diff --git a/compiler/rustc_hir_analysis/src/collect.rs b/compiler/rustc_hir_analysis/src/collect.rs
index 9b7826a5b2dc4..632ab3120d091 100644
--- a/compiler/rustc_hir_analysis/src/collect.rs
+++ b/compiler/rustc_hir_analysis/src/collect.rs
@@ -18,7 +18,9 @@ use rustc_ast::Recovered;
 use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::{FxHashSet, FxIndexMap};
 use rustc_data_structures::unord::UnordMap;
-use rustc_errors::{struct_span_code_err, Applicability, Diag, ErrorGuaranteed, StashKey, E0228};
+use rustc_errors::{
+    struct_span_code_err, Applicability, Diag, DiagCtxtHandle, ErrorGuaranteed, StashKey, E0228,
+};
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::intravisit::{self, walk_generics, Visitor};
@@ -161,7 +163,7 @@ pub struct CollectItemTypesVisitor<'tcx> {
 /// and suggest adding type parameters in the appropriate place, taking into consideration any and
 /// all already existing generic type parameters to avoid suggesting a name that is already in use.
 pub(crate) fn placeholder_type_error<'tcx>(
-    tcx: TyCtxt<'tcx>,
+    cx: &dyn HirTyLowerer<'tcx>,
     generics: Option<&hir::Generics<'_>>,
     placeholder_types: Vec<Span>,
     suggest: bool,
@@ -172,21 +174,21 @@ pub(crate) fn placeholder_type_error<'tcx>(
         return;
     }
 
-    placeholder_type_error_diag(tcx, generics, placeholder_types, vec![], suggest, hir_ty, kind)
+    placeholder_type_error_diag(cx, generics, placeholder_types, vec![], suggest, hir_ty, kind)
         .emit();
 }
 
-pub(crate) fn placeholder_type_error_diag<'tcx>(
-    tcx: TyCtxt<'tcx>,
+pub(crate) fn placeholder_type_error_diag<'cx, 'tcx>(
+    cx: &'cx dyn HirTyLowerer<'tcx>,
     generics: Option<&hir::Generics<'_>>,
     placeholder_types: Vec<Span>,
     additional_spans: Vec<Span>,
     suggest: bool,
     hir_ty: Option<&hir::Ty<'_>>,
     kind: &'static str,
-) -> Diag<'tcx> {
+) -> Diag<'cx> {
     if placeholder_types.is_empty() {
-        return bad_placeholder(tcx, additional_spans, kind);
+        return bad_placeholder(cx, additional_spans, kind);
     }
 
     let params = generics.map(|g| g.params).unwrap_or_default();
@@ -210,7 +212,7 @@ pub(crate) fn placeholder_type_error_diag<'tcx>(
     }
 
     let mut err =
-        bad_placeholder(tcx, placeholder_types.into_iter().chain(additional_spans).collect(), kind);
+        bad_placeholder(cx, placeholder_types.into_iter().chain(additional_spans).collect(), kind);
 
     // Suggest, but only if it is not a function in const or static
     if suggest {
@@ -224,7 +226,7 @@ pub(crate) fn placeholder_type_error_diag<'tcx>(
 
             // Check if parent is const or static
             is_const_or_static = matches!(
-                tcx.parent_hir_node(hir_ty.hir_id),
+                cx.tcx().parent_hir_node(hir_ty.hir_id),
                 Node::Item(&hir::Item {
                     kind: hir::ItemKind::Const(..) | hir::ItemKind::Static(..),
                     ..
@@ -267,7 +269,16 @@ fn reject_placeholder_type_signatures_in_item<'tcx>(
     let mut visitor = HirPlaceholderCollector::default();
     visitor.visit_item(item);
 
-    placeholder_type_error(tcx, Some(generics), visitor.0, suggest, None, item.kind.descr());
+    let icx = ItemCtxt::new(tcx, item.owner_id.def_id);
+
+    placeholder_type_error(
+        icx.lowerer(),
+        Some(generics),
+        visitor.0,
+        suggest,
+        None,
+        item.kind.descr(),
+    );
 }
 
 impl<'tcx> Visitor<'tcx> for CollectItemTypesVisitor<'tcx> {
@@ -329,15 +340,15 @@ impl<'tcx> Visitor<'tcx> for CollectItemTypesVisitor<'tcx> {
 ///////////////////////////////////////////////////////////////////////////
 // Utility types and common code for the above passes.
 
-fn bad_placeholder<'tcx>(
-    tcx: TyCtxt<'tcx>,
+fn bad_placeholder<'cx, 'tcx>(
+    cx: &'cx dyn HirTyLowerer<'tcx>,
     mut spans: Vec<Span>,
     kind: &'static str,
-) -> Diag<'tcx> {
+) -> Diag<'cx> {
     let kind = if kind.ends_with('s') { format!("{kind}es") } else { format!("{kind}s") };
 
     spans.sort();
-    tcx.dcx().create_err(errors::PlaceholderNotAllowedItemSignatures { spans, kind })
+    cx.dcx().create_err(errors::PlaceholderNotAllowedItemSignatures { spans, kind })
 }
 
 impl<'tcx> ItemCtxt<'tcx> {
@@ -370,6 +381,10 @@ impl<'tcx> HirTyLowerer<'tcx> for ItemCtxt<'tcx> {
         self.tcx
     }
 
+    fn dcx(&self) -> DiagCtxtHandle<'_> {
+        self.tcx.dcx().taintable_handle(&self.tainted_by_errors)
+    }
+
     fn item_def_id(&self) -> LocalDefId {
         self.item_def_id
     }
@@ -377,14 +392,13 @@ impl<'tcx> HirTyLowerer<'tcx> for ItemCtxt<'tcx> {
     fn re_infer(&self, span: Span, reason: RegionInferReason<'_>) -> ty::Region<'tcx> {
         if let RegionInferReason::BorrowedObjectLifetimeDefault = reason {
             let e = struct_span_code_err!(
-                self.tcx().dcx(),
+                self.dcx(),
                 span,
                 E0228,
                 "the lifetime bound for this object type cannot be deduced \
                 from context; please supply an explicit bound"
             )
             .emit();
-            self.set_tainted_by_errors(e);
             ty::Region::new_error(self.tcx(), e)
         } else {
             // This indicates an illegal lifetime in a non-assoc-trait position
@@ -509,10 +523,6 @@ impl<'tcx> HirTyLowerer<'tcx> for ItemCtxt<'tcx> {
         None
     }
 
-    fn set_tainted_by_errors(&self, err: ErrorGuaranteed) {
-        self.tainted_by_errors.set(Some(err));
-    }
-
     fn lower_fn_sig(
         &self,
         decl: &hir::FnDecl<'tcx>,
@@ -570,7 +580,7 @@ impl<'tcx> HirTyLowerer<'tcx> for ItemCtxt<'tcx> {
             // `ident_span` to not emit an error twice when we have `fn foo(_: fn() -> _)`.
 
             let mut diag = crate::collect::placeholder_type_error_diag(
-                tcx,
+                self,
                 generics,
                 visitor.0,
                 infer_replacements.iter().map(|(s, _)| *s).collect(),
@@ -590,7 +600,7 @@ impl<'tcx> HirTyLowerer<'tcx> for ItemCtxt<'tcx> {
                 );
             }
 
-            self.set_tainted_by_errors(diag.emit());
+            diag.emit();
         }
 
         (input_tys, output_ty)
@@ -639,6 +649,7 @@ fn lower_item(tcx: TyCtxt<'_>, item_id: hir::ItemId) {
     let it = tcx.hir().item(item_id);
     debug!(item = %it.ident, id = %it.hir_id());
     let def_id = item_id.owner_id.def_id;
+    let icx = ItemCtxt::new(tcx, def_id);
 
     match &it.kind {
         // These don't define types.
@@ -663,7 +674,7 @@ fn lower_item(tcx: TyCtxt<'_>, item_id: hir::ItemId) {
                         let mut visitor = HirPlaceholderCollector::default();
                         visitor.visit_foreign_item(item);
                         placeholder_type_error(
-                            tcx,
+                            icx.lowerer(),
                             None,
                             visitor.0,
                             false,
@@ -742,7 +753,14 @@ fn lower_item(tcx: TyCtxt<'_>, item_id: hir::ItemId) {
             if !ty.is_suggestable_infer_ty() {
                 let mut visitor = HirPlaceholderCollector::default();
                 visitor.visit_item(it);
-                placeholder_type_error(tcx, None, visitor.0, false, None, it.kind.descr());
+                placeholder_type_error(
+                    icx.lowerer(),
+                    None,
+                    visitor.0,
+                    false,
+                    None,
+                    it.kind.descr(),
+                );
             }
         }
 
@@ -760,6 +778,7 @@ fn lower_trait_item(tcx: TyCtxt<'_>, trait_item_id: hir::TraitItemId) {
     let trait_item = tcx.hir().trait_item(trait_item_id);
     let def_id = trait_item_id.owner_id;
     tcx.ensure().generics_of(def_id);
+    let icx = ItemCtxt::new(tcx, def_id.def_id);
 
     match trait_item.kind {
         hir::TraitItemKind::Fn(..) => {
@@ -776,7 +795,14 @@ fn lower_trait_item(tcx: TyCtxt<'_>, trait_item_id: hir::TraitItemId) {
                 // Account for `const C: _;`.
                 let mut visitor = HirPlaceholderCollector::default();
                 visitor.visit_trait_item(trait_item);
-                placeholder_type_error(tcx, None, visitor.0, false, None, "associated constant");
+                placeholder_type_error(
+                    icx.lowerer(),
+                    None,
+                    visitor.0,
+                    false,
+                    None,
+                    "associated constant",
+                );
             }
         }
 
@@ -787,7 +813,7 @@ fn lower_trait_item(tcx: TyCtxt<'_>, trait_item_id: hir::TraitItemId) {
             // Account for `type T = _;`.
             let mut visitor = HirPlaceholderCollector::default();
             visitor.visit_trait_item(trait_item);
-            placeholder_type_error(tcx, None, visitor.0, false, None, "associated type");
+            placeholder_type_error(icx.lowerer(), None, visitor.0, false, None, "associated type");
         }
 
         hir::TraitItemKind::Type(_, None) => {
@@ -798,7 +824,7 @@ fn lower_trait_item(tcx: TyCtxt<'_>, trait_item_id: hir::TraitItemId) {
             let mut visitor = HirPlaceholderCollector::default();
             visitor.visit_trait_item(trait_item);
 
-            placeholder_type_error(tcx, None, visitor.0, false, None, "associated type");
+            placeholder_type_error(icx.lowerer(), None, visitor.0, false, None, "associated type");
         }
     };
 
@@ -811,6 +837,7 @@ fn lower_impl_item(tcx: TyCtxt<'_>, impl_item_id: hir::ImplItemId) {
     tcx.ensure().type_of(def_id);
     tcx.ensure().predicates_of(def_id);
     let impl_item = tcx.hir().impl_item(impl_item_id);
+    let icx = ItemCtxt::new(tcx, def_id.def_id);
     match impl_item.kind {
         hir::ImplItemKind::Fn(..) => {
             tcx.ensure().codegen_fn_attrs(def_id);
@@ -821,14 +848,21 @@ fn lower_impl_item(tcx: TyCtxt<'_>, impl_item_id: hir::ImplItemId) {
             let mut visitor = HirPlaceholderCollector::default();
             visitor.visit_impl_item(impl_item);
 
-            placeholder_type_error(tcx, None, visitor.0, false, None, "associated type");
+            placeholder_type_error(icx.lowerer(), None, visitor.0, false, None, "associated type");
         }
         hir::ImplItemKind::Const(ty, _) => {
             // Account for `const T: _ = ..;`
             if !ty.is_suggestable_infer_ty() {
                 let mut visitor = HirPlaceholderCollector::default();
                 visitor.visit_impl_item(impl_item);
-                placeholder_type_error(tcx, None, visitor.0, false, None, "associated constant");
+                placeholder_type_error(
+                    icx.lowerer(),
+                    None,
+                    visitor.0,
+                    false,
+                    None,
+                    "associated constant",
+                );
             }
         }
     }
@@ -1385,7 +1419,7 @@ fn fn_sig(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::EarlyBinder<'_, ty::PolyFn
             ..
         })
         | Item(hir::Item { kind: ItemKind::Fn(sig, generics, _), .. }) => {
-            infer_return_ty_for_fn_sig(tcx, sig, generics, def_id, &icx)
+            infer_return_ty_for_fn_sig(sig, generics, def_id, &icx)
         }
 
         ImplItem(hir::ImplItem { kind: ImplItemKind::Fn(sig, _), generics, .. }) => {
@@ -1402,7 +1436,7 @@ fn fn_sig(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::EarlyBinder<'_, ty::PolyFn
                     None,
                 )
             } else {
-                infer_return_ty_for_fn_sig(tcx, sig, generics, def_id, &icx)
+                infer_return_ty_for_fn_sig(sig, generics, def_id, &icx)
             }
         }
 
@@ -1455,12 +1489,12 @@ fn fn_sig(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::EarlyBinder<'_, ty::PolyFn
 }
 
 fn infer_return_ty_for_fn_sig<'tcx>(
-    tcx: TyCtxt<'tcx>,
     sig: &hir::FnSig<'tcx>,
     generics: &hir::Generics<'_>,
     def_id: LocalDefId,
     icx: &ItemCtxt<'tcx>,
 ) -> ty::PolyFnSig<'tcx> {
+    let tcx = icx.tcx;
     let hir_id = tcx.local_def_id_to_hir_id(def_id);
 
     match sig.decl.output.get_infer_ret_ty() {
@@ -1492,7 +1526,7 @@ fn infer_return_ty_for_fn_sig<'tcx>(
             let mut visitor = HirPlaceholderCollector::default();
             visitor.visit_ty(ty);
 
-            let mut diag = bad_placeholder(tcx, visitor.0, "return type");
+            let mut diag = bad_placeholder(icx.lowerer(), visitor.0, "return type");
             let ret_ty = fn_sig.output();
             // Don't leak types into signatures unless they're nameable!
             // For example, if a function returns itself, we don't want that
diff --git a/compiler/rustc_hir_analysis/src/collect/type_of.rs b/compiler/rustc_hir_analysis/src/collect/type_of.rs
index 1e2b0c4323385..974dd415f464c 100644
--- a/compiler/rustc_hir_analysis/src/collect/type_of.rs
+++ b/compiler/rustc_hir_analysis/src/collect/type_of.rs
@@ -12,6 +12,7 @@ use rustc_span::symbol::Ident;
 use rustc_span::{Span, DUMMY_SP};
 
 use crate::errors::TypeofReservedKeywordUsed;
+use crate::hir_ty_lowering::HirTyLowerer;
 
 use super::bad_placeholder;
 use super::ItemCtxt;
@@ -357,7 +358,7 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::EarlyBinder<'_
                 .and_then(|body_id| {
                     ty.is_suggestable_infer_ty().then(|| {
                         infer_placeholder_type(
-                            tcx,
+                            icx.lowerer(),
                             def_id,
                             body_id,
                             ty.span,
@@ -381,7 +382,7 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::EarlyBinder<'_
             ImplItemKind::Const(ty, body_id) => {
                 if ty.is_suggestable_infer_ty() {
                     infer_placeholder_type(
-                        tcx,
+                        icx.lowerer(),
                         def_id,
                         body_id,
                         ty.span,
@@ -405,7 +406,7 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::EarlyBinder<'_
             ItemKind::Static(ty, .., body_id) => {
                 if ty.is_suggestable_infer_ty() {
                     infer_placeholder_type(
-                        tcx,
+                        icx.lowerer(),
                         def_id,
                         body_id,
                         ty.span,
@@ -418,7 +419,14 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::EarlyBinder<'_
             }
             ItemKind::Const(ty, _, body_id) => {
                 if ty.is_suggestable_infer_ty() {
-                    infer_placeholder_type(tcx, def_id, body_id, ty.span, item.ident, "constant")
+                    infer_placeholder_type(
+                        icx.lowerer(),
+                        def_id,
+                        body_id,
+                        ty.span,
+                        item.ident,
+                        "constant",
+                    )
                 } else {
                     icx.lower_ty(ty)
                 }
@@ -559,21 +567,22 @@ pub(super) fn type_of_opaque(
     }
 }
 
-fn infer_placeholder_type<'a>(
-    tcx: TyCtxt<'a>,
+fn infer_placeholder_type<'tcx>(
+    cx: &dyn HirTyLowerer<'tcx>,
     def_id: LocalDefId,
     body_id: hir::BodyId,
     span: Span,
     item_ident: Ident,
     kind: &'static str,
-) -> Ty<'a> {
+) -> Ty<'tcx> {
+    let tcx = cx.tcx();
     let ty = tcx.diagnostic_only_typeck(def_id).node_type(body_id.hir_id);
 
     // If this came from a free `const` or `static mut?` item,
     // then the user may have written e.g. `const A = 42;`.
     // In this case, the parser has stashed a diagnostic for
     // us to improve in typeck so we do that now.
-    let guar = tcx
+    let guar = cx
         .dcx()
         .try_steal_modify_and_emit_err(span, StashKey::ItemNoType, |err| {
             if !ty.references_error() {
@@ -602,7 +611,7 @@ fn infer_placeholder_type<'a>(
             }
         })
         .unwrap_or_else(|| {
-            let mut diag = bad_placeholder(tcx, vec![span], kind);
+            let mut diag = bad_placeholder(cx, vec![span], kind);
 
             if !ty.references_error() {
                 if let Some(ty) = ty.make_suggestable(tcx, false, None) {
diff --git a/compiler/rustc_hir_analysis/src/hir_ty_lowering/bounds.rs b/compiler/rustc_hir_analysis/src/hir_ty_lowering/bounds.rs
index 802215b2843ee..a1feef9e15b7e 100644
--- a/compiler/rustc_hir_analysis/src/hir_ty_lowering/bounds.rs
+++ b/compiler/rustc_hir_analysis/src/hir_ty_lowering/bounds.rs
@@ -76,7 +76,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
         }
 
         if unbounds.len() > 1 {
-            tcx.dcx().emit_err(errors::MultipleRelaxedDefaultBounds {
+            self.dcx().emit_err(errors::MultipleRelaxedDefaultBounds {
                 spans: unbounds.iter().map(|ptr| ptr.span).collect(),
             });
         }
@@ -90,7 +90,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                 continue;
             }
             // There was a `?Trait` bound, but it was not `?Sized`; warn.
-            tcx.dcx().span_warn(
+            self.dcx().span_warn(
                 unbound.span,
                 "relaxing a default bound only does something for `?Sized`; \
                 all other traits are not bound by default",
@@ -310,7 +310,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
         duplicates
             .entry(assoc_item.def_id)
             .and_modify(|prev_span| {
-                tcx.dcx().emit_err(errors::ValueOfAssociatedStructAlreadySpecified {
+                self.dcx().emit_err(errors::ValueOfAssociatedStructAlreadySpecified {
                     span: constraint.span,
                     prev_span: *prev_span,
                     item_name: constraint.ident,
@@ -338,7 +338,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                         .into(),
                         ty::GenericParamDefKind::Type { .. } => {
                             let guar = *emitted_bad_param_err.get_or_insert_with(|| {
-                                tcx.dcx().emit_err(
+                                self.dcx().emit_err(
                                     crate::errors::ReturnTypeNotationIllegalParam::Type {
                                         span: path_span,
                                         param_span: tcx.def_span(param.def_id),
@@ -349,7 +349,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                         }
                         ty::GenericParamDefKind::Const { .. } => {
                             let guar = *emitted_bad_param_err.get_or_insert_with(|| {
-                                tcx.dcx().emit_err(
+                                self.dcx().emit_err(
                                     crate::errors::ReturnTypeNotationIllegalParam::Const {
                                         span: path_span,
                                         param_span: tcx.def_span(param.def_id),
@@ -371,7 +371,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             {
                 alias_ty.into()
             } else {
-                return Err(tcx.dcx().emit_err(crate::errors::ReturnTypeNotationOnNonRpitit {
+                return Err(self.dcx().emit_err(crate::errors::ReturnTypeNotationOnNonRpitit {
                     span: constraint.span,
                     ty: tcx.liberate_late_bound_regions(assoc_item.def_id, output),
                     fn_span: tcx.hir().span_if_local(assoc_item.def_id),
@@ -417,7 +417,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                 let ty = alias_term
                     .map_bound(|alias| tcx.type_of(alias.def_id).instantiate(tcx, alias.args));
                 let ty =
-                    check_assoc_const_binding_type(tcx, constraint.ident, ty, constraint.hir_id);
+                    check_assoc_const_binding_type(self, constraint.ident, ty, constraint.hir_id);
                 tcx.feed_anon_const_type(anon_const.def_id, ty::EarlyBinder::bind(ty));
             }
 
@@ -426,7 +426,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
 
         match constraint.kind {
             hir::AssocItemConstraintKind::Equality { .. } if let ty::AssocKind::Fn = assoc_kind => {
-                return Err(tcx.dcx().emit_err(crate::errors::ReturnTypeNotationEqualityBound {
+                return Err(self.dcx().emit_err(crate::errors::ReturnTypeNotationEqualityBound {
                     span: constraint.span,
                 }));
             }
@@ -462,7 +462,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                     late_bound_in_term,
                     |br_name| {
                         struct_span_code_err!(
-                            tcx.dcx(),
+                            self.dcx(),
                             constraint.span,
                             E0582,
                             "binding for associated type `{}` references {}, \
@@ -519,7 +519,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
 ///
 /// [^1]: <https://github.com/rust-lang/project-const-generics/issues/28>.
 fn check_assoc_const_binding_type<'tcx>(
-    tcx: TyCtxt<'tcx>,
+    cx: &dyn HirTyLowerer<'tcx>,
     assoc_const: Ident,
     ty: ty::Binder<'tcx, Ty<'tcx>>,
     hir_id: hir::HirId,
@@ -536,13 +536,14 @@ fn check_assoc_const_binding_type<'tcx>(
     }
 
     let mut collector = GenericParamAndBoundVarCollector {
-        tcx,
+        cx,
         params: Default::default(),
         vars: Default::default(),
         depth: ty::INNERMOST,
     };
     let mut guar = ty.visit_with(&mut collector).break_value();
 
+    let tcx = cx.tcx();
     let ty_note = ty
         .make_suggestable(tcx, false, None)
         .map(|ty| crate::errors::TyOfAssocConstBindingNote { assoc_const, ty });
@@ -556,7 +557,7 @@ fn check_assoc_const_binding_type<'tcx>(
     for index in collector.params {
         let param = generics.param_at(index as _, tcx);
         let is_self_param = param.name == rustc_span::symbol::kw::SelfUpper;
-        guar.get_or_insert(tcx.dcx().emit_err(crate::errors::ParamInTyOfAssocConstBinding {
+        guar.get_or_insert(cx.dcx().emit_err(crate::errors::ParamInTyOfAssocConstBinding {
             span: assoc_const.span,
             assoc_const,
             param_name: param.name,
@@ -574,7 +575,7 @@ fn check_assoc_const_binding_type<'tcx>(
         }));
     }
     for (var_def_id, var_name) in collector.vars {
-        guar.get_or_insert(tcx.dcx().emit_err(
+        guar.get_or_insert(cx.dcx().emit_err(
             crate::errors::EscapingBoundVarInTyOfAssocConstBinding {
                 span: assoc_const.span,
                 assoc_const,
@@ -590,14 +591,14 @@ fn check_assoc_const_binding_type<'tcx>(
     Ty::new_error(tcx, guar)
 }
 
-struct GenericParamAndBoundVarCollector<'tcx> {
-    tcx: TyCtxt<'tcx>,
+struct GenericParamAndBoundVarCollector<'a, 'tcx> {
+    cx: &'a dyn HirTyLowerer<'tcx>,
     params: FxIndexSet<u32>,
     vars: FxIndexSet<(DefId, Symbol)>,
     depth: ty::DebruijnIndex,
 }
 
-impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for GenericParamAndBoundVarCollector<'tcx> {
+impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for GenericParamAndBoundVarCollector<'_, 'tcx> {
     type Result = ControlFlow<ErrorGuaranteed>;
 
     fn visit_binder<T: TypeVisitable<TyCtxt<'tcx>>>(
@@ -620,7 +621,7 @@ impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for GenericParamAndBoundVarCollector<'tcx>
                     ty::BoundTyKind::Param(def_id, name) => (def_id, name),
                     ty::BoundTyKind::Anon => {
                         let reported = self
-                            .tcx
+                            .cx
                             .dcx()
                             .delayed_bug(format!("unexpected anon bound ty: {:?}", bt.var));
                         return ControlFlow::Break(reported);
@@ -643,7 +644,7 @@ impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for GenericParamAndBoundVarCollector<'tcx>
                     ty::BrNamed(def_id, name) => (def_id, name),
                     ty::BrAnon | ty::BrEnv => {
                         let guar = self
-                            .tcx
+                            .cx
                             .dcx()
                             .delayed_bug(format!("unexpected bound region kind: {:?}", br.kind));
                         return ControlFlow::Break(guar);
@@ -661,7 +662,7 @@ impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for GenericParamAndBoundVarCollector<'tcx>
                 self.params.insert(param.index);
             }
             ty::ConstKind::Bound(db, ty::BoundVar { .. }) if db >= self.depth => {
-                let guar = self.tcx.dcx().delayed_bug("unexpected escaping late-bound const var");
+                let guar = self.cx.dcx().delayed_bug("unexpected escaping late-bound const var");
                 return ControlFlow::Break(guar);
             }
             _ if ct.has_param() || ct.has_bound_vars() => return ct.super_visit_with(self),
diff --git a/compiler/rustc_hir_analysis/src/hir_ty_lowering/errors.rs b/compiler/rustc_hir_analysis/src/hir_ty_lowering/errors.rs
index e8bd7f2a5b223..ebd2a63d55514 100644
--- a/compiler/rustc_hir_analysis/src/hir_ty_lowering/errors.rs
+++ b/compiler/rustc_hir_analysis/src/hir_ty_lowering/errors.rs
@@ -46,7 +46,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             return;
         }
 
-        self.tcx().dcx().emit_err(MissingTypeParams {
+        self.dcx().emit_err(MissingTypeParams {
             span,
             def_span: self.tcx().def_span(def_id),
             span_snippet: self.tcx().sess.source_map().span_to_snippet(span).ok(),
@@ -109,7 +109,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
 
         if is_impl {
             let trait_name = self.tcx().def_path_str(trait_def_id);
-            self.tcx().dcx().emit_err(ManualImplementation { span, trait_name });
+            self.dcx().emit_err(ManualImplementation { span, trait_name });
         }
     }
 
@@ -156,7 +156,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
 
         if is_dummy {
             err.label = Some(errors::AssocItemNotFoundLabel::NotFound { span });
-            return tcx.dcx().emit_err(err);
+            return self.dcx().emit_err(err);
         }
 
         let all_candidate_names: Vec<_> = all_candidates()
@@ -174,7 +174,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                 assoc_kind: assoc_kind_str,
                 suggested_name,
             });
-            return tcx.dcx().emit_err(err);
+            return self.dcx().emit_err(err);
         }
 
         // If we didn't find a good item in the supertraits (or couldn't get
@@ -239,10 +239,10 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                             assoc_kind: assoc_kind_str,
                             suggested_name,
                         });
-                        return tcx.dcx().emit_err(err);
+                        return self.dcx().emit_err(err);
                     }
 
-                    let mut err = tcx.dcx().create_err(err);
+                    let mut err = self.dcx().create_err(err);
                     if suggest_constraining_type_param(
                         tcx,
                         generics,
@@ -264,7 +264,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                     }
                     return err.emit();
                 }
-                return tcx.dcx().emit_err(err);
+                return self.dcx().emit_err(err);
             }
         }
 
@@ -291,7 +291,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             err.label = Some(errors::AssocItemNotFoundLabel::NotFound { span: assoc_name.span });
         }
 
-        tcx.dcx().emit_err(err)
+        self.dcx().emit_err(err)
     }
 
     fn complain_about_assoc_kind_mismatch(
@@ -347,7 +347,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             (ident.span, None, assoc_kind, assoc_item.kind)
         };
 
-        tcx.dcx().emit_err(errors::AssocKindMismatch {
+        self.dcx().emit_err(errors::AssocKindMismatch {
             span,
             expected: super::assoc_kind_str(expected),
             got: super::assoc_kind_str(got),
@@ -366,8 +366,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
         traits: &[String],
         name: Symbol,
     ) -> ErrorGuaranteed {
-        let mut err =
-            struct_span_code_err!(self.tcx().dcx(), span, E0223, "ambiguous associated type");
+        let mut err = struct_span_code_err!(self.dcx(), span, E0223, "ambiguous associated type");
         if self
             .tcx()
             .resolutions(())
@@ -463,9 +462,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                 }
             }
         }
-        let reported = err.emit();
-        self.set_tainted_by_errors(reported);
-        reported
+        err.emit()
     }
 
     pub(crate) fn complain_about_ambiguous_inherent_assoc_ty(
@@ -475,16 +472,14 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
         span: Span,
     ) -> ErrorGuaranteed {
         let mut err = struct_span_code_err!(
-            self.tcx().dcx(),
+            self.dcx(),
             name.span,
             E0034,
             "multiple applicable items in scope"
         );
         err.span_label(name.span, format!("multiple `{name}` found"));
         self.note_ambiguous_inherent_assoc_ty(&mut err, candidates, span);
-        let reported = err.emit();
-        self.set_tainted_by_errors(reported);
-        reported
+        err.emit()
     }
 
     // FIXME(fmease): Heavily adapted from `rustc_hir_typeck::method::suggest`. Deduplicate.
@@ -576,7 +571,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             };
 
             let mut err = struct_span_code_err!(
-                tcx.dcx(),
+                self.dcx(),
                 name.span,
                 E0220,
                 "associated type `{name}` not found for `{self_ty}` in the current scope"
@@ -662,7 +657,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
         bounds.sort();
         bounds.dedup();
 
-        let mut err = tcx.dcx().struct_span_err(
+        let mut err = self.dcx().struct_span_err(
             name.span,
             format!("the associated type `{name}` exists for `{self_ty}`, but its trait bounds were not satisfied")
         );
@@ -829,7 +824,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
 
         trait_bound_spans.sort();
         let mut err = struct_span_code_err!(
-            tcx.dcx(),
+            self.dcx(),
             trait_bound_spans,
             E0191,
             "the value of the associated type{} {} must be specified",
@@ -974,7 +969,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             }
         }
 
-        self.set_tainted_by_errors(err.emit());
+        err.emit();
     }
 
     /// On ambiguous associated type, look for an associated function whose name matches the
@@ -1011,17 +1006,14 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                 .filter_by_name_unhygienic(Symbol::intern(&name))
                 .next()
         {
-            let reported =
-                struct_span_code_err!(tcx.dcx(), span, E0223, "ambiguous associated type")
-                    .with_span_suggestion_verbose(
-                        ident2.span.to(ident3.span),
-                        format!("there is an associated function with a similar name: `{name}`"),
-                        name,
-                        Applicability::MaybeIncorrect,
-                    )
-                    .emit();
-            self.set_tainted_by_errors(reported);
-            Err(reported)
+            Err(struct_span_code_err!(self.dcx(), span, E0223, "ambiguous associated type")
+                .with_span_suggestion_verbose(
+                    ident2.span.to(ident3.span),
+                    format!("there is an associated function with a similar name: `{name}`"),
+                    name,
+                    Applicability::MaybeIncorrect,
+                )
+                .emit())
         } else {
             Ok(())
         }
@@ -1120,7 +1112,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
         let last_span = *arg_spans.last().unwrap();
         let span: MultiSpan = arg_spans.into();
         let mut err = struct_span_code_err!(
-            self.tcx().dcx(),
+            self.dcx(),
             span,
             E0109,
             "{kind} arguments are not allowed on {this_type}",
@@ -1130,20 +1122,17 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             err.span_label(span, format!("not allowed on {what}"));
         }
         generics_args_err_extend(self.tcx(), segments, &mut err, err_extend);
-        let reported = err.emit();
-        self.set_tainted_by_errors(reported);
-        reported
+        err.emit()
     }
 
     pub fn report_trait_object_addition_traits_error(
         &self,
         regular_traits: &Vec<TraitAliasExpansionInfo<'_>>,
     ) -> ErrorGuaranteed {
-        let tcx = self.tcx();
         let first_trait = &regular_traits[0];
         let additional_trait = &regular_traits[1];
         let mut err = struct_span_code_err!(
-            tcx.dcx(),
+            self.dcx(),
             additional_trait.bottom().1,
             E0225,
             "only auto traits can be used as additional traits in a trait object"
@@ -1169,9 +1158,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
              for more information on them, visit \
              <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits>",
         );
-        let reported = err.emit();
-        self.set_tainted_by_errors(reported);
-        reported
+        err.emit()
     }
 
     pub fn report_trait_object_with_no_traits_error(
@@ -1185,20 +1172,19 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             .map(|&(trait_ref, _)| trait_ref.def_id())
             .find(|&trait_ref| tcx.is_trait_alias(trait_ref))
             .map(|trait_ref| tcx.def_span(trait_ref));
-        let reported =
-            tcx.dcx().emit_err(TraitObjectDeclaredWithNoTraits { span, trait_alias_span });
-        self.set_tainted_by_errors(reported);
-        reported
+
+        self.dcx().emit_err(TraitObjectDeclaredWithNoTraits { span, trait_alias_span })
     }
 }
 
 /// Emit an error for the given associated item constraint.
 pub fn prohibit_assoc_item_constraint(
-    tcx: TyCtxt<'_>,
+    cx: &dyn HirTyLowerer<'_>,
     constraint: &hir::AssocItemConstraint<'_>,
     segment: Option<(DefId, &hir::PathSegment<'_>, Span)>,
 ) -> ErrorGuaranteed {
-    let mut err = tcx.dcx().create_err(AssocItemConstraintsNotAllowedHere {
+    let tcx = cx.tcx();
+    let mut err = cx.dcx().create_err(AssocItemConstraintsNotAllowedHere {
         span: constraint.span,
         fn_trait_expansion: if let Some((_, segment, span)) = segment
             && segment.args().parenthesized == hir::GenericArgsParentheses::ParenSugar
diff --git a/compiler/rustc_hir_analysis/src/hir_ty_lowering/generics.rs b/compiler/rustc_hir_analysis/src/hir_ty_lowering/generics.rs
index 90836f0a54f45..b1c77db9f3700 100644
--- a/compiler/rustc_hir_analysis/src/hir_ty_lowering/generics.rs
+++ b/compiler/rustc_hir_analysis/src/hir_ty_lowering/generics.rs
@@ -1,4 +1,4 @@
-use super::IsMethodCall;
+use super::{HirTyLowerer, IsMethodCall};
 use crate::errors::wrong_number_of_generic_args::{GenericArgsInfo, WrongNumberOfGenericArgs};
 use crate::hir_ty_lowering::{
     errors::prohibit_assoc_item_constraint, ExplicitLateBound, GenericArgCountMismatch,
@@ -13,7 +13,7 @@ use rustc_hir::def::{DefKind, Res};
 use rustc_hir::def_id::DefId;
 use rustc_hir::GenericArg;
 use rustc_middle::ty::{
-    self, GenericArgsRef, GenericParamDef, GenericParamDefKind, IsSuggestable, Ty, TyCtxt,
+    self, GenericArgsRef, GenericParamDef, GenericParamDefKind, IsSuggestable, Ty,
 };
 use rustc_session::lint::builtin::LATE_BOUND_LIFETIME_ARGUMENTS;
 use rustc_span::symbol::{kw, sym};
@@ -22,15 +22,16 @@ use smallvec::SmallVec;
 /// Report an error that a generic argument did not match the generic parameter that was
 /// expected.
 fn generic_arg_mismatch_err(
-    tcx: TyCtxt<'_>,
+    cx: &dyn HirTyLowerer<'_>,
     arg: &GenericArg<'_>,
     param: &GenericParamDef,
     possible_ordering_error: bool,
     help: Option<String>,
 ) -> ErrorGuaranteed {
+    let tcx = cx.tcx();
     let sess = tcx.sess;
     let mut err = struct_span_code_err!(
-        tcx.dcx(),
+        cx.dcx(),
         arg.span(),
         E0747,
         "{} provided when a {} was expected",
@@ -171,7 +172,7 @@ fn generic_arg_mismatch_err(
 /// - `inferred_kind`: if no parameter was provided, and inference
 ///   is enabled, then creates a suitable inference variable.
 pub fn lower_generic_args<'tcx: 'a, 'a>(
-    tcx: TyCtxt<'tcx>,
+    cx: &dyn HirTyLowerer<'tcx>,
     def_id: DefId,
     parent_args: &[ty::GenericArg<'tcx>],
     has_self: bool,
@@ -179,6 +180,7 @@ pub fn lower_generic_args<'tcx: 'a, 'a>(
     arg_count: &GenericArgCountResult,
     ctx: &mut impl GenericArgsLowerer<'a, 'tcx>,
 ) -> GenericArgsRef<'tcx> {
+    let tcx = cx.tcx();
     // Collect the segments of the path; we need to instantiate arguments
     // for parameters throughout the entire path (wherever there are
     // generic parameters).
@@ -326,7 +328,7 @@ pub fn lower_generic_args<'tcx: 'a, 'a>(
                                 param_types_present.dedup();
 
                                 generic_arg_mismatch_err(
-                                    tcx,
+                                    cx,
                                     arg,
                                     param,
                                     !args_iter.clone().is_sorted_by_key(|arg| arg.to_ord()),
@@ -381,7 +383,7 @@ pub fn lower_generic_args<'tcx: 'a, 'a>(
                         assert_eq!(kind, "lifetime");
                         let (provided_arg, param) =
                             force_infer_lt.expect("lifetimes ought to have been inferred");
-                        generic_arg_mismatch_err(tcx, provided_arg, param, false, None);
+                        generic_arg_mismatch_err(cx, provided_arg, param, false, None);
                     }
 
                     break;
@@ -405,7 +407,7 @@ pub fn lower_generic_args<'tcx: 'a, 'a>(
 /// Checks that the correct number of generic arguments have been provided.
 /// Used specifically for function calls.
 pub fn check_generic_arg_count_for_call(
-    tcx: TyCtxt<'_>,
+    cx: &dyn HirTyLowerer<'_>,
     def_id: DefId,
     generics: &ty::Generics,
     seg: &hir::PathSegment<'_>,
@@ -416,14 +418,14 @@ pub fn check_generic_arg_count_for_call(
         IsMethodCall::No => GenericArgPosition::Value,
     };
     let has_self = generics.parent.is_none() && generics.has_self;
-    check_generic_arg_count(tcx, def_id, seg, generics, gen_pos, has_self)
+    check_generic_arg_count(cx, def_id, seg, generics, gen_pos, has_self)
 }
 
 /// Checks that the correct number of generic arguments have been provided.
 /// This is used both for datatypes and function calls.
-#[instrument(skip(tcx, gen_pos), level = "debug")]
+#[instrument(skip(cx, gen_pos), level = "debug")]
 pub(crate) fn check_generic_arg_count(
-    tcx: TyCtxt<'_>,
+    cx: &dyn HirTyLowerer<'_>,
     def_id: DefId,
     seg: &hir::PathSegment<'_>,
     gen_params: &ty::Generics,
@@ -456,11 +458,11 @@ pub(crate) fn check_generic_arg_count(
     if gen_pos != GenericArgPosition::Type
         && let Some(c) = gen_args.constraints.first()
     {
-        prohibit_assoc_item_constraint(tcx, c, None);
+        prohibit_assoc_item_constraint(cx, c, None);
     }
 
     let explicit_late_bound =
-        prohibit_explicit_late_bound_lifetimes(tcx, gen_params, gen_args, gen_pos);
+        prohibit_explicit_late_bound_lifetimes(cx, gen_params, gen_args, gen_pos);
 
     let mut invalid_args = vec![];
 
@@ -486,8 +488,8 @@ pub(crate) fn check_generic_arg_count(
             GenericArgsInfo::MissingLifetimes { num_missing_args }
         };
 
-        let reported = tcx.dcx().emit_err(WrongNumberOfGenericArgs::new(
-            tcx,
+        let reported = cx.dcx().emit_err(WrongNumberOfGenericArgs::new(
+            cx.tcx(),
             gen_args_info,
             seg,
             gen_params,
@@ -571,9 +573,9 @@ pub(crate) fn check_generic_arg_count(
         debug!(?gen_args_info);
 
         let reported = gen_args.has_err().unwrap_or_else(|| {
-            tcx.dcx()
+            cx.dcx()
                 .create_err(WrongNumberOfGenericArgs::new(
-                    tcx,
+                    cx.tcx(),
                     gen_args_info,
                     seg,
                     gen_params,
@@ -621,7 +623,7 @@ pub(crate) fn check_generic_arg_count(
 /// Prohibits explicit lifetime arguments if late-bound lifetime parameters
 /// are present. This is used both for datatypes and function calls.
 pub(crate) fn prohibit_explicit_late_bound_lifetimes(
-    tcx: TyCtxt<'_>,
+    cx: &dyn HirTyLowerer<'_>,
     def: &ty::Generics,
     args: &hir::GenericArgs<'_>,
     position: GenericArgPosition,
@@ -642,13 +644,13 @@ pub(crate) fn prohibit_explicit_late_bound_lifetimes(
         if position == GenericArgPosition::Value
             && args.num_lifetime_params() != param_counts.lifetimes
         {
-            struct_span_code_err!(tcx.dcx(), span, E0794, "{}", msg)
+            struct_span_code_err!(cx.dcx(), span, E0794, "{}", msg)
                 .with_span_note(span_late, note)
                 .emit();
         } else {
             let mut multispan = MultiSpan::from_span(span);
             multispan.push_span_label(span_late, note);
-            tcx.node_span_lint(
+            cx.tcx().node_span_lint(
                 LATE_BOUND_LIFETIME_ARGUMENTS,
                 args.args[0].hir_id(),
                 multispan,
diff --git a/compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs b/compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs
index b7fa736ffcc6f..29c71c3fa50b5 100644
--- a/compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs
+++ b/compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs
@@ -60,7 +60,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             let msg = "trait objects must include the `dyn` keyword";
             let label = "add `dyn` keyword before this trait";
             let mut diag =
-                rustc_errors::struct_span_code_err!(tcx.dcx(), self_ty.span, E0782, "{}", msg);
+                rustc_errors::struct_span_code_err!(self.dcx(), self_ty.span, E0782, "{}", msg);
             if self_ty.span.can_be_used_for_suggestions()
                 && !self.maybe_suggest_impl_trait(self_ty, &mut diag)
             {
diff --git a/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs b/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs
index 0747686b38bf9..a665306f2c6a8 100644
--- a/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs
+++ b/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs
@@ -28,7 +28,8 @@ use crate::require_c_abi_if_c_variadic;
 use rustc_ast::TraitObjectSyntax;
 use rustc_data_structures::fx::{FxHashSet, FxIndexMap};
 use rustc_errors::{
-    codes::*, struct_span_code_err, Applicability, Diag, ErrorGuaranteed, FatalError,
+    codes::*, struct_span_code_err, Applicability, Diag, DiagCtxtHandle, ErrorGuaranteed,
+    FatalError,
 };
 use rustc_hir as hir;
 use rustc_hir::def::{CtorOf, DefKind, Namespace, Res};
@@ -102,6 +103,8 @@ pub enum RegionInferReason<'a> {
 pub trait HirTyLowerer<'tcx> {
     fn tcx(&self) -> TyCtxt<'tcx>;
 
+    fn dcx(&self) -> DiagCtxtHandle<'_>;
+
     /// Returns the [`LocalDefId`] of the overarching item whose constituents get lowered.
     fn item_def_id(&self) -> LocalDefId;
 
@@ -177,12 +180,6 @@ pub trait HirTyLowerer<'tcx> {
     /// The inference context of the lowering context if applicable.
     fn infcx(&self) -> Option<&InferCtxt<'tcx>>;
 
-    /// Taint the context with errors.
-    ///
-    /// Invoke this when you encounter an error from some prior pass like name resolution.
-    /// This is used to help suppress derived errors typeck might otherwise report.
-    fn set_tainted_by_errors(&self, e: ErrorGuaranteed);
-
     /// Convenience method for coercing the lowering context into a trait object type.
     ///
     /// Most lowering routines are defined on the trait object type directly
@@ -323,7 +320,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             ty::BoundConstness::NotConst,
         );
         if let Some(c) = item_segment.args().constraints.first() {
-            prohibit_assoc_item_constraint(self.tcx(), c, Some((def_id, item_segment, span)));
+            prohibit_assoc_item_constraint(self, c, Some((def_id, item_segment, span)));
         }
         args
     }
@@ -394,7 +391,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
         }
 
         let mut arg_count = check_generic_arg_count(
-            tcx,
+            self,
             def_id,
             segment,
             generics,
@@ -402,10 +399,6 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             self_ty.is_some(),
         );
 
-        if let Err(err) = &arg_count.correct {
-            self.set_tainted_by_errors(err.reported);
-        }
-
         // Skip processing if type has no generic parameters.
         // Traits always have `Self` as a generic parameter, which means they will not return early
         // here and so associated item constraints will be handled regardless of whether there are
@@ -562,11 +555,10 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             && generics.has_self
             && !tcx.is_const_trait(def_id)
         {
-            let reported = tcx.dcx().emit_err(crate::errors::ConstBoundForNonConstTrait {
+            let reported = self.dcx().emit_err(crate::errors::ConstBoundForNonConstTrait {
                 span,
                 modifier: constness.as_str(),
             });
-            self.set_tainted_by_errors(reported);
             arg_count.correct = Err(GenericArgCountMismatch { reported, invalid_args: vec![] });
         }
 
@@ -579,7 +571,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             incorrect_args: &arg_count.correct,
         };
         let args = lower_generic_args(
-            tcx,
+            self,
             def_id,
             parent_args,
             self_ty.is_some(),
@@ -609,7 +601,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             ty::BoundConstness::NotConst,
         );
         if let Some(c) = item_segment.args().constraints.first() {
-            prohibit_assoc_item_constraint(self.tcx(), c, Some((item_def_id, item_segment, span)));
+            prohibit_assoc_item_constraint(self, c, Some((item_def_id, item_segment, span)));
         }
         args
     }
@@ -715,7 +707,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             // would not be well-formed!
             if polarity != ty::PredicatePolarity::Positive {
                 assert!(
-                    self.tcx().dcx().has_errors().is_some(),
+                    self.dcx().has_errors().is_some(),
                     "negative trait bounds should not have assoc item constraints",
                 );
                 continue;
@@ -761,11 +753,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             constness,
         );
         if let Some(c) = trait_segment.args().constraints.first() {
-            prohibit_assoc_item_constraint(
-                self.tcx(),
-                c,
-                Some((trait_def_id, trait_segment, span)),
-            );
+            prohibit_assoc_item_constraint(self, c, Some((trait_def_id, trait_segment, span)));
         }
         ty::TraitRef::new_from_args(self.tcx(), trait_def_id, generic_args)
     }
@@ -877,7 +865,6 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                 span,
                 constraint,
             );
-            self.set_tainted_by_errors(reported);
             return Err(reported);
         };
         debug!(?bound);
@@ -887,7 +874,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
 
             let assoc_kind_str = assoc_kind_str(assoc_kind);
             let ty_param_name = &ty_param_name.to_string();
-            let mut err = tcx.dcx().create_err(crate::errors::AmbiguousAssocItem {
+            let mut err = self.dcx().create_err(crate::errors::AmbiguousAssocItem {
                 span,
                 assoc_kind: assoc_kind_str,
                 assoc_name,
@@ -960,7 +947,6 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                 ));
             }
             let reported = err.emit();
-            self.set_tainted_by_errors(reported);
             if !where_bounds.is_empty() {
                 return Err(reported);
             }
@@ -1059,7 +1045,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                 // trait reference.
                 let Some(trait_ref) = tcx.impl_trait_ref(impl_def_id) else {
                     // A cycle error occurred, most likely.
-                    tcx.dcx().span_bug(span, "expected cycle error");
+                    self.dcx().span_bug(span, "expected cycle error");
                 };
 
                 self.probe_single_bound_for_assoc_item(
@@ -1089,10 +1075,10 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                 let reported = if variant_resolution.is_some() {
                     // Variant in type position
                     let msg = format!("expected type, found variant `{assoc_ident}`");
-                    tcx.dcx().span_err(span, msg)
+                    self.dcx().span_err(span, msg)
                 } else if qself_ty.is_enum() {
                     let mut err = struct_span_code_err!(
-                        tcx.dcx(),
+                        self.dcx(),
                         assoc_ident.span,
                         E0599,
                         "no variant named `{}` found for enum `{}`",
@@ -1133,7 +1119,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                 } else if let ty::Alias(ty::Opaque, alias_ty) = qself_ty.kind() {
                     // `<impl Trait as OtherTrait>::Assoc` makes no sense.
                     struct_span_code_err!(
-                        tcx.dcx(),
+                        self.dcx(),
                         tcx.def_span(alias_ty.def_id),
                         E0667,
                         "`impl Trait` is not allowed in path parameters"
@@ -1153,7 +1139,6 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                         assoc_ident.name,
                     )
                 };
-                self.set_tainted_by_errors(reported);
                 return Err(reported);
             }
         };
@@ -1404,13 +1389,12 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
         let tcx = self.tcx();
 
         if !tcx.visibility(item_def_id).is_accessible_from(scope, tcx) {
-            let reported = tcx.dcx().emit_err(crate::errors::AssocItemIsPrivate {
+            self.dcx().emit_err(crate::errors::AssocItemIsPrivate {
                 span,
                 kind: tcx.def_descr(item_def_id),
                 name: ident,
                 defined_here_label: tcx.def_span(item_def_id),
             });
-            self.set_tainted_by_errors(reported);
         }
 
         tcx.check_stability(item_def_id, Some(block), span, None);
@@ -1564,7 +1548,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
         for segment in segments {
             // Only emit the first error to avoid overloading the user with error messages.
             if let Some(c) = segment.args().constraints.first() {
-                return Err(prohibit_assoc_item_constraint(self.tcx(), c, None));
+                return Err(prohibit_assoc_item_constraint(self, c, None));
             }
         }
 
@@ -1824,7 +1808,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                 // `AlwaysApplicable` impl needs a `T: ?Sized` bound for
                 // this to compile if we were to normalize here.
                 if forbid_generic && ty.has_param() {
-                    let mut err = tcx.dcx().struct_span_err(
+                    let mut err = self.dcx().struct_span_err(
                         path.span,
                         "generic `Self` types are currently not permitted in anonymous constants",
                     );
@@ -1836,7 +1820,6 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                         err.span_note(impl_.self_ty.span, "not a concrete type");
                     }
                     let reported = err.emit();
-                    self.set_tainted_by_errors(reported);
                     Ty::new_error(tcx, reported)
                 } else {
                     ty
@@ -1877,7 +1860,6 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                     .tcx()
                     .dcx()
                     .span_delayed_bug(path.span, "path with `Res::Err` but no error emitted");
-                self.set_tainted_by_errors(e);
                 Ty::new_error(self.tcx(), e)
             }
             Res::Def(..) => {
@@ -1888,7 +1870,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                 );
                 Ty::new_error(
                     self.tcx(),
-                    self.tcx().dcx().span_delayed_bug(span, "incorrect resolution for `Self`"),
+                    self.dcx().span_delayed_bug(span, "incorrect resolution for `Self`"),
                 )
             }
             _ => span_bug!(span, "unexpected resolution: {:?}", path.res),
@@ -1961,7 +1943,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
         let sig_span = self.tcx().def_span(sig_id);
         let mut try_emit = |descr| {
             if emit {
-                self.tcx().dcx().emit_err(crate::errors::NotSupportedDelegation {
+                self.dcx().emit_err(crate::errors::NotSupportedDelegation {
                     span,
                     descr,
                     callee_span: sig_span,
@@ -2011,8 +1993,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
     ) -> Ty<'tcx> {
         if self.check_delegation_constraints(sig_id, span, idx == hir::InferDelegationKind::Output)
         {
-            let e = self.tcx().dcx().span_delayed_bug(span, "not supported delegation case");
-            self.set_tainted_by_errors(e);
+            let e = self.dcx().span_delayed_bug(span, "not supported delegation case");
             return Ty::new_error(self.tcx(), e);
         };
         let sig = self.tcx().fn_sig(sig_id);
@@ -2177,7 +2158,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                 let ty = self.lower_ty(ty);
                 let pat_ty = match pat.kind {
                     hir::PatKind::Wild => {
-                        let err = tcx.dcx().emit_err(WildPatTy { span: pat.span });
+                        let err = self.dcx().emit_err(WildPatTy { span: pat.span });
                         Ty::new_error(tcx, err)
                     }
                     hir::PatKind::Range(start, end, include_end) => {
@@ -2357,7 +2338,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
 
         self.validate_late_bound_regions(late_bound_in_args, late_bound_in_ret, |br_name| {
             struct_span_code_err!(
-                tcx.dcx(),
+                self.dcx(),
                 decl.output.span(),
                 E0581,
                 "return type references {}, which is not constrained by the fn input types",
@@ -2408,11 +2389,11 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
     }
 
     #[instrument(level = "trace", skip(self, generate_err))]
-    fn validate_late_bound_regions(
-        &self,
+    fn validate_late_bound_regions<'cx>(
+        &'cx self,
         constrained_regions: FxHashSet<ty::BoundRegionKind>,
         referenced_regions: FxHashSet<ty::BoundRegionKind>,
-        generate_err: impl Fn(&str) -> Diag<'tcx>,
+        generate_err: impl Fn(&str) -> Diag<'cx>,
     ) {
         for br in referenced_regions.difference(&constrained_regions) {
             let br_name = match *br {
@@ -2437,7 +2418,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                 err.note("consider introducing a named lifetime parameter");
             }
 
-            self.set_tainted_by_errors(err.emit());
+            err.emit();
         }
     }
 
@@ -2478,7 +2459,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
         // error.
         let r = derived_region_bounds[0];
         if derived_region_bounds[1..].iter().any(|r1| r != *r1) {
-            self.set_tainted_by_errors(tcx.dcx().emit_err(AmbiguousLifetimeBound { span }));
+            self.dcx().emit_err(AmbiguousLifetimeBound { span });
         }
         Some(r)
     }
diff --git a/compiler/rustc_hir_analysis/src/hir_ty_lowering/object_safety.rs b/compiler/rustc_hir_analysis/src/hir_ty_lowering/object_safety.rs
index 8ef4740431c42..aafadc7f9cbea 100644
--- a/compiler/rustc_hir_analysis/src/hir_ty_lowering/object_safety.rs
+++ b/compiler/rustc_hir_analysis/src/hir_ty_lowering/object_safety.rs
@@ -236,7 +236,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                             Ty::new_misc_error(tcx).into()
                         } else if arg.walk().any(|arg| arg == dummy_self.into()) {
                             references_self = true;
-                            let guar = tcx.dcx().span_delayed_bug(
+                            let guar = self.dcx().span_delayed_bug(
                                 span,
                                 "trait object trait bounds reference `Self`",
                             );
@@ -262,8 +262,8 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
 
                 if references_self {
                     let def_id = i.bottom().0.def_id();
-                    let reported = struct_span_code_err!(
-                        tcx.dcx(),
+                    struct_span_code_err!(
+                        self.dcx(),
                         i.bottom().1,
                         E0038,
                         "the {} `{}` cannot be made into an object",
@@ -275,7 +275,6 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                             .error_msg(),
                     )
                     .emit();
-                    self.set_tainted_by_errors(reported);
                 }
 
                 ty::ExistentialTraitRef { def_id: trait_ref.def_id, args }
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs
index e35130c66a22c..ea9567f4e3dcb 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs
@@ -1139,7 +1139,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             // parameter's value explicitly, so we have to do some error-
             // checking here.
             let arg_count =
-                check_generic_arg_count_for_call(tcx, def_id, generics, seg, IsMethodCall::No);
+                check_generic_arg_count_for_call(self, def_id, generics, seg, IsMethodCall::No);
 
             if let ExplicitLateBound::Yes = arg_count.explicit_late_bound {
                 explicit_late_bound = ExplicitLateBound::Yes;
@@ -1375,7 +1375,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         let args_raw = self_ctor_args.unwrap_or_else(|| {
             lower_generic_args(
-                tcx,
+                self,
                 def_id,
                 &[],
                 has_self,
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs
index da68da029b417..b5796fbd48a88 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs
@@ -5,7 +5,7 @@ mod checks;
 mod inspect_obligations;
 mod suggestions;
 
-use rustc_errors::{DiagCtxtHandle, ErrorGuaranteed};
+use rustc_errors::DiagCtxtHandle;
 
 use crate::coercion::DynamicCoerceMany;
 use crate::fallback::DivergingFallbackBehavior;
@@ -217,6 +217,10 @@ impl<'tcx> HirTyLowerer<'tcx> for FnCtxt<'_, 'tcx> {
         self.tcx
     }
 
+    fn dcx(&self) -> DiagCtxtHandle<'_> {
+        self.root_ctxt.dcx()
+    }
+
     fn item_def_id(&self) -> LocalDefId {
         self.body_id
     }
@@ -338,10 +342,6 @@ impl<'tcx> HirTyLowerer<'tcx> for FnCtxt<'_, 'tcx> {
         Some(&self.infcx)
     }
 
-    fn set_tainted_by_errors(&self, e: ErrorGuaranteed) {
-        self.infcx.set_tainted_by_errors(e)
-    }
-
     fn lower_fn_sig(
         &self,
         decl: &rustc_hir::FnDecl<'tcx>,
diff --git a/compiler/rustc_hir_typeck/src/method/confirm.rs b/compiler/rustc_hir_typeck/src/method/confirm.rs
index 02844bcadac6e..e574fde14fb0a 100644
--- a/compiler/rustc_hir_typeck/src/method/confirm.rs
+++ b/compiler/rustc_hir_typeck/src/method/confirm.rs
@@ -354,7 +354,7 @@ impl<'a, 'tcx> ConfirmContext<'a, 'tcx> {
         let generics = self.tcx.generics_of(pick.item.def_id);
 
         let arg_count_correct = check_generic_arg_count_for_call(
-            self.tcx,
+            self.fcx,
             pick.item.def_id,
             generics,
             seg,
@@ -425,7 +425,7 @@ impl<'a, 'tcx> ConfirmContext<'a, 'tcx> {
         }
 
         let args = lower_generic_args(
-            self.tcx,
+            self.fcx,
             pick.item.def_id,
             parent_args,
             false,
diff --git a/tests/ui/associated-types/associated-types-eq-expr-path.rs b/tests/ui/associated-types/associated-types-eq-expr-path.rs
index 67831f913039a..3179811274e81 100644
--- a/tests/ui/associated-types/associated-types-eq-expr-path.rs
+++ b/tests/ui/associated-types/associated-types-eq-expr-path.rs
@@ -7,11 +7,12 @@ trait Foo {
 
 impl Foo for isize {
     type A = usize;
-    fn bar() -> isize { 42 }
+    fn bar() -> isize {
+        42
+    }
 }
 
 pub fn main() {
     let x: isize = Foo::<A = usize>::bar();
     //~^ ERROR associated item constraints are not allowed here
-    //~| ERROR cannot call
 }
diff --git a/tests/ui/associated-types/associated-types-eq-expr-path.stderr b/tests/ui/associated-types/associated-types-eq-expr-path.stderr
index 4f28b3cb2de33..bbe021fbc55f0 100644
--- a/tests/ui/associated-types/associated-types-eq-expr-path.stderr
+++ b/tests/ui/associated-types/associated-types-eq-expr-path.stderr
@@ -1,25 +1,9 @@
 error[E0229]: associated item constraints are not allowed here
-  --> $DIR/associated-types-eq-expr-path.rs:14:26
+  --> $DIR/associated-types-eq-expr-path.rs:16:26
    |
 LL |     let x: isize = Foo::<A = usize>::bar();
    |                          ^^^^^^^^^ associated item constraint not allowed here
 
-error[E0790]: cannot call associated function on trait without specifying the corresponding `impl` type
-  --> $DIR/associated-types-eq-expr-path.rs:14:20
-   |
-LL |     fn bar() -> isize;
-   |     ------------------ `Foo::bar` defined here
-...
-LL |     let x: isize = Foo::<A = usize>::bar();
-   |                    ^^^^^^^^^^^^^^^^^^^^^^^ cannot call associated function of trait
-   |
-help: use the fully-qualified path to the only available implementation
-   |
-LL -     let x: isize = Foo::<A = usize>::bar();
-LL +     let x: isize = <isize as Foo<A = usize>>::bar();
-   |
-
-error: aborting due to 2 previous errors
+error: aborting due to 1 previous error
 
-Some errors have detailed explanations: E0229, E0790.
-For more information about an error, try `rustc --explain E0229`.
+For more information about this error, try `rustc --explain E0229`.
diff --git a/tests/ui/const-generics/assoc_const_as_type_argument.rs b/tests/ui/const-generics/assoc_const_as_type_argument.rs
index bec6102417c5f..ffc7f116a94ef 100644
--- a/tests/ui/const-generics/assoc_const_as_type_argument.rs
+++ b/tests/ui/const-generics/assoc_const_as_type_argument.rs
@@ -8,7 +8,6 @@ fn foo<T: Trait>() {
     bar::<<T as Trait>::ASSOC>();
     //~^ ERROR: expected associated type, found associated constant `Trait::ASSOC`
     //~| ERROR: unresolved item provided when a constant was expected
-    //~| ERROR type annotations needed
 }
 
 fn main() {}
diff --git a/tests/ui/const-generics/assoc_const_as_type_argument.stderr b/tests/ui/const-generics/assoc_const_as_type_argument.stderr
index 53edc19b28ca2..ac00954613506 100644
--- a/tests/ui/const-generics/assoc_const_as_type_argument.stderr
+++ b/tests/ui/const-generics/assoc_const_as_type_argument.stderr
@@ -15,19 +15,7 @@ help: if this generic argument was intended as a const parameter, surround it wi
 LL |     bar::<{ <T as Trait>::ASSOC }>();
    |           +                     +
 
-error[E0284]: type annotations needed
-  --> $DIR/assoc_const_as_type_argument.rs:8:5
-   |
-LL |     bar::<<T as Trait>::ASSOC>();
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer the value of the const parameter `N` declared on the function `bar`
-   |
-note: required by a const generic parameter in `bar`
-  --> $DIR/assoc_const_as_type_argument.rs:5:8
-   |
-LL | fn bar<const N: usize>() {}
-   |        ^^^^^^^^^^^^^^ required by this const generic parameter in `bar`
-
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 
-Some errors have detailed explanations: E0284, E0575, E0747.
-For more information about an error, try `rustc --explain E0284`.
+Some errors have detailed explanations: E0575, E0747.
+For more information about an error, try `rustc --explain E0575`.
diff --git a/tests/ui/const-generics/const-arg-in-const-arg.min.stderr b/tests/ui/const-generics/const-arg-in-const-arg.min.stderr
index 2ea9d6b35b451..ce7fce2599360 100644
--- a/tests/ui/const-generics/const-arg-in-const-arg.min.stderr
+++ b/tests/ui/const-generics/const-arg-in-const-arg.min.stderr
@@ -17,7 +17,7 @@ LL |     let _: [u8; bar::<N>()];
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:19:23
+  --> $DIR/const-arg-in-const-arg.rs:18:23
    |
 LL |     let _: [u8; faz::<'a>(&())];
    |                       ^^ cannot perform const operation using `'a`
@@ -26,7 +26,7 @@ LL |     let _: [u8; faz::<'a>(&())];
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:21:23
+  --> $DIR/const-arg-in-const-arg.rs:20:23
    |
 LL |     let _: [u8; baz::<'a>(&())];
    |                       ^^ cannot perform const operation using `'a`
@@ -35,7 +35,7 @@ LL |     let _: [u8; baz::<'a>(&())];
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:22:23
+  --> $DIR/const-arg-in-const-arg.rs:21:23
    |
 LL |     let _: [u8; faz::<'b>(&())];
    |                       ^^ cannot perform const operation using `'b`
@@ -44,7 +44,7 @@ LL |     let _: [u8; faz::<'b>(&())];
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:24:23
+  --> $DIR/const-arg-in-const-arg.rs:23:23
    |
 LL |     let _: [u8; baz::<'b>(&())];
    |                       ^^ cannot perform const operation using `'b`
@@ -53,7 +53,7 @@ LL |     let _: [u8; baz::<'b>(&())];
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:27:23
+  --> $DIR/const-arg-in-const-arg.rs:26:23
    |
 LL |     let _ = [0; bar::<N>()];
    |                       ^ cannot perform const operation using `N`
@@ -62,7 +62,7 @@ LL |     let _ = [0; bar::<N>()];
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:30:23
+  --> $DIR/const-arg-in-const-arg.rs:28:23
    |
 LL |     let _ = [0; faz::<'a>(&())];
    |                       ^^ cannot perform const operation using `'a`
@@ -71,7 +71,7 @@ LL |     let _ = [0; faz::<'a>(&())];
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:32:23
+  --> $DIR/const-arg-in-const-arg.rs:30:23
    |
 LL |     let _ = [0; baz::<'a>(&())];
    |                       ^^ cannot perform const operation using `'a`
@@ -80,7 +80,7 @@ LL |     let _ = [0; baz::<'a>(&())];
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:33:23
+  --> $DIR/const-arg-in-const-arg.rs:31:23
    |
 LL |     let _ = [0; faz::<'b>(&())];
    |                       ^^ cannot perform const operation using `'b`
@@ -89,7 +89,7 @@ LL |     let _ = [0; faz::<'b>(&())];
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:35:23
+  --> $DIR/const-arg-in-const-arg.rs:33:23
    |
 LL |     let _ = [0; baz::<'b>(&())];
    |                       ^^ cannot perform const operation using `'b`
@@ -98,7 +98,7 @@ LL |     let _ = [0; baz::<'b>(&())];
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:36:24
+  --> $DIR/const-arg-in-const-arg.rs:34:24
    |
 LL |     let _: Foo<{ foo::<T>() }>;
    |                        ^ cannot perform const operation using `T`
@@ -107,7 +107,7 @@ LL |     let _: Foo<{ foo::<T>() }>;
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:37:24
+  --> $DIR/const-arg-in-const-arg.rs:35:24
    |
 LL |     let _: Foo<{ bar::<N>() }>;
    |                        ^ cannot perform const operation using `N`
@@ -116,7 +116,7 @@ LL |     let _: Foo<{ bar::<N>() }>;
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:40:24
+  --> $DIR/const-arg-in-const-arg.rs:37:24
    |
 LL |     let _: Foo<{ faz::<'a>(&()) }>;
    |                        ^^ cannot perform const operation using `'a`
@@ -125,7 +125,7 @@ LL |     let _: Foo<{ faz::<'a>(&()) }>;
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:42:24
+  --> $DIR/const-arg-in-const-arg.rs:39:24
    |
 LL |     let _: Foo<{ baz::<'a>(&()) }>;
    |                        ^^ cannot perform const operation using `'a`
@@ -134,7 +134,7 @@ LL |     let _: Foo<{ baz::<'a>(&()) }>;
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:43:24
+  --> $DIR/const-arg-in-const-arg.rs:40:24
    |
 LL |     let _: Foo<{ faz::<'b>(&()) }>;
    |                        ^^ cannot perform const operation using `'b`
@@ -143,7 +143,7 @@ LL |     let _: Foo<{ faz::<'b>(&()) }>;
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:45:24
+  --> $DIR/const-arg-in-const-arg.rs:42:24
    |
 LL |     let _: Foo<{ baz::<'b>(&()) }>;
    |                        ^^ cannot perform const operation using `'b`
@@ -152,7 +152,7 @@ LL |     let _: Foo<{ baz::<'b>(&()) }>;
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:46:27
+  --> $DIR/const-arg-in-const-arg.rs:43:27
    |
 LL |     let _ = Foo::<{ foo::<T>() }>;
    |                           ^ cannot perform const operation using `T`
@@ -161,7 +161,7 @@ LL |     let _ = Foo::<{ foo::<T>() }>;
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:47:27
+  --> $DIR/const-arg-in-const-arg.rs:44:27
    |
 LL |     let _ = Foo::<{ bar::<N>() }>;
    |                           ^ cannot perform const operation using `N`
@@ -170,7 +170,7 @@ LL |     let _ = Foo::<{ bar::<N>() }>;
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:50:27
+  --> $DIR/const-arg-in-const-arg.rs:46:27
    |
 LL |     let _ = Foo::<{ faz::<'a>(&()) }>;
    |                           ^^ cannot perform const operation using `'a`
@@ -179,7 +179,7 @@ LL |     let _ = Foo::<{ faz::<'a>(&()) }>;
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:52:27
+  --> $DIR/const-arg-in-const-arg.rs:48:27
    |
 LL |     let _ = Foo::<{ baz::<'a>(&()) }>;
    |                           ^^ cannot perform const operation using `'a`
@@ -188,7 +188,7 @@ LL |     let _ = Foo::<{ baz::<'a>(&()) }>;
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:53:27
+  --> $DIR/const-arg-in-const-arg.rs:49:27
    |
 LL |     let _ = Foo::<{ faz::<'b>(&()) }>;
    |                           ^^ cannot perform const operation using `'b`
@@ -197,7 +197,7 @@ LL |     let _ = Foo::<{ faz::<'b>(&()) }>;
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
 error: generic parameters may not be used in const operations
-  --> $DIR/const-arg-in-const-arg.rs:55:27
+  --> $DIR/const-arg-in-const-arg.rs:51:27
    |
 LL |     let _ = Foo::<{ baz::<'b>(&()) }>;
    |                           ^^ cannot perform const operation using `'b`
@@ -216,20 +216,8 @@ help: if this generic argument was intended as a const parameter, surround it wi
 LL |     let _: [u8; bar::<{ N }>()];
    |                       +   +
 
-error[E0284]: type annotations needed
-  --> $DIR/const-arg-in-const-arg.rs:16:17
-   |
-LL |     let _: [u8; bar::<N>()];
-   |                 ^^^^^^^^ cannot infer the value of the const parameter `N` declared on the function `bar`
-   |
-note: required by a const generic parameter in `bar`
-  --> $DIR/const-arg-in-const-arg.rs:9:14
-   |
-LL | const fn bar<const N: usize>() -> usize { N }
-   |              ^^^^^^^^^^^^^^ required by this const generic parameter in `bar`
-
 error[E0794]: cannot specify lifetime arguments explicitly if late bound lifetime parameters are present
-  --> $DIR/const-arg-in-const-arg.rs:19:23
+  --> $DIR/const-arg-in-const-arg.rs:18:23
    |
 LL |     let _: [u8; faz::<'a>(&())];
    |                       ^^
@@ -241,7 +229,7 @@ LL | const fn faz<'a>(_: &'a ()) -> usize { 13 }
    |              ^^
 
 error[E0794]: cannot specify lifetime arguments explicitly if late bound lifetime parameters are present
-  --> $DIR/const-arg-in-const-arg.rs:22:23
+  --> $DIR/const-arg-in-const-arg.rs:21:23
    |
 LL |     let _: [u8; faz::<'b>(&())];
    |                       ^^
@@ -253,7 +241,7 @@ LL | const fn faz<'a>(_: &'a ()) -> usize { 13 }
    |              ^^
 
 error[E0747]: unresolved item provided when a constant was expected
-  --> $DIR/const-arg-in-const-arg.rs:37:24
+  --> $DIR/const-arg-in-const-arg.rs:35:24
    |
 LL |     let _: Foo<{ bar::<N>() }>;
    |                        ^
@@ -263,20 +251,8 @@ help: if this generic argument was intended as a const parameter, surround it wi
 LL |     let _: Foo<{ bar::<{ N }>() }>;
    |                        +   +
 
-error[E0284]: type annotations needed
-  --> $DIR/const-arg-in-const-arg.rs:37:18
-   |
-LL |     let _: Foo<{ bar::<N>() }>;
-   |                  ^^^^^^^^ cannot infer the value of the const parameter `N` declared on the function `bar`
-   |
-note: required by a const generic parameter in `bar`
-  --> $DIR/const-arg-in-const-arg.rs:9:14
-   |
-LL | const fn bar<const N: usize>() -> usize { N }
-   |              ^^^^^^^^^^^^^^ required by this const generic parameter in `bar`
-
 error[E0794]: cannot specify lifetime arguments explicitly if late bound lifetime parameters are present
-  --> $DIR/const-arg-in-const-arg.rs:40:24
+  --> $DIR/const-arg-in-const-arg.rs:37:24
    |
 LL |     let _: Foo<{ faz::<'a>(&()) }>;
    |                        ^^
@@ -288,7 +264,7 @@ LL | const fn faz<'a>(_: &'a ()) -> usize { 13 }
    |              ^^
 
 error[E0794]: cannot specify lifetime arguments explicitly if late bound lifetime parameters are present
-  --> $DIR/const-arg-in-const-arg.rs:43:24
+  --> $DIR/const-arg-in-const-arg.rs:40:24
    |
 LL |     let _: Foo<{ faz::<'b>(&()) }>;
    |                        ^^
@@ -300,7 +276,7 @@ LL | const fn faz<'a>(_: &'a ()) -> usize { 13 }
    |              ^^
 
 error: constant expression depends on a generic parameter
-  --> $DIR/const-arg-in-const-arg.rs:26:17
+  --> $DIR/const-arg-in-const-arg.rs:25:17
    |
 LL |     let _ = [0; foo::<T>()];
    |                 ^^^^^^^^^^
@@ -308,7 +284,7 @@ LL |     let _ = [0; foo::<T>()];
    = note: this may fail depending on what value the parameter takes
 
 error[E0747]: unresolved item provided when a constant was expected
-  --> $DIR/const-arg-in-const-arg.rs:27:23
+  --> $DIR/const-arg-in-const-arg.rs:26:23
    |
 LL |     let _ = [0; bar::<N>()];
    |                       ^
@@ -318,20 +294,8 @@ help: if this generic argument was intended as a const parameter, surround it wi
 LL |     let _ = [0; bar::<{ N }>()];
    |                       +   +
 
-error[E0284]: type annotations needed
-  --> $DIR/const-arg-in-const-arg.rs:27:17
-   |
-LL |     let _ = [0; bar::<N>()];
-   |                 ^^^^^^^^ cannot infer the value of the const parameter `N` declared on the function `bar`
-   |
-note: required by a const generic parameter in `bar`
-  --> $DIR/const-arg-in-const-arg.rs:9:14
-   |
-LL | const fn bar<const N: usize>() -> usize { N }
-   |              ^^^^^^^^^^^^^^ required by this const generic parameter in `bar`
-
 error[E0794]: cannot specify lifetime arguments explicitly if late bound lifetime parameters are present
-  --> $DIR/const-arg-in-const-arg.rs:30:23
+  --> $DIR/const-arg-in-const-arg.rs:28:23
    |
 LL |     let _ = [0; faz::<'a>(&())];
    |                       ^^
@@ -343,7 +307,7 @@ LL | const fn faz<'a>(_: &'a ()) -> usize { 13 }
    |              ^^
 
 error[E0794]: cannot specify lifetime arguments explicitly if late bound lifetime parameters are present
-  --> $DIR/const-arg-in-const-arg.rs:33:23
+  --> $DIR/const-arg-in-const-arg.rs:31:23
    |
 LL |     let _ = [0; faz::<'b>(&())];
    |                       ^^
@@ -355,7 +319,7 @@ LL | const fn faz<'a>(_: &'a ()) -> usize { 13 }
    |              ^^
 
 error[E0747]: unresolved item provided when a constant was expected
-  --> $DIR/const-arg-in-const-arg.rs:47:27
+  --> $DIR/const-arg-in-const-arg.rs:44:27
    |
 LL |     let _ = Foo::<{ bar::<N>() }>;
    |                           ^
@@ -365,20 +329,8 @@ help: if this generic argument was intended as a const parameter, surround it wi
 LL |     let _ = Foo::<{ bar::<{ N }>() }>;
    |                           +   +
 
-error[E0284]: type annotations needed
-  --> $DIR/const-arg-in-const-arg.rs:47:21
-   |
-LL |     let _ = Foo::<{ bar::<N>() }>;
-   |                     ^^^^^^^^ cannot infer the value of the const parameter `N` declared on the function `bar`
-   |
-note: required by a const generic parameter in `bar`
-  --> $DIR/const-arg-in-const-arg.rs:9:14
-   |
-LL | const fn bar<const N: usize>() -> usize { N }
-   |              ^^^^^^^^^^^^^^ required by this const generic parameter in `bar`
-
 error[E0794]: cannot specify lifetime arguments explicitly if late bound lifetime parameters are present
-  --> $DIR/const-arg-in-const-arg.rs:50:27
+  --> $DIR/const-arg-in-const-arg.rs:46:27
    |
 LL |     let _ = Foo::<{ faz::<'a>(&()) }>;
    |                           ^^
@@ -390,7 +342,7 @@ LL | const fn faz<'a>(_: &'a ()) -> usize { 13 }
    |              ^^
 
 error[E0794]: cannot specify lifetime arguments explicitly if late bound lifetime parameters are present
-  --> $DIR/const-arg-in-const-arg.rs:53:27
+  --> $DIR/const-arg-in-const-arg.rs:49:27
    |
 LL |     let _ = Foo::<{ faz::<'b>(&()) }>;
    |                           ^^
@@ -401,7 +353,7 @@ note: the late bound lifetime parameter is introduced here
 LL | const fn faz<'a>(_: &'a ()) -> usize { 13 }
    |              ^^
 
-error: aborting due to 40 previous errors
+error: aborting due to 36 previous errors
 
-Some errors have detailed explanations: E0284, E0747, E0794.
-For more information about an error, try `rustc --explain E0284`.
+Some errors have detailed explanations: E0747, E0794.
+For more information about an error, try `rustc --explain E0747`.
diff --git a/tests/ui/const-generics/const-arg-in-const-arg.rs b/tests/ui/const-generics/const-arg-in-const-arg.rs
index b95c63309f782..27b74489fe8e0 100644
--- a/tests/ui/const-generics/const-arg-in-const-arg.rs
+++ b/tests/ui/const-generics/const-arg-in-const-arg.rs
@@ -15,7 +15,6 @@ fn test<'a, 'b, T, const N: usize>() where &'b (): Sized {
     let _: [u8; foo::<T>()]; //[min]~ ERROR generic parameters may not
     let _: [u8; bar::<N>()]; //[min]~ ERROR generic parameters may not
                              //[min]~^ ERROR unresolved item provided when a constant was expected
-                             //[min]~| ERROR type annotations needed
     let _: [u8; faz::<'a>(&())]; //[min]~ ERROR generic parameters may not
                                  //[min]~^ ERROR cannot specify lifetime arguments
     let _: [u8; baz::<'a>(&())]; //[min]~ ERROR generic parameters may not
@@ -26,7 +25,6 @@ fn test<'a, 'b, T, const N: usize>() where &'b (): Sized {
     let _ = [0; foo::<T>()]; //[min]~ ERROR constant expression depends on a generic parameter
     let _ = [0; bar::<N>()]; //[min]~ ERROR generic parameters may not
                              //[min]~^ ERROR unresolved item provided when a constant was expected
-                             //[min]~| ERROR type annotations needed
     let _ = [0; faz::<'a>(&())]; //[min]~ ERROR generic parameters may not
                                  //[min]~^ ERROR cannot specify lifetime arguments
     let _ = [0; baz::<'a>(&())]; //[min]~ ERROR generic parameters may not
@@ -36,7 +34,6 @@ fn test<'a, 'b, T, const N: usize>() where &'b (): Sized {
     let _: Foo<{ foo::<T>() }>; //[min]~ ERROR generic parameters may not
     let _: Foo<{ bar::<N>() }>; //[min]~ ERROR generic parameters may not
                                 //[min]~^ ERROR unresolved item provided when a constant was expected
-                                //[min]~| ERROR type annotations needed
     let _: Foo<{ faz::<'a>(&()) }>; //[min]~ ERROR generic parameters may not
                                     //[min]~^ ERROR cannot specify lifetime arguments
     let _: Foo<{ baz::<'a>(&()) }>; //[min]~ ERROR generic parameters may not
@@ -46,7 +43,6 @@ fn test<'a, 'b, T, const N: usize>() where &'b (): Sized {
     let _ = Foo::<{ foo::<T>() }>; //[min]~ ERROR generic parameters may not
     let _ = Foo::<{ bar::<N>() }>; //[min]~ ERROR generic parameters may not
                                    //[min]~^ ERROR unresolved item provided when a constant was expected
-                                   //[min]~| ERROR type annotations needed
     let _ = Foo::<{ faz::<'a>(&()) }>; //[min]~ ERROR generic parameters may not
                                        //[min]~^ ERROR cannot specify lifetime arguments
     let _ = Foo::<{ baz::<'a>(&()) }>; //[min]~ ERROR generic parameters may not
diff --git a/tests/ui/const-generics/issues/issue-62878.min.stderr b/tests/ui/const-generics/issues/issue-62878.min.stderr
index 3fd50bbe29803..5205726d73845 100644
--- a/tests/ui/const-generics/issues/issue-62878.min.stderr
+++ b/tests/ui/const-generics/issues/issue-62878.min.stderr
@@ -30,31 +30,7 @@ help: add `#![feature(generic_arg_infer)]` to the crate attributes to enable
 LL + #![feature(generic_arg_infer)]
    |
 
-error[E0284]: type annotations needed
-  --> $DIR/issue-62878.rs:10:5
-   |
-LL |     foo::<_, { [1] }>();
-   |     ^^^^^^^^^^^^^^^^^ cannot infer the value of the const parameter `N` declared on the function `foo`
-   |
-note: required by a const generic parameter in `foo`
-  --> $DIR/issue-62878.rs:5:8
-   |
-LL | fn foo<const N: usize, const A: [u8; N]>() {}
-   |        ^^^^^^^^^^^^^^ required by this const generic parameter in `foo`
-
-error[E0284]: type annotations needed
-  --> $DIR/issue-62878.rs:10:5
-   |
-LL |     foo::<_, { [1] }>();
-   |     ^^^^^^^^^^^^^^^^^ cannot infer the value of the const parameter `A` declared on the function `foo`
-   |
-note: required by a const generic parameter in `foo`
-  --> $DIR/issue-62878.rs:5:24
-   |
-LL | fn foo<const N: usize, const A: [u8; N]>() {}
-   |                        ^^^^^^^^^^^^^^^^ required by this const generic parameter in `foo`
-
-error: aborting due to 5 previous errors
+error: aborting due to 3 previous errors
 
-Some errors have detailed explanations: E0284, E0747, E0770.
-For more information about an error, try `rustc --explain E0284`.
+Some errors have detailed explanations: E0747, E0770.
+For more information about an error, try `rustc --explain E0747`.
diff --git a/tests/ui/const-generics/issues/issue-62878.rs b/tests/ui/const-generics/issues/issue-62878.rs
index c784e95edd824..0b5269df85ee1 100644
--- a/tests/ui/const-generics/issues/issue-62878.rs
+++ b/tests/ui/const-generics/issues/issue-62878.rs
@@ -9,6 +9,4 @@ fn foo<const N: usize, const A: [u8; N]>() {}
 fn main() {
     foo::<_, { [1] }>();
     //[min]~^ ERROR: type provided when a constant was expected
-    //[min]~| ERROR type annotations needed
-    //[min]~| ERROR type annotations needed
 }
diff --git a/tests/ui/const-generics/min_const_generics/const-expression-suggest-missing-braces.rs b/tests/ui/const-generics/min_const_generics/const-expression-suggest-missing-braces.rs
index 497c020bde43e..e12e07a28e763 100644
--- a/tests/ui/const-generics/min_const_generics/const-expression-suggest-missing-braces.rs
+++ b/tests/ui/const-generics/min_const_generics/const-expression-suggest-missing-braces.rs
@@ -12,7 +12,6 @@ fn b() {
     //~^ ERROR expected trait, found constant `BAR`
     //~| ERROR expected trait, found constant `BAR`
     //~| ERROR type provided when a constant was expected
-    //~| ERROR type annotations needed
 }
 fn c() {
     foo::<3 + 3>(); //~ ERROR expressions must be enclosed in braces
diff --git a/tests/ui/const-generics/min_const_generics/const-expression-suggest-missing-braces.stderr b/tests/ui/const-generics/min_const_generics/const-expression-suggest-missing-braces.stderr
index c2ba517f60960..d9bcc523b1fc4 100644
--- a/tests/ui/const-generics/min_const_generics/const-expression-suggest-missing-braces.stderr
+++ b/tests/ui/const-generics/min_const_generics/const-expression-suggest-missing-braces.stderr
@@ -10,7 +10,7 @@ LL |     foo::<{ BAR + 3 }>();
    |           +         +
 
 error: expressions must be enclosed in braces to be used as const generic arguments
-  --> $DIR/const-expression-suggest-missing-braces.rs:18:11
+  --> $DIR/const-expression-suggest-missing-braces.rs:17:11
    |
 LL |     foo::<3 + 3>();
    |           ^^^^^
@@ -21,7 +21,7 @@ LL |     foo::<{ 3 + 3 }>();
    |           +       +
 
 error: expected one of `,` or `>`, found `-`
-  --> $DIR/const-expression-suggest-missing-braces.rs:21:15
+  --> $DIR/const-expression-suggest-missing-braces.rs:20:15
    |
 LL |     foo::<BAR - 3>();
    |               ^ expected one of `,` or `>`
@@ -32,7 +32,7 @@ LL |     foo::<{ BAR - 3 }>();
    |           +         +
 
 error: expected one of `,` or `>`, found `-`
-  --> $DIR/const-expression-suggest-missing-braces.rs:24:15
+  --> $DIR/const-expression-suggest-missing-braces.rs:23:15
    |
 LL |     foo::<BAR - BAR>();
    |               ^ expected one of `,` or `>`
@@ -43,7 +43,7 @@ LL |     foo::<{ BAR - BAR }>();
    |           +           +
 
 error: expressions must be enclosed in braces to be used as const generic arguments
-  --> $DIR/const-expression-suggest-missing-braces.rs:27:11
+  --> $DIR/const-expression-suggest-missing-braces.rs:26:11
    |
 LL |     foo::<100 - BAR>();
    |           ^^^^^^^^^
@@ -54,7 +54,7 @@ LL |     foo::<{ 100 - BAR }>();
    |           +           +
 
 error: expected one of `,` or `>`, found `(`
-  --> $DIR/const-expression-suggest-missing-braces.rs:30:19
+  --> $DIR/const-expression-suggest-missing-braces.rs:29:19
    |
 LL |     foo::<bar<i32>()>();
    |                   ^ expected one of `,` or `>`
@@ -65,7 +65,7 @@ LL |     foo::<{ bar<i32>() }>();
    |           +            +
 
 error: expected one of `,` or `>`, found `(`
-  --> $DIR/const-expression-suggest-missing-braces.rs:33:21
+  --> $DIR/const-expression-suggest-missing-braces.rs:32:21
    |
 LL |     foo::<bar::<i32>()>();
    |                     ^ expected one of `,` or `>`
@@ -76,7 +76,7 @@ LL |     foo::<{ bar::<i32>() }>();
    |           +              +
 
 error: expected one of `,` or `>`, found `(`
-  --> $DIR/const-expression-suggest-missing-braces.rs:36:21
+  --> $DIR/const-expression-suggest-missing-braces.rs:35:21
    |
 LL |     foo::<bar::<i32>() + BAR>();
    |                     ^ expected one of `,` or `>`
@@ -87,7 +87,7 @@ LL |     foo::<{ bar::<i32>() + BAR }>();
    |           +                    +
 
 error: expected one of `,` or `>`, found `(`
-  --> $DIR/const-expression-suggest-missing-braces.rs:39:21
+  --> $DIR/const-expression-suggest-missing-braces.rs:38:21
    |
 LL |     foo::<bar::<i32>() - BAR>();
    |                     ^ expected one of `,` or `>`
@@ -98,7 +98,7 @@ LL |     foo::<{ bar::<i32>() - BAR }>();
    |           +                    +
 
 error: expected one of `,` or `>`, found `-`
-  --> $DIR/const-expression-suggest-missing-braces.rs:42:15
+  --> $DIR/const-expression-suggest-missing-braces.rs:41:15
    |
 LL |     foo::<BAR - bar::<i32>()>();
    |               ^ expected one of `,` or `>`
@@ -109,7 +109,7 @@ LL |     foo::<{ BAR - bar::<i32>() }>();
    |           +                    +
 
 error: expected one of `,` or `>`, found `-`
-  --> $DIR/const-expression-suggest-missing-braces.rs:45:15
+  --> $DIR/const-expression-suggest-missing-braces.rs:44:15
    |
 LL |     foo::<BAR - bar::<i32>()>();
    |               ^ expected one of `,` or `>`
@@ -137,19 +137,7 @@ error[E0747]: type provided when a constant was expected
 LL |     foo::<BAR + BAR>();
    |           ^^^^^^^^^
 
-error[E0284]: type annotations needed
-  --> $DIR/const-expression-suggest-missing-braces.rs:11:5
-   |
-LL |     foo::<BAR + BAR>();
-   |     ^^^^^^^^^^^^^^^^ cannot infer the value of the const parameter `C` declared on the function `foo`
-   |
-note: required by a const generic parameter in `foo`
-  --> $DIR/const-expression-suggest-missing-braces.rs:1:8
-   |
-LL | fn foo<const C: usize>() {}
-   |        ^^^^^^^^^^^^^^ required by this const generic parameter in `foo`
-
-error: aborting due to 15 previous errors
+error: aborting due to 14 previous errors
 
-Some errors have detailed explanations: E0284, E0404, E0747.
-For more information about an error, try `rustc --explain E0284`.
+Some errors have detailed explanations: E0404, E0747.
+For more information about an error, try `rustc --explain E0404`.
diff --git a/tests/ui/const-generics/min_const_generics/macro-fail.rs b/tests/ui/const-generics/min_const_generics/macro-fail.rs
index 25726490c2cca..8cfa5293cc28f 100644
--- a/tests/ui/const-generics/min_const_generics/macro-fail.rs
+++ b/tests/ui/const-generics/min_const_generics/macro-fail.rs
@@ -16,7 +16,6 @@ fn make_marker() -> impl Marker<gimme_a_const!(marker)> {
   //~| ERROR: type provided when a constant was expected
   Example::<gimme_a_const!(marker)>
   //~^ ERROR: type provided when a constant was expected
-  //~| ERROR type annotations needed
 }
 
 fn from_marker(_: impl Marker<{
@@ -37,10 +36,8 @@ fn main() {
 
   let _fail = Example::<external_macro!()>;
   //~^ ERROR: type provided when a constant
-  //~| ERROR type annotations needed
 
   let _fail = Example::<gimme_a_const!()>;
   //~^ ERROR unexpected end of macro invocation
   //~| ERROR: type provided when a constant was expected
-  //~| ERROR type annotations needed
 }
diff --git a/tests/ui/const-generics/min_const_generics/macro-fail.stderr b/tests/ui/const-generics/min_const_generics/macro-fail.stderr
index 4e183fe5b1c55..34764982bb046 100644
--- a/tests/ui/const-generics/min_const_generics/macro-fail.stderr
+++ b/tests/ui/const-generics/min_const_generics/macro-fail.stderr
@@ -1,5 +1,5 @@
 error: expected type, found `{`
-  --> $DIR/macro-fail.rs:31:27
+  --> $DIR/macro-fail.rs:30:27
    |
 LL | fn make_marker() -> impl Marker<gimme_a_const!(marker)> {
    |                                 ----------------------
@@ -13,7 +13,7 @@ LL |       ($rusty: ident) => {{ let $rusty = 3; *&$rusty }}
    = note: this error originates in the macro `gimme_a_const` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: expected type, found `{`
-  --> $DIR/macro-fail.rs:31:27
+  --> $DIR/macro-fail.rs:30:27
    |
 LL |   Example::<gimme_a_const!(marker)>
    |             ----------------------
@@ -41,7 +41,7 @@ LL |   let _fail = Example::<external_macro!()>;
    = note: this error originates in the macro `external_macro` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: unexpected end of macro invocation
-  --> $DIR/macro-fail.rs:42:25
+  --> $DIR/macro-fail.rs:40:25
    |
 LL |     macro_rules! gimme_a_const {
    |     -------------------------- when calling this macro
@@ -50,7 +50,7 @@ LL |   let _fail = Example::<gimme_a_const!()>;
    |                         ^^^^^^^^^^^^^^^^ missing tokens in macro arguments
    |
 note: while trying to match meta-variable `$rusty:ident`
-  --> $DIR/macro-fail.rs:31:8
+  --> $DIR/macro-fail.rs:30:8
    |
 LL |       ($rusty: ident) => {{ let $rusty = 3; *&$rusty }}
    |        ^^^^^^^^^^^^^
@@ -75,63 +75,18 @@ error[E0747]: type provided when a constant was expected
 LL |   Example::<gimme_a_const!(marker)>
    |             ^^^^^^^^^^^^^^^^^^^^^^
 
-error[E0284]: type annotations needed
-  --> $DIR/macro-fail.rs:17:3
-   |
-LL |   Example::<gimme_a_const!(marker)>
-   |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer the value of the const parameter `N` declared on the struct `Example`
-   |
-note: required by a const generic parameter in `Example`
-  --> $DIR/macro-fail.rs:1:16
-   |
-LL | struct Example<const N: usize>;
-   |                ^^^^^^^^^^^^^^ required by this const generic parameter in `Example`
-
 error[E0747]: type provided when a constant was expected
-  --> $DIR/macro-fail.rs:38:25
+  --> $DIR/macro-fail.rs:37:25
    |
 LL |   let _fail = Example::<external_macro!()>;
    |                         ^^^^^^^^^^^^^^^^^
 
 error[E0747]: type provided when a constant was expected
-  --> $DIR/macro-fail.rs:42:25
+  --> $DIR/macro-fail.rs:40:25
    |
 LL |   let _fail = Example::<gimme_a_const!()>;
    |                         ^^^^^^^^^^^^^^^^
 
-error[E0284]: type annotations needed for `Example<_>`
-  --> $DIR/macro-fail.rs:38:7
-   |
-LL |   let _fail = Example::<external_macro!()>;
-   |       ^^^^^   ---------------------------- type must be known at this point
-   |
-note: required by a const generic parameter in `Example`
-  --> $DIR/macro-fail.rs:1:16
-   |
-LL | struct Example<const N: usize>;
-   |                ^^^^^^^^^^^^^^ required by this const generic parameter in `Example`
-help: consider giving `_fail` an explicit type, where the value of const parameter `N` is specified
-   |
-LL |   let _fail: Example<N> = Example::<external_macro!()>;
-   |            ++++++++++++
-
-error[E0284]: type annotations needed for `Example<_>`
-  --> $DIR/macro-fail.rs:42:7
-   |
-LL |   let _fail = Example::<gimme_a_const!()>;
-   |       ^^^^^   --------------------------- type must be known at this point
-   |
-note: required by a const generic parameter in `Example`
-  --> $DIR/macro-fail.rs:1:16
-   |
-LL | struct Example<const N: usize>;
-   |                ^^^^^^^^^^^^^^ required by this const generic parameter in `Example`
-help: consider giving `_fail` an explicit type, where the value of const parameter `N` is specified
-   |
-LL |   let _fail: Example<N> = Example::<gimme_a_const!()>;
-   |            ++++++++++++
-
-error: aborting due to 12 previous errors
+error: aborting due to 9 previous errors
 
-Some errors have detailed explanations: E0284, E0747.
-For more information about an error, try `rustc --explain E0284`.
+For more information about this error, try `rustc --explain E0747`.
diff --git a/tests/ui/const-generics/suggest_const_for_array.rs b/tests/ui/const-generics/suggest_const_for_array.rs
index 4d29d0693759f..b52fd152f976a 100644
--- a/tests/ui/const-generics/suggest_const_for_array.rs
+++ b/tests/ui/const-generics/suggest_const_for_array.rs
@@ -5,8 +5,6 @@ fn example<const N: usize>() {}
 fn other() {
     example::<[usize; 3]>();
     //~^ ERROR type provided when a const
-    //~| ERROR type annotations needed
     example::<[usize; 4 + 5]>();
     //~^ ERROR type provided when a const
-    //~| ERROR type annotations needed
 }
diff --git a/tests/ui/const-generics/suggest_const_for_array.stderr b/tests/ui/const-generics/suggest_const_for_array.stderr
index c867914070bb7..f0ad8368e5d71 100644
--- a/tests/ui/const-generics/suggest_const_for_array.stderr
+++ b/tests/ui/const-generics/suggest_const_for_array.stderr
@@ -5,36 +5,11 @@ LL |     example::<[usize; 3]>();
    |               ^^^^^^^^^^ help: array type provided where a `usize` was expected, try: `{ 3 }`
 
 error[E0747]: type provided when a constant was expected
-  --> $DIR/suggest_const_for_array.rs:9:15
+  --> $DIR/suggest_const_for_array.rs:8:15
    |
 LL |     example::<[usize; 4 + 5]>();
    |               ^^^^^^^^^^^^^^ help: array type provided where a `usize` was expected, try: `{ 4 + 5 }`
 
-error[E0284]: type annotations needed
-  --> $DIR/suggest_const_for_array.rs:6:5
-   |
-LL |     example::<[usize; 3]>();
-   |     ^^^^^^^^^^^^^^^^^^^^^ cannot infer the value of the const parameter `N` declared on the function `example`
-   |
-note: required by a const generic parameter in `example`
-  --> $DIR/suggest_const_for_array.rs:3:12
-   |
-LL | fn example<const N: usize>() {}
-   |            ^^^^^^^^^^^^^^ required by this const generic parameter in `example`
-
-error[E0284]: type annotations needed
-  --> $DIR/suggest_const_for_array.rs:9:5
-   |
-LL |     example::<[usize; 4 + 5]>();
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer the value of the const parameter `N` declared on the function `example`
-   |
-note: required by a const generic parameter in `example`
-  --> $DIR/suggest_const_for_array.rs:3:12
-   |
-LL | fn example<const N: usize>() {}
-   |            ^^^^^^^^^^^^^^ required by this const generic parameter in `example`
-
-error: aborting due to 4 previous errors
+error: aborting due to 2 previous errors
 
-Some errors have detailed explanations: E0284, E0747.
-For more information about an error, try `rustc --explain E0284`.
+For more information about this error, try `rustc --explain E0747`.
diff --git a/tests/ui/generics/generic-function-item-where-type.rs b/tests/ui/generics/generic-function-item-where-type.rs
index 0e36018389e96..e1b0578cadbe9 100644
--- a/tests/ui/generics/generic-function-item-where-type.rs
+++ b/tests/ui/generics/generic-function-item-where-type.rs
@@ -3,5 +3,4 @@ fn foo<U>() {}
 fn main() {
     foo::<main>()
     //~^ ERROR constant provided when a type was expected
-    //~| ERROR type annotations needed
 }
diff --git a/tests/ui/generics/generic-function-item-where-type.stderr b/tests/ui/generics/generic-function-item-where-type.stderr
index 5b0c9a8ee6df5..00e62843cb4b6 100644
--- a/tests/ui/generics/generic-function-item-where-type.stderr
+++ b/tests/ui/generics/generic-function-item-where-type.stderr
@@ -7,13 +7,6 @@ LL |     foo::<main>()
    = help: `main` is a function item, not a type
    = help: function item types cannot be named directly
 
-error[E0282]: type annotations needed
-  --> $DIR/generic-function-item-where-type.rs:4:5
-   |
-LL |     foo::<main>()
-   |     ^^^^^^^^^^^ cannot infer type of the type parameter `U` declared on the function `foo`
-
-error: aborting due to 2 previous errors
+error: aborting due to 1 previous error
 
-Some errors have detailed explanations: E0282, E0747.
-For more information about an error, try `rustc --explain E0282`.
+For more information about this error, try `rustc --explain E0747`.