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-rw-r--r--compiler/rustc_infer/src/infer/error_reporting/mod.rs500
-rw-r--r--compiler/rustc_middle/src/ty/context.rs25
-rw-r--r--tests/ui/associated-inherent-types/regionck-1.stderr9
-rw-r--r--tests/ui/async-await/in-trait/async-generics-and-bounds.stderr8
-rw-r--r--tests/ui/async-await/in-trait/async-generics.stderr8
-rw-r--r--tests/ui/error-codes/E0311.fixed2
-rw-r--r--tests/ui/error-codes/E0311.stderr4
-rw-r--r--tests/ui/generic-associated-types/issue-84931.stderr9
-rw-r--r--tests/ui/lifetimes/lifetime-doesnt-live-long-enough.stderr16
-rw-r--r--tests/ui/lifetimes/suggest-introducing-and-adding-missing-lifetime.fixed2
-rw-r--r--tests/ui/lifetimes/suggest-introducing-and-adding-missing-lifetime.stderr4
-rw-r--r--tests/ui/nll/ty-outlives/projection-no-regions-closure.stderr16
-rw-r--r--tests/ui/nll/ty-outlives/projection-no-regions-fn.stderr16
-rw-r--r--tests/ui/regions/regions-close-associated-type-into-object.stderr32
-rw-r--r--tests/ui/regions/regions-infer-bound-from-trait-self.stderr8
-rw-r--r--tests/ui/suggestions/lifetimes/issue-105544.fixed8
-rw-r--r--tests/ui/suggestions/lifetimes/issue-105544.stderr16
-rw-r--r--tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature-2.fixed7
-rw-r--r--tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature-2.rs7
-rw-r--r--tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature-2.stderr10
-rw-r--r--tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature.stderr14
-rw-r--r--tests/ui/suggestions/lifetimes/type-param-bound-scope.fixed47
-rw-r--r--tests/ui/suggestions/lifetimes/type-param-bound-scope.rs47
-rw-r--r--tests/ui/suggestions/lifetimes/type-param-bound-scope.stderr58
-rw-r--r--tests/ui/suggestions/lifetimes/type-param-missing-lifetime.fixed52
-rw-r--r--tests/ui/suggestions/lifetimes/type-param-missing-lifetime.rs52
-rw-r--r--tests/ui/suggestions/lifetimes/type-param-missing-lifetime.stderr95
-rw-r--r--tests/ui/wf/wf-trait-associated-type-region.stderr8
28 files changed, 696 insertions, 384 deletions
diff --git a/compiler/rustc_infer/src/infer/error_reporting/mod.rs b/compiler/rustc_infer/src/infer/error_reporting/mod.rs
index 72cfc1337e2..0e48d09d6c6 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/mod.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/mod.rs
@@ -66,13 +66,12 @@ use rustc_hir::def::DefKind;
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::intravisit::Visitor;
 use rustc_hir::lang_items::LangItem;
-use rustc_hir::Node;
 use rustc_middle::dep_graph::DepContext;
 use rustc_middle::ty::print::with_forced_trimmed_paths;
 use rustc_middle::ty::relate::{self, RelateResult, TypeRelation};
 use rustc_middle::ty::{
-    self, error::TypeError, List, Region, Ty, TyCtxt, TypeFoldable, TypeSuperVisitable,
-    TypeVisitable, TypeVisitableExt,
+    self, error::TypeError, IsSuggestable, List, Region, Ty, TyCtxt, TypeFoldable,
+    TypeSuperVisitable, TypeVisitable, TypeVisitableExt,
 };
 use rustc_span::{sym, symbol::kw, BytePos, DesugaringKind, Pos, Span};
 use rustc_target::spec::abi;
@@ -2317,126 +2316,6 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
         bound_kind: GenericKind<'tcx>,
         sub: Region<'tcx>,
     ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
-        // Attempt to obtain the span of the parameter so we can
-        // suggest adding an explicit lifetime bound to it.
-        let generics = self.tcx.generics_of(generic_param_scope);
-        // type_param_span is (span, has_bounds)
-        let mut is_synthetic = false;
-        let mut ast_generics = None;
-        let type_param_span = match bound_kind {
-            GenericKind::Param(ref param) => {
-                // Account for the case where `param` corresponds to `Self`,
-                // which doesn't have the expected type argument.
-                if !(generics.has_self && param.index == 0) {
-                    let type_param = generics.type_param(param, self.tcx);
-                    is_synthetic = type_param.kind.is_synthetic();
-                    type_param.def_id.as_local().map(|def_id| {
-                        // Get the `hir::Param` to verify whether it already has any bounds.
-                        // We do this to avoid suggesting code that ends up as `T: 'a'b`,
-                        // instead we suggest `T: 'a + 'b` in that case.
-                        let hir_id = self.tcx.hir().local_def_id_to_hir_id(def_id);
-                        ast_generics = self.tcx.hir().get_generics(hir_id.owner.def_id);
-                        let bounds =
-                            ast_generics.and_then(|g| g.bounds_span_for_suggestions(def_id));
-                        // `sp` only covers `T`, change it so that it covers
-                        // `T:` when appropriate
-                        if let Some(span) = bounds {
-                            (span, true)
-                        } else {
-                            let sp = self.tcx.def_span(def_id);
-                            (sp.shrink_to_hi(), false)
-                        }
-                    })
-                } else {
-                    None
-                }
-            }
-            _ => None,
-        };
-
-        let new_lt = {
-            let mut possible = (b'a'..=b'z').map(|c| format!("'{}", c as char));
-            let lts_names =
-                iter::successors(Some(generics), |g| g.parent.map(|p| self.tcx.generics_of(p)))
-                    .flat_map(|g| &g.params)
-                    .filter(|p| matches!(p.kind, ty::GenericParamDefKind::Lifetime))
-                    .map(|p| p.name.as_str())
-                    .collect::<Vec<_>>();
-            possible
-                .find(|candidate| !lts_names.contains(&&candidate[..]))
-                .unwrap_or("'lt".to_string())
-        };
-
-        let mut add_lt_suggs: Vec<Option<_>> = vec![];
-        if is_synthetic {
-            if let Some(ast_generics) = ast_generics {
-                let named_lifetime_param_exist = ast_generics.params.iter().any(|p| {
-                    matches!(
-                        p.kind,
-                        hir::GenericParamKind::Lifetime { kind: hir::LifetimeParamKind::Explicit }
-                    )
-                });
-                if named_lifetime_param_exist && let [param, ..] = ast_generics.params
-                {
-                    add_lt_suggs.push(Some((
-                        self.tcx.def_span(param.def_id).shrink_to_lo(),
-                        format!("{new_lt}, "),
-                    )));
-                } else {
-                    add_lt_suggs
-                        .push(Some((ast_generics.span.shrink_to_hi(), format!("<{new_lt}>"))));
-                }
-            }
-        } else {
-            if let [param, ..] = &generics.params[..] && let Some(def_id) = param.def_id.as_local()
-            {
-                add_lt_suggs
-                    .push(Some((self.tcx.def_span(def_id).shrink_to_lo(), format!("{new_lt}, "))));
-            }
-        }
-
-        if let Some(ast_generics) = ast_generics {
-            for p in ast_generics.params {
-                if p.is_elided_lifetime() {
-                    if self
-                        .tcx
-                        .sess
-                        .source_map()
-                        .span_to_prev_source(p.span.shrink_to_hi())
-                        .ok()
-                        .is_some_and(|s| *s.as_bytes().last().unwrap() == b'&')
-                    {
-                        add_lt_suggs
-                            .push(Some(
-                                (
-                                    p.span.shrink_to_hi(),
-                                    if let Ok(snip) = self.tcx.sess.source_map().span_to_next_source(p.span)
-                                        && snip.starts_with(' ')
-                                    {
-                                        new_lt.to_string()
-                                    } else {
-                                        format!("{new_lt} ")
-                                    }
-                                )
-                            ));
-                    } else {
-                        add_lt_suggs.push(Some((p.span.shrink_to_hi(), format!("<{new_lt}>"))));
-                    }
-                }
-            }
-        }
-
-        let labeled_user_string = match bound_kind {
-            GenericKind::Param(ref p) => format!("the parameter type `{p}`"),
-            GenericKind::Alias(ref p) => match p.kind(self.tcx) {
-                ty::AliasKind::Projection | ty::AliasKind::Inherent => {
-                    format!("the associated type `{p}`")
-                }
-                ty::AliasKind::Weak => format!("the type alias `{p}`"),
-                ty::AliasKind::Opaque => format!("the opaque type `{p}`"),
-            },
-        };
-
         if let Some(SubregionOrigin::CompareImplItemObligation {
             span,
             impl_item_def_id,
@@ -2451,165 +2330,33 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
             );
         }
 
-        fn binding_suggestion<'tcx, S: fmt::Display>(
-            err: &mut Diagnostic,
-            type_param_span: Option<(Span, bool)>,
-            bound_kind: GenericKind<'tcx>,
-            sub: S,
-            add_lt_suggs: Vec<Option<(Span, String)>>,
-        ) {
-            let msg = "consider adding an explicit lifetime bound";
-            if let Some((sp, has_lifetimes)) = type_param_span {
-                let suggestion =
-                    if has_lifetimes { format!(" + {sub}") } else { format!(": {sub}") };
-                let mut suggestions = vec![(sp, suggestion)];
-                for add_lt_sugg in add_lt_suggs.into_iter().flatten() {
-                    suggestions.push(add_lt_sugg);
-                }
-                err.multipart_suggestion_verbose(
-                    format!("{msg}..."),
-                    suggestions,
-                    Applicability::MaybeIncorrect, // Issue #41966
-                );
-            } else {
-                let consider = format!("{msg} `{bound_kind}: {sub}`...");
-                err.help(consider);
-            }
-        }
-
-        let new_binding_suggestion =
-            |err: &mut Diagnostic, type_param_span: Option<(Span, bool)>| {
-                let msg = "consider introducing an explicit lifetime bound";
-                if let Some((sp, has_lifetimes)) = type_param_span {
-                    let suggestion =
-                        if has_lifetimes { format!(" + {new_lt}") } else { format!(": {new_lt}") };
-                    let mut sugg =
-                        vec![(sp, suggestion), (span.shrink_to_hi(), format!(" + {new_lt}"))];
-                    for lt in add_lt_suggs.clone().into_iter().flatten() {
-                        sugg.push(lt);
-                        sugg.rotate_right(1);
-                    }
-                    // `MaybeIncorrect` due to issue #41966.
-                    err.multipart_suggestion(msg, sugg, Applicability::MaybeIncorrect);
-                }
-            };
-
-        #[derive(Debug)]
-        enum SubOrigin<'hir> {
-            GAT(&'hir hir::Generics<'hir>),
-            Impl,
-            Trait,
-            Fn,
-            Unknown,
-        }
-        let sub_origin = 'origin: {
-            match *sub {
-                ty::ReEarlyBound(ty::EarlyBoundRegion { def_id, .. }) => {
-                    let node = self.tcx.hir().get_if_local(def_id).unwrap();
-                    match node {
-                        Node::GenericParam(param) => {
-                            for h in self.tcx.hir().parent_iter(param.hir_id) {
-                                break 'origin match h.1 {
-                                    Node::ImplItem(hir::ImplItem {
-                                        kind: hir::ImplItemKind::Type(..),
-                                        generics,
-                                        ..
-                                    })
-                                    | Node::TraitItem(hir::TraitItem {
-                                        kind: hir::TraitItemKind::Type(..),
-                                        generics,
-                                        ..
-                                    }) => SubOrigin::GAT(generics),
-                                    Node::ImplItem(hir::ImplItem {
-                                        kind: hir::ImplItemKind::Fn(..),
-                                        ..
-                                    })
-                                    | Node::TraitItem(hir::TraitItem {
-                                        kind: hir::TraitItemKind::Fn(..),
-                                        ..
-                                    })
-                                    | Node::Item(hir::Item {
-                                        kind: hir::ItemKind::Fn(..), ..
-                                    }) => SubOrigin::Fn,
-                                    Node::Item(hir::Item {
-                                        kind: hir::ItemKind::Trait(..),
-                                        ..
-                                    }) => SubOrigin::Trait,
-                                    Node::Item(hir::Item {
-                                        kind: hir::ItemKind::Impl(..), ..
-                                    }) => SubOrigin::Impl,
-                                    _ => continue,
-                                };
-                            }
-                        }
-                        _ => {}
-                    }
+        let labeled_user_string = match bound_kind {
+            GenericKind::Param(ref p) => format!("the parameter type `{p}`"),
+            GenericKind::Alias(ref p) => match p.kind(self.tcx) {
+                ty::AliasKind::Projection | ty::AliasKind::Inherent => {
+                    format!("the associated type `{p}`")
                 }
-                _ => {}
-            }
-            SubOrigin::Unknown
+                ty::AliasKind::Weak => format!("the type alias `{p}`"),
+                ty::AliasKind::Opaque => format!("the opaque type `{p}`"),
+            },
         };
-        debug!(?sub_origin);
-
-        let mut err = match (*sub, sub_origin) {
-            // In the case of GATs, we have to be careful. If we a type parameter `T` on an impl,
-            // but a lifetime `'a` on an associated type, then we might need to suggest adding
-            // `where T: 'a`. Importantly, this is on the GAT span, not on the `T` declaration.
-            (ty::ReEarlyBound(ty::EarlyBoundRegion { name: _, .. }), SubOrigin::GAT(generics)) => {
-                // Does the required lifetime have a nice name we can print?
-                let mut err = struct_span_err!(
-                    self.tcx.sess,
-                    span,
-                    E0309,
-                    "{} may not live long enough",
-                    labeled_user_string
-                );
-                let pred = format!("{bound_kind}: {sub}");
-                let suggestion = format!("{} {}", generics.add_where_or_trailing_comma(), pred,);
-                err.span_suggestion(
-                    generics.tail_span_for_predicate_suggestion(),
-                    "consider adding a where clause",
-                    suggestion,
-                    Applicability::MaybeIncorrect,
-                );
-                err
-            }
-            (
-                ty::ReEarlyBound(ty::EarlyBoundRegion { name, .. })
-                | ty::ReFree(ty::FreeRegion { bound_region: ty::BrNamed(_, name), .. }),
-                _,
-            ) if name != kw::UnderscoreLifetime => {
-                // Does the required lifetime have a nice name we can print?
-                let mut err = struct_span_err!(
-                    self.tcx.sess,
-                    span,
-                    E0309,
-                    "{} may not live long enough",
-                    labeled_user_string
-                );
-                // Explicitly use the name instead of `sub`'s `Display` impl. The `Display` impl
-                // for the bound is not suitable for suggestions when `-Zverbose` is set because it
-                // uses `Debug` output, so we handle it specially here so that suggestions are
-                // always correct.
-                binding_suggestion(&mut err, type_param_span, bound_kind, name, vec![]);
-                err
-            }
-
-            (ty::ReStatic, _) => {
-                // Does the required lifetime have a nice name we can print?
-                let mut err = struct_span_err!(
-                    self.tcx.sess,
-                    span,
-                    E0310,
-                    "{} may not live long enough",
-                    labeled_user_string
-                );
-                binding_suggestion(&mut err, type_param_span, bound_kind, "'static", vec![]);
-                err
-            }
 
+        let mut err = match sub.kind() {
+            ty::ReEarlyBound(_) | ty::ReFree(_) if sub.has_name() => struct_span_err!(
+                self.tcx.sess,
+                span,
+                E0309,
+                "{} may not live long enough",
+                labeled_user_string
+            ),
+            ty::ReStatic => struct_span_err!(
+                self.tcx.sess,
+                span,
+                E0310,
+                "{} may not live long enough",
+                labeled_user_string
+            ),
             _ => {
-                // If not, be less specific.
                 let mut err = struct_span_err!(
                     self.tcx.sess,
                     span,
@@ -2625,37 +2372,192 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                     "...",
                     None,
                 );
-                if let Some(infer::RelateParamBound(_, t, _)) = origin {
-                    let t = self.resolve_vars_if_possible(t);
-                    match t.kind() {
-                        // We've got:
-                        // fn get_later<G, T>(g: G, dest: &mut T) -> impl FnOnce() + '_
-                        // suggest:
-                        // fn get_later<'a, G: 'a, T>(g: G, dest: &mut T) -> impl FnOnce() + '_ + 'a
-                        ty::Closure(..) | ty::Alias(ty::Opaque, ..) => {
-                            new_binding_suggestion(&mut err, type_param_span);
-                        }
-                        _ => {
-                            binding_suggestion(
-                                &mut err,
-                                type_param_span,
-                                bound_kind,
-                                new_lt,
-                                add_lt_suggs,
-                            );
-                        }
-                    }
-                }
                 err
             }
         };
 
+        'suggestion: {
+            let msg = "consider adding an explicit lifetime bound";
+
+            if (bound_kind, sub).has_infer_regions()
+                || (bound_kind, sub).has_placeholders()
+                || !bound_kind.is_suggestable(self.tcx, false)
+            {
+                let lt_name = sub.get_name_or_anon().to_string();
+                err.help(format!("{msg} `{bound_kind}: {lt_name}`..."));
+                break 'suggestion;
+            }
+
+            let mut generic_param_scope = generic_param_scope;
+            while self.tcx.def_kind(generic_param_scope) == DefKind::OpaqueTy {
+                generic_param_scope = self.tcx.local_parent(generic_param_scope);
+            }
+
+            // type_param_sugg_span is (span, has_bounds)
+            let (type_scope, type_param_sugg_span) = match bound_kind {
+                GenericKind::Param(ref param) => {
+                    let generics = self.tcx.generics_of(generic_param_scope);
+                    let def_id = generics.type_param(param, self.tcx).def_id.expect_local();
+                    let scope = self.tcx.local_def_id_to_hir_id(def_id).owner.def_id;
+                    // Get the `hir::Param` to verify whether it already has any bounds.
+                    // We do this to avoid suggesting code that ends up as `T: 'a'b`,
+                    // instead we suggest `T: 'a + 'b` in that case.
+                    let hir_generics = self.tcx.hir().get_generics(scope).unwrap();
+                    let sugg_span = match hir_generics.bounds_span_for_suggestions(def_id) {
+                        Some(span) => Some((span, true)),
+                        // If `param` corresponds to `Self`, no usable suggestion span.
+                        None if generics.has_self && param.index == 0 => None,
+                        None => Some((self.tcx.def_span(def_id).shrink_to_hi(), false)),
+                    };
+                    (scope, sugg_span)
+                }
+                _ => (generic_param_scope, None),
+            };
+            let suggestion_scope = {
+                let lifetime_scope = match sub.kind() {
+                    ty::ReStatic => hir::def_id::CRATE_DEF_ID,
+                    _ => match self.tcx.is_suitable_region(sub) {
+                        Some(info) => info.def_id,
+                        None => generic_param_scope,
+                    },
+                };
+                match self.tcx.is_descendant_of(type_scope.into(), lifetime_scope.into()) {
+                    true => type_scope,
+                    false => lifetime_scope,
+                }
+            };
+
+            let mut suggs = vec![];
+            let lt_name = self.suggest_name_region(sub, &mut suggs);
+
+            if let Some((sp, has_lifetimes)) = type_param_sugg_span
+                && suggestion_scope == type_scope
+            {
+                let suggestion =
+                    if has_lifetimes { format!(" + {lt_name}") } else { format!(": {lt_name}") };
+                suggs.push((sp, suggestion))
+            } else {
+                let generics = self.tcx.hir().get_generics(suggestion_scope).unwrap();
+                let pred = format!("{bound_kind}: {lt_name}");
+                let suggestion = format!("{} {}", generics.add_where_or_trailing_comma(), pred,);
+                suggs.push((generics.tail_span_for_predicate_suggestion(), suggestion))
+            }
+
+            err.multipart_suggestion_verbose(
+                format!("{msg}..."),
+                suggs,
+                Applicability::MaybeIncorrect, // Issue #41966
+            );
+        }
+
         if let Some(origin) = origin {
             self.note_region_origin(&mut err, &origin);
         }
         err
     }
 
+    pub fn suggest_name_region(
+        &self,
+        lifetime: Region<'tcx>,
+        add_lt_suggs: &mut Vec<(Span, String)>,
+    ) -> String {
+        struct LifetimeReplaceVisitor<'tcx, 'a> {
+            tcx: TyCtxt<'tcx>,
+            needle: hir::LifetimeName,
+            new_lt: &'a str,
+            add_lt_suggs: &'a mut Vec<(Span, String)>,
+        }
+
+        impl<'hir, 'tcx> hir::intravisit::Visitor<'hir> for LifetimeReplaceVisitor<'tcx, '_> {
+            fn visit_lifetime(&mut self, lt: &'hir hir::Lifetime) {
+                if lt.res == self.needle {
+                    let (pos, span) = lt.suggestion_position();
+                    let new_lt = &self.new_lt;
+                    let sugg = match pos {
+                        hir::LifetimeSuggestionPosition::Normal => format!("{new_lt}"),
+                        hir::LifetimeSuggestionPosition::Ampersand => format!("{new_lt} "),
+                        hir::LifetimeSuggestionPosition::ElidedPath => format!("<{new_lt}>"),
+                        hir::LifetimeSuggestionPosition::ElidedPathArgument => {
+                            format!("{new_lt}, ")
+                        }
+                        hir::LifetimeSuggestionPosition::ObjectDefault => format!("+ {new_lt}"),
+                    };
+                    self.add_lt_suggs.push((span, sugg));
+                }
+            }
+
+            fn visit_ty(&mut self, ty: &'hir hir::Ty<'hir>) {
+                let hir::TyKind::OpaqueDef(item_id, _, _) = ty.kind else {
+                    return hir::intravisit::walk_ty(self, ty);
+                };
+                let opaque_ty = self.tcx.hir().item(item_id).expect_opaque_ty();
+                if let Some(&(_, b)) =
+                    opaque_ty.lifetime_mapping.iter().find(|&(a, _)| a.res == self.needle)
+                {
+                    let prev_needle =
+                        std::mem::replace(&mut self.needle, hir::LifetimeName::Param(b));
+                    for bound in opaque_ty.bounds {
+                        self.visit_param_bound(bound);
+                    }
+                    self.needle = prev_needle;
+                }
+            }
+        }
+
+        let (lifetime_def_id, lifetime_scope) = match self.tcx.is_suitable_region(lifetime) {
+            Some(info) if !lifetime.has_name() => {
+                (info.boundregion.get_id().unwrap().expect_local(), info.def_id)
+            }
+            _ => return lifetime.get_name_or_anon().to_string(),
+        };
+
+        let new_lt = {
+            let generics = self.tcx.generics_of(lifetime_scope);
+            let mut used_names =
+                iter::successors(Some(generics), |g| g.parent.map(|p| self.tcx.generics_of(p)))
+                    .flat_map(|g| &g.params)
+                    .filter(|p| matches!(p.kind, ty::GenericParamDefKind::Lifetime))
+                    .map(|p| p.name)
+                    .collect::<Vec<_>>();
+            if let Some(hir_id) = self.tcx.opt_local_def_id_to_hir_id(lifetime_scope) {
+                // consider late-bound lifetimes ...
+                used_names.extend(self.tcx.late_bound_vars(hir_id).into_iter().filter_map(|p| {
+                    match p {
+                        ty::BoundVariableKind::Region(lt) => lt.get_name(),
+                        _ => None,
+                    }
+                }))
+            }
+            (b'a'..=b'z')
+                .map(|c| format!("'{}", c as char))
+                .find(|candidate| !used_names.iter().any(|e| e.as_str() == candidate))
+                .unwrap_or("'lt".to_string())
+        };
+
+        let mut visitor = LifetimeReplaceVisitor {
+            tcx: self.tcx,
+            needle: hir::LifetimeName::Param(lifetime_def_id),
+            add_lt_suggs,
+            new_lt: &new_lt,
+        };
+        match self.tcx.hir().expect_owner(lifetime_scope) {
+            hir::OwnerNode::Item(i) => visitor.visit_item(i),
+            hir::OwnerNode::ForeignItem(i) => visitor.visit_foreign_item(i),
+            hir::OwnerNode::ImplItem(i) => visitor.visit_impl_item(i),
+            hir::OwnerNode::TraitItem(i) => visitor.visit_trait_item(i),
+            hir::OwnerNode::Crate(_) => bug!("OwnerNode::Crate doesn't not have generics"),
+        }
+
+        let ast_generics = self.tcx.hir().get_generics(lifetime_scope).unwrap();
+        let sugg = ast_generics
+            .span_for_lifetime_suggestion()
+            .map(|span| (span, format!("{new_lt}, ")))
+            .unwrap_or_else(|| (ast_generics.span, format!("<{new_lt}>")));
+        add_lt_suggs.push(sugg);
+
+        new_lt
+    }
+
     fn report_sub_sup_conflict(
         &self,
         var_origin: RegionVariableOrigin,
diff --git a/compiler/rustc_middle/src/ty/context.rs b/compiler/rustc_middle/src/ty/context.rs
index 83adbc3c790..1ccb81dcb9b 100644
--- a/compiler/rustc_middle/src/ty/context.rs
+++ b/compiler/rustc_middle/src/ty/context.rs
@@ -1057,16 +1057,21 @@ impl<'tcx> TyCtxt<'tcx> {
     }
 
     /// Returns the `DefId` and the `BoundRegionKind` corresponding to the given region.
-    pub fn is_suitable_region(self, region: Region<'tcx>) -> Option<FreeRegionInfo> {
-        let (suitable_region_binding_scope, bound_region) = match *region {
-            ty::ReFree(ref free_region) => {
-                (free_region.scope.expect_local(), free_region.bound_region)
+    pub fn is_suitable_region(self, mut region: Region<'tcx>) -> Option<FreeRegionInfo> {
+        let (suitable_region_binding_scope, bound_region) = loop {
+            let def_id = match region.kind() {
+                ty::ReFree(fr) => fr.bound_region.get_id()?.as_local()?,
+                ty::ReEarlyBound(ebr) => ebr.def_id.expect_local(),
+                _ => return None, // not a free region
+            };
+            let scope = self.local_parent(def_id);
+            if self.def_kind(scope) == DefKind::OpaqueTy {
+                // Lifetime params of opaque types are synthetic and thus irrelevant to
+                // diagnostics. Map them back to their origin!
+                region = self.map_rpit_lifetime_to_fn_lifetime(def_id);
+                continue;
             }
-            ty::ReEarlyBound(ref ebr) => (
-                self.local_parent(ebr.def_id.expect_local()),
-                ty::BoundRegionKind::BrNamed(ebr.def_id, ebr.name),
-            ),
-            _ => return None, // not a free region
+            break (scope, ty::BrNamed(def_id.into(), self.item_name(def_id.into())));
         };
 
         let is_impl_item = match self.hir().find_by_def_id(suitable_region_binding_scope) {
@@ -1074,7 +1079,7 @@ impl<'tcx> TyCtxt<'tcx> {
             Some(Node::ImplItem(..)) => {
                 self.is_bound_region_in_impl_item(suitable_region_binding_scope)
             }
-            _ => return None,
+            _ => false,
         };
 
         Some(FreeRegionInfo {
diff --git a/tests/ui/associated-inherent-types/regionck-1.stderr b/tests/ui/associated-inherent-types/regionck-1.stderr
index b17d89ca306..5899b1c3c9d 100644
--- a/tests/ui/associated-inherent-types/regionck-1.stderr
+++ b/tests/ui/associated-inherent-types/regionck-1.stderr
@@ -2,9 +2,12 @@ error[E0309]: the parameter type `T` may not live long enough
   --> $DIR/regionck-1.rs:9:30
    |
 LL |     type NoTyOutliv<'a, T> = &'a T;
-   |                              ^^^^^- help: consider adding a where clause: `where T: 'a`
-   |                              |
-   |                              ...so that the reference type `&'a T` does not outlive the data it points at
+   |                              ^^^^^ ...so that the reference type `&'a T` does not outlive the data it points at
+   |
+help: consider adding an explicit lifetime bound...
+   |
+LL |     type NoTyOutliv<'a, T: 'a> = &'a T;
+   |                          ++++
 
 error[E0491]: in type `&'a &'b ()`, reference has a longer lifetime than the data it references
   --> $DIR/regionck-1.rs:10:31
diff --git a/tests/ui/async-await/in-trait/async-generics-and-bounds.stderr b/tests/ui/async-await/in-trait/async-generics-and-bounds.stderr
index 90b40e221e4..3c450069d04 100644
--- a/tests/ui/async-await/in-trait/async-generics-and-bounds.stderr
+++ b/tests/ui/async-await/in-trait/async-generics-and-bounds.stderr
@@ -14,6 +14,10 @@ note: ...so that the reference type `&(T, U)` does not outlive the data it point
    |
 LL |     async fn foo(&self) -> &(T, U) where T: Debug + Sized, U: Hash;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+help: consider adding an explicit lifetime bound...
+   |
+LL |     async fn foo<'a>(&'a self) -> &'a (T, U) where T: Debug + Sized, U: Hash, U: 'a;
+   |                 ++++  ++           ++                                       +++++++
 
 error[E0311]: the parameter type `T` may not live long enough
   --> $DIR/async-generics-and-bounds.rs:12:5
@@ -31,6 +35,10 @@ note: ...so that the reference type `&(T, U)` does not outlive the data it point
    |
 LL |     async fn foo(&self) -> &(T, U) where T: Debug + Sized, U: Hash;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+help: consider adding an explicit lifetime bound...
+   |
+LL |     async fn foo<'a>(&'a self) -> &'a (T, U) where T: Debug + Sized, U: Hash, T: 'a;
+   |                 ++++  ++           ++                                       +++++++
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/async-await/in-trait/async-generics.stderr b/tests/ui/async-await/in-trait/async-generics.stderr
index 07f986e94e0..90a81164090 100644
--- a/tests/ui/async-await/in-trait/async-generics.stderr
+++ b/tests/ui/async-await/in-trait/async-generics.stderr
@@ -14,6 +14,10 @@ note: ...so that the reference type `&(T, U)` does not outlive the data it point
    |
 LL |     async fn foo(&self) -> &(T, U);
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+help: consider adding an explicit lifetime bound...
+   |
+LL |     async fn foo<'a>(&'a self) -> &'a (T, U) where U: 'a;
+   |                 ++++  ++           ++        +++++++++++
 
 error[E0311]: the parameter type `T` may not live long enough
   --> $DIR/async-generics.rs:9:5
@@ -31,6 +35,10 @@ note: ...so that the reference type `&(T, U)` does not outlive the data it point
    |
 LL |     async fn foo(&self) -> &(T, U);
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+help: consider adding an explicit lifetime bound...
+   |
+LL |     async fn foo<'a>(&'a self) -> &'a (T, U) where T: 'a;
+   |                 ++++  ++           ++        +++++++++++
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/error-codes/E0311.fixed b/tests/ui/error-codes/E0311.fixed
index 4410a4d707a..09ceecd0666 100644
--- a/tests/ui/error-codes/E0311.fixed
+++ b/tests/ui/error-codes/E0311.fixed
@@ -2,7 +2,7 @@
 
 #![allow(warnings)]
 
-fn no_restriction<'a, T: 'a>(x: &'a ()) -> &() {
+fn no_restriction<'a, T: 'a>(x: &'a ()) -> &'a () {
     with_restriction::<T>(x) //~ ERROR E0311
 }
 
diff --git a/tests/ui/error-codes/E0311.stderr b/tests/ui/error-codes/E0311.stderr
index b0e6dd1e272..de13a6148f3 100644
--- a/tests/ui/error-codes/E0311.stderr
+++ b/tests/ui/error-codes/E0311.stderr
@@ -16,8 +16,8 @@ LL |     with_restriction::<T>(x)
    |     ^^^^^^^^^^^^^^^^^^^^^
 help: consider adding an explicit lifetime bound...
    |
-LL | fn no_restriction<'a, T: 'a>(x: &'a ()) -> &() {
-   |                   +++  ++++      ++
+LL | fn no_restriction<'a, T: 'a>(x: &'a ()) -> &'a () {
+   |                   +++  ++++      ++         ++
 
 error: aborting due to previous error
 
diff --git a/tests/ui/generic-associated-types/issue-84931.stderr b/tests/ui/generic-associated-types/issue-84931.stderr
index fffea98a449..a78cd08636e 100644
--- a/tests/ui/generic-associated-types/issue-84931.stderr
+++ b/tests/ui/generic-associated-types/issue-84931.stderr
@@ -2,9 +2,12 @@ error[E0309]: the parameter type `T` may not live long enough
   --> $DIR/issue-84931.rs:14:21
    |
 LL |     type Item<'a> = &'a mut T;
-   |                     ^^^^^^^^^- help: consider adding a where clause: `where T: 'a`
-   |                     |
-   |                     ...so that the reference type `&'a mut T` does not outlive the data it points at
+   |                     ^^^^^^^^^ ...so that the reference type `&'a mut T` does not outlive the data it points at
+   |
+help: consider adding an explicit lifetime bound...
+   |
+LL |     type Item<'a> = &'a mut T where T: 'a;
+   |                               +++++++++++
 
 error: aborting due to previous error
 
diff --git a/tests/ui/lifetimes/lifetime-doesnt-live-long-enough.stderr b/tests/ui/lifetimes/lifetime-doesnt-live-long-enough.stderr
index affb4e8d044..af19bdad58c 100644
--- a/tests/ui/lifetimes/lifetime-doesnt-live-long-enough.stderr
+++ b/tests/ui/lifetimes/lifetime-doesnt-live-long-enough.stderr
@@ -17,8 +17,8 @@ LL |     fn generic_in_parent<'a, L: X<&'a Nested<K>>>() {
    |
 help: consider adding an explicit lifetime bound...
    |
-LL | impl<K: 'a> Nested<K> {
-   |       ++++
+LL |     fn generic_in_parent<'a, L: X<&'a Nested<K>>>() where K: 'a {
+   |                                                     +++++++++++
 
 error[E0309]: the parameter type `M` may not live long enough
   --> $DIR/lifetime-doesnt-live-long-enough.rs:44:36
@@ -39,17 +39,19 @@ LL |     fn foo<'a, L: X<&'a Nested<K>>>();
    |
 help: consider adding an explicit lifetime bound...
    |
-LL | trait X<K: 'a>: Sized {
-   |          ++++
+LL |     fn foo<'a, L: X<&'a Nested<K>>>() where K: 'a;
+   |                                       +++++++++++
 
 error[E0309]: the parameter type `Self` may not live long enough
   --> $DIR/lifetime-doesnt-live-long-enough.rs:28:19
    |
 LL |     fn bar<'a, L: X<&'a Nested<Self>>>();
-   |                   ^^^^^^^^^^^^^^^^^^^
+   |                   ^^^^^^^^^^^^^^^^^^^ ...so that the reference type `&'a Nested<Self>` does not outlive the data it points at
    |
-   = help: consider adding an explicit lifetime bound `Self: 'a`...
-   = note: ...so that the reference type `&'a Nested<Self>` does not outlive the data it points at
+help: consider adding an explicit lifetime bound...
+   |
+LL |     fn bar<'a, L: X<&'a Nested<Self>>>() where Self: 'a;
+   |                                          ++++++++++++++
 
 error[E0309]: the parameter type `L` may not live long enough
   --> $DIR/lifetime-doesnt-live-long-enough.rs:32:22
diff --git a/tests/ui/lifetimes/suggest-introducing-and-adding-missing-lifetime.fixed b/tests/ui/lifetimes/suggest-introducing-and-adding-missing-lifetime.fixed
index f977f0bd3a8..7c415490439 100644
--- a/tests/ui/lifetimes/suggest-introducing-and-adding-missing-lifetime.fixed
+++ b/tests/ui/lifetimes/suggest-introducing-and-adding-missing-lifetime.fixed
@@ -2,7 +2,7 @@
 
 #![allow(warnings)]
 
-fn no_restriction<'a, T: 'a>(x: &'a ()) -> &() {
+fn no_restriction<'a, T: 'a>(x: &'a ()) -> &'a () {
     with_restriction::<T>(x) //~ ERROR the parameter type `T` may not live long enough
 }
 
diff --git a/tests/ui/lifetimes/suggest-introducing-and-adding-missing-lifetime.stderr b/tests/ui/lifetimes/suggest-introducing-and-adding-missing-lifetime.stderr
index 2d58d3a02f3..b64f5147c0b 100644
--- a/tests/ui/lifetimes/suggest-introducing-and-adding-missing-lifetime.stderr
+++ b/tests/ui/lifetimes/suggest-introducing-and-adding-missing-lifetime.stderr
@@ -16,8 +16,8 @@ LL |     with_restriction::<T>(x)
    |     ^^^^^^^^^^^^^^^^^^^^^
 help: consider adding an explicit lifetime bound...
    |
-LL | fn no_restriction<'a, T: 'a>(x: &'a ()) -> &() {
-   |                   +++  ++++      ++
+LL | fn no_restriction<'a, T: 'a>(x: &'a ()) -> &'a () {
+   |                   +++  ++++      ++         ++
 
 error: aborting due to previous error
 
diff --git a/tests/ui/nll/ty-outlives/projection-no-regions-closure.stderr b/tests/ui/nll/ty-outlives/projection-no-regions-closure.stderr
index 433024c30bb..b7d9477e74d 100644
--- a/tests/ui/nll/ty-outlives/projection-no-regions-closure.stderr
+++ b/tests/ui/nll/ty-outlives/projection-no-regions-closure.stderr
@@ -26,10 +26,12 @@ error[E0309]: the associated type `<T as Iterator>::Item` may not live long enou
   --> $DIR/projection-no-regions-closure.rs:25:31
    |
 LL |     with_signature(x, |mut y| Box::new(y.next()))
-   |                               ^^^^^^^^^^^^^^^^^^
+   |                               ^^^^^^^^^^^^^^^^^^ ...so that the type `<T as Iterator>::Item` will meet its required lifetime bounds
    |
-   = help: consider adding an explicit lifetime bound `<T as Iterator>::Item: 'a`...
-   = note: ...so that the type `<T as Iterator>::Item` will meet its required lifetime bounds
+help: consider adding an explicit lifetime bound...
+   |
+LL |     T: Iterator, <T as Iterator>::Item: 'a
+   |                ~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 note: external requirements
   --> $DIR/projection-no-regions-closure.rs:34:23
@@ -83,10 +85,12 @@ error[E0309]: the associated type `<T as Iterator>::Item` may not live long enou
   --> $DIR/projection-no-regions-closure.rs:42:31
    |
 LL |     with_signature(x, |mut y| Box::new(y.next()))
-   |                               ^^^^^^^^^^^^^^^^^^
+   |                               ^^^^^^^^^^^^^^^^^^ ...so that the type `<T as Iterator>::Item` will meet its required lifetime bounds
+   |
+help: consider adding an explicit lifetime bound...
    |
-   = help: consider adding an explicit lifetime bound `<T as Iterator>::Item: 'a`...
-   = note: ...so that the type `<T as Iterator>::Item` will meet its required lifetime bounds
+LL |     T: 'b + Iterator, <T as Iterator>::Item: 'a
+   |                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 note: external requirements
   --> $DIR/projection-no-regions-closure.rs:52:23
diff --git a/tests/ui/nll/ty-outlives/projection-no-regions-fn.stderr b/tests/ui/nll/ty-outlives/projection-no-regions-fn.stderr
index e0ff544fe47..712fc74fce9 100644
--- a/tests/ui/nll/ty-outlives/projection-no-regions-fn.stderr
+++ b/tests/ui/nll/ty-outlives/projection-no-regions-fn.stderr
@@ -2,19 +2,23 @@ error[E0309]: the associated type `<T as Iterator>::Item` may not live long enou
   --> $DIR/projection-no-regions-fn.rs:13:5
    |
 LL |     Box::new(x.next())
-   |     ^^^^^^^^^^^^^^^^^^
+   |     ^^^^^^^^^^^^^^^^^^ ...so that the type `<T as Iterator>::Item` will meet its required lifetime bounds
    |
-   = help: consider adding an explicit lifetime bound `<T as Iterator>::Item: 'a`...
-   = note: ...so that the type `<T as Iterator>::Item` will meet its required lifetime bounds
+help: consider adding an explicit lifetime bound...
+   |
+LL |     T: Iterator, <T as Iterator>::Item: 'a
+   |                ~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error[E0309]: the associated type `<T as Iterator>::Item` may not live long enough
   --> $DIR/projection-no-regions-fn.rs:28:5
    |
 LL |     Box::new(x.next())
-   |     ^^^^^^^^^^^^^^^^^^
+   |     ^^^^^^^^^^^^^^^^^^ ...so that the type `<T as Iterator>::Item` will meet its required lifetime bounds
+   |
+help: consider adding an explicit lifetime bound...
    |
-   = help: consider adding an explicit lifetime bound `<T as Iterator>::Item: 'a`...
-   = note: ...so that the type `<T as Iterator>::Item` will meet its required lifetime bounds
+LL |     T: 'b + Iterator, <T as Iterator>::Item: 'a
+   |                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/regions/regions-close-associated-type-into-object.stderr b/tests/ui/regions/regions-close-associated-type-into-object.stderr
index f7dcaa9d97e..77bb66b222e 100644
--- a/tests/ui/regions/regions-close-associated-type-into-object.stderr
+++ b/tests/ui/regions/regions-close-associated-type-into-object.stderr
@@ -2,37 +2,45 @@ error[E0310]: the associated type `<T as Iter>::Item` may not live long enough
   --> $DIR/regions-close-associated-type-into-object.rs:15:5
    |
 LL |     Box::new(item)
-   |     ^^^^^^^^^^^^^^
+   |     ^^^^^^^^^^^^^^ ...so that the type `<T as Iter>::Item` will meet its required lifetime bounds
    |
-   = help: consider adding an explicit lifetime bound `<T as Iter>::Item: 'static`...
-   = note: ...so that the type `<T as Iter>::Item` will meet its required lifetime bounds
+help: consider adding an explicit lifetime bound...
+   |
+LL | fn bad1<T: Iter>(v: T) -> Box<dyn X + 'static> where <T as Iter>::Item: 'static
+   |                                                ++++++++++++++++++++++++++++++++
 
 error[E0310]: the associated type `<T as Iter>::Item` may not live long enough
   --> $DIR/regions-close-associated-type-into-object.rs:22:5
    |
 LL |     Box::new(item)
-   |     ^^^^^^^^^^^^^^
+   |     ^^^^^^^^^^^^^^ ...so that the type `<T as Iter>::Item` will meet its required lifetime bounds
+   |
+help: consider adding an explicit lifetime bound...
    |
-   = help: consider adding an explicit lifetime bound `<T as Iter>::Item: 'static`...
-   = note: ...so that the type `<T as Iter>::Item` will meet its required lifetime bounds
+LL |     where Box<T::Item> : X, <T as Iter>::Item: 'static
+   |                           ++++++++++++++++++++++++++++
 
 error[E0309]: the associated type `<T as Iter>::Item` may not live long enough
   --> $DIR/regions-close-associated-type-into-object.rs:28:5
    |
 LL |     Box::new(item)
-   |     ^^^^^^^^^^^^^^
+   |     ^^^^^^^^^^^^^^ ...so that the type `<T as Iter>::Item` will meet its required lifetime bounds
    |
-   = help: consider adding an explicit lifetime bound `<T as Iter>::Item: 'a`...
-   = note: ...so that the type `<T as Iter>::Item` will meet its required lifetime bounds
+help: consider adding an explicit lifetime bound...
+   |
+LL | fn bad3<'a, T: Iter>(v: T) -> Box<dyn X + 'a> where <T as Iter>::Item: 'a
+   |                                               +++++++++++++++++++++++++++
 
 error[E0309]: the associated type `<T as Iter>::Item` may not live long enough
   --> $DIR/regions-close-associated-type-into-object.rs:35:5
    |
 LL |     Box::new(item)
-   |     ^^^^^^^^^^^^^^
+   |     ^^^^^^^^^^^^^^ ...so that the type `<T as Iter>::Item` will meet its required lifetime bounds
+   |
+help: consider adding an explicit lifetime bound...
    |
-   = help: consider adding an explicit lifetime bound `<T as Iter>::Item: 'a`...
-   = note: ...so that the type `<T as Iter>::Item` will meet its required lifetime bounds
+LL |     where Box<T::Item> : X, <T as Iter>::Item: 'a
+   |                           +++++++++++++++++++++++
 
 error: aborting due to 4 previous errors
 
diff --git a/tests/ui/regions/regions-infer-bound-from-trait-self.stderr b/tests/ui/regions/regions-infer-bound-from-trait-self.stderr
index e88f79a3a8c..e61aa61b662 100644
--- a/tests/ui/regions/regions-infer-bound-from-trait-self.stderr
+++ b/tests/ui/regions/regions-infer-bound-from-trait-self.stderr
@@ -2,10 +2,12 @@ error[E0309]: the parameter type `Self` may not live long enough
   --> $DIR/regions-infer-bound-from-trait-self.rs:46:9
    |
 LL |         check_bound(x, self)
-   |         ^^^^^^^^^^^^^^^^^^^^
+   |         ^^^^^^^^^^^^^^^^^^^^ ...so that the type `Self` will meet its required lifetime bounds
    |
-   = help: consider adding an explicit lifetime bound `Self: 'a`...
-   = note: ...so that the type `Self` will meet its required lifetime bounds
+help: consider adding an explicit lifetime bound...
+   |
+LL | trait InheritsFromNothing<'a> : Sized where Self: 'a {
+   |                                       ++++++++++++++
 
 error: aborting due to previous error
 
diff --git a/tests/ui/suggestions/lifetimes/issue-105544.fixed b/tests/ui/suggestions/lifetimes/issue-105544.fixed
index 47087eb4749..ffd976b5fd2 100644
--- a/tests/ui/suggestions/lifetimes/issue-105544.fixed
+++ b/tests/ui/suggestions/lifetimes/issue-105544.fixed
@@ -2,7 +2,7 @@
 
 #![allow(warnings)]
 
-fn foo<'a>(d: impl Sized + 'a, p: &'a mut ()) -> impl Sized + '_ { //~ NOTE the parameter type `impl Sized` must be valid for the anonymous lifetime defined here...
+fn foo<'a>(d: impl Sized + 'a, p: &'a mut ()) -> impl Sized + 'a { //~ NOTE the parameter type `impl Sized` must be valid for the anonymous lifetime defined here...
 //~^ HELP consider adding an explicit lifetime bound
     (d, p)
     //~^ ERROR the parameter type `impl Sized` may not live long enough
@@ -15,14 +15,14 @@ fn foo1<'b>(d: impl Sized + 'b, p: &'b mut ()) -> impl Sized + '_ {
     //~^ ERROR the parameter type `impl Sized` may not live long enough
 }
 
-fn foo2<'b, 'a>(d: impl Sized + 'a + 'b, p: &'b mut ()) -> impl Sized + '_ { //~ NOTE the parameter type `impl Sized + 'a` must be valid for the anonymous lifetime defined here...
+fn foo2<'b, 'a>(d: impl Sized + 'a + 'b, p: &'b mut ()) -> impl Sized + 'b { //~ NOTE the parameter type `impl Sized + 'a` must be valid for the anonymous lifetime defined here...
 //~^ HELP consider adding an explicit lifetime bound
     (d, p)
     //~^ ERROR the parameter type `impl Sized + 'a` may not live long enough
     //~| NOTE ...so that the type `impl Sized + 'a` will meet its required lifetime bounds
 }
 
-fn bar<'a, T : Sized + 'a>(d: T, p: &'a mut ()) -> impl Sized + '_ { //~ NOTE the parameter type `T` must be valid for the anonymous lifetime defined here...
+fn bar<'a, T : Sized + 'a>(d: T, p: &'a  mut ()) -> impl Sized + 'a { //~ NOTE the parameter type `T` must be valid for the anonymous lifetime defined here...
 //~^ HELP consider adding an explicit lifetime bound
     (d, p)
     //~^ ERROR the parameter type `T` may not live long enough
@@ -35,7 +35,7 @@ fn bar1<'b, T : Sized + 'b>(d: T, p: &'b mut ()) -> impl Sized + '_ {
     //~^ ERROR the parameter type `T` may not live long enough
 }
 
-fn bar2<'b, 'a, T : Sized + 'a + 'b>(d: T, p: &'b mut ()) -> impl Sized + '_ { //~ NOTE the parameter type `T` must be valid for the anonymous lifetime defined here...
+fn bar2<'b, 'a, T : Sized + 'a + 'b>(d: T, p: &'b mut ()) -> impl Sized + 'b { //~ NOTE the parameter type `T` must be valid for the anonymous lifetime defined here...
 //~^ HELP consider adding an explicit lifetime bound
     (d, p)
     //~^ ERROR the parameter type `T` may not live long enough
diff --git a/tests/ui/suggestions/lifetimes/issue-105544.stderr b/tests/ui/suggestions/lifetimes/issue-105544.stderr
index 08fe21b11b5..7849ff0ff3f 100644
--- a/tests/ui/suggestions/lifetimes/issue-105544.stderr
+++ b/tests/ui/suggestions/lifetimes/issue-105544.stderr
@@ -16,8 +16,8 @@ LL |     (d, p)
    |     ^^^^^^
 help: consider adding an explicit lifetime bound...
    |
-LL | fn foo<'a>(d: impl Sized + 'a, p: &'a mut ()) -> impl Sized + '_ {
-   |       ++++               ++++      ++
+LL | fn foo<'a>(d: impl Sized + 'a, p: &'a mut ()) -> impl Sized + 'a {
+   |       ++++               ++++      ++                         ~~
 
 error[E0309]: the parameter type `impl Sized` may not live long enough
   --> $DIR/issue-105544.rs:14:5
@@ -48,8 +48,8 @@ LL |     (d, p)
    |     ^^^^^^
 help: consider adding an explicit lifetime bound...
    |
-LL | fn foo2<'b, 'a>(d: impl Sized + 'a + 'b, p: &'b mut ()) -> impl Sized + '_ {
-   |         +++                        ++++      ++
+LL | fn foo2<'b, 'a>(d: impl Sized + 'a + 'b, p: &'b mut ()) -> impl Sized + 'b {
+   |         +++                        ++++      ++                         ~~
 
 error[E0311]: the parameter type `T` may not live long enough
   --> $DIR/issue-105544.rs:27:5
@@ -69,8 +69,8 @@ LL |     (d, p)
    |     ^^^^^^
 help: consider adding an explicit lifetime bound...
    |
-LL | fn bar<'a, T : Sized + 'a>(d: T, p: &'a mut ()) -> impl Sized + '_ {
-   |        +++           ++++            ++
+LL | fn bar<'a, T : Sized + 'a>(d: T, p: &'a  mut ()) -> impl Sized + 'a {
+   |        +++           ++++            ++                          ~~
 
 error[E0309]: the parameter type `T` may not live long enough
   --> $DIR/issue-105544.rs:34:5
@@ -101,8 +101,8 @@ LL |     (d, p)
    |     ^^^^^^
 help: consider adding an explicit lifetime bound...
    |
-LL | fn bar2<'b, 'a, T : Sized + 'a + 'b>(d: T, p: &'b mut ()) -> impl Sized + '_ {
-   |         +++                    ++++            ++
+LL | fn bar2<'b, 'a, T : Sized + 'a + 'b>(d: T, p: &'b mut ()) -> impl Sized + 'b {
+   |         +++                    ++++            ++                         ~~
 
 error: aborting due to 6 previous errors
 
diff --git a/tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature-2.fixed b/tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature-2.fixed
index 4013d98c3cf..474986283fc 100644
--- a/tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature-2.fixed
+++ b/tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature-2.fixed
@@ -19,11 +19,16 @@ trait Test {
     fn test(&self);
 }
 
-fn func<'a, T: Test + 'a>(foo: &'a Foo<'a>, t: T) {
+fn func<'a, T: Test + 'a>(_dummy: &Foo, foo: &Foo<'a>, t: T) {
     foo.bar(move |_| {
     //~^ ERROR the parameter type `T` may not live long enough
         t.test();
     });
 }
 
+// Test that the suggested fix does not overconstrain `func`. See #115375.
+fn test_func<'a, T: Test + 'a>(dummy: &Foo, foo: &Foo<'a>, t: T) {
+    func(dummy, foo, t);
+}
+
 fn main() {}
diff --git a/tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature-2.rs b/tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature-2.rs
index 4096d95e5fd..99c8e9626af 100644
--- a/tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature-2.rs
+++ b/tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature-2.rs
@@ -19,11 +19,16 @@ trait Test {
     fn test(&self);
 }
 
-fn func<T: Test>(foo: &Foo, t: T) {
+fn func<T: Test>(_dummy: &Foo, foo: &Foo, t: T) {
     foo.bar(move |_| {
     //~^ ERROR the parameter type `T` may not live long enough
         t.test();
     });
 }
 
+// Test that the suggested fix does not overconstrain `func`. See #115375.
+fn test_func<'a, T: Test + 'a>(dummy: &Foo, foo: &Foo<'a>, t: T) {
+    func(dummy, foo, t);
+}
+
 fn main() {}
diff --git a/tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature-2.stderr b/tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature-2.stderr
index 936d87f7968..df4da491f04 100644
--- a/tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature-2.stderr
+++ b/tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature-2.stderr
@@ -8,10 +8,10 @@ LL | |     });
    | |______^
    |
 note: the parameter type `T` must be valid for the anonymous lifetime defined here...
-  --> $DIR/missing-lifetimes-in-signature-2.rs:22:24
+  --> $DIR/missing-lifetimes-in-signature-2.rs:22:38
    |
-LL | fn func<T: Test>(foo: &Foo, t: T) {
-   |                        ^^^
+LL | fn func<T: Test>(_dummy: &Foo, foo: &Foo, t: T) {
+   |                                      ^^^
 note: ...so that the type `T` will meet its required lifetime bounds
   --> $DIR/missing-lifetimes-in-signature-2.rs:23:5
    |
@@ -22,8 +22,8 @@ LL | |     });
    | |______^
 help: consider adding an explicit lifetime bound...
    |
-LL | fn func<'a, T: Test + 'a>(foo: &'a Foo<'a>, t: T) {
-   |         +++         ++++        ++    ++++
+LL | fn func<'a, T: Test + 'a>(_dummy: &Foo, foo: &Foo<'a>, t: T) {
+   |         +++         ++++                         ++++
 
 error: aborting due to previous error
 
diff --git a/tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature.stderr b/tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature.stderr
index 318ea4083d1..5f9a0881cdd 100644
--- a/tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature.stderr
+++ b/tests/ui/suggestions/lifetimes/missing-lifetimes-in-signature.stderr
@@ -49,7 +49,7 @@ LL | |     }
    | |_____^
 help: consider adding an explicit lifetime bound...
    |
-LL ~ fn bar<'a, G, T>(g: G, dest: &'a mut T) -> impl FnOnce() + '_
+LL ~ fn bar<'a, G, T>(g: G, dest: &'a mut T) -> impl FnOnce() + 'a
 LL | where
 LL ~     G: Get<T> + 'a,
    |
@@ -78,8 +78,8 @@ LL | |     }
    | |_____^
 help: consider adding an explicit lifetime bound...
    |
-LL | fn qux<'b, 'a, G: 'a + 'b, T>(g: G, dest: &'b mut T) -> impl FnOnce() + '_
-   |        +++           ++++                  ++
+LL | fn qux<'b, 'a, G: 'a + 'b, T>(g: G, dest: &'b mut T) -> impl FnOnce() + 'b
+   |        +++           ++++                  ++                           ~~
 
 error[E0311]: the parameter type `G` may not live long enough
   --> $DIR/missing-lifetimes-in-signature.rs:61:9
@@ -105,8 +105,8 @@ LL | |         }
    | |_________^
 help: consider adding an explicit lifetime bound...
    |
-LL |     fn qux<'c, 'b, G: Get<T> + 'b + 'c, T>(g: G, dest: &'c mut T) -> impl FnOnce() + '_ {
-   |            +++                    ++++                  ++
+LL |     fn qux<'c, 'b, G: Get<T> + 'b + 'c, T>(g: G, dest: &'c mut T) -> impl FnOnce() + 'c {
+   |            +++                    ++++                  ++                           ~~
 
 error[E0311]: the parameter type `G` may not live long enough
   --> $DIR/missing-lifetimes-in-signature.rs:73:5
@@ -134,8 +134,8 @@ LL | |     }
    | |_____^
 help: consider adding an explicit lifetime bound...
    |
-LL | fn bat<'b, 'a, G: 'a + 'b, T>(g: G, dest: &'b mut T) -> impl FnOnce() + '_ + 'a
-   |        +++           ++++                  ++
+LL | fn bat<'b, 'a, G: 'a + 'b, T>(g: G, dest: &'b mut T) -> impl FnOnce() + 'b + 'a
+   |        +++           ++++                  ++                           ~~
 
 error[E0621]: explicit lifetime required in the type of `dest`
   --> $DIR/missing-lifetimes-in-signature.rs:73:5
diff --git a/tests/ui/suggestions/lifetimes/type-param-bound-scope.fixed b/tests/ui/suggestions/lifetimes/type-param-bound-scope.fixed
new file mode 100644
index 00000000000..470cc67b973
--- /dev/null
+++ b/tests/ui/suggestions/lifetimes/type-param-bound-scope.fixed
@@ -0,0 +1,47 @@
+// Make sure we suggest the bound `T: 'a` in the correct scope:
+// trait, impl or associated fn.
+// run-rustfix
+
+struct Inv<'a>(Option<*mut &'a u8>);
+
+fn check_bound<'a, A: 'a>(_: A, _: Inv<'a>) {}
+
+trait Trait1<'a>: Sized where Self: 'a {
+    fn foo(self, lt: Inv<'a>) {
+        check_bound(self, lt)
+        //~^ ERROR parameter type `Self` may not live long enough
+    }
+}
+
+trait Trait2: Sized {
+    fn foo<'a>(self, lt: Inv<'a>) where Self: 'a {
+        check_bound(self, lt)
+        //~^ ERROR parameter type `Self` may not live long enough
+    }
+}
+
+trait Trait3<T> {
+    fn foo<'a>(arg: T, lt: Inv<'a>) where T: 'a {
+        check_bound(arg, lt)
+        //~^ ERROR parameter type `T` may not live long enough
+    }
+}
+
+trait Trait4<'a> {
+    fn foo<T: 'a>(arg: T, lt: Inv<'a>) {
+        check_bound(arg, lt)
+        //~^ ERROR parameter type `T` may not live long enough
+    }
+}
+
+trait Trait5<'a> {
+    fn foo(self, _: Inv<'a>);
+}
+impl<'a, T: 'a> Trait5<'a> for T {
+    fn foo(self, lt: Inv<'a>) {
+        check_bound(self, lt);
+        //~^ ERROR parameter type `T` may not live long enough
+    }
+}
+
+fn main() {}
diff --git a/tests/ui/suggestions/lifetimes/type-param-bound-scope.rs b/tests/ui/suggestions/lifetimes/type-param-bound-scope.rs
new file mode 100644
index 00000000000..874788e13ef
--- /dev/null
+++ b/tests/ui/suggestions/lifetimes/type-param-bound-scope.rs
@@ -0,0 +1,47 @@
+// Make sure we suggest the bound `T: 'a` in the correct scope:
+// trait, impl or associated fn.
+// run-rustfix
+
+struct Inv<'a>(Option<*mut &'a u8>);
+
+fn check_bound<'a, A: 'a>(_: A, _: Inv<'a>) {}
+
+trait Trait1<'a>: Sized {
+    fn foo(self, lt: Inv<'a>) {
+        check_bound(self, lt)
+        //~^ ERROR parameter type `Self` may not live long enough
+    }
+}
+
+trait Trait2: Sized {
+    fn foo<'a>(self, lt: Inv<'a>) {
+        check_bound(self, lt)
+        //~^ ERROR parameter type `Self` may not live long enough
+    }
+}
+
+trait Trait3<T> {
+    fn foo<'a>(arg: T, lt: Inv<'a>) {
+        check_bound(arg, lt)
+        //~^ ERROR parameter type `T` may not live long enough
+    }
+}
+
+trait Trait4<'a> {
+    fn foo<T>(arg: T, lt: Inv<'a>) {
+        check_bound(arg, lt)
+        //~^ ERROR parameter type `T` may not live long enough
+    }
+}
+
+trait Trait5<'a> {
+    fn foo(self, _: Inv<'a>);
+}
+impl<'a, T> Trait5<'a> for T {
+    fn foo(self, lt: Inv<'a>) {
+        check_bound(self, lt);
+        //~^ ERROR parameter type `T` may not live long enough
+    }
+}
+
+fn main() {}
diff --git a/tests/ui/suggestions/lifetimes/type-param-bound-scope.stderr b/tests/ui/suggestions/lifetimes/type-param-bound-scope.stderr
new file mode 100644
index 00000000000..c9c963df5ee
--- /dev/null
+++ b/tests/ui/suggestions/lifetimes/type-param-bound-scope.stderr
@@ -0,0 +1,58 @@
+error[E0309]: the parameter type `Self` may not live long enough
+  --> $DIR/type-param-bound-scope.rs:11:9
+   |
+LL |         check_bound(self, lt)
+   |         ^^^^^^^^^^^^^^^^^^^^^ ...so that the type `Self` will meet its required lifetime bounds
+   |
+help: consider adding an explicit lifetime bound...
+   |
+LL | trait Trait1<'a>: Sized where Self: 'a {
+   |                         ++++++++++++++
+
+error[E0309]: the parameter type `Self` may not live long enough
+  --> $DIR/type-param-bound-scope.rs:18:9
+   |
+LL |         check_bound(self, lt)
+   |         ^^^^^^^^^^^^^^^^^^^^^ ...so that the type `Self` will meet its required lifetime bounds
+   |
+help: consider adding an explicit lifetime bound...
+   |
+LL |     fn foo<'a>(self, lt: Inv<'a>) where Self: 'a {
+   |                                   ++++++++++++++
+
+error[E0309]: the parameter type `T` may not live long enough
+  --> $DIR/type-param-bound-scope.rs:25:9
+   |
+LL |         check_bound(arg, lt)
+   |         ^^^^^^^^^^^^^^^^^^^^ ...so that the type `T` will meet its required lifetime bounds
+   |
+help: consider adding an explicit lifetime bound...
+   |
+LL |     fn foo<'a>(arg: T, lt: Inv<'a>) where T: 'a {
+   |                                     +++++++++++
+
+error[E0309]: the parameter type `T` may not live long enough
+  --> $DIR/type-param-bound-scope.rs:32:9
+   |
+LL |         check_bound(arg, lt)
+   |         ^^^^^^^^^^^^^^^^^^^^ ...so that the type `T` will meet its required lifetime bounds
+   |
+help: consider adding an explicit lifetime bound...
+   |
+LL |     fn foo<T: 'a>(arg: T, lt: Inv<'a>) {
+   |             ++++
+
+error[E0309]: the parameter type `T` may not live long enough
+  --> $DIR/type-param-bound-scope.rs:42:9
+   |
+LL |         check_bound(self, lt);
+   |         ^^^^^^^^^^^^^^^^^^^^^ ...so that the type `T` will meet its required lifetime bounds
+   |
+help: consider adding an explicit lifetime bound...
+   |
+LL | impl<'a, T: 'a> Trait5<'a> for T {
+   |           ++++
+
+error: aborting due to 5 previous errors
+
+For more information about this error, try `rustc --explain E0309`.
diff --git a/tests/ui/suggestions/lifetimes/type-param-missing-lifetime.fixed b/tests/ui/suggestions/lifetimes/type-param-missing-lifetime.fixed
new file mode 100644
index 00000000000..e30c556457e
--- /dev/null
+++ b/tests/ui/suggestions/lifetimes/type-param-missing-lifetime.fixed
@@ -0,0 +1,52 @@
+// We want to suggest a bound `T: 'a` but `'a` is elided,
+// run-rustfix
+// edition: 2018
+#![allow(dead_code)]
+
+struct Inv<'a>(Option<*mut &'a u8>);
+
+fn check_bound<'a, A: 'a>(_: A, _: Inv<'a>) {}
+
+struct Elided<'a, T = ()>(Inv<'a>, T);
+
+struct MyTy<X>(X);
+
+impl<'a, X> MyTy<Elided<'a, X>> {
+    async fn foo<A: 'a>(self, arg: A, _: &str) -> &str {
+        check_bound(arg, self.0 .0);
+        //~^ ERROR parameter type `A` may not live long enough
+        ""
+    }
+}
+
+// Make sure the new lifetime name doesn't conflict with
+// other early- or late-bound lifetimes in-scope.
+impl<'a, A> MyTy<(A, &'a ())> {
+    async fn foo2<'b>(
+        arg: A,
+        lt: Inv<'b>,
+    ) -> (
+        impl Into<&'b str> + Into<&'b str> + 'b,
+        impl Into<Option<Elided<'b>>> + 'b,
+        impl Into<Option<Elided<'b, ()>>>,
+    ) where A: 'b {
+        check_bound(arg, lt);
+        //~^ ERROR parameter type `A` may not live long enough
+        ("", None, None)
+    }
+
+    // same as above but there is a late-bound lifetime named `'b`.
+    async fn bar2<'c, 'b>(_dummy: &'a u8, arg: A, lt: Inv<'c>) where A: 'c {
+        check_bound(arg, lt);
+        //~^ ERROR parameter type `A` may not live long enough
+    }
+}
+
+impl<'a, A: 'a> MyTy<Elided<'a, A>> {
+    async fn foo3(self) {
+        check_bound(self.0 .1, self.0 .0);
+        //~^ ERROR parameter type `A` may not live long enough
+    }
+}
+
+fn main() {}
diff --git a/tests/ui/suggestions/lifetimes/type-param-missing-lifetime.rs b/tests/ui/suggestions/lifetimes/type-param-missing-lifetime.rs
new file mode 100644
index 00000000000..85f08808b73
--- /dev/null
+++ b/tests/ui/suggestions/lifetimes/type-param-missing-lifetime.rs
@@ -0,0 +1,52 @@
+// We want to suggest a bound `T: 'a` but `'a` is elided,
+// run-rustfix
+// edition: 2018
+#![allow(dead_code)]
+
+struct Inv<'a>(Option<*mut &'a u8>);
+
+fn check_bound<'a, A: 'a>(_: A, _: Inv<'a>) {}
+
+struct Elided<'a, T = ()>(Inv<'a>, T);
+
+struct MyTy<X>(X);
+
+impl<X> MyTy<Elided<'_, X>> {
+    async fn foo<A>(self, arg: A, _: &str) -> &str {
+        check_bound(arg, self.0 .0);
+        //~^ ERROR parameter type `A` may not live long enough
+        ""
+    }
+}
+
+// Make sure the new lifetime name doesn't conflict with
+// other early- or late-bound lifetimes in-scope.
+impl<'a, A> MyTy<(A, &'a ())> {
+    async fn foo2(
+        arg: A,
+        lt: Inv<'_>,
+    ) -> (
+        impl Into<&str> + Into<&'_ str> + '_,
+        impl Into<Option<Elided>> + '_,
+        impl Into<Option<Elided<()>>>,
+    ) {
+        check_bound(arg, lt);
+        //~^ ERROR parameter type `A` may not live long enough
+        ("", None, None)
+    }
+
+    // same as above but there is a late-bound lifetime named `'b`.
+    async fn bar2<'b>(_dummy: &'a u8, arg: A, lt: Inv<'_>) {
+        check_bound(arg, lt);
+        //~^ ERROR parameter type `A` may not live long enough
+    }
+}
+
+impl<A> MyTy<Elided<'_, A>> {
+    async fn foo3(self) {
+        check_bound(self.0 .1, self.0 .0);
+        //~^ ERROR parameter type `A` may not live long enough
+    }
+}
+
+fn main() {}
diff --git a/tests/ui/suggestions/lifetimes/type-param-missing-lifetime.stderr b/tests/ui/suggestions/lifetimes/type-param-missing-lifetime.stderr
new file mode 100644
index 00000000000..ed062d38f76
--- /dev/null
+++ b/tests/ui/suggestions/lifetimes/type-param-missing-lifetime.stderr
@@ -0,0 +1,95 @@
+error[E0311]: the parameter type `A` may not live long enough
+  --> $DIR/type-param-missing-lifetime.rs:16:9
+   |
+LL |         check_bound(arg, self.0 .0);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+note: the parameter type `A` must be valid for the anonymous lifetime as defined here...
+  --> $DIR/type-param-missing-lifetime.rs:14:21
+   |
+LL | impl<X> MyTy<Elided<'_, X>> {
+   |                     ^^
+note: ...so that the type `A` will meet its required lifetime bounds
+  --> $DIR/type-param-missing-lifetime.rs:16:9
+   |
+LL |         check_bound(arg, self.0 .0);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+help: consider adding an explicit lifetime bound...
+   |
+LL ~ impl<'a, X> MyTy<Elided<'a, X>> {
+LL ~     async fn foo<A: 'a>(self, arg: A, _: &str) -> &str {
+   |
+
+error[E0311]: the parameter type `A` may not live long enough
+  --> $DIR/type-param-missing-lifetime.rs:33:9
+   |
+LL |         check_bound(arg, lt);
+   |         ^^^^^^^^^^^^^^^^^^^^
+   |
+note: the parameter type `A` must be valid for the anonymous lifetime defined here...
+  --> $DIR/type-param-missing-lifetime.rs:27:13
+   |
+LL |         lt: Inv<'_>,
+   |             ^^^^^^^
+note: ...so that the type `A` will meet its required lifetime bounds
+  --> $DIR/type-param-missing-lifetime.rs:33:9
+   |
+LL |         check_bound(arg, lt);
+   |         ^^^^^^^^^^^^^^^^^^^^
+help: consider adding an explicit lifetime bound...
+   |
+LL ~     async fn foo2<'b>(
+LL |         arg: A,
+LL ~         lt: Inv<'b>,
+LL |     ) -> (
+LL ~         impl Into<&'b str> + Into<&'b str> + 'b,
+LL ~         impl Into<Option<Elided<'b>>> + 'b,
+LL ~         impl Into<Option<Elided<'b, ()>>>,
+LL ~     ) where A: 'b {
+   |
+
+error[E0311]: the parameter type `A` may not live long enough
+  --> $DIR/type-param-missing-lifetime.rs:40:9
+   |
+LL |         check_bound(arg, lt);
+   |         ^^^^^^^^^^^^^^^^^^^^
+   |
+note: the parameter type `A` must be valid for the anonymous lifetime defined here...
+  --> $DIR/type-param-missing-lifetime.rs:39:51
+   |
+LL |     async fn bar2<'b>(_dummy: &'a u8, arg: A, lt: Inv<'_>) {
+   |                                                   ^^^^^^^
+note: ...so that the type `A` will meet its required lifetime bounds
+  --> $DIR/type-param-missing-lifetime.rs:40:9
+   |
+LL |         check_bound(arg, lt);
+   |         ^^^^^^^^^^^^^^^^^^^^
+help: consider adding an explicit lifetime bound...
+   |
+LL |     async fn bar2<'c, 'b>(_dummy: &'a u8, arg: A, lt: Inv<'c>) where A: 'c {
+   |                   +++                                     ~~   +++++++++++
+
+error[E0311]: the parameter type `A` may not live long enough
+  --> $DIR/type-param-missing-lifetime.rs:47:9
+   |
+LL |         check_bound(self.0 .1, self.0 .0);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+note: the parameter type `A` must be valid for the anonymous lifetime as defined here...
+  --> $DIR/type-param-missing-lifetime.rs:45:21
+   |
+LL | impl<A> MyTy<Elided<'_, A>> {
+   |                     ^^
+note: ...so that the type `A` will meet its required lifetime bounds
+  --> $DIR/type-param-missing-lifetime.rs:47:9
+   |
+LL |         check_bound(self.0 .1, self.0 .0);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+help: consider adding an explicit lifetime bound...
+   |
+LL | impl<'a, A: 'a> MyTy<Elided<'a, A>> {
+   |      +++  ++++              ~~
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0311`.
diff --git a/tests/ui/wf/wf-trait-associated-type-region.stderr b/tests/ui/wf/wf-trait-associated-type-region.stderr
index 6e2cc8aba4b..2411b21953c 100644
--- a/tests/ui/wf/wf-trait-associated-type-region.stderr
+++ b/tests/ui/wf/wf-trait-associated-type-region.stderr
@@ -2,10 +2,12 @@ error[E0309]: the associated type `<Self as SomeTrait<'a>>::Type1` may not live
   --> $DIR/wf-trait-associated-type-region.rs:9:18
    |
 LL |     type Type2 = &'a Self::Type1;
-   |                  ^^^^^^^^^^^^^^^
+   |                  ^^^^^^^^^^^^^^^ ...so that the reference type `&'a <Self as SomeTrait<'a>>::Type1` does not outlive the data it points at
    |
-   = help: consider adding an explicit lifetime bound `<Self as SomeTrait<'a>>::Type1: 'a`...
-   = note: ...so that the reference type `&'a <Self as SomeTrait<'a>>::Type1` does not outlive the data it points at
+help: consider adding an explicit lifetime bound...
+   |
+LL |     type Type2 = &'a Self::Type1 where <Self as SomeTrait<'a>>::Type1: 'a;
+   |                                  ++++++++++++++++++++++++++++++++++++++++
 
 error: aborting due to previous error