub sub: AssocTyParenthesesSub,
 }
 
-#[derive(Clone, Copy)]
+#[derive(Clone, Copy, Subdiagnostic)]
 pub enum AssocTyParenthesesSub {
-    Empty { parentheses_span: Span },
-    NotEmpty { open_param: Span, close_param: Span },
-}
-
-impl AddToDiagnostic for AssocTyParenthesesSub {
-    fn add_to_diagnostic_with<F>(self, diag: &mut Diagnostic, _: F)
-    where
-        F: Fn(&mut Diagnostic, SubdiagnosticMessage) -> SubdiagnosticMessage,
-    {
-        match self {
-            Self::Empty { parentheses_span } => diag.multipart_suggestion(
-                fluent::ast_lowering::remove_parentheses,
-                vec![(parentheses_span, String::new())],
-                Applicability::MaybeIncorrect,
-            ),
-            Self::NotEmpty { open_param, close_param } => diag.multipart_suggestion(
-                fluent::ast_lowering::use_angle_brackets,
-                vec![(open_param, String::from("<")), (close_param, String::from(">"))],
-                Applicability::MaybeIncorrect,
-            ),
-        };
-    }
+    #[multipart_suggestion(ast_lowering::remove_parentheses)]
+    Empty {
+        #[suggestion_part(code = "")]
+        parentheses_span: Span,
+    },
+    #[multipart_suggestion(ast_lowering::use_angle_brackets)]
+    NotEmpty {
+        #[suggestion_part(code = "<")]
+        open_param: Span,
+        #[suggestion_part(code = ">")]
+        close_param: Span,
+    },
 }
 
 #[derive(Diagnostic)]
diff --git a/compiler/rustc_ast_passes/src/ast_validation.rs b/compiler/rustc_ast_passes/src/ast_validation.rs
index f42aca685f60e..7865c523f758c 100644
--- a/compiler/rustc_ast_passes/src/ast_validation.rs
+++ b/compiler/rustc_ast_passes/src/ast_validation.rs
@@ -14,6 +14,7 @@ use rustc_ast::*;
 use rustc_ast_pretty::pprust::{self, State};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_errors::{error_code, fluent, pluralize, struct_span_err, Applicability};
+use rustc_macros::Subdiagnostic;
 use rustc_parse::validate_attr;
 use rustc_session::lint::builtin::{
     DEPRECATED_WHERE_CLAUSE_LOCATION, MISSING_ABI, PATTERNS_IN_FNS_WITHOUT_BODY,
@@ -1805,15 +1806,17 @@ pub fn check_crate(session: &Session, krate: &Crate, lints: &mut LintBuffer) ->
 }
 
 /// Used to forbid `let` expressions in certain syntactic locations.
-#[derive(Clone, Copy)]
+#[derive(Clone, Copy, Subdiagnostic)]
 pub(crate) enum ForbiddenLetReason {
     /// `let` is not valid and the source environment is not important
     GenericForbidden,
     /// A let chain with the `||` operator
-    NotSupportedOr(Span),
+    #[note(ast_passes::not_supported_or)]
+    NotSupportedOr(#[primary_span] Span),
     /// A let chain with invalid parentheses
     ///
     /// For example, `let 1 = 1 && (expr && expr)` is allowed
     /// but `(let 1 = 1 && (let 1 = 1 && (let 1 = 1))) && let a = 1` is not
-    NotSupportedParentheses(Span),
+    #[note(ast_passes::not_supported_parentheses)]
+    NotSupportedParentheses(#[primary_span] Span),
 }
diff --git a/compiler/rustc_ast_passes/src/errors.rs b/compiler/rustc_ast_passes/src/errors.rs
index ba2ed24fc08fc..8319352bd24bd 100644
--- a/compiler/rustc_ast_passes/src/errors.rs
+++ b/compiler/rustc_ast_passes/src/errors.rs
@@ -16,23 +16,6 @@ pub struct ForbiddenLet {
     pub(crate) reason: ForbiddenLetReason,
 }
 
-impl AddToDiagnostic for ForbiddenLetReason {
-    fn add_to_diagnostic_with<F>(self, diag: &mut Diagnostic, _: F)
-    where
-        F: Fn(&mut Diagnostic, SubdiagnosticMessage) -> SubdiagnosticMessage,
-    {
-        match self {
-            Self::GenericForbidden => {}
-            Self::NotSupportedOr(span) => {
-                diag.span_note(span, fluent::ast_passes::not_supported_or);
-            }
-            Self::NotSupportedParentheses(span) => {
-                diag.span_note(span, fluent::ast_passes::not_supported_parentheses);
-            }
-        }
-    }
-}
-
 #[derive(Diagnostic)]
 #[diag(ast_passes::forbidden_let_stable)]
 #[note]
diff --git a/compiler/rustc_error_messages/locales/en-US/infer.ftl b/compiler/rustc_error_messages/locales/en-US/infer.ftl
index 65371a285911e..18b3408b06ab4 100644
--- a/compiler/rustc_error_messages/locales/en-US/infer.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/infer.ftl
@@ -164,7 +164,9 @@ infer_region_explanation = {$pref_kind ->
 }
 
 infer_mismatched_static_lifetime = incompatible lifetime on type
-infer_msl_impl_note = ...does not necessarily outlive the static lifetime introduced by the compatible `impl`
+infer_does_not_outlive_static_from_impl = ...does not necessarily outlive the static lifetime introduced by the compatible `impl`
+infer_implicit_static_lifetime_note = this has an implicit `'static` lifetime requirement
+infer_implicit_static_lifetime_suggestion = consider relaxing the implicit `'static` requirement
 infer_msl_introduces_static = introduces a `'static` lifetime requirement
 infer_msl_unmet_req = because this has an unmet lifetime requirement
 infer_msl_trait_note = this has an implicit `'static` lifetime requirement
diff --git a/compiler/rustc_error_messages/locales/en-US/session.ftl b/compiler/rustc_error_messages/locales/en-US/session.ftl
index 47127ea8e9ce8..e2277923072f9 100644
--- a/compiler/rustc_error_messages/locales/en-US/session.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/session.ftl
@@ -54,3 +54,7 @@ session_crate_name_empty = crate name must not be empty
 session_invalid_character_in_create_name = invalid character `{$character}` in crate name: `{$crate_name}`
 
 session_expr_parentheses_needed = parentheses are required to parse this as an expression
+
+session_skipping_const_checks = skipping const checks
+session_unleashed_feature_help_named = skipping check for `{$gate}` feature
+session_unleashed_feature_help_unnamed = skipping check that does not even have a feature gate
diff --git a/compiler/rustc_errors/src/diagnostic.rs b/compiler/rustc_errors/src/diagnostic.rs
index 518c59dba5366..a63fc0ca285da 100644
--- a/compiler/rustc_errors/src/diagnostic.rs
+++ b/compiler/rustc_errors/src/diagnostic.rs
@@ -567,6 +567,11 @@ impl Diagnostic {
         style: SuggestionStyle,
     ) -> &mut Self {
         assert!(!suggestion.is_empty());
+        debug_assert!(
+            !(suggestion.iter().any(|(sp, text)| sp.is_empty() && text.is_empty())),
+            "Span must not be empty and have no suggestion"
+        );
+
         self.push_suggestion(CodeSuggestion {
             substitutions: vec![Substitution {
                 parts: suggestion
@@ -644,6 +649,10 @@ impl Diagnostic {
         applicability: Applicability,
         style: SuggestionStyle,
     ) -> &mut Self {
+        debug_assert!(
+            !(sp.is_empty() && suggestion.to_string().is_empty()),
+            "Span must not be empty and have no suggestion"
+        );
         self.push_suggestion(CodeSuggestion {
             substitutions: vec![Substitution {
                 parts: vec![SubstitutionPart { snippet: suggestion.to_string(), span: sp }],
@@ -684,6 +693,12 @@ impl Diagnostic {
     ) -> &mut Self {
         let mut suggestions: Vec<_> = suggestions.collect();
         suggestions.sort();
+
+        debug_assert!(
+            !(sp.is_empty() && suggestions.iter().any(|suggestion| suggestion.is_empty())),
+            "Span must not be empty and have no suggestion"
+        );
+
         let substitutions = suggestions
             .into_iter()
             .map(|snippet| Substitution { parts: vec![SubstitutionPart { snippet, span: sp }] })
@@ -705,8 +720,18 @@ impl Diagnostic {
         suggestions: impl Iterator<Item = Vec<(Span, String)>>,
         applicability: Applicability,
     ) -> &mut Self {
+        let suggestions: Vec<_> = suggestions.collect();
+        debug_assert!(
+            !(suggestions
+                .iter()
+                .flat_map(|suggs| suggs)
+                .any(|(sp, suggestion)| sp.is_empty() && suggestion.is_empty())),
+            "Span must not be empty and have no suggestion"
+        );
+
         self.push_suggestion(CodeSuggestion {
             substitutions: suggestions
+                .into_iter()
                 .map(|sugg| Substitution {
                     parts: sugg
                         .into_iter()
diff --git a/compiler/rustc_errors/src/diagnostic_impls.rs b/compiler/rustc_errors/src/diagnostic_impls.rs
index 860f24871bcdc..571b7dbfd1b04 100644
--- a/compiler/rustc_errors/src/diagnostic_impls.rs
+++ b/compiler/rustc_errors/src/diagnostic_impls.rs
@@ -1,14 +1,14 @@
 use crate::{
     fluent, DiagnosticArgValue, DiagnosticBuilder, Handler, IntoDiagnostic, IntoDiagnosticArg,
 };
-use rustc_target::abi::TargetDataLayoutErrors;
-use rustc_target::spec::{PanicStrategy, SplitDebuginfo, StackProtector, TargetTriple};
-
 use rustc_ast as ast;
 use rustc_ast_pretty::pprust;
 use rustc_hir as hir;
+use rustc_lint_defs::Level;
 use rustc_span::edition::Edition;
 use rustc_span::symbol::{Ident, MacroRulesNormalizedIdent, Symbol};
+use rustc_target::abi::TargetDataLayoutErrors;
+use rustc_target::spec::{PanicStrategy, SplitDebuginfo, StackProtector, TargetTriple};
 use std::borrow::Cow;
 use std::fmt;
 use std::num::ParseIntError;
@@ -155,6 +155,21 @@ impl IntoDiagnosticArg for ast::token::TokenKind {
     }
 }
 
+impl IntoDiagnosticArg for Level {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(Cow::Borrowed(match self {
+            Level::Allow => "-A",
+            Level::Warn => "-W",
+            Level::ForceWarn(_) => "--force-warn",
+            Level::Deny => "-D",
+            Level::Forbid => "-F",
+            Level::Expect(_) => {
+                unreachable!("lints with the level of `expect` should not run this code");
+            }
+        }))
+    }
+}
+
 impl IntoDiagnostic<'_, !> for TargetDataLayoutErrors<'_> {
     fn into_diagnostic(self, handler: &Handler) -> DiagnosticBuilder<'_, !> {
         let mut diag;
diff --git a/compiler/rustc_expand/src/base.rs b/compiler/rustc_expand/src/base.rs
index cd8a525e062c5..052ca229f0127 100644
--- a/compiler/rustc_expand/src/base.rs
+++ b/compiler/rustc_expand/src/base.rs
@@ -22,7 +22,7 @@ use rustc_span::edition::Edition;
 use rustc_span::hygiene::{AstPass, ExpnData, ExpnKind, LocalExpnId};
 use rustc_span::source_map::SourceMap;
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
-use rustc_span::{FileName, Span, DUMMY_SP};
+use rustc_span::{BytePos, FileName, Span, DUMMY_SP};
 use smallvec::{smallvec, SmallVec};
 
 use std::default::Default;
@@ -1228,8 +1228,9 @@ pub fn expr_to_spanned_string<'a>(
             ast::LitKind::Str(s, style) => return Ok((s, style, expr.span)),
             ast::LitKind::ByteStr(_) => {
                 let mut err = cx.struct_span_err(l.span, err_msg);
+                let span = expr.span.shrink_to_lo();
                 err.span_suggestion(
-                    expr.span.shrink_to_lo(),
+                    span.with_hi(span.lo() + BytePos(1)),
                     "consider removing the leading `b`",
                     "",
                     Applicability::MaybeIncorrect,
diff --git a/compiler/rustc_hir_analysis/src/astconv/mod.rs b/compiler/rustc_hir_analysis/src/astconv/mod.rs
index 9b9ef2b1fbd02..a0350c26d827c 100644
--- a/compiler/rustc_hir_analysis/src/astconv/mod.rs
+++ b/compiler/rustc_hir_analysis/src/astconv/mod.rs
@@ -3051,24 +3051,27 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                     .map_or(false, |s| s.trim_end().ends_with('<'));
 
             let is_global = poly_trait_ref.trait_ref.path.is_global();
-            let sugg = Vec::from_iter([
-                (
-                    self_ty.span.shrink_to_lo(),
-                    format!(
-                        "{}dyn {}",
-                        if needs_bracket { "<" } else { "" },
-                        if is_global { "(" } else { "" },
-                    ),
+
+            let mut sugg = Vec::from_iter([(
+                self_ty.span.shrink_to_lo(),
+                format!(
+                    "{}dyn {}",
+                    if needs_bracket { "<" } else { "" },
+                    if is_global { "(" } else { "" },
                 ),
-                (
+            )]);
+
+            if is_global || needs_bracket {
+                sugg.push((
                     self_ty.span.shrink_to_hi(),
                     format!(
                         "{}{}",
                         if is_global { ")" } else { "" },
                         if needs_bracket { ">" } else { "" },
                     ),
-                ),
-            ]);
+                ));
+            }
+
             if self_ty.span.edition() >= Edition::Edition2021 {
                 let msg = "trait objects must include the `dyn` keyword";
                 let label = "add `dyn` keyword before this trait";
diff --git a/compiler/rustc_infer/src/errors/mod.rs b/compiler/rustc_infer/src/errors/mod.rs
index 500900d3d4a74..25e8630bf6bd7 100644
--- a/compiler/rustc_infer/src/errors/mod.rs
+++ b/compiler/rustc_infer/src/errors/mod.rs
@@ -459,47 +459,34 @@ impl AddToDiagnostic for IntroducesStaticBecauseUnmetLifetimeReq {
     }
 }
 
-pub struct ImplNote {
-    pub impl_span: Option<Span>,
-}
-
-impl AddToDiagnostic for ImplNote {
-    fn add_to_diagnostic_with<F>(self, diag: &mut Diagnostic, _: F)
-    where
-        F: Fn(&mut Diagnostic, SubdiagnosticMessage) -> SubdiagnosticMessage,
-    {
-        match self.impl_span {
-            Some(span) => diag.span_note(span, fluent::infer::msl_impl_note),
-            None => diag.note(fluent::infer::msl_impl_note),
-        };
-    }
-}
-
-pub enum TraitSubdiag {
-    Note { span: Span },
-    Sugg { span: Span },
+// FIXME(#100717): replace with a `Option<Span>` when subdiagnostic supports that
+#[derive(Subdiagnostic)]
+pub enum DoesNotOutliveStaticFromImpl {
+    #[note(infer::does_not_outlive_static_from_impl)]
+    Spanned {
+        #[primary_span]
+        span: Span,
+    },
+    #[note(infer::does_not_outlive_static_from_impl)]
+    Unspanned,
 }
 
-// FIXME(#100717) used in `Vec<TraitSubdiag>` so requires eager translation/list support
-impl AddToDiagnostic for TraitSubdiag {
-    fn add_to_diagnostic_with<F>(self, diag: &mut Diagnostic, _: F)
-    where
-        F: Fn(&mut Diagnostic, SubdiagnosticMessage) -> SubdiagnosticMessage,
-    {
-        match self {
-            TraitSubdiag::Note { span } => {
-                diag.span_note(span, "this has an implicit `'static` lifetime requirement");
-            }
-            TraitSubdiag::Sugg { span } => {
-                diag.span_suggestion_verbose(
-                    span,
-                    "consider relaxing the implicit `'static` requirement",
-                    " + '_".to_owned(),
-                    rustc_errors::Applicability::MaybeIncorrect,
-                );
-            }
-        }
-    }
+#[derive(Subdiagnostic)]
+pub enum ImplicitStaticLifetimeSubdiag {
+    #[note(infer::implicit_static_lifetime_note)]
+    Note {
+        #[primary_span]
+        span: Span,
+    },
+    #[suggestion_verbose(
+        infer::implicit_static_lifetime_suggestion,
+        code = " + '_",
+        applicability = "maybe-incorrect"
+    )]
+    Sugg {
+        #[primary_span]
+        span: Span,
+    },
 }
 
 #[derive(Diagnostic)]
@@ -512,7 +499,7 @@ pub struct MismatchedStaticLifetime<'a> {
     #[subdiagnostic]
     pub expl: Option<note_and_explain::RegionExplanation<'a>>,
     #[subdiagnostic]
-    pub impl_note: ImplNote,
-    #[subdiagnostic]
-    pub trait_subdiags: Vec<TraitSubdiag>,
+    pub does_not_outlive_static_from_impl: DoesNotOutliveStaticFromImpl,
+    #[subdiagnostic(eager)]
+    pub implicit_static_lifetimes: Vec<ImplicitStaticLifetimeSubdiag>,
 }
diff --git a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/mismatched_static_lifetime.rs b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/mismatched_static_lifetime.rs
index 1410e2b63b0b8..c5f2a1a3f7dce 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/mismatched_static_lifetime.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/mismatched_static_lifetime.rs
@@ -2,7 +2,9 @@
 //! to hold.
 
 use crate::errors::{note_and_explain, IntroducesStaticBecauseUnmetLifetimeReq};
-use crate::errors::{ImplNote, MismatchedStaticLifetime, TraitSubdiag};
+use crate::errors::{
+    DoesNotOutliveStaticFromImpl, ImplicitStaticLifetimeSubdiag, MismatchedStaticLifetime,
+};
 use crate::infer::error_reporting::nice_region_error::NiceRegionError;
 use crate::infer::lexical_region_resolve::RegionResolutionError;
 use crate::infer::{SubregionOrigin, TypeTrace};
@@ -56,7 +58,7 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
             note_and_explain::SuffixKind::Continues,
         );
         let mut impl_span = None;
-        let mut trait_subdiags = Vec::new();
+        let mut implicit_static_lifetimes = Vec::new();
         if let Some(impl_node) = self.tcx().hir().get_if_local(*impl_def_id) {
             // If an impl is local, then maybe this isn't what they want. Try to
             // be as helpful as possible with implicit lifetimes.
@@ -90,10 +92,12 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
                 // Otherwise, point at all implicit static lifetimes
 
                 for span in &traits {
-                    trait_subdiags.push(TraitSubdiag::Note { span: *span });
+                    implicit_static_lifetimes
+                        .push(ImplicitStaticLifetimeSubdiag::Note { span: *span });
                     // It would be nice to put this immediately under the above note, but they get
                     // pushed to the end.
-                    trait_subdiags.push(TraitSubdiag::Sugg { span: span.shrink_to_hi() });
+                    implicit_static_lifetimes
+                        .push(ImplicitStaticLifetimeSubdiag::Sugg { span: span.shrink_to_hi() });
                 }
             }
         } else {
@@ -105,8 +109,10 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
             cause_span: cause.span,
             unmet_lifetime_reqs: multispan_subdiag,
             expl,
-            impl_note: ImplNote { impl_span },
-            trait_subdiags,
+            does_not_outlive_static_from_impl: impl_span
+                .map(|span| DoesNotOutliveStaticFromImpl::Spanned { span })
+                .unwrap_or(DoesNotOutliveStaticFromImpl::Unspanned),
+            implicit_static_lifetimes,
         };
         let reported = self.tcx().sess.emit_err(err);
         Some(reported)
diff --git a/compiler/rustc_lint/src/builtin.rs b/compiler/rustc_lint/src/builtin.rs
index 886e25f2d788b..715ba4ca156d4 100644
--- a/compiler/rustc_lint/src/builtin.rs
+++ b/compiler/rustc_lint/src/builtin.rs
@@ -3176,6 +3176,7 @@ declare_lint! {
     /// ### Example
     ///
     /// ```rust,compile_fail
+    /// # #![feature(asm_experimental_arch)]
     /// use std::arch::asm;
     ///
     /// fn main() {
diff --git a/compiler/rustc_lint/src/errors.rs b/compiler/rustc_lint/src/errors.rs
index 97d012fb611d0..34b70030a5828 100644
--- a/compiler/rustc_lint/src/errors.rs
+++ b/compiler/rustc_lint/src/errors.rs
@@ -88,34 +88,13 @@ pub struct BuiltinEllpisisInclusiveRangePatterns {
     pub replace: String,
 }
 
+#[derive(Subdiagnostic)]
+#[note(lint::requested_level)]
 pub struct RequestedLevel {
     pub level: Level,
     pub lint_name: String,
 }
 
-impl AddToDiagnostic for RequestedLevel {
-    fn add_to_diagnostic_with<F>(self, diag: &mut Diagnostic, _: F)
-    where
-        F: Fn(&mut Diagnostic, SubdiagnosticMessage) -> SubdiagnosticMessage,
-    {
-        diag.note(fluent::lint::requested_level);
-        diag.set_arg(
-            "level",
-            match self.level {
-                Level::Allow => "-A",
-                Level::Warn => "-W",
-                Level::ForceWarn(_) => "--force-warn",
-                Level::Deny => "-D",
-                Level::Forbid => "-F",
-                Level::Expect(_) => {
-                    unreachable!("lints with the level of `expect` should not run this code");
-                }
-            },
-        );
-        diag.set_arg("lint_name", self.lint_name);
-    }
-}
-
 #[derive(Diagnostic)]
 #[diag(lint::unsupported_group, code = "E0602")]
 pub struct UnsupportedGroup {
diff --git a/compiler/rustc_lint/src/unused.rs b/compiler/rustc_lint/src/unused.rs
index 787c9518b5089..36657909b19ee 100644
--- a/compiler/rustc_lint/src/unused.rs
+++ b/compiler/rustc_lint/src/unused.rs
@@ -7,6 +7,7 @@ use rustc_errors::{fluent, pluralize, Applicability, MultiSpan};
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::def_id::DefId;
+use rustc_infer::traits::util::elaborate_predicates_with_span;
 use rustc_middle::ty::adjustment;
 use rustc_middle::ty::{self, Ty};
 use rustc_span::symbol::Symbol;
@@ -204,10 +205,13 @@ impl<'tcx> LateLintPass<'tcx> for UnusedResults {
                 ty::Adt(def, _) => check_must_use_def(cx, def.did(), span, descr_pre, descr_post),
                 ty::Opaque(def, _) => {
                     let mut has_emitted = false;
-                    for &(predicate, _) in cx.tcx.explicit_item_bounds(def) {
+                    for obligation in elaborate_predicates_with_span(
+                        cx.tcx,
+                        cx.tcx.explicit_item_bounds(def).iter().cloned(),
+                    ) {
                         // We only look at the `DefId`, so it is safe to skip the binder here.
                         if let ty::PredicateKind::Trait(ref poly_trait_predicate) =
-                            predicate.kind().skip_binder()
+                            obligation.predicate.kind().skip_binder()
                         {
                             let def_id = poly_trait_predicate.trait_ref.def_id;
                             let descr_pre =
diff --git a/compiler/rustc_lint_defs/src/builtin.rs b/compiler/rustc_lint_defs/src/builtin.rs
index 8390d80a458cf..d6cc31331a3bc 100644
--- a/compiler/rustc_lint_defs/src/builtin.rs
+++ b/compiler/rustc_lint_defs/src/builtin.rs
@@ -2878,7 +2878,7 @@ declare_lint! {
     /// ### Example
     ///
     /// ```rust
-    /// #![feature(naked_functions)]
+    /// #![feature(asm_experimental_arch, naked_functions)]
     ///
     /// use std::arch::asm;
     ///
diff --git a/compiler/rustc_macros/src/diagnostics/diagnostic_builder.rs b/compiler/rustc_macros/src/diagnostics/diagnostic_builder.rs
index dcbe89251cb36..9f7d2661a3e8b 100644
--- a/compiler/rustc_macros/src/diagnostics/diagnostic_builder.rs
+++ b/compiler/rustc_macros/src/diagnostics/diagnostic_builder.rs
@@ -5,7 +5,7 @@ use crate::diagnostics::error::{
     DiagnosticDeriveError,
 };
 use crate::diagnostics::utils::{
-    build_field_mapping, report_error_if_not_applied_to_span, report_type_error,
+    build_field_mapping, is_doc_comment, report_error_if_not_applied_to_span, report_type_error,
     should_generate_set_arg, type_is_unit, type_matches_path, FieldInfo, FieldInnerTy, FieldMap,
     HasFieldMap, SetOnce, SpannedOption, SubdiagnosticKind,
 };
@@ -152,8 +152,12 @@ impl<'a> DiagnosticDeriveVariantBuilder<'a> {
     fn parse_subdiag_attribute(
         &self,
         attr: &Attribute,
-    ) -> Result<(SubdiagnosticKind, Path), DiagnosticDeriveError> {
-        let (subdiag, slug) = SubdiagnosticKind::from_attr(attr, self)?;
+    ) -> Result<Option<(SubdiagnosticKind, Path)>, DiagnosticDeriveError> {
+        let Some((subdiag, slug)) = SubdiagnosticKind::from_attr(attr, self)? else {
+            // Some attributes aren't errors - like documentation comments - but also aren't
+            // subdiagnostics.
+            return Ok(None);
+        };
 
         if let SubdiagnosticKind::MultipartSuggestion { .. } = subdiag {
             let meta = attr.parse_meta()?;
@@ -170,7 +174,7 @@ impl<'a> DiagnosticDeriveVariantBuilder<'a> {
             SubdiagnosticKind::MultipartSuggestion { .. } => unreachable!(),
         });
 
-        Ok((subdiag, slug))
+        Ok(Some((subdiag, slug)))
     }
 
     /// Establishes state in the `DiagnosticDeriveBuilder` resulting from the struct
@@ -182,6 +186,11 @@ impl<'a> DiagnosticDeriveVariantBuilder<'a> {
     ) -> Result<TokenStream, DiagnosticDeriveError> {
         let diag = &self.parent.diag;
 
+        // Always allow documentation comments.
+        if is_doc_comment(attr) {
+            return Ok(quote! {});
+        }
+
         let name = attr.path.segments.last().unwrap().ident.to_string();
         let name = name.as_str();
         let meta = attr.parse_meta()?;
@@ -250,7 +259,11 @@ impl<'a> DiagnosticDeriveVariantBuilder<'a> {
             return Ok(tokens);
         }
 
-        let (subdiag, slug) = self.parse_subdiag_attribute(attr)?;
+        let Some((subdiag, slug)) = self.parse_subdiag_attribute(attr)? else {
+            // Some attributes aren't errors - like documentation comments - but also aren't
+            // subdiagnostics.
+            return Ok(quote! {});
+        };
         let fn_ident = format_ident!("{}", subdiag);
         match subdiag {
             SubdiagnosticKind::Note | SubdiagnosticKind::Help | SubdiagnosticKind::Warn => {
@@ -291,6 +304,11 @@ impl<'a> DiagnosticDeriveVariantBuilder<'a> {
             .attrs
             .iter()
             .map(move |attr| {
+                // Always allow documentation comments.
+                if is_doc_comment(attr) {
+                    return quote! {};
+                }
+
                 let name = attr.path.segments.last().unwrap().ident.to_string();
                 let needs_clone =
                     name == "primary_span" && matches!(inner_ty, FieldInnerTy::Vec(_));
@@ -397,8 +415,11 @@ impl<'a> DiagnosticDeriveVariantBuilder<'a> {
             _ => (),
         }
 
-        let (subdiag, slug) = self.parse_subdiag_attribute(attr)?;
-
+        let Some((subdiag, slug)) = self.parse_subdiag_attribute(attr)? else {
+            // Some attributes aren't errors - like documentation comments - but also aren't
+            // subdiagnostics.
+            return Ok(quote! {});
+        };
         let fn_ident = format_ident!("{}", subdiag);
         match subdiag {
             SubdiagnosticKind::Label => {
diff --git a/compiler/rustc_macros/src/diagnostics/subdiagnostic.rs b/compiler/rustc_macros/src/diagnostics/subdiagnostic.rs
index 3d4c3ab9fd7c9..d1acb71384220 100644
--- a/compiler/rustc_macros/src/diagnostics/subdiagnostic.rs
+++ b/compiler/rustc_macros/src/diagnostics/subdiagnostic.rs
@@ -5,9 +5,9 @@ use crate::diagnostics::error::{
     DiagnosticDeriveError,
 };
 use crate::diagnostics::utils::{
-    build_field_mapping, new_code_ident, report_error_if_not_applied_to_applicability,
-    report_error_if_not_applied_to_span, FieldInfo, FieldInnerTy, FieldMap, HasFieldMap, SetOnce,
-    SpannedOption, SubdiagnosticKind,
+    build_field_mapping, is_doc_comment, new_code_ident,
+    report_error_if_not_applied_to_applicability, report_error_if_not_applied_to_span, FieldInfo,
+    FieldInnerTy, FieldMap, HasFieldMap, SetOnce, SpannedOption, SubdiagnosticKind,
 };
 use proc_macro2::TokenStream;
 use quote::{format_ident, quote};
@@ -41,8 +41,14 @@ impl SubdiagnosticDeriveBuilder {
                 }
             }
 
-            if matches!(ast.data, syn::Data::Enum(..)) {
+            let is_enum = matches!(ast.data, syn::Data::Enum(..));
+            if is_enum {
                 for attr in &ast.attrs {
+                    // Always allow documentation comments.
+                    if is_doc_comment(attr) {
+                        continue;
+                    }
+
                     span_err(
                         attr.span().unwrap(),
                         "unsupported type attribute for subdiagnostic enum",
@@ -62,6 +68,7 @@ impl SubdiagnosticDeriveBuilder {
                     span_field: None,
                     applicability: None,
                     has_suggestion_parts: false,
+                    is_enum,
                 };
                 builder.into_tokens().unwrap_or_else(|v| v.to_compile_error())
             });
@@ -79,7 +86,7 @@ impl SubdiagnosticDeriveBuilder {
             gen impl rustc_errors::AddToDiagnostic for @Self {
                 fn add_to_diagnostic_with<__F>(self, #diag: &mut rustc_errors::Diagnostic, #f: __F)
                 where
-                    __F: Fn(
+                    __F: core::ops::Fn(
                         &mut rustc_errors::Diagnostic,
                         rustc_errors::SubdiagnosticMessage
                     ) -> rustc_errors::SubdiagnosticMessage,
@@ -122,6 +129,9 @@ struct SubdiagnosticDeriveVariantBuilder<'parent, 'a> {
     /// Set to true when a `#[suggestion_part]` field is encountered, used to generate an error
     /// during finalization if still `false`.
     has_suggestion_parts: bool,
+
+    /// Set to true when this variant is an enum variant rather than just the body of a struct.
+    is_enum: bool,
 }
 
 impl<'parent, 'a> HasFieldMap for SubdiagnosticDeriveVariantBuilder<'parent, 'a> {
@@ -173,7 +183,11 @@ impl<'parent, 'a> SubdiagnosticDeriveVariantBuilder<'parent, 'a> {
         let mut kind_slugs = vec![];
 
         for attr in self.variant.ast().attrs {
-            let (kind, slug) = SubdiagnosticKind::from_attr(attr, self)?;
+            let Some((kind, slug)) = SubdiagnosticKind::from_attr(attr, self)? else {
+                // Some attributes aren't errors - like documentation comments - but also aren't
+                // subdiagnostics.
+                continue;
+            };
 
             let Some(slug) = slug else {
                 let name = attr.path.segments.last().unwrap().ident.to_string();
@@ -227,6 +241,11 @@ impl<'parent, 'a> SubdiagnosticDeriveVariantBuilder<'parent, 'a> {
         ast.attrs
             .iter()
             .map(|attr| {
+                // Always allow documentation comments.
+                if is_doc_comment(attr) {
+                    return quote! {};
+                }
+
                 let info = FieldInfo {
                     binding,
                     ty: inner_ty.inner_type().unwrap_or(&ast.ty),
@@ -290,6 +309,8 @@ impl<'parent, 'a> SubdiagnosticDeriveVariantBuilder<'parent, 'a> {
                     report_error_if_not_applied_to_span(attr, &info)?;
 
                     let binding = info.binding.binding.clone();
+                    // FIXME(#100717): support `Option<Span>` on `primary_span` like in the
+                    // diagnostic derive
                     self.span_field.set_once(binding, span);
                 }
 
@@ -443,10 +464,16 @@ impl<'parent, 'a> SubdiagnosticDeriveVariantBuilder<'parent, 'a> {
     pub fn into_tokens(&mut self) -> Result<TokenStream, DiagnosticDeriveError> {
         let kind_slugs = self.identify_kind()?;
         if kind_slugs.is_empty() {
-            throw_span_err!(
-                self.variant.ast().ident.span().unwrap(),
-                "subdiagnostic kind not specified"
-            );
+            if self.is_enum {
+                // It's okay for a variant to not be a subdiagnostic at all..
+                return Ok(quote! {});
+            } else {
+                // ..but structs should always be _something_.
+                throw_span_err!(
+                    self.variant.ast().ident.span().unwrap(),
+                    "subdiagnostic kind not specified"
+                );
+            }
         };
 
         let kind_stats: KindsStatistics = kind_slugs.iter().map(|(kind, _slug)| kind).collect();
diff --git a/compiler/rustc_macros/src/diagnostics/utils.rs b/compiler/rustc_macros/src/diagnostics/utils.rs
index 4fd4adc511267..61d5007fc30f0 100644
--- a/compiler/rustc_macros/src/diagnostics/utils.rs
+++ b/compiler/rustc_macros/src/diagnostics/utils.rs
@@ -477,7 +477,12 @@ impl SubdiagnosticKind {
     pub(super) fn from_attr(
         attr: &Attribute,
         fields: &impl HasFieldMap,
-    ) -> Result<(SubdiagnosticKind, Option<Path>), DiagnosticDeriveError> {
+    ) -> Result<Option<(SubdiagnosticKind, Option<Path>)>, DiagnosticDeriveError> {
+        // Always allow documentation comments.
+        if is_doc_comment(attr) {
+            return Ok(None);
+        }
+
         let span = attr.span().unwrap();
 
         let name = attr.path.segments.last().unwrap().ident.to_string();
@@ -526,7 +531,9 @@ impl SubdiagnosticKind {
                     | SubdiagnosticKind::Note
                     | SubdiagnosticKind::Help
                     | SubdiagnosticKind::Warn
-                    | SubdiagnosticKind::MultipartSuggestion { .. } => return Ok((kind, None)),
+                    | SubdiagnosticKind::MultipartSuggestion { .. } => {
+                        return Ok(Some((kind, None)));
+                    }
                     SubdiagnosticKind::Suggestion { .. } => {
                         throw_span_err!(span, "suggestion without `code = \"...\"`")
                     }
@@ -626,7 +633,7 @@ impl SubdiagnosticKind {
             | SubdiagnosticKind::MultipartSuggestion { .. } => {}
         }
 
-        Ok((kind, slug))
+        Ok(Some((kind, slug)))
     }
 }
 
@@ -654,3 +661,7 @@ impl quote::IdentFragment for SubdiagnosticKind {
 pub(super) fn should_generate_set_arg(field: &Field) -> bool {
     field.attrs.is_empty()
 }
+
+pub(super) fn is_doc_comment(attr: &Attribute) -> bool {
+    attr.path.segments.last().unwrap().ident.to_string() == "doc"
+}
diff --git a/compiler/rustc_parse/src/parser/diagnostics.rs b/compiler/rustc_parse/src/parser/diagnostics.rs
index 40d85c833a7dd..d654d84cdd594 100644
--- a/compiler/rustc_parse/src/parser/diagnostics.rs
+++ b/compiler/rustc_parse/src/parser/diagnostics.rs
@@ -1374,9 +1374,17 @@ impl<'a> Parser<'a> {
         kind: IncDecRecovery,
         (pre_span, post_span): (Span, Span),
     ) -> MultiSugg {
+        let mut patches = Vec::new();
+
+        if !pre_span.is_empty() {
+            patches.push((pre_span, String::new()));
+        }
+
+        patches.push((post_span, format!(" {}= 1", kind.op.chr())));
+
         MultiSugg {
             msg: format!("use `{}= 1` instead", kind.op.chr()),
-            patches: vec![(pre_span, String::new()), (post_span, format!(" {}= 1", kind.op.chr()))],
+            patches,
             applicability: Applicability::MachineApplicable,
         }
     }
diff --git a/compiler/rustc_resolve/src/diagnostics.rs b/compiler/rustc_resolve/src/diagnostics.rs
index c4644d4f076e2..5d868ebec9448 100644
--- a/compiler/rustc_resolve/src/diagnostics.rs
+++ b/compiler/rustc_resolve/src/diagnostics.rs
@@ -24,7 +24,7 @@ use rustc_span::hygiene::MacroKind;
 use rustc_span::lev_distance::find_best_match_for_name;
 use rustc_span::source_map::SourceMap;
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
-use rustc_span::{BytePos, Span};
+use rustc_span::{BytePos, Span, SyntaxContext};
 
 use crate::imports::{Import, ImportKind, ImportResolver};
 use crate::late::{PatternSource, Rib};
@@ -47,6 +47,7 @@ pub(crate) type Suggestion = (Vec<(Span, String)>, String, Applicability);
 /// similarly named label and whether or not it is reachable.
 pub(crate) type LabelSuggestion = (Ident, bool);
 
+#[derive(Debug)]
 pub(crate) enum SuggestionTarget {
     /// The target has a similar name as the name used by the programmer (probably a typo)
     SimilarlyNamed,
@@ -54,6 +55,7 @@ pub(crate) enum SuggestionTarget {
     SingleItem,
 }
 
+#[derive(Debug)]
 pub(crate) struct TypoSuggestion {
     pub candidate: Symbol,
     pub res: Res,
@@ -482,11 +484,12 @@ impl<'a> Resolver<'a> {
         module: Module<'a>,
         names: &mut Vec<TypoSuggestion>,
         filter_fn: &impl Fn(Res) -> bool,
+        ctxt: Option<SyntaxContext>,
     ) {
         for (key, resolution) in self.resolutions(module).borrow().iter() {
             if let Some(binding) = resolution.borrow().binding {
                 let res = binding.res();
-                if filter_fn(res) {
+                if filter_fn(res) && ctxt.map_or(true, |ctxt| ctxt == key.ident.span.ctxt()) {
                     names.push(TypoSuggestion::typo_from_res(key.ident.name, res));
                 }
             }
@@ -1181,10 +1184,10 @@ impl<'a> Resolver<'a> {
                 Scope::CrateRoot => {
                     let root_ident = Ident::new(kw::PathRoot, ident.span);
                     let root_module = this.resolve_crate_root(root_ident);
-                    this.add_module_candidates(root_module, &mut suggestions, filter_fn);
+                    this.add_module_candidates(root_module, &mut suggestions, filter_fn, None);
                 }
                 Scope::Module(module, _) => {
-                    this.add_module_candidates(module, &mut suggestions, filter_fn);
+                    this.add_module_candidates(module, &mut suggestions, filter_fn, None);
                 }
                 Scope::MacroUsePrelude => {
                     suggestions.extend(this.macro_use_prelude.iter().filter_map(
@@ -1221,7 +1224,7 @@ impl<'a> Resolver<'a> {
                 Scope::StdLibPrelude => {
                     if let Some(prelude) = this.prelude {
                         let mut tmp_suggestions = Vec::new();
-                        this.add_module_candidates(prelude, &mut tmp_suggestions, filter_fn);
+                        this.add_module_candidates(prelude, &mut tmp_suggestions, filter_fn, None);
                         suggestions.extend(
                             tmp_suggestions
                                 .into_iter()
diff --git a/compiler/rustc_resolve/src/late/diagnostics.rs b/compiler/rustc_resolve/src/late/diagnostics.rs
index 4fd5bc1d60a47..e3dba2366a40e 100644
--- a/compiler/rustc_resolve/src/late/diagnostics.rs
+++ b/compiler/rustc_resolve/src/late/diagnostics.rs
@@ -131,6 +131,7 @@ pub(super) enum LifetimeElisionCandidate {
 }
 
 /// Only used for diagnostics.
+#[derive(Debug)]
 struct BaseError {
     msg: String,
     fallback_label: String,
@@ -140,6 +141,22 @@ struct BaseError {
     suggestion: Option<(Span, &'static str, String)>,
 }
 
+#[derive(Debug)]
+enum TypoCandidate {
+    Typo(TypoSuggestion),
+    Shadowed(Res),
+    None,
+}
+
+impl TypoCandidate {
+    fn to_opt_suggestion(self) -> Option<TypoSuggestion> {
+        match self {
+            TypoCandidate::Typo(sugg) => Some(sugg),
+            TypoCandidate::Shadowed(_) | TypoCandidate::None => None,
+        }
+    }
+}
+
 impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
     fn def_span(&self, def_id: DefId) -> Option<Span> {
         match def_id.krate {
@@ -496,7 +513,8 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
         }
 
         // Try Levenshtein algorithm.
-        let typo_sugg = self.lookup_typo_candidate(path, source.namespace(), is_expected);
+        let typo_sugg =
+            self.lookup_typo_candidate(path, source.namespace(), is_expected).to_opt_suggestion();
         if path.len() == 1 && self.self_type_is_available() {
             if let Some(candidate) = self.lookup_assoc_candidate(ident, ns, is_expected) {
                 let self_is_available = self.self_value_is_available(path[0].ident.span);
@@ -660,7 +678,18 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
         let is_expected = &|res| source.is_expected(res);
         let ident_span = path.last().map_or(span, |ident| ident.ident.span);
         let typo_sugg = self.lookup_typo_candidate(path, source.namespace(), is_expected);
+        if let TypoCandidate::Shadowed(res) = typo_sugg
+            && let Some(id) = res.opt_def_id()
+            && let Some(sugg_span) = self.r.opt_span(id)
+        {
+            err.span_label(
+                sugg_span,
+                format!("you might have meant to refer to this {}", res.descr()),
+            );
+            return true;
+        }
         let mut fallback = false;
+        let typo_sugg = typo_sugg.to_opt_suggestion();
         if !self.r.add_typo_suggestion(err, typo_sugg, ident_span) {
             fallback = true;
             match self.diagnostic_metadata.current_let_binding {
@@ -1581,22 +1610,38 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
         path: &[Segment],
         ns: Namespace,
         filter_fn: &impl Fn(Res) -> bool,
-    ) -> Option<TypoSuggestion> {
+    ) -> TypoCandidate {
         let mut names = Vec::new();
         if path.len() == 1 {
+            let mut ctxt = path.last().unwrap().ident.span.ctxt();
+
             // Search in lexical scope.
             // Walk backwards up the ribs in scope and collect candidates.
             for rib in self.ribs[ns].iter().rev() {
+                let rib_ctxt = if rib.kind.contains_params() {
+                    ctxt.normalize_to_macros_2_0()
+                } else {
+                    ctxt.normalize_to_macro_rules()
+                };
+
                 // Locals and type parameters
                 for (ident, &res) in &rib.bindings {
-                    if filter_fn(res) {
+                    if filter_fn(res) && ident.span.ctxt() == rib_ctxt {
                         names.push(TypoSuggestion::typo_from_res(ident.name, res));
                     }
                 }
+
+                if let RibKind::MacroDefinition(def) = rib.kind && def == self.r.macro_def(ctxt) {
+                    // If an invocation of this macro created `ident`, give up on `ident`
+                    // and switch to `ident`'s source from the macro definition.
+                    ctxt.remove_mark();
+                    continue;
+                }
+
                 // Items in scope
                 if let RibKind::ModuleRibKind(module) = rib.kind {
                     // Items from this module
-                    self.r.add_module_candidates(module, &mut names, &filter_fn);
+                    self.r.add_module_candidates(module, &mut names, &filter_fn, Some(ctxt));
 
                     if let ModuleKind::Block = module.kind {
                         // We can see through blocks
@@ -1622,7 +1667,7 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
                             }));
 
                             if let Some(prelude) = self.r.prelude {
-                                self.r.add_module_candidates(prelude, &mut names, &filter_fn);
+                                self.r.add_module_candidates(prelude, &mut names, &filter_fn, None);
                             }
                         }
                         break;
@@ -1641,7 +1686,7 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
             if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
                 self.resolve_path(mod_path, Some(TypeNS), None)
             {
-                self.r.add_module_candidates(module, &mut names, &filter_fn);
+                self.r.add_module_candidates(module, &mut names, &filter_fn, None);
             }
         }
 
@@ -1654,10 +1699,17 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
             name,
             None,
         ) {
-            Some(found) if found != name => {
-                names.into_iter().find(|suggestion| suggestion.candidate == found)
+            Some(found) => {
+                let Some(sugg) = names.into_iter().find(|suggestion| suggestion.candidate == found) else {
+                    return TypoCandidate::None;
+                };
+                if found == name {
+                    TypoCandidate::Shadowed(sugg.res)
+                } else {
+                    TypoCandidate::Typo(sugg)
+                }
             }
-            _ => None,
+            _ => TypoCandidate::None,
         }
     }
 
diff --git a/compiler/rustc_session/src/errors.rs b/compiler/rustc_session/src/errors.rs
index d12796f289e96..500ab4a584cab 100644
--- a/compiler/rustc_session/src/errors.rs
+++ b/compiler/rustc_session/src/errors.rs
@@ -1,9 +1,7 @@
 use std::num::NonZeroU32;
 
 use crate::cgu_reuse_tracker::CguReuse;
-use rustc_errors::{
-    fluent, DiagnosticBuilder, ErrorGuaranteed, Handler, IntoDiagnostic, MultiSpan,
-};
+use rustc_errors::MultiSpan;
 use rustc_macros::Diagnostic;
 use rustc_span::{Span, Symbol};
 use rustc_target::spec::{SplitDebuginfo, StackProtector, TargetTriple};
@@ -148,24 +146,15 @@ pub struct CrateNameEmpty {
     pub span: Option<Span>,
 }
 
+#[derive(Diagnostic)]
+#[diag(session::invalid_character_in_create_name)]
 pub struct InvalidCharacterInCrateName<'a> {
+    #[primary_span]
     pub span: Option<Span>,
     pub character: char,
     pub crate_name: &'a str,
 }
 
-impl IntoDiagnostic<'_> for InvalidCharacterInCrateName<'_> {
-    fn into_diagnostic(self, sess: &Handler) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
-        let mut diag = sess.struct_err(fluent::session::invalid_character_in_create_name);
-        if let Some(sp) = self.span {
-            diag.set_span(sp);
-        }
-        diag.set_arg("character", self.character);
-        diag.set_arg("crate_name", self.crate_name);
-        diag
-    }
-}
-
 #[derive(Subdiagnostic)]
 #[multipart_suggestion(session::expr_parentheses_needed, applicability = "machine-applicable")]
 pub struct ExprParenthesesNeeded {
@@ -180,3 +169,25 @@ impl ExprParenthesesNeeded {
         ExprParenthesesNeeded { left: s.shrink_to_lo(), right: s.shrink_to_hi() }
     }
 }
+
+#[derive(Diagnostic)]
+#[diag(session::skipping_const_checks)]
+pub struct SkippingConstChecks {
+    #[subdiagnostic(eager)]
+    pub unleashed_features: Vec<UnleashedFeatureHelp>,
+}
+
+#[derive(Subdiagnostic)]
+pub enum UnleashedFeatureHelp {
+    #[help(session::unleashed_feature_help_named)]
+    Named {
+        #[primary_span]
+        span: Span,
+        gate: Symbol,
+    },
+    #[help(session::unleashed_feature_help_unnamed)]
+    Unnamed {
+        #[primary_span]
+        span: Span,
+    },
+}
diff --git a/compiler/rustc_session/src/session.rs b/compiler/rustc_session/src/session.rs
index b5e25f45fa757..100c66f63641c 100644
--- a/compiler/rustc_session/src/session.rs
+++ b/compiler/rustc_session/src/session.rs
@@ -5,9 +5,10 @@ use crate::config::{self, CrateType, InstrumentCoverage, OptLevel, OutputType, S
 use crate::errors::{
     CannotEnableCrtStaticLinux, CannotMixAndMatchSanitizers, LinkerPluginToWindowsNotSupported,
     NotCircumventFeature, ProfileSampleUseFileDoesNotExist, ProfileUseFileDoesNotExist,
-    SanitizerCfiEnabled, SanitizerNotSupported, SanitizersNotSupported,
+    SanitizerCfiEnabled, SanitizerNotSupported, SanitizersNotSupported, SkippingConstChecks,
     SplitDebugInfoUnstablePlatform, StackProtectorNotSupportedForTarget,
-    TargetRequiresUnwindTables, UnstableVirtualFunctionElimination, UnsupportedDwarfVersion,
+    TargetRequiresUnwindTables, UnleashedFeatureHelp, UnstableVirtualFunctionElimination,
+    UnsupportedDwarfVersion,
 };
 use crate::parse::{add_feature_diagnostics, ParseSess};
 use crate::search_paths::{PathKind, SearchPath};
@@ -232,21 +233,19 @@ impl Session {
         if !unleashed_features.is_empty() {
             let mut must_err = false;
             // Create a diagnostic pointing at where things got unleashed.
-            // FIXME(#100717): needs eager translation/lists
-            #[allow(rustc::untranslatable_diagnostic)]
-            #[allow(rustc::diagnostic_outside_of_impl)]
-            let mut diag = self.struct_warn("skipping const checks");
-            for &(span, feature_gate) in unleashed_features.iter() {
-                // FIXME: `span_label` doesn't do anything, so we use "help" as a hack.
-                if let Some(gate) = feature_gate {
-                    diag.span_help(span, &format!("skipping check for `{gate}` feature"));
-                    // The unleash flag must *not* be used to just "hack around" feature gates.
-                    must_err = true;
-                } else {
-                    diag.span_help(span, "skipping check that does not even have a feature gate");
-                }
-            }
-            diag.emit();
+            self.emit_warning(SkippingConstChecks {
+                unleashed_features: unleashed_features
+                    .iter()
+                    .map(|(span, gate)| {
+                        gate.map(|gate| {
+                            must_err = true;
+                            UnleashedFeatureHelp::Named { span: *span, gate }
+                        })
+                        .unwrap_or(UnleashedFeatureHelp::Unnamed { span: *span })
+                    })
+                    .collect(),
+            });
+
             // If we should err, make sure we did.
             if must_err && self.has_errors().is_none() {
                 // We have skipped a feature gate, and not run into other errors... reject.
diff --git a/src/librustdoc/html/static/css/noscript.css b/src/librustdoc/html/static/css/noscript.css
index 0a19a99abf054..63b35f5d0df0d 100644
--- a/src/librustdoc/html/static/css/noscript.css
+++ b/src/librustdoc/html/static/css/noscript.css
@@ -14,7 +14,7 @@ rules.
 	display: none;
 }
 
-.sub {
+nav.sub {
 	/* The search bar and related controls don't work without JS */
 	display: none;
 }
diff --git a/src/librustdoc/html/static/css/rustdoc.css b/src/librustdoc/html/static/css/rustdoc.css
index 746a510c488f9..afe1ca5d7e520 100644
--- a/src/librustdoc/html/static/css/rustdoc.css
+++ b/src/librustdoc/html/static/css/rustdoc.css
@@ -365,15 +365,8 @@ img {
 	overflow: visible;
 }
 
-.sub-container {
-	display: flex;
-	flex-direction: row;
-	flex-wrap: nowrap;
-}
-
 .sub-logo-container {
-	display: block;
-	margin-right: 20px;
+	line-height: 0;
 }
 
 .sub-logo-container > img {
@@ -696,14 +689,21 @@ pre, .rustdoc.source .example-wrap {
 }
 
 nav.sub {
-	position: relative;
 	flex-grow: 1;
-	margin-bottom: 25px;
+	flex-flow: row nowrap;
+	margin: 4px 0 25px 0;
+	display: flex;
+	align-items: center;
+}
+nav.sub form {
+	flex-grow: 1;
 }
 .source nav.sub {
+	margin: 0 0 15px 0;
+}
+.source nav.sub form {
 	margin-left: 32px;
 }
-nav.sub form { display: inline; }
 
 a {
 	text-decoration: none;
@@ -796,7 +796,6 @@ table,
 	position: relative;
 	display: flex;
 	height: 34px;
-	margin-top: 4px;
 }
 .search-results-title {
 	margin-top: 0;
@@ -1822,10 +1821,6 @@ in storage.js
 		margin-left: 0px;
 	}
 
-	.source .content {
-		margin-top: 10px;
-	}
-
 	.anchor {
 		display: none !important;
 	}
@@ -1934,6 +1929,11 @@ in storage.js
 	.impl-items > .item-info {
 		margin-left: 34px;
 	}
+
+	.source nav.sub {
+		margin: 0;
+		padding: 8px;
+	}
 }
 
 @media print {
@@ -1962,12 +1962,12 @@ in storage.js
 		overflow-wrap: anywhere;
 	}
 
-	.sub-container {
+	nav.sub {
 		flex-direction: column;
 	}
 
-	.sub-logo-container {
-		align-self: center;
+	nav.sub form {
+		align-self: stretch;
 	}
 
 	.sub-logo-container > img {
diff --git a/src/librustdoc/html/templates/page.html b/src/librustdoc/html/templates/page.html
index 20a314a1c00e3..2a111f94e5078 100644
--- a/src/librustdoc/html/templates/page.html
+++ b/src/librustdoc/html/templates/page.html
@@ -102,7 +102,7 @@ <h2></h2> {#- -#}
     </nav> {#- -#}
     <main> {#- -#}
         <div class="width-limiter"> {#- -#}
-            <div class="sub-container"> {#- -#}
+            <nav class="sub"> {#- -#}
                 {%- if page.css_class == "source" -%}
                 <a class="sub-logo-container" href="{{page.root_path|safe}}{{krate_with_trailing_slash|safe}}index.html"> {#- -#}
                     {%- if !layout.logo.is_empty()  %}
@@ -112,30 +112,28 @@ <h2></h2> {#- -#}
                     {%- endif -%}
                 </a> {#- -#}
                 {%- endif -%}
-                <nav class="sub"> {#- -#}
-                    <form class="search-form"> {#- -#}
-                        <div class="search-container"> {#- -#}
-                            <span></span> {#- This empty span is a hacky fix for Safari - See #93184 -#}
-                            <input {# -#}
-                                class="search-input" {# -#}
-                                name="search" {# -#}
-                                autocomplete="off" {# -#}
-                                spellcheck="false" {# -#}
-                                placeholder="Click or press ‘S’ to search, ‘?’ for more options…" {# -#}
-                                type="search"> {#- -#}
-                            <div id="help-button" title="help" tabindex="-1"> {#- -#}
-                                <a href="{{page.root_path|safe}}help.html">?</a> {#- -#}
-                            </div> {#- -#}
-                            <div id="settings-menu" tabindex="-1"> {#- -#}
-                                <a href="{{page.root_path|safe}}settings.html" title="settings"> {#- -#}
-                                    <img width="22" height="22" alt="Change settings" {# -#}
-                                     src="{{static_root_path|safe}}wheel{{page.resource_suffix}}.svg"> {#- -#}
-                                </a> {#- -#}
-                            </div> {#- -#}
+                <form class="search-form"> {#- -#}
+                    <div class="search-container"> {#- -#}
+                        <span></span> {#- This empty span is a hacky fix for Safari - See #93184 -#}
+                        <input {# -#}
+                            class="search-input" {# -#}
+                            name="search" {# -#}
+                            autocomplete="off" {# -#}
+                            spellcheck="false" {# -#}
+                            placeholder="Click or press ‘S’ to search, ‘?’ for more options…" {# -#}
+                            type="search"> {#- -#}
+                        <div id="help-button" title="help" tabindex="-1"> {#- -#}
+                            <a href="{{page.root_path|safe}}help.html">?</a> {#- -#}
                         </div> {#- -#}
-                    </form> {#- -#}
-                </nav> {#- -#}
-            </div> {#- -#}
+                        <div id="settings-menu" tabindex="-1"> {#- -#}
+                            <a href="{{page.root_path|safe}}settings.html" title="settings"> {#- -#}
+                                <img width="22" height="22" alt="Change settings" {# -#}
+                                 src="{{static_root_path|safe}}wheel{{page.resource_suffix}}.svg"> {#- -#}
+                            </a> {#- -#}
+                        </div> {#- -#}
+                    </div> {#- -#}
+                </form> {#- -#}
+            </nav> {#- -#}
             <section id="main-content" class="content">{{- content|safe -}}</section> {#- -#}
         </div> {#- -#}
     </main> {#- -#}
diff --git a/src/test/pretty/raw-str-nonexpr.rs b/src/test/pretty/raw-str-nonexpr.rs
index 7af80979b4349..12440b5ae6ed5 100644
--- a/src/test/pretty/raw-str-nonexpr.rs
+++ b/src/test/pretty/raw-str-nonexpr.rs
@@ -1,3 +1,4 @@
+// needs-asm-support
 // pp-exact
 
 #[cfg(foo = r#"just parse this"#)]
diff --git a/src/test/run-make-fulldeps/intrinsic-unreachable/Makefile b/src/test/run-make-fulldeps/intrinsic-unreachable/Makefile
index 3c4dade0f5215..ff9cc57098c6b 100644
--- a/src/test/run-make-fulldeps/intrinsic-unreachable/Makefile
+++ b/src/test/run-make-fulldeps/intrinsic-unreachable/Makefile
@@ -1,5 +1,6 @@
 include ../tools.mk
 
+# needs-asm-support
 # ignore-windows-msvc
 #
 # Because of Windows exception handling, the code is not necessarily any shorter.
diff --git a/src/test/rustdoc-gui/help-page.goml b/src/test/rustdoc-gui/help-page.goml
index 51f089cce747f..521e14748af12 100644
--- a/src/test/rustdoc-gui/help-page.goml
+++ b/src/test/rustdoc-gui/help-page.goml
@@ -5,12 +5,12 @@ wait-for: "#help"
 assert-css: ("#help", {"display": "block"})
 click: "#help-button > a"
 assert-css: ("#help", {"display": "block"})
-compare-elements-property: (".sub-container", "#help", ["offsetWidth"])
-compare-elements-position: (".sub-container", "#help", ("x"))
+compare-elements-property: (".sub", "#help", ["offsetWidth"])
+compare-elements-position: (".sub", "#help", ("x"))
 size: (500, 1000) // Try mobile next.
 assert-css: ("#help", {"display": "block"})
-compare-elements-property: (".sub-container", "#help", ["offsetWidth"])
-compare-elements-position: (".sub-container", "#help", ("x"))
+compare-elements-property: (".sub", "#help", ["offsetWidth"])
+compare-elements-position: (".sub", "#help", ("x"))
 
 // This test ensures that opening the help popover without switching pages works.
 goto: "file://" + |DOC_PATH| + "/test_docs/index.html"
@@ -20,5 +20,5 @@ click: "#help-button > a"
 assert-css: ("#help", {"display": "block"})
 click: "#help-button > a"
 assert-css: ("#help", {"display": "none"})
-compare-elements-property-false: (".sub-container", "#help", ["offsetWidth"])
-compare-elements-position-false: (".sub-container", "#help", ("x"))
+compare-elements-property-false: (".sub", "#help", ["offsetWidth"])
+compare-elements-position-false: (".sub", "#help", ("x"))
diff --git a/src/test/rustdoc-gui/settings.goml b/src/test/rustdoc-gui/settings.goml
index ed4e9c2516b0b..f258f4d2a838e 100644
--- a/src/test/rustdoc-gui/settings.goml
+++ b/src/test/rustdoc-gui/settings.goml
@@ -147,7 +147,7 @@ assert-css: (
 )
 
 assert-attribute-false: ("#settings", {"class": "popover"}, CONTAINS)
-compare-elements-position: (".sub-container", "#settings", ("x"))
+compare-elements-position: (".sub form", "#settings", ("x"))
 
 // We now check the display with JS disabled.
 assert-false: "noscript section"
diff --git a/src/test/rustdoc-gui/source-code-page.goml b/src/test/rustdoc-gui/source-code-page.goml
index 76260d621eae1..29d65fc7ebc7a 100644
--- a/src/test/rustdoc-gui/source-code-page.goml
+++ b/src/test/rustdoc-gui/source-code-page.goml
@@ -23,7 +23,7 @@ assert-css: (".src-line-numbers", {"text-align": "right"})
 show-text: true
 goto: "file://" + |DOC_PATH| + "/src/test_docs/lib.rs.html"
 // We use this assert-position to know where we will click.
-assert-position: ("//*[@id='1']", {"x": 104, "y": 103})
+assert-position: ("//*[@id='1']", {"x": 104, "y": 112})
 // We click on the left of the "1" span but still in the "src-line-number" `<pre>`.
 click: (103, 103)
 assert-document-property: ({"URL": "/lib.rs.html"}, ENDS_WITH)
@@ -47,3 +47,25 @@ assert-property: ("#source-sidebar details:first-of-type", {"open": "false"})
 
 // Check the spacing.
 assert-css: ("#source-sidebar > details.dir-entry", {"padding-left": "4px"})
+
+// Check the search form
+assert-css: ("nav.sub", {"flex-direction": "row"})
+// The goal of this test is to ensure the search input is perfectly centered
+// between the top of the page and the top of the gray code block.
+// To check this, we maintain the invariant:
+//
+// offsetTop[nav.sub form] = offsetTop[#main-content] - offsetHeight[nav.sub form] - offsetTop[nav.sub form]
+assert-property: ("nav.sub form", {"offsetTop": 28, "offsetHeight": 34})
+assert-property: ("#main-content", {"offsetTop": 90})
+// 28 = 90 - 34 - 28
+
+// Now do the same check on moderately-sized mobile.
+size: (700, 700)
+assert-css: ("nav.sub", {"flex-direction": "row"})
+assert-property: ("nav.sub form", {"offsetTop": 21, "offsetHeight": 34})
+assert-property: ("#main-content", {"offsetTop": 76})
+// 21 = 76 - 34 - 21
+
+// Tiny mobile gets a different display where the logo is stacked on top.
+size: (450, 700)
+assert-css: ("nav.sub", {"flex-direction": "column"})
diff --git a/src/test/ui-fulldeps/session-diagnostic/diagnostic-derive.rs b/src/test/ui-fulldeps/session-diagnostic/diagnostic-derive.rs
index e873c36e0b39a..b8deb48d49add 100644
--- a/src/test/ui-fulldeps/session-diagnostic/diagnostic-derive.rs
+++ b/src/test/ui-fulldeps/session-diagnostic/diagnostic-derive.rs
@@ -749,3 +749,12 @@ struct SubdiagnosticEagerSuggestion {
     #[subdiagnostic(eager)]
     sub: SubdiagnosticWithSuggestion,
 }
+
+/// with a doc comment on the type..
+#[derive(Diagnostic)]
+#[diag(compiletest::example, code = "E0123")]
+struct WithDocComment {
+    /// ..and the field
+    #[primary_span]
+    span: Span,
+}
diff --git a/src/test/ui-fulldeps/session-diagnostic/subdiagnostic-derive.rs b/src/test/ui-fulldeps/session-diagnostic/subdiagnostic-derive.rs
index 84ee5af42dea5..2fe93d46d0ac0 100644
--- a/src/test/ui-fulldeps/session-diagnostic/subdiagnostic-derive.rs
+++ b/src/test/ui-fulldeps/session-diagnostic/subdiagnostic-derive.rs
@@ -237,7 +237,6 @@ enum V {
         var: String,
     },
     B {
-    //~^ ERROR subdiagnostic kind not specified
         #[primary_span]
         span: Span,
         var: String,
@@ -641,3 +640,24 @@ struct BJ {
     span: Span,
     r#type: String,
 }
+
+/// with a doc comment on the type..
+#[derive(Subdiagnostic)]
+#[label(parser::add_paren)]
+struct BK {
+    /// ..and the field
+    #[primary_span]
+    span: Span,
+}
+
+/// with a doc comment on the type..
+#[derive(Subdiagnostic)]
+enum BL {
+    /// ..and the variant..
+    #[label(parser::add_paren)]
+    Foo {
+        /// ..and the field
+        #[primary_span]
+        span: Span,
+    }
+}
diff --git a/src/test/ui-fulldeps/session-diagnostic/subdiagnostic-derive.stderr b/src/test/ui-fulldeps/session-diagnostic/subdiagnostic-derive.stderr
index 171b89e657d81..1173d24248bc4 100644
--- a/src/test/ui-fulldeps/session-diagnostic/subdiagnostic-derive.stderr
+++ b/src/test/ui-fulldeps/session-diagnostic/subdiagnostic-derive.stderr
@@ -134,20 +134,14 @@ error: diagnostic slug must be first argument of a `#[label(...)]` attribute
 LL |     #[label(code = "...")]
    |     ^^^^^^^^^^^^^^^^^^^^^^
 
-error: subdiagnostic kind not specified
-  --> $DIR/subdiagnostic-derive.rs:239:5
-   |
-LL |     B {
-   |     ^
-
 error: the `#[primary_span]` attribute can only be applied to fields of type `Span` or `MultiSpan`
-  --> $DIR/subdiagnostic-derive.rs:251:5
+  --> $DIR/subdiagnostic-derive.rs:250:5
    |
 LL |     #[primary_span]
    |     ^^^^^^^^^^^^^^^
 
 error: label without `#[primary_span]` field
-  --> $DIR/subdiagnostic-derive.rs:248:1
+  --> $DIR/subdiagnostic-derive.rs:247:1
    |
 LL | / #[label(parser::add_paren)]
 LL | |
@@ -159,13 +153,13 @@ LL | | }
    | |_^
 
 error: `#[applicability]` is only valid on suggestions
-  --> $DIR/subdiagnostic-derive.rs:261:5
+  --> $DIR/subdiagnostic-derive.rs:260:5
    |
 LL |     #[applicability]
    |     ^^^^^^^^^^^^^^^^
 
 error: `#[bar]` is not a valid attribute
-  --> $DIR/subdiagnostic-derive.rs:271:5
+  --> $DIR/subdiagnostic-derive.rs:270:5
    |
 LL |     #[bar]
    |     ^^^^^^
@@ -173,13 +167,13 @@ LL |     #[bar]
    = help: only `primary_span`, `applicability` and `skip_arg` are valid field attributes
 
 error: `#[bar = ...]` is not a valid attribute
-  --> $DIR/subdiagnostic-derive.rs:282:5
+  --> $DIR/subdiagnostic-derive.rs:281:5
    |
 LL |     #[bar = "..."]
    |     ^^^^^^^^^^^^^^
 
 error: `#[bar(...)]` is not a valid attribute
-  --> $DIR/subdiagnostic-derive.rs:293:5
+  --> $DIR/subdiagnostic-derive.rs:292:5
    |
 LL |     #[bar("...")]
    |     ^^^^^^^^^^^^^
@@ -187,7 +181,7 @@ LL |     #[bar("...")]
    = help: only `primary_span`, `applicability` and `skip_arg` are valid field attributes
 
 error: unexpected unsupported untagged union
-  --> $DIR/subdiagnostic-derive.rs:309:1
+  --> $DIR/subdiagnostic-derive.rs:308:1
    |
 LL | / union AC {
 LL | |
@@ -197,7 +191,7 @@ LL | | }
    | |_^
 
 error: `#[label(parser::add_paren)]` is not a valid attribute
-  --> $DIR/subdiagnostic-derive.rs:324:28
+  --> $DIR/subdiagnostic-derive.rs:323:28
    |
 LL | #[label(parser::add_paren, parser::add_paren)]
    |                            ^^^^^^^^^^^^^^^^^
@@ -205,67 +199,67 @@ LL | #[label(parser::add_paren, parser::add_paren)]
    = help: a diagnostic slug must be the first argument to the attribute
 
 error: specified multiple times
-  --> $DIR/subdiagnostic-derive.rs:337:5
+  --> $DIR/subdiagnostic-derive.rs:336:5
    |
 LL |     #[primary_span]
    |     ^^^^^^^^^^^^^^^
    |
 note: previously specified here
-  --> $DIR/subdiagnostic-derive.rs:334:5
+  --> $DIR/subdiagnostic-derive.rs:333:5
    |
 LL |     #[primary_span]
    |     ^^^^^^^^^^^^^^^
 
 error: subdiagnostic kind not specified
-  --> $DIR/subdiagnostic-derive.rs:343:8
+  --> $DIR/subdiagnostic-derive.rs:342:8
    |
 LL | struct AG {
    |        ^^
 
 error: specified multiple times
-  --> $DIR/subdiagnostic-derive.rs:380:47
+  --> $DIR/subdiagnostic-derive.rs:379:47
    |
 LL | #[suggestion(parser::add_paren, code = "...", code = "...")]
    |                                               ^^^^^^^^^^^^
    |
 note: previously specified here
-  --> $DIR/subdiagnostic-derive.rs:380:33
+  --> $DIR/subdiagnostic-derive.rs:379:33
    |
 LL | #[suggestion(parser::add_paren, code = "...", code = "...")]
    |                                 ^^^^^^^^^^^^
 
 error: specified multiple times
-  --> $DIR/subdiagnostic-derive.rs:398:5
+  --> $DIR/subdiagnostic-derive.rs:397:5
    |
 LL |     #[applicability]
    |     ^^^^^^^^^^^^^^^^
    |
 note: previously specified here
-  --> $DIR/subdiagnostic-derive.rs:395:5
+  --> $DIR/subdiagnostic-derive.rs:394:5
    |
 LL |     #[applicability]
    |     ^^^^^^^^^^^^^^^^
 
 error: the `#[applicability]` attribute can only be applied to fields of type `Applicability`
-  --> $DIR/subdiagnostic-derive.rs:408:5
+  --> $DIR/subdiagnostic-derive.rs:407:5
    |
 LL |     #[applicability]
    |     ^^^^^^^^^^^^^^^^
 
 error: suggestion without `code = "..."`
-  --> $DIR/subdiagnostic-derive.rs:421:1
+  --> $DIR/subdiagnostic-derive.rs:420:1
    |
 LL | #[suggestion(parser::add_paren)]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: invalid applicability
-  --> $DIR/subdiagnostic-derive.rs:431:46
+  --> $DIR/subdiagnostic-derive.rs:430:46
    |
 LL | #[suggestion(parser::add_paren, code ="...", applicability = "foo")]
    |                                              ^^^^^^^^^^^^^^^^^^^^^
 
 error: suggestion without `#[primary_span]` field
-  --> $DIR/subdiagnostic-derive.rs:449:1
+  --> $DIR/subdiagnostic-derive.rs:448:1
    |
 LL | / #[suggestion(parser::add_paren, code = "...")]
 LL | |
@@ -275,25 +269,25 @@ LL | | }
    | |_^
 
 error: unsupported type attribute for subdiagnostic enum
-  --> $DIR/subdiagnostic-derive.rs:463:1
+  --> $DIR/subdiagnostic-derive.rs:462:1
    |
 LL | #[label]
    | ^^^^^^^^
 
 error: `var` doesn't refer to a field on this type
-  --> $DIR/subdiagnostic-derive.rs:483:39
+  --> $DIR/subdiagnostic-derive.rs:482:39
    |
 LL | #[suggestion(parser::add_paren, code ="{var}", applicability = "machine-applicable")]
    |                                       ^^^^^^^
 
 error: `var` doesn't refer to a field on this type
-  --> $DIR/subdiagnostic-derive.rs:502:43
+  --> $DIR/subdiagnostic-derive.rs:501:43
    |
 LL |     #[suggestion(parser::add_paren, code ="{var}", applicability = "machine-applicable")]
    |                                           ^^^^^^^
 
 error: `#[suggestion_part]` is not a valid attribute
-  --> $DIR/subdiagnostic-derive.rs:525:5
+  --> $DIR/subdiagnostic-derive.rs:524:5
    |
 LL |     #[suggestion_part]
    |     ^^^^^^^^^^^^^^^^^^
@@ -301,7 +295,7 @@ LL |     #[suggestion_part]
    = help: `#[suggestion_part(...)]` is only valid in multipart suggestions, use `#[primary_span]` instead
 
 error: `#[suggestion_part(...)]` is not a valid attribute
-  --> $DIR/subdiagnostic-derive.rs:528:5
+  --> $DIR/subdiagnostic-derive.rs:527:5
    |
 LL |     #[suggestion_part(code = "...")]
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -309,7 +303,7 @@ LL |     #[suggestion_part(code = "...")]
    = help: `#[suggestion_part(...)]` is only valid in multipart suggestions
 
 error: suggestion without `#[primary_span]` field
-  --> $DIR/subdiagnostic-derive.rs:522:1
+  --> $DIR/subdiagnostic-derive.rs:521:1
    |
 LL | / #[suggestion(parser::add_paren, code = "...")]
 LL | |
@@ -321,7 +315,7 @@ LL | | }
    | |_^
 
 error: `#[multipart_suggestion(code = ...)]` is not a valid attribute
-  --> $DIR/subdiagnostic-derive.rs:537:43
+  --> $DIR/subdiagnostic-derive.rs:536:43
    |
 LL | #[multipart_suggestion(parser::add_paren, code = "...", applicability = "machine-applicable")]
    |                                           ^^^^^^^^^^^^
@@ -329,7 +323,7 @@ LL | #[multipart_suggestion(parser::add_paren, code = "...", applicability = "ma
    = help: only `applicability` is a valid nested attributes
 
 error: multipart suggestion without any `#[suggestion_part(...)]` fields
-  --> $DIR/subdiagnostic-derive.rs:537:1
+  --> $DIR/subdiagnostic-derive.rs:536:1
    |
 LL | / #[multipart_suggestion(parser::add_paren, code = "...", applicability = "machine-applicable")]
 LL | |
@@ -340,19 +334,19 @@ LL | | }
    | |_^
 
 error: `#[suggestion_part(...)]` attribute without `code = "..."`
-  --> $DIR/subdiagnostic-derive.rs:547:5
+  --> $DIR/subdiagnostic-derive.rs:546:5
    |
 LL |     #[suggestion_part]
    |     ^^^^^^^^^^^^^^^^^^
 
 error: `#[suggestion_part(...)]` attribute without `code = "..."`
-  --> $DIR/subdiagnostic-derive.rs:555:5
+  --> $DIR/subdiagnostic-derive.rs:554:5
    |
 LL |     #[suggestion_part()]
    |     ^^^^^^^^^^^^^^^^^^^^
 
 error: `#[primary_span]` is not a valid attribute
-  --> $DIR/subdiagnostic-derive.rs:564:5
+  --> $DIR/subdiagnostic-derive.rs:563:5
    |
 LL |     #[primary_span]
    |     ^^^^^^^^^^^^^^^
@@ -360,7 +354,7 @@ LL |     #[primary_span]
    = help: multipart suggestions use one or more `#[suggestion_part]`s rather than one `#[primary_span]`
 
 error: multipart suggestion without any `#[suggestion_part(...)]` fields
-  --> $DIR/subdiagnostic-derive.rs:561:1
+  --> $DIR/subdiagnostic-derive.rs:560:1
    |
 LL | / #[multipart_suggestion(parser::add_paren)]
 LL | |
@@ -372,19 +366,19 @@ LL | | }
    | |_^
 
 error: `#[suggestion_part(...)]` attribute without `code = "..."`
-  --> $DIR/subdiagnostic-derive.rs:572:5
+  --> $DIR/subdiagnostic-derive.rs:571:5
    |
 LL |     #[suggestion_part]
    |     ^^^^^^^^^^^^^^^^^^
 
 error: `#[suggestion_part(...)]` attribute without `code = "..."`
-  --> $DIR/subdiagnostic-derive.rs:575:5
+  --> $DIR/subdiagnostic-derive.rs:574:5
    |
 LL |     #[suggestion_part()]
    |     ^^^^^^^^^^^^^^^^^^^^
 
 error: `#[suggestion_part(foo = ...)]` is not a valid attribute
-  --> $DIR/subdiagnostic-derive.rs:578:23
+  --> $DIR/subdiagnostic-derive.rs:577:23
    |
 LL |     #[suggestion_part(foo = "bar")]
    |                       ^^^^^^^^^^^
@@ -392,31 +386,31 @@ LL |     #[suggestion_part(foo = "bar")]
    = help: `code` is the only valid nested attribute
 
 error: the `#[suggestion_part(...)]` attribute can only be applied to fields of type `Span` or `MultiSpan`
-  --> $DIR/subdiagnostic-derive.rs:581:5
+  --> $DIR/subdiagnostic-derive.rs:580:5
    |
 LL |     #[suggestion_part(code = "...")]
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: the `#[suggestion_part(...)]` attribute can only be applied to fields of type `Span` or `MultiSpan`
-  --> $DIR/subdiagnostic-derive.rs:584:5
+  --> $DIR/subdiagnostic-derive.rs:583:5
    |
 LL |     #[suggestion_part()]
    |     ^^^^^^^^^^^^^^^^^^^^
 
 error: specified multiple times
-  --> $DIR/subdiagnostic-derive.rs:592:37
+  --> $DIR/subdiagnostic-derive.rs:591:37
    |
 LL |     #[suggestion_part(code = "...", code = ",,,")]
    |                                     ^^^^^^^^^^^^
    |
 note: previously specified here
-  --> $DIR/subdiagnostic-derive.rs:592:23
+  --> $DIR/subdiagnostic-derive.rs:591:23
    |
 LL |     #[suggestion_part(code = "...", code = ",,,")]
    |                       ^^^^^^^^^^^^
 
 error: `#[applicability]` has no effect if all `#[suggestion]`/`#[multipart_suggestion]` attributes have a static `applicability = "..."`
-  --> $DIR/subdiagnostic-derive.rs:621:5
+  --> $DIR/subdiagnostic-derive.rs:620:5
    |
 LL |     #[applicability]
    |     ^^^^^^^^^^^^^^^^
@@ -458,19 +452,19 @@ LL |     #[bar("...")]
    |       ^^^
 
 error: cannot find attribute `bar` in this scope
-  --> $DIR/subdiagnostic-derive.rs:271:7
+  --> $DIR/subdiagnostic-derive.rs:270:7
    |
 LL |     #[bar]
    |       ^^^
 
 error: cannot find attribute `bar` in this scope
-  --> $DIR/subdiagnostic-derive.rs:282:7
+  --> $DIR/subdiagnostic-derive.rs:281:7
    |
 LL |     #[bar = "..."]
    |       ^^^
 
 error: cannot find attribute `bar` in this scope
-  --> $DIR/subdiagnostic-derive.rs:293:7
+  --> $DIR/subdiagnostic-derive.rs:292:7
    |
 LL |     #[bar("...")]
    |       ^^^
@@ -481,6 +475,6 @@ error[E0425]: cannot find value `slug` in module `rustc_errors::fluent`
 LL | #[label(slug)]
    |         ^^^^ not found in `rustc_errors::fluent`
 
-error: aborting due to 68 previous errors
+error: aborting due to 67 previous errors
 
 For more information about this error, try `rustc --explain E0425`.
diff --git a/src/test/ui/asm/unpretty-expanded.rs b/src/test/ui/asm/unpretty-expanded.rs
index 6128f49b89a34..25cf1c3d730eb 100644
--- a/src/test/ui/asm/unpretty-expanded.rs
+++ b/src/test/ui/asm/unpretty-expanded.rs
@@ -1,3 +1,4 @@
+// needs-asm-support
 // check-pass
 // compile-flags: -Zunpretty=expanded
 core::arch::global_asm!("x: .byte 42");
diff --git a/src/test/ui/asm/unpretty-expanded.stdout b/src/test/ui/asm/unpretty-expanded.stdout
index 15b60d1559c65..ab1b5f45e5c8a 100644
--- a/src/test/ui/asm/unpretty-expanded.stdout
+++ b/src/test/ui/asm/unpretty-expanded.stdout
@@ -4,6 +4,7 @@
 use ::std::prelude::rust_2015::*;
 #[macro_use]
 extern crate std;
+// needs-asm-support
 // check-pass
 // compile-flags: -Zunpretty=expanded
 global_asm! ("x: .byte 42");
diff --git a/src/test/ui/empty_global_asm.rs b/src/test/ui/empty_global_asm.rs
index dbcc7be057814..af13762d11857 100644
--- a/src/test/ui/empty_global_asm.rs
+++ b/src/test/ui/empty_global_asm.rs
@@ -1,21 +1,8 @@
+// needs-asm-support
 // run-pass
 
-#[allow(unused_imports)]
 use std::arch::global_asm;
 
-#[cfg(target_arch = "x86")]
-global_asm!("");
-
-#[cfg(target_arch = "x86_64")]
-global_asm!("");
-
-#[cfg(target_arch = "arm")]
-global_asm!("");
-
-#[cfg(target_arch = "aarch64")]
-global_asm!("");
-
-#[cfg(target_arch = "mips")]
 global_asm!("");
 
 fn main() {}
diff --git a/src/test/ui/hygiene/globs.stderr b/src/test/ui/hygiene/globs.stderr
index bcfcc28adf776..1f2a96a4c411a 100644
--- a/src/test/ui/hygiene/globs.stderr
+++ b/src/test/ui/hygiene/globs.stderr
@@ -1,9 +1,16 @@
 error[E0425]: cannot find function `f` in this scope
   --> $DIR/globs.rs:22:9
    |
+LL |     pub fn g() {}
+   |     ---------- similarly named function `g` defined here
+...
 LL |         f();
-   |         ^ not found in this scope
+   |         ^
+   |
+help: a function with a similar name exists
    |
+LL |         g();
+   |         ~
 help: consider importing this function
    |
 LL | use foo::f;
@@ -12,8 +19,11 @@ LL | use foo::f;
 error[E0425]: cannot find function `g` in this scope
   --> $DIR/globs.rs:15:5
    |
+LL |       pub fn f() {}
+   |       ---------- similarly named function `f` defined here
+...
 LL |       g();
-   |       ^ not found in this scope
+   |       ^
 ...
 LL | /     m! {
 LL | |         use bar::*;
@@ -23,6 +33,10 @@ LL | |     }
    | |_____- in this macro invocation
    |
    = note: this error originates in the macro `m` (in Nightly builds, run with -Z macro-backtrace for more info)
+help: a function with a similar name exists
+   |
+LL |     f();
+   |     ~
 help: consider importing this function
    |
 LL | use bar::g;
diff --git a/src/test/ui/hygiene/rustc-macro-transparency.stderr b/src/test/ui/hygiene/rustc-macro-transparency.stderr
index 17d05dd09636c..1d2a1e1249864 100644
--- a/src/test/ui/hygiene/rustc-macro-transparency.stderr
+++ b/src/test/ui/hygiene/rustc-macro-transparency.stderr
@@ -19,14 +19,8 @@ LL |     semitransparent;
 error[E0423]: expected value, found macro `opaque`
   --> $DIR/rustc-macro-transparency.rs:30:5
    |
-LL |     struct Opaque;
-   |     -------------- similarly named unit struct `Opaque` defined here
-...
 LL |     opaque;
-   |     ^^^^^^
-   |     |
-   |     not a value
-   |     help: a unit struct with a similar name exists (notice the capitalization): `Opaque`
+   |     ^^^^^^ not a value
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/lexical-scopes.stderr b/src/test/ui/lexical-scopes.stderr
index 08e4be2c0c352..535985452232d 100644
--- a/src/test/ui/lexical-scopes.stderr
+++ b/src/test/ui/lexical-scopes.stderr
@@ -1,6 +1,8 @@
 error[E0574]: expected struct, variant or union type, found type parameter `T`
   --> $DIR/lexical-scopes.rs:3:13
    |
+LL | struct T { i: i32 }
+   | ------------------- you might have meant to refer to this struct
 LL | fn f<T>() {
    |      - found this type parameter
 LL |     let t = T { i: 0 };
diff --git a/src/test/ui/lint/unused/unused-supertrait.rs b/src/test/ui/lint/unused/unused-supertrait.rs
new file mode 100644
index 0000000000000..64a8e5204579c
--- /dev/null
+++ b/src/test/ui/lint/unused/unused-supertrait.rs
@@ -0,0 +1,11 @@
+#![deny(unused_must_use)]
+
+fn it() -> impl ExactSizeIterator<Item = ()> {
+    let x: Box<dyn ExactSizeIterator<Item = ()>> = todo!();
+    x
+}
+
+fn main() {
+    it();
+    //~^ ERROR unused implementer of `Iterator` that must be used
+}
diff --git a/src/test/ui/lint/unused/unused-supertrait.stderr b/src/test/ui/lint/unused/unused-supertrait.stderr
new file mode 100644
index 0000000000000..d2f8c00784817
--- /dev/null
+++ b/src/test/ui/lint/unused/unused-supertrait.stderr
@@ -0,0 +1,15 @@
+error: unused implementer of `Iterator` that must be used
+  --> $DIR/unused-supertrait.rs:9:5
+   |
+LL |     it();
+   |     ^^^^^
+   |
+   = note: iterators are lazy and do nothing unless consumed
+note: the lint level is defined here
+  --> $DIR/unused-supertrait.rs:1:9
+   |
+LL | #![deny(unused_must_use)]
+   |         ^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/macros/macro-context.stderr b/src/test/ui/macros/macro-context.stderr
index 2a2e0c6c66a51..f597c398b7c17 100644
--- a/src/test/ui/macros/macro-context.stderr
+++ b/src/test/ui/macros/macro-context.stderr
@@ -57,7 +57,7 @@ error[E0425]: cannot find value `i` in this scope
   --> $DIR/macro-context.rs:3:13
    |
 LL |     () => ( i ; typeof );
-   |             ^ help: a local variable with a similar name exists: `a`
+   |             ^ not found in this scope
 ...
 LL |     let i = m!();
    |             ---- in this macro invocation
diff --git a/src/test/ui/proc-macro/gen-macro-rules-hygiene.stderr b/src/test/ui/proc-macro/gen-macro-rules-hygiene.stderr
index 6060f872f227a..df7c4f72eb0b6 100644
--- a/src/test/ui/proc-macro/gen-macro-rules-hygiene.stderr
+++ b/src/test/ui/proc-macro/gen-macro-rules-hygiene.stderr
@@ -13,7 +13,7 @@ error[E0425]: cannot find value `local_use` in this scope
   --> $DIR/gen-macro-rules-hygiene.rs:12:1
    |
 LL | gen_macro_rules!();
-   | ^^^^^^^^^^^^^^^^^^ not found in this scope
+   | ^^^^^^^^^^^^^^^^^^ help: a local variable with a similar name exists: `local_def`
 ...
 LL |         generated!();
    |         ------------ in this macro invocation
@@ -24,7 +24,7 @@ error[E0425]: cannot find value `local_def` in this scope
   --> $DIR/gen-macro-rules-hygiene.rs:21:9
    |
 LL |         local_def;
-   |         ^^^^^^^^^ not found in this scope
+   |         ^^^^^^^^^ help: a local variable with a similar name exists: `local_use`
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/proc-macro/mixed-site-span.stderr b/src/test/ui/proc-macro/mixed-site-span.stderr
index eab4317ded85d..1378608012464 100644
--- a/src/test/ui/proc-macro/mixed-site-span.stderr
+++ b/src/test/ui/proc-macro/mixed-site-span.stderr
@@ -10,7 +10,7 @@ error[E0425]: cannot find value `local_use` in this scope
   --> $DIR/mixed-site-span.rs:13:9
    |
 LL |         proc_macro_rules!();
-   |         ^^^^^^^^^^^^^^^^^^^ not found in this scope
+   |         ^^^^^^^^^^^^^^^^^^^ help: a local variable with a similar name exists: `local_def`
    |
    = note: this error originates in the macro `proc_macro_rules` (in Nightly builds, run with -Z macro-backtrace for more info)
 
@@ -18,7 +18,7 @@ error[E0425]: cannot find value `local_def` in this scope
   --> $DIR/mixed-site-span.rs:17:9
    |
 LL |         local_def;
-   |         ^^^^^^^^^ not found in this scope
+   |         ^^^^^^^^^ help: a local variable with a similar name exists: `local_use`
 
 error[E0412]: cannot find type `ItemUse` in crate `$crate`
   --> $DIR/mixed-site-span.rs:24:1
diff --git a/src/test/ui/resolve/point-at-type-parameter-shadowing-another-type.stderr b/src/test/ui/resolve/point-at-type-parameter-shadowing-another-type.stderr
index af9f4612ab342..eb26cd9cabb82 100644
--- a/src/test/ui/resolve/point-at-type-parameter-shadowing-another-type.stderr
+++ b/src/test/ui/resolve/point-at-type-parameter-shadowing-another-type.stderr
@@ -1,11 +1,16 @@
 error[E0574]: expected struct, variant or union type, found type parameter `Baz`
   --> $DIR/point-at-type-parameter-shadowing-another-type.rs:16:13
    |
-LL | impl<Baz> Foo<Baz> for Bar {
-   |      --- found this type parameter
+LL | / struct Baz {
+LL | |     num: usize,
+LL | | }
+   | |_- you might have meant to refer to this struct
+LL |
+LL |   impl<Baz> Foo<Baz> for Bar {
+   |        --- found this type parameter
 ...
-LL |             Baz { num } => num,
-   |             ^^^ not a struct, variant or union type
+LL |               Baz { num } => num,
+   |               ^^^ not a struct, variant or union type
 
 error: aborting due to previous error
 
diff --git a/src/tools/clippy/clippy_lints/src/manual_assert.rs b/src/tools/clippy/clippy_lints/src/manual_assert.rs
index 825ec84b4a812..b8ed9b9ec18f7 100644
--- a/src/tools/clippy/clippy_lints/src/manual_assert.rs
+++ b/src/tools/clippy/clippy_lints/src/manual_assert.rs
@@ -69,11 +69,13 @@ impl<'tcx> LateLintPass<'tcx> for ManualAssert {
                     "only a `panic!` in `if`-then statement",
                     |diag| {
                         // comments can be noisy, do not show them to the user
-                        diag.tool_only_span_suggestion(
-                                    expr.span.shrink_to_lo(),
-                                    "add comments back",
-                                    comments,
-                                    applicability);
+                        if !comments.is_empty() {
+                            diag.tool_only_span_suggestion(
+                                        expr.span.shrink_to_lo(),
+                                        "add comments back",
+                                        comments,
+                                        applicability);
+                        }
                         diag.span_suggestion(
                                     expr.span,
                                     "try instead",
diff --git a/src/tools/clippy/clippy_lints/src/needless_late_init.rs b/src/tools/clippy/clippy_lints/src/needless_late_init.rs
index 9d26e5900866c..67debe7e08af6 100644
--- a/src/tools/clippy/clippy_lints/src/needless_late_init.rs
+++ b/src/tools/clippy/clippy_lints/src/needless_late_init.rs
@@ -180,10 +180,13 @@ fn assignment_suggestions<'tcx>(
     let suggestions = assignments
         .iter()
         .flat_map(|assignment| {
-            [
-                assignment.span.until(assignment.rhs_span),
-                assignment.rhs_span.shrink_to_hi().with_hi(assignment.span.hi()),
-            ]
+            let mut spans = vec![assignment.span.until(assignment.rhs_span)];
+
+            if assignment.rhs_span.hi() != assignment.span.hi() {
+                spans.push(assignment.rhs_span.shrink_to_hi().with_hi(assignment.span.hi()));
+            }
+
+            spans
         })
         .map(|span| (span, String::new()))
         .collect::<Vec<(Span, String)>>();
diff --git a/src/tools/clippy/tests/ui/entry.fixed b/src/tools/clippy/tests/ui/entry.fixed
index e43635abcd112..79c29c04e0596 100644
--- a/src/tools/clippy/tests/ui/entry.fixed
+++ b/src/tools/clippy/tests/ui/entry.fixed
@@ -1,3 +1,4 @@
+// needs-asm-support
 // run-rustfix
 
 #![allow(unused, clippy::needless_pass_by_value, clippy::collapsible_if)]
diff --git a/src/tools/clippy/tests/ui/entry.rs b/src/tools/clippy/tests/ui/entry.rs
index d999b3b7dc80d..2d7985457d8b4 100644
--- a/src/tools/clippy/tests/ui/entry.rs
+++ b/src/tools/clippy/tests/ui/entry.rs
@@ -1,3 +1,4 @@
+// needs-asm-support
 // run-rustfix
 
 #![allow(unused, clippy::needless_pass_by_value, clippy::collapsible_if)]
diff --git a/src/tools/clippy/tests/ui/entry.stderr b/src/tools/clippy/tests/ui/entry.stderr
index 2ef9966525cef..2c4c49d2522ca 100644
--- a/src/tools/clippy/tests/ui/entry.stderr
+++ b/src/tools/clippy/tests/ui/entry.stderr
@@ -1,5 +1,5 @@
 error: usage of `contains_key` followed by `insert` on a `HashMap`
-  --> $DIR/entry.rs:24:5
+  --> $DIR/entry.rs:25:5
    |
 LL | /     if !m.contains_key(&k) {
 LL | |         m.insert(k, v);
@@ -9,7 +9,7 @@ LL | |     }
    = note: `-D clippy::map-entry` implied by `-D warnings`
 
 error: usage of `contains_key` followed by `insert` on a `HashMap`
-  --> $DIR/entry.rs:29:5
+  --> $DIR/entry.rs:30:5
    |
 LL | /     if !m.contains_key(&k) {
 LL | |         if true {
@@ -32,7 +32,7 @@ LL +     });
    |
 
 error: usage of `contains_key` followed by `insert` on a `HashMap`
-  --> $DIR/entry.rs:38:5
+  --> $DIR/entry.rs:39:5
    |
 LL | /     if !m.contains_key(&k) {
 LL | |         if true {
@@ -55,7 +55,7 @@ LL +     });
    |
 
 error: usage of `contains_key` followed by `insert` on a `HashMap`
-  --> $DIR/entry.rs:47:5
+  --> $DIR/entry.rs:48:5
    |
 LL | /     if !m.contains_key(&k) {
 LL | |         if true {
@@ -79,7 +79,7 @@ LL +     }
    |
 
 error: usage of `contains_key` followed by `insert` on a `HashMap`
-  --> $DIR/entry.rs:57:5
+  --> $DIR/entry.rs:58:5
    |
 LL | /     if !m.contains_key(&k) {
 LL | |         foo();
@@ -96,7 +96,7 @@ LL +     });
    |
 
 error: usage of `contains_key` followed by `insert` on a `HashMap`
-  --> $DIR/entry.rs:63:5
+  --> $DIR/entry.rs:64:5
    |
 LL | /     if !m.contains_key(&k) {
 LL | |         match 0 {
@@ -122,7 +122,7 @@ LL +     });
    |
 
 error: usage of `contains_key` followed by `insert` on a `HashMap`
-  --> $DIR/entry.rs:75:5
+  --> $DIR/entry.rs:76:5
    |
 LL | /     if !m.contains_key(&k) {
 LL | |         match 0 {
@@ -146,7 +146,7 @@ LL +     }
    |
 
 error: usage of `contains_key` followed by `insert` on a `HashMap`
-  --> $DIR/entry.rs:85:5
+  --> $DIR/entry.rs:86:5
    |
 LL | /     if !m.contains_key(&k) {
 LL | |         foo();
@@ -187,7 +187,7 @@ LL +     });
    |
 
 error: usage of `contains_key` followed by `insert` on a `HashMap`
-  --> $DIR/entry.rs:119:5
+  --> $DIR/entry.rs:120:5
    |
 LL | /     if !m.contains_key(&m!(k)) {
 LL | |         m.insert(m!(k), m!(v));
@@ -195,7 +195,7 @@ LL | |     }
    | |_____^ help: try this: `m.entry(m!(k)).or_insert_with(|| m!(v));`
 
 error: usage of `contains_key` followed by `insert` on a `HashMap`
-  --> $DIR/entry.rs:151:5
+  --> $DIR/entry.rs:152:5
    |
 LL | /     if !m.contains_key(&k) {
 LL | |         let x = (String::new(), String::new());
diff --git a/src/tools/clippy/tests/ui/manual_assert.edition2018.stderr b/src/tools/clippy/tests/ui/manual_assert.edition2018.stderr
index 7718588fdf6f4..237638ee1344c 100644
--- a/src/tools/clippy/tests/ui/manual_assert.edition2018.stderr
+++ b/src/tools/clippy/tests/ui/manual_assert.edition2018.stderr
@@ -4,13 +4,9 @@ error: only a `panic!` in `if`-then statement
 LL | /     if !a.is_empty() {
 LL | |         panic!("qaqaq{:?}", a);
 LL | |     }
-   | |_____^
+   | |_____^ help: try instead: `assert!(a.is_empty(), "qaqaq{:?}", a);`
    |
    = note: `-D clippy::manual-assert` implied by `-D warnings`
-help: try instead
-   |
-LL |     assert!(a.is_empty(), "qaqaq{:?}", a);
-   |
 
 error: only a `panic!` in `if`-then statement
   --> $DIR/manual_assert.rs:34:5
@@ -18,12 +14,7 @@ error: only a `panic!` in `if`-then statement
 LL | /     if !a.is_empty() {
 LL | |         panic!("qwqwq");
 LL | |     }
-   | |_____^
-   |
-help: try instead
-   |
-LL |     assert!(a.is_empty(), "qwqwq");
-   |
+   | |_____^ help: try instead: `assert!(a.is_empty(), "qwqwq");`
 
 error: only a `panic!` in `if`-then statement
   --> $DIR/manual_assert.rs:51:5
@@ -31,12 +22,7 @@ error: only a `panic!` in `if`-then statement
 LL | /     if b.is_empty() {
 LL | |         panic!("panic1");
 LL | |     }
-   | |_____^
-   |
-help: try instead
-   |
-LL |     assert!(!b.is_empty(), "panic1");
-   |
+   | |_____^ help: try instead: `assert!(!b.is_empty(), "panic1");`
 
 error: only a `panic!` in `if`-then statement
   --> $DIR/manual_assert.rs:54:5
@@ -44,12 +30,7 @@ error: only a `panic!` in `if`-then statement
 LL | /     if b.is_empty() && a.is_empty() {
 LL | |         panic!("panic2");
 LL | |     }
-   | |_____^
-   |
-help: try instead
-   |
-LL |     assert!(!(b.is_empty() && a.is_empty()), "panic2");
-   |
+   | |_____^ help: try instead: `assert!(!(b.is_empty() && a.is_empty()), "panic2");`
 
 error: only a `panic!` in `if`-then statement
   --> $DIR/manual_assert.rs:57:5
@@ -57,12 +38,7 @@ error: only a `panic!` in `if`-then statement
 LL | /     if a.is_empty() && !b.is_empty() {
 LL | |         panic!("panic3");
 LL | |     }
-   | |_____^
-   |
-help: try instead
-   |
-LL |     assert!(!(a.is_empty() && !b.is_empty()), "panic3");
-   |
+   | |_____^ help: try instead: `assert!(!(a.is_empty() && !b.is_empty()), "panic3");`
 
 error: only a `panic!` in `if`-then statement
   --> $DIR/manual_assert.rs:60:5
@@ -70,12 +46,7 @@ error: only a `panic!` in `if`-then statement
 LL | /     if b.is_empty() || a.is_empty() {
 LL | |         panic!("panic4");
 LL | |     }
-   | |_____^
-   |
-help: try instead
-   |
-LL |     assert!(!(b.is_empty() || a.is_empty()), "panic4");
-   |
+   | |_____^ help: try instead: `assert!(!(b.is_empty() || a.is_empty()), "panic4");`
 
 error: only a `panic!` in `if`-then statement
   --> $DIR/manual_assert.rs:63:5
@@ -83,12 +54,7 @@ error: only a `panic!` in `if`-then statement
 LL | /     if a.is_empty() || !b.is_empty() {
 LL | |         panic!("panic5");
 LL | |     }
-   | |_____^
-   |
-help: try instead
-   |
-LL |     assert!(!(a.is_empty() || !b.is_empty()), "panic5");
-   |
+   | |_____^ help: try instead: `assert!(!(a.is_empty() || !b.is_empty()), "panic5");`
 
 error: only a `panic!` in `if`-then statement
   --> $DIR/manual_assert.rs:66:5
@@ -96,12 +62,7 @@ error: only a `panic!` in `if`-then statement
 LL | /     if a.is_empty() {
 LL | |         panic!("with expansion {}", one!())
 LL | |     }
-   | |_____^
-   |
-help: try instead
-   |
-LL |     assert!(!a.is_empty(), "with expansion {}", one!());
-   |
+   | |_____^ help: try instead: `assert!(!a.is_empty(), "with expansion {}", one!());`
 
 error: only a `panic!` in `if`-then statement
   --> $DIR/manual_assert.rs:73:5
diff --git a/src/tools/clippy/tests/ui/manual_assert.edition2021.stderr b/src/tools/clippy/tests/ui/manual_assert.edition2021.stderr
index 7718588fdf6f4..237638ee1344c 100644
--- a/src/tools/clippy/tests/ui/manual_assert.edition2021.stderr
+++ b/src/tools/clippy/tests/ui/manual_assert.edition2021.stderr
@@ -4,13 +4,9 @@ error: only a `panic!` in `if`-then statement
 LL | /     if !a.is_empty() {
 LL | |         panic!("qaqaq{:?}", a);
 LL | |     }
-   | |_____^
+   | |_____^ help: try instead: `assert!(a.is_empty(), "qaqaq{:?}", a);`
    |
    = note: `-D clippy::manual-assert` implied by `-D warnings`
-help: try instead
-   |
-LL |     assert!(a.is_empty(), "qaqaq{:?}", a);
-   |
 
 error: only a `panic!` in `if`-then statement
   --> $DIR/manual_assert.rs:34:5
@@ -18,12 +14,7 @@ error: only a `panic!` in `if`-then statement
 LL | /     if !a.is_empty() {
 LL | |         panic!("qwqwq");
 LL | |     }
-   | |_____^
-   |
-help: try instead
-   |
-LL |     assert!(a.is_empty(), "qwqwq");
-   |
+   | |_____^ help: try instead: `assert!(a.is_empty(), "qwqwq");`
 
 error: only a `panic!` in `if`-then statement
   --> $DIR/manual_assert.rs:51:5
@@ -31,12 +22,7 @@ error: only a `panic!` in `if`-then statement
 LL | /     if b.is_empty() {
 LL | |         panic!("panic1");
 LL | |     }
-   | |_____^
-   |
-help: try instead
-   |
-LL |     assert!(!b.is_empty(), "panic1");
-   |
+   | |_____^ help: try instead: `assert!(!b.is_empty(), "panic1");`
 
 error: only a `panic!` in `if`-then statement
   --> $DIR/manual_assert.rs:54:5
@@ -44,12 +30,7 @@ error: only a `panic!` in `if`-then statement
 LL | /     if b.is_empty() && a.is_empty() {
 LL | |         panic!("panic2");
 LL | |     }
-   | |_____^
-   |
-help: try instead
-   |
-LL |     assert!(!(b.is_empty() && a.is_empty()), "panic2");
-   |
+   | |_____^ help: try instead: `assert!(!(b.is_empty() && a.is_empty()), "panic2");`
 
 error: only a `panic!` in `if`-then statement
   --> $DIR/manual_assert.rs:57:5
@@ -57,12 +38,7 @@ error: only a `panic!` in `if`-then statement
 LL | /     if a.is_empty() && !b.is_empty() {
 LL | |         panic!("panic3");
 LL | |     }
-   | |_____^
-   |
-help: try instead
-   |
-LL |     assert!(!(a.is_empty() && !b.is_empty()), "panic3");
-   |
+   | |_____^ help: try instead: `assert!(!(a.is_empty() && !b.is_empty()), "panic3");`
 
 error: only a `panic!` in `if`-then statement
   --> $DIR/manual_assert.rs:60:5
@@ -70,12 +46,7 @@ error: only a `panic!` in `if`-then statement
 LL | /     if b.is_empty() || a.is_empty() {
 LL | |         panic!("panic4");
 LL | |     }
-   | |_____^
-   |
-help: try instead
-   |
-LL |     assert!(!(b.is_empty() || a.is_empty()), "panic4");
-   |
+   | |_____^ help: try instead: `assert!(!(b.is_empty() || a.is_empty()), "panic4");`
 
 error: only a `panic!` in `if`-then statement
   --> $DIR/manual_assert.rs:63:5
@@ -83,12 +54,7 @@ error: only a `panic!` in `if`-then statement
 LL | /     if a.is_empty() || !b.is_empty() {
 LL | |         panic!("panic5");
 LL | |     }
-   | |_____^
-   |
-help: try instead
-   |
-LL |     assert!(!(a.is_empty() || !b.is_empty()), "panic5");
-   |
+   | |_____^ help: try instead: `assert!(!(a.is_empty() || !b.is_empty()), "panic5");`
 
 error: only a `panic!` in `if`-then statement
   --> $DIR/manual_assert.rs:66:5
@@ -96,12 +62,7 @@ error: only a `panic!` in `if`-then statement
 LL | /     if a.is_empty() {
 LL | |         panic!("with expansion {}", one!())
 LL | |     }
-   | |_____^
-   |
-help: try instead
-   |
-LL |     assert!(!a.is_empty(), "with expansion {}", one!());
-   |
+   | |_____^ help: try instead: `assert!(!a.is_empty(), "with expansion {}", one!());`
 
 error: only a `panic!` in `if`-then statement
   --> $DIR/manual_assert.rs:73:5
diff --git a/src/tools/clippy/tests/ui/missing_doc.rs b/src/tools/clippy/tests/ui/missing_doc.rs
index 29cc026a8fd39..590ad63c90be3 100644
--- a/src/tools/clippy/tests/ui/missing_doc.rs
+++ b/src/tools/clippy/tests/ui/missing_doc.rs
@@ -1,3 +1,4 @@
+// needs-asm-support
 // aux-build: proc_macro_with_span.rs
 
 #![warn(clippy::missing_docs_in_private_items)]
diff --git a/src/tools/clippy/tests/ui/missing_doc.stderr b/src/tools/clippy/tests/ui/missing_doc.stderr
index 6c8e66f464377..d3bef28bf64c6 100644
--- a/src/tools/clippy/tests/ui/missing_doc.stderr
+++ b/src/tools/clippy/tests/ui/missing_doc.stderr
@@ -1,5 +1,5 @@
 error: missing documentation for a type alias
-  --> $DIR/missing_doc.rs:15:1
+  --> $DIR/missing_doc.rs:16:1
    |
 LL | type Typedef = String;
    | ^^^^^^^^^^^^^^^^^^^^^^
@@ -7,37 +7,37 @@ LL | type Typedef = String;
    = note: `-D clippy::missing-docs-in-private-items` implied by `-D warnings`
 
 error: missing documentation for a type alias
-  --> $DIR/missing_doc.rs:16:1
+  --> $DIR/missing_doc.rs:17:1
    |
 LL | pub type PubTypedef = String;
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: missing documentation for a module
-  --> $DIR/missing_doc.rs:18:1
+  --> $DIR/missing_doc.rs:19:1
    |
 LL | mod module_no_dox {}
    | ^^^^^^^^^^^^^^^^^^^^
 
 error: missing documentation for a module
-  --> $DIR/missing_doc.rs:19:1
+  --> $DIR/missing_doc.rs:20:1
    |
 LL | pub mod pub_module_no_dox {}
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: missing documentation for a function
-  --> $DIR/missing_doc.rs:23:1
+  --> $DIR/missing_doc.rs:24:1
    |
 LL | pub fn foo2() {}
    | ^^^^^^^^^^^^^^^^
 
 error: missing documentation for a function
-  --> $DIR/missing_doc.rs:24:1
+  --> $DIR/missing_doc.rs:25:1
    |
 LL | fn foo3() {}
    | ^^^^^^^^^^^^
 
 error: missing documentation for an enum
-  --> $DIR/missing_doc.rs:38:1
+  --> $DIR/missing_doc.rs:39:1
    |
 LL | / enum Baz {
 LL | |     BazA { a: isize, b: isize },
@@ -46,31 +46,31 @@ LL | | }
    | |_^
 
 error: missing documentation for a variant
-  --> $DIR/missing_doc.rs:39:5
+  --> $DIR/missing_doc.rs:40:5
    |
 LL |     BazA { a: isize, b: isize },
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: missing documentation for a struct field
-  --> $DIR/missing_doc.rs:39:12
+  --> $DIR/missing_doc.rs:40:12
    |
 LL |     BazA { a: isize, b: isize },
    |            ^^^^^^^^
 
 error: missing documentation for a struct field
-  --> $DIR/missing_doc.rs:39:22
+  --> $DIR/missing_doc.rs:40:22
    |
 LL |     BazA { a: isize, b: isize },
    |                      ^^^^^^^^
 
 error: missing documentation for a variant
-  --> $DIR/missing_doc.rs:40:5
+  --> $DIR/missing_doc.rs:41:5
    |
 LL |     BarB,
    |     ^^^^
 
 error: missing documentation for an enum
-  --> $DIR/missing_doc.rs:43:1
+  --> $DIR/missing_doc.rs:44:1
    |
 LL | / pub enum PubBaz {
 LL | |     PubBazA { a: isize },
@@ -78,43 +78,43 @@ LL | | }
    | |_^
 
 error: missing documentation for a variant
-  --> $DIR/missing_doc.rs:44:5
+  --> $DIR/missing_doc.rs:45:5
    |
 LL |     PubBazA { a: isize },
    |     ^^^^^^^^^^^^^^^^^^^^
 
 error: missing documentation for a struct field
-  --> $DIR/missing_doc.rs:44:15
+  --> $DIR/missing_doc.rs:45:15
    |
 LL |     PubBazA { a: isize },
    |               ^^^^^^^^
 
 error: missing documentation for a constant
-  --> $DIR/missing_doc.rs:64:1
+  --> $DIR/missing_doc.rs:65:1
    |
 LL | const FOO: u32 = 0;
    | ^^^^^^^^^^^^^^^^^^^
 
 error: missing documentation for a constant
-  --> $DIR/missing_doc.rs:71:1
+  --> $DIR/missing_doc.rs:72:1
    |
 LL | pub const FOO4: u32 = 0;
    | ^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: missing documentation for a static
-  --> $DIR/missing_doc.rs:73:1
+  --> $DIR/missing_doc.rs:74:1
    |
 LL | static BAR: u32 = 0;
    | ^^^^^^^^^^^^^^^^^^^^
 
 error: missing documentation for a static
-  --> $DIR/missing_doc.rs:80:1
+  --> $DIR/missing_doc.rs:81:1
    |
 LL | pub static BAR4: u32 = 0;
    | ^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: missing documentation for a module
-  --> $DIR/missing_doc.rs:82:1
+  --> $DIR/missing_doc.rs:83:1
    |
 LL | / mod internal_impl {
 LL | |     /// dox
@@ -126,31 +126,31 @@ LL | | }
    | |_^
 
 error: missing documentation for a function
-  --> $DIR/missing_doc.rs:85:5
+  --> $DIR/missing_doc.rs:86:5
    |
 LL |     pub fn undocumented1() {}
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: missing documentation for a function
-  --> $DIR/missing_doc.rs:86:5
+  --> $DIR/missing_doc.rs:87:5
    |
 LL |     pub fn undocumented2() {}
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: missing documentation for a function
-  --> $DIR/missing_doc.rs:87:5
+  --> $DIR/missing_doc.rs:88:5
    |
 LL |     fn undocumented3() {}
    |     ^^^^^^^^^^^^^^^^^^^^^
 
 error: missing documentation for a function
-  --> $DIR/missing_doc.rs:92:9
+  --> $DIR/missing_doc.rs:93:9
    |
 LL |         pub fn also_undocumented1() {}
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: missing documentation for a function
-  --> $DIR/missing_doc.rs:93:9
+  --> $DIR/missing_doc.rs:94:9
    |
 LL |         fn also_undocumented2() {}
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^