Merging upstream version 1.71.1+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

17 files changed, 491 insertions, 231 deletions

diff --git a/compiler/rustc_ty_utils/Cargo.toml b/compiler/rustc_ty_utils/Cargo.toml
index 52fbd3ae0..51885c9b4 100644
--- a/compiler/rustc_ty_utils/Cargo.toml
+++ b/compiler/rustc_ty_utils/Cargo.toml
@@ -9,6 +9,7 @@ rustc_middle = { path = "../rustc_middle" }
 rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_errors = { path = "../rustc_errors" }
 rustc_hir = { path = "../rustc_hir" }
+rustc_fluent_macro = { path = "../rustc_fluent_macro" }
 rustc_infer = { path = "../rustc_infer" }
 rustc_macros = { path = "../rustc_macros" }
 rustc_span = { path = "../rustc_span" }
diff --git a/compiler/rustc_ty_utils/messages.ftl b/compiler/rustc_ty_utils/messages.ftl
index 15a14112f..c416aa52a 100644
--- a/compiler/rustc_ty_utils/messages.ftl
+++ b/compiler/rustc_ty_utils/messages.ftl
@@ -1,57 +1,65 @@
-ty_utils_needs_drop_overflow = overflow while checking whether `{$query_ty}` requires drop
+ty_utils_address_and_deref_not_supported = dereferencing or taking the address is not supported in generic constants
 
-ty_utils_generic_constant_too_complex = overly complex generic constant
-    .help = consider moving this anonymous constant into a `const` function
-    .maybe_supported = this operation may be supported in the future
+ty_utils_adt_not_supported = struct/enum construction is not supported in generic constants
 
-ty_utils_borrow_not_supported = borrowing is not supported in generic constants
+ty_utils_array_not_supported = array construction is not supported in generic constants
 
-ty_utils_address_and_deref_not_supported = dereferencing or taking the address is not supported in generic constants
+ty_utils_assign_not_supported = assignment is not supported in generic constants
 
-ty_utils_array_not_supported = array construction is not supported in generic constants
+ty_utils_binary_not_supported = unsupported binary operation in generic constants
 
 ty_utils_block_not_supported = blocks are not supported in generic constants
 
-ty_utils_never_to_any_not_supported = coercing the `never` type is not supported in generic constants
-
-ty_utils_tuple_not_supported = tuple construction is not supported in generic constants
+ty_utils_borrow_not_supported = borrowing is not supported in generic constants
 
-ty_utils_index_not_supported = indexing is not supported in generic constants
+ty_utils_box_not_supported = allocations are not allowed in generic constants
 
-ty_utils_field_not_supported = field access is not supported in generic constants
+ty_utils_closure_and_return_not_supported = closures and function keywords are not supported in generic constants
 
 ty_utils_const_block_not_supported = const blocks are not supported in generic constants
 
-ty_utils_adt_not_supported = struct/enum construction is not supported in generic constants
+ty_utils_control_flow_not_supported = control flow is not supported in generic constants
 
-ty_utils_pointer_not_supported = pointer casts are not allowed in generic constants
+ty_utils_field_not_supported = field access is not supported in generic constants
 
-ty_utils_yield_not_supported = generator control flow is not allowed in generic constants
+ty_utils_generic_constant_too_complex = overly complex generic constant
+    .help = consider moving this anonymous constant into a `const` function
+    .maybe_supported = this operation may be supported in the future
 
-ty_utils_loop_not_supported = loops and loop control flow are not supported in generic constants
+ty_utils_impl_trait_duplicate_arg = non-defining opaque type use in defining scope
+    .label = generic argument `{$arg}` used twice
+    .note = for this opaque type
 
-ty_utils_box_not_supported = allocations are not allowed in generic constants
+ty_utils_impl_trait_not_param = non-defining opaque type use in defining scope
+    .label = argument `{$arg}` is not a generic parameter
+    .note = for this opaque type
 
-ty_utils_binary_not_supported = unsupported binary operation in generic constants
+ty_utils_index_not_supported = indexing is not supported in generic constants
+
+ty_utils_inline_asm_not_supported = assembly is not supported in generic constants
 
 ty_utils_logical_op_not_supported = unsupported operation in generic constants, short-circuiting operations would imply control flow
 
-ty_utils_assign_not_supported = assignment is not supported in generic constants
+ty_utils_loop_not_supported = loops and loop control flow are not supported in generic constants
 
-ty_utils_closure_and_return_not_supported = closures and function keywords are not supported in generic constants
+ty_utils_multiple_array_fields_simd_type = monomorphising SIMD type `{$ty}` with more than one array field
 
-ty_utils_control_flow_not_supported = control flow is not supported in generic constants
+ty_utils_needs_drop_overflow = overflow while checking whether `{$query_ty}` requires drop
 
-ty_utils_inline_asm_not_supported = assembly is not supported in generic constants
+ty_utils_never_to_any_not_supported = coercing the `never` type is not supported in generic constants
+
+ty_utils_non_primitive_simd_type = monomorphising SIMD type `{$ty}` with a non-primitive-scalar (integer/float/pointer) element type `{$e_ty}`
 
 ty_utils_operation_not_supported = unsupported operation in generic constants
 
-ty_utils_unexpected_fnptr_associated_item = `FnPtr` trait with unexpected associated item
+ty_utils_oversized_simd_type = monomorphising SIMD type `{$ty}` of length greater than {$max_lanes}
 
-ty_utils_zero_length_simd_type = monomorphising SIMD type `{$ty}` of zero length
+ty_utils_pointer_not_supported = pointer casts are not allowed in generic constants
 
-ty_utils_multiple_array_fields_simd_type = monomorphising SIMD type `{$ty}` with more than one array field
+ty_utils_tuple_not_supported = tuple construction is not supported in generic constants
 
-ty_utils_oversized_simd_type = monomorphising SIMD type `{$ty}` of length greater than {$max_lanes}
+ty_utils_unexpected_fnptr_associated_item = `FnPtr` trait with unexpected associated item
 
-ty_utils_non_primitive_simd_type = monomorphising SIMD type `{$ty}` with a non-primitive-scalar (integer/float/pointer) element type `{$e_ty}`
+ty_utils_yield_not_supported = generator control flow is not allowed in generic constants
+
+ty_utils_zero_length_simd_type = monomorphising SIMD type `{$ty}` of zero length
diff --git a/compiler/rustc_ty_utils/src/abi.rs b/compiler/rustc_ty_utils/src/abi.rs
index 271284b2d..15c191046 100644
--- a/compiler/rustc_ty_utils/src/abi.rs
+++ b/compiler/rustc_ty_utils/src/abi.rs
@@ -1,5 +1,6 @@
 use rustc_hir as hir;
 use rustc_hir::lang_items::LangItem;
+use rustc_middle::query::Providers;
 use rustc_middle::ty::layout::{
     fn_can_unwind, FnAbiError, HasParamEnv, HasTyCtxt, LayoutCx, LayoutOf, TyAndLayout,
 };
@@ -14,8 +15,8 @@ use rustc_target::spec::abi::Abi as SpecAbi;
 
 use std::iter;
 
-pub fn provide(providers: &mut ty::query::Providers) {
-    *providers = ty::query::Providers { fn_abi_of_fn_ptr, fn_abi_of_instance, ..*providers };
+pub fn provide(providers: &mut Providers) {
+    *providers = Providers { fn_abi_of_fn_ptr, fn_abi_of_instance, ..*providers };
 }
 
 // NOTE(eddyb) this is private to avoid using it from outside of
@@ -237,6 +238,7 @@ fn adjust_for_rust_scalar<'tcx>(
     layout: TyAndLayout<'tcx>,
     offset: Size,
     is_return: bool,
+    drop_target_pointee: Option<Ty<'tcx>>,
 ) {
     // Booleans are always a noundef i1 that needs to be zero-extended.
     if scalar.is_bool() {
@@ -250,14 +252,24 @@ fn adjust_for_rust_scalar<'tcx>(
     }
 
     // Only pointer types handled below.
-    let Scalar::Initialized { value: Pointer(_), valid_range} = scalar else { return };
+    let Scalar::Initialized { value: Pointer(_), valid_range } = scalar else { return };
 
-    if !valid_range.contains(0) {
+    // Set `nonnull` if the validity range excludes zero, or for the argument to `drop_in_place`,
+    // which must be nonnull per its documented safety requirements.
+    if !valid_range.contains(0) || drop_target_pointee.is_some() {
         attrs.set(ArgAttribute::NonNull);
     }
 
     if let Some(pointee) = layout.pointee_info_at(&cx, offset) {
-        if let Some(kind) = pointee.safe {
+        let kind = if let Some(kind) = pointee.safe {
+            Some(kind)
+        } else if let Some(pointee) = drop_target_pointee {
+            // The argument to `drop_in_place` is semantically equivalent to a mutable reference.
+            Some(PointerKind::MutableRef { unpin: pointee.is_unpin(cx.tcx, cx.param_env()) })
+        } else {
+            None
+        };
+        if let Some(kind) = kind {
             attrs.pointee_align = Some(pointee.align);
 
             // `Box` are not necessarily dereferenceable for the entire duration of the function as
@@ -361,10 +373,18 @@ fn fn_abi_new_uncached<'tcx>(
     use SpecAbi::*;
     let rust_abi = matches!(sig.abi, RustIntrinsic | PlatformIntrinsic | Rust | RustCall);
 
+    let is_drop_in_place =
+        fn_def_id.is_some() && fn_def_id == cx.tcx.lang_items().drop_in_place_fn();
+
     let arg_of = |ty: Ty<'tcx>, arg_idx: Option<usize>| -> Result<_, FnAbiError<'tcx>> {
         let span = tracing::debug_span!("arg_of");
         let _entered = span.enter();
         let is_return = arg_idx.is_none();
+        let is_drop_target = is_drop_in_place && arg_idx == Some(0);
+        let drop_target_pointee = is_drop_target.then(|| match ty.kind() {
+            ty::RawPtr(ty::TypeAndMut { ty, .. }) => *ty,
+            _ => bug!("argument to drop_in_place is not a raw ptr: {:?}", ty),
+        });
 
         let layout = cx.layout_of(ty)?;
         let layout = if force_thin_self_ptr && arg_idx == Some(0) {
@@ -378,7 +398,15 @@ fn fn_abi_new_uncached<'tcx>(
 
         let mut arg = ArgAbi::new(cx, layout, |layout, scalar, offset| {
             let mut attrs = ArgAttributes::new();
-            adjust_for_rust_scalar(*cx, &mut attrs, scalar, *layout, offset, is_return);
+            adjust_for_rust_scalar(
+                *cx,
+                &mut attrs,
+                scalar,
+                *layout,
+                offset,
+                is_return,
+                drop_target_pointee,
+            );
             attrs
         });
 
diff --git a/compiler/rustc_ty_utils/src/assoc.rs b/compiler/rustc_ty_utils/src/assoc.rs
index de1e1a527..ed574f22e 100644
--- a/compiler/rustc_ty_utils/src/assoc.rs
+++ b/compiler/rustc_ty_utils/src/assoc.rs
@@ -4,11 +4,12 @@ use rustc_hir::def::DefKind;
 use rustc_hir::def_id::{DefId, DefIdMap, LocalDefId};
 use rustc_hir::definitions::DefPathData;
 use rustc_hir::intravisit::{self, Visitor};
+use rustc_middle::query::Providers;
 use rustc_middle::ty::{self, ImplTraitInTraitData, InternalSubsts, TyCtxt};
 use rustc_span::symbol::kw;
 
-pub fn provide(providers: &mut ty::query::Providers) {
-    *providers = ty::query::Providers {
+pub fn provide(providers: &mut Providers) {
+    *providers = Providers {
         associated_item,
         associated_item_def_ids,
         associated_items,
@@ -334,7 +335,7 @@ fn associated_type_for_impl_trait_in_trait(
             parent_count,
             params,
             param_def_id_to_index,
-            has_self: false,
+            has_self: opaque_ty_generics.has_self,
             has_late_bound_regions: opaque_ty_generics.has_late_bound_regions,
         }
     });
diff --git a/compiler/rustc_ty_utils/src/common_traits.rs b/compiler/rustc_ty_utils/src/common_traits.rs
index 3b1abdcb2..51b908881 100644
--- a/compiler/rustc_ty_utils/src/common_traits.rs
+++ b/compiler/rustc_ty_utils/src/common_traits.rs
@@ -2,6 +2,7 @@
 
 use rustc_hir::lang_items::LangItem;
 use rustc_infer::infer::TyCtxtInferExt;
+use rustc_middle::query::Providers;
 use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_trait_selection::traits;
 
@@ -32,12 +33,6 @@ fn is_item_raw<'tcx>(
     traits::type_known_to_meet_bound_modulo_regions(&infcx, param_env, ty, trait_def_id)
 }
 
-pub(crate) fn provide(providers: &mut ty::query::Providers) {
-    *providers = ty::query::Providers {
-        is_copy_raw,
-        is_sized_raw,
-        is_freeze_raw,
-        is_unpin_raw,
-        ..*providers
-    };
+pub(crate) fn provide(providers: &mut Providers) {
+    *providers = Providers { is_copy_raw, is_sized_raw, is_freeze_raw, is_unpin_raw, ..*providers };
 }
diff --git a/compiler/rustc_ty_utils/src/consts.rs b/compiler/rustc_ty_utils/src/consts.rs
index b67607a4d..1219bb400 100644
--- a/compiler/rustc_ty_utils/src/consts.rs
+++ b/compiler/rustc_ty_utils/src/consts.rs
@@ -2,6 +2,7 @@ use rustc_errors::ErrorGuaranteed;
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::LocalDefId;
 use rustc_middle::mir::interpret::{LitToConstError, LitToConstInput};
+use rustc_middle::query::Providers;
 use rustc_middle::thir::visit;
 use rustc_middle::thir::visit::Visitor;
 use rustc_middle::ty::abstract_const::CastKind;
@@ -115,9 +116,7 @@ fn recurse_build<'tcx>(
             let sp = node.span;
             match tcx.at(sp).lit_to_const(LitToConstInput { lit: &lit.node, ty: node.ty, neg }) {
                 Ok(c) => c,
-                Err(LitToConstError::Reported(guar)) => {
-                    tcx.const_error_with_guaranteed(node.ty, guar)
-                }
+                Err(LitToConstError::Reported(guar)) => tcx.const_error(node.ty, guar),
                 Err(LitToConstError::TypeError) => {
                     bug!("encountered type error in lit_to_const")
                 }
@@ -132,7 +131,7 @@ fn recurse_build<'tcx>(
             tcx.mk_const(val, node.ty)
         }
         &ExprKind::NamedConst { def_id, substs, user_ty: _ } => {
-            let uneval = ty::UnevaluatedConst::new(ty::WithOptConstParam::unknown(def_id), substs);
+            let uneval = ty::UnevaluatedConst::new(def_id, substs);
             tcx.mk_const(uneval, node.ty)
         }
         ExprKind::ConstParam { param, .. } => tcx.mk_const(*param, node.ty),
@@ -256,6 +255,7 @@ fn recurse_build<'tcx>(
         ExprKind::VarRef { .. }
         | ExprKind::UpvarRef { .. }
         | ExprKind::StaticRef { .. }
+        | ExprKind::OffsetOf { .. }
         | ExprKind::ThreadLocalRef(_) => {
             error(GenericConstantTooComplexSub::OperationNotSupported(node.span))?
         }
@@ -347,6 +347,7 @@ impl<'a, 'tcx> IsThirPolymorphic<'a, 'tcx> {
             | thir::ExprKind::ZstLiteral { .. }
             | thir::ExprKind::StaticRef { .. }
             | thir::ExprKind::InlineAsm(_)
+            | thir::ExprKind::OffsetOf { .. }
             | thir::ExprKind::ThreadLocalRef(_)
             | thir::ExprKind::Yield { .. } => false,
         }
@@ -391,52 +392,36 @@ impl<'a, 'tcx> visit::Visitor<'a, 'tcx> for IsThirPolymorphic<'a, 'tcx> {
 /// Builds an abstract const, do not use this directly, but use `AbstractConst::new` instead.
 pub fn thir_abstract_const(
     tcx: TyCtxt<'_>,
-    def: ty::WithOptConstParam<LocalDefId>,
-) -> Result<Option<ty::Const<'_>>, ErrorGuaranteed> {
-    if tcx.features().generic_const_exprs {
-        match tcx.def_kind(def.did) {
-            // FIXME(generic_const_exprs): We currently only do this for anonymous constants,
-            // meaning that we do not look into associated constants. I(@lcnr) am not yet sure whether
-            // we want to look into them or treat them as opaque projections.
-            //
-            // Right now we do neither of that and simply always fail to unify them.
-            DefKind::AnonConst | DefKind::InlineConst => (),
-            _ => return Ok(None),
-        }
-
-        let body = tcx.thir_body(def)?;
-        let (body, body_id) = (&*body.0.borrow(), body.1);
+    def: LocalDefId,
+) -> Result<Option<ty::EarlyBinder<ty::Const<'_>>>, ErrorGuaranteed> {
+    if !tcx.features().generic_const_exprs {
+        return Ok(None);
+    }
 
-        let mut is_poly_vis = IsThirPolymorphic { is_poly: false, thir: body };
-        visit::walk_expr(&mut is_poly_vis, &body[body_id]);
-        if !is_poly_vis.is_poly {
-            return Ok(None);
-        }
+    match tcx.def_kind(def) {
+        // FIXME(generic_const_exprs): We currently only do this for anonymous constants,
+        // meaning that we do not look into associated constants. I(@lcnr) am not yet sure whether
+        // we want to look into them or treat them as opaque projections.
+        //
+        // Right now we do neither of that and simply always fail to unify them.
+        DefKind::AnonConst | DefKind::InlineConst => (),
+        _ => return Ok(None),
+    }
 
-        let root_span = body.exprs[body_id].span;
+    let body = tcx.thir_body(def)?;
+    let (body, body_id) = (&*body.0.borrow(), body.1);
 
-        Some(recurse_build(tcx, body, body_id, root_span)).transpose()
-    } else {
-        Ok(None)
+    let mut is_poly_vis = IsThirPolymorphic { is_poly: false, thir: body };
+    visit::walk_expr(&mut is_poly_vis, &body[body_id]);
+    if !is_poly_vis.is_poly {
+        return Ok(None);
     }
+
+    let root_span = body.exprs[body_id].span;
+
+    Ok(Some(ty::EarlyBinder(recurse_build(tcx, body, body_id, root_span)?)))
 }
 
-pub fn provide(providers: &mut ty::query::Providers) {
-    *providers = ty::query::Providers {
-        destructure_const,
-        thir_abstract_const: |tcx, def_id| {
-            if let Some(def) = ty::WithOptConstParam::try_lookup(def_id, tcx) {
-                tcx.thir_abstract_const_of_const_arg(def)
-            } else {
-                thir_abstract_const(tcx, ty::WithOptConstParam::unknown(def_id))
-            }
-        },
-        thir_abstract_const_of_const_arg: |tcx, (did, param_did)| {
-            thir_abstract_const(
-                tcx,
-                ty::WithOptConstParam { did, const_param_did: Some(param_did) },
-            )
-        },
-        ..*providers
-    };
+pub fn provide(providers: &mut Providers) {
+    *providers = Providers { destructure_const, thir_abstract_const, ..*providers };
 }
diff --git a/compiler/rustc_ty_utils/src/errors.rs b/compiler/rustc_ty_utils/src/errors.rs
index 3d3fc50e6..553bf40ef 100644
--- a/compiler/rustc_ty_utils/src/errors.rs
+++ b/compiler/rustc_ty_utils/src/errors.rs
@@ -1,7 +1,7 @@
 //! Errors emitted by ty_utils
 
 use rustc_macros::{Diagnostic, Subdiagnostic};
-use rustc_middle::ty::Ty;
+use rustc_middle::ty::{GenericArg, Ty};
 use rustc_span::Span;
 
 #[derive(Diagnostic)]
@@ -100,3 +100,25 @@ pub struct NonPrimitiveSimdType<'tcx> {
     pub ty: Ty<'tcx>,
     pub e_ty: Ty<'tcx>,
 }
+
+#[derive(Diagnostic)]
+#[diag(ty_utils_impl_trait_duplicate_arg)]
+pub struct DuplicateArg<'tcx> {
+    pub arg: GenericArg<'tcx>,
+    #[primary_span]
+    #[label]
+    pub span: Span,
+    #[note]
+    pub opaque_span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(ty_utils_impl_trait_not_param)]
+pub struct NotParam<'tcx> {
+    pub arg: GenericArg<'tcx>,
+    #[primary_span]
+    #[label]
+    pub span: Span,
+    #[note]
+    pub opaque_span: Span,
+}
diff --git a/compiler/rustc_ty_utils/src/implied_bounds.rs b/compiler/rustc_ty_utils/src/implied_bounds.rs
index 56d6cc28b..081be0658 100644
--- a/compiler/rustc_ty_utils/src/implied_bounds.rs
+++ b/compiler/rustc_ty_utils/src/implied_bounds.rs
@@ -1,8 +1,9 @@
 use rustc_hir::{def::DefKind, def_id::DefId};
+use rustc_middle::query::Providers;
 use rustc_middle::ty::{self, Ty, TyCtxt};
 
-pub fn provide(providers: &mut ty::query::Providers) {
-    *providers = ty::query::Providers { assumed_wf_types, ..*providers };
+pub fn provide(providers: &mut Providers) {
+    *providers = Providers { assumed_wf_types, ..*providers };
 }
 
 fn assumed_wf_types(tcx: TyCtxt<'_>, def_id: DefId) -> &ty::List<Ty<'_>> {
@@ -31,6 +32,18 @@ fn assumed_wf_types(tcx: TyCtxt<'_>, def_id: DefId) -> &ty::List<Ty<'_>> {
             }
         }
         DefKind::AssocConst | DefKind::AssocTy => tcx.assumed_wf_types(tcx.parent(def_id)),
+        DefKind::OpaqueTy => match tcx.def_kind(tcx.parent(def_id)) {
+            DefKind::TyAlias => ty::List::empty(),
+            DefKind::AssocTy => tcx.assumed_wf_types(tcx.parent(def_id)),
+            // Nested opaque types only occur in associated types:
+            // ` type Opaque<T> = impl Trait<&'static T, AssocTy = impl Nested>; `
+            // assumed_wf_types should include those of `Opaque<T>`, `Opaque<T>` itself
+            // and `&'static T`.
+            DefKind::OpaqueTy => bug!("unimplemented implied bounds for neseted opaque types"),
+            def_kind @ _ => {
+                bug!("unimplemented implied bounds for opaque types with parent {def_kind:?}")
+            }
+        },
         DefKind::Mod
         | DefKind::Struct
         | DefKind::Union
@@ -51,7 +64,6 @@ fn assumed_wf_types(tcx: TyCtxt<'_>, def_id: DefId) -> &ty::List<Ty<'_>> {
         | DefKind::ForeignMod
         | DefKind::AnonConst
         | DefKind::InlineConst
-        | DefKind::OpaqueTy
         | DefKind::ImplTraitPlaceholder
         | DefKind::Field
         | DefKind::LifetimeParam
diff --git a/compiler/rustc_ty_utils/src/instance.rs b/compiler/rustc_ty_utils/src/instance.rs
index 0a6c11809..36a20c78f 100644
--- a/compiler/rustc_ty_utils/src/instance.rs
+++ b/compiler/rustc_ty_utils/src/instance.rs
@@ -1,6 +1,7 @@
 use rustc_errors::ErrorGuaranteed;
-use rustc_hir::def_id::{DefId, LocalDefId};
+use rustc_hir::def_id::DefId;
 use rustc_infer::infer::TyCtxtInferExt;
+use rustc_middle::query::Providers;
 use rustc_middle::traits::CodegenObligationError;
 use rustc_middle::ty::subst::SubstsRef;
 use rustc_middle::ty::{self, Instance, TyCtxt, TypeVisitableExt};
@@ -14,54 +15,25 @@ fn resolve_instance<'tcx>(
     tcx: TyCtxt<'tcx>,
     key: ty::ParamEnvAnd<'tcx, (DefId, SubstsRef<'tcx>)>,
 ) -> Result<Option<Instance<'tcx>>, ErrorGuaranteed> {
-    let (param_env, (did, substs)) = key.into_parts();
-    if let Some(did) = did.as_local() {
-        if let Some(param_did) = tcx.opt_const_param_of(did) {
-            return tcx.resolve_instance_of_const_arg(param_env.and((did, param_did, substs)));
-        }
-    }
-
-    inner_resolve_instance(tcx, param_env.and((ty::WithOptConstParam::unknown(did), substs)))
-}
-
-fn resolve_instance_of_const_arg<'tcx>(
-    tcx: TyCtxt<'tcx>,
-    key: ty::ParamEnvAnd<'tcx, (LocalDefId, DefId, SubstsRef<'tcx>)>,
-) -> Result<Option<Instance<'tcx>>, ErrorGuaranteed> {
-    let (param_env, (did, const_param_did, substs)) = key.into_parts();
-    inner_resolve_instance(
-        tcx,
-        param_env.and((
-            ty::WithOptConstParam { did: did.to_def_id(), const_param_did: Some(const_param_did) },
-            substs,
-        )),
-    )
-}
-
-fn inner_resolve_instance<'tcx>(
-    tcx: TyCtxt<'tcx>,
-    key: ty::ParamEnvAnd<'tcx, (ty::WithOptConstParam<DefId>, SubstsRef<'tcx>)>,
-) -> Result<Option<Instance<'tcx>>, ErrorGuaranteed> {
     let (param_env, (def, substs)) = key.into_parts();
 
-    let result = if let Some(trait_def_id) = tcx.trait_of_item(def.did) {
+    let result = if let Some(trait_def_id) = tcx.trait_of_item(def) {
         debug!(" => associated item, attempting to find impl in param_env {:#?}", param_env);
         resolve_associated_item(
             tcx,
-            def.did,
+            def,
             param_env,
             trait_def_id,
             tcx.normalize_erasing_regions(param_env, substs),
         )
     } else {
-        let ty = tcx.type_of(def.def_id_for_type_of());
-        let item_type =
-            tcx.subst_and_normalize_erasing_regions(substs, param_env, ty.skip_binder());
+        let ty = tcx.type_of(def);
+        let item_type = tcx.subst_and_normalize_erasing_regions(substs, param_env, ty);
 
         let def = match *item_type.kind() {
             ty::FnDef(def_id, ..) if tcx.is_intrinsic(def_id) => {
                 debug!(" => intrinsic");
-                ty::InstanceDef::Intrinsic(def.did)
+                ty::InstanceDef::Intrinsic(def)
             }
             ty::FnDef(def_id, substs) if Some(def_id) == tcx.lang_items().drop_in_place_fn() => {
                 let ty = substs.type_at(0);
@@ -113,7 +85,7 @@ fn resolve_associated_item<'tcx>(
         Err(CodegenObligationError::Ambiguity) => {
             let reported = tcx.sess.delay_span_bug(
                 tcx.def_span(trait_item_id),
-                &format!(
+                format!(
                     "encountered ambiguity selecting `{trait_ref:?}` during codegen, presuming due to \
                      overflow or prior type error",
                 ),
@@ -132,8 +104,8 @@ fn resolve_associated_item<'tcx>(
                 "resolving ImplSource::UserDefined: {:?}, {:?}, {:?}, {:?}",
                 param_env, trait_item_id, rcvr_substs, impl_data
             );
-            assert!(!rcvr_substs.needs_infer());
-            assert!(!trait_ref.needs_infer());
+            assert!(!rcvr_substs.has_infer());
+            assert!(!trait_ref.has_infer());
 
             let trait_def_id = tcx.trait_id_of_impl(impl_data.impl_def_id).unwrap();
             let trait_def = tcx.trait_def(trait_def_id);
@@ -205,19 +177,52 @@ fn resolve_associated_item<'tcx>(
 
             Some(ty::Instance::new(leaf_def.item.def_id, substs))
         }
-        traits::ImplSource::Generator(generator_data) => Some(Instance {
-            def: ty::InstanceDef::Item(ty::WithOptConstParam::unknown(
-                generator_data.generator_def_id,
-            )),
-            substs: generator_data.substs,
-        }),
-        traits::ImplSource::Future(future_data) => Some(Instance {
-            def: ty::InstanceDef::Item(ty::WithOptConstParam::unknown(
-                future_data.generator_def_id,
-            )),
-            substs: future_data.substs,
-        }),
+        traits::ImplSource::Generator(generator_data) => {
+            if cfg!(debug_assertions) && tcx.item_name(trait_item_id) != sym::resume {
+                // For compiler developers who'd like to add new items to `Generator`,
+                // you either need to generate a shim body, or perhaps return
+                // `InstanceDef::Item` pointing to a trait default method body if
+                // it is given a default implementation by the trait.
+                span_bug!(
+                    tcx.def_span(generator_data.generator_def_id),
+                    "no definition for `{trait_ref}::{}` for built-in generator type",
+                    tcx.item_name(trait_item_id)
+                )
+            }
+            Some(Instance {
+                def: ty::InstanceDef::Item(generator_data.generator_def_id),
+                substs: generator_data.substs,
+            })
+        }
+        traits::ImplSource::Future(future_data) => {
+            if Some(trait_item_id) == tcx.lang_items().future_poll_fn() {
+                // `Future::poll` is generated by the compiler.
+                Some(Instance {
+                    def: ty::InstanceDef::Item(future_data.generator_def_id),
+                    substs: future_data.substs,
+                })
+            } else {
+                // All other methods are default methods of the `Future` trait.
+                // (this assumes that `ImplSource::Future` is only used for methods on `Future`)
+                debug_assert!(tcx.impl_defaultness(trait_item_id).has_value());
+                Some(Instance::new(trait_item_id, rcvr_substs))
+            }
+        }
         traits::ImplSource::Closure(closure_data) => {
+            if cfg!(debug_assertions)
+                && ![sym::call, sym::call_mut, sym::call_once]
+                    .contains(&tcx.item_name(trait_item_id))
+            {
+                // For compiler developers who'd like to add new items to `Fn`/`FnMut`/`FnOnce`,
+                // you either need to generate a shim body, or perhaps return
+                // `InstanceDef::Item` pointing to a trait default method body if
+                // it is given a default implementation by the trait.
+                span_bug!(
+                    tcx.def_span(closure_data.closure_def_id),
+                    "no definition for `{trait_ref}::{}` for built-in closure type",
+                    tcx.item_name(trait_item_id)
+                )
+            }
             let trait_closure_kind = tcx.fn_trait_kind_from_def_id(trait_id).unwrap();
             Instance::resolve_closure(
                 tcx,
@@ -227,22 +232,37 @@ fn resolve_associated_item<'tcx>(
             )
         }
         traits::ImplSource::FnPointer(ref data) => match data.fn_ty.kind() {
-            ty::FnDef(..) | ty::FnPtr(..) => Some(Instance {
-                def: ty::InstanceDef::FnPtrShim(trait_item_id, data.fn_ty),
-                substs: rcvr_substs,
-            }),
-            _ => None,
-        },
-        traits::ImplSource::Object(ref data) => {
-            if let Some(index) = traits::get_vtable_index_of_object_method(tcx, data, trait_item_id)
-            {
+            ty::FnDef(..) | ty::FnPtr(..) => {
+                if cfg!(debug_assertions)
+                    && ![sym::call, sym::call_mut, sym::call_once]
+                        .contains(&tcx.item_name(trait_item_id))
+                {
+                    // For compiler developers who'd like to add new items to `Fn`/`FnMut`/`FnOnce`,
+                    // you either need to generate a shim body, or perhaps return
+                    // `InstanceDef::Item` pointing to a trait default method body if
+                    // it is given a default implementation by the trait.
+                    bug!(
+                        "no definition for `{trait_ref}::{}` for built-in fn type",
+                        tcx.item_name(trait_item_id)
+                    )
+                }
                 Some(Instance {
-                    def: ty::InstanceDef::Virtual(trait_item_id, index),
+                    def: ty::InstanceDef::FnPtrShim(trait_item_id, data.fn_ty),
                     substs: rcvr_substs,
                 })
-            } else {
-                None
             }
+            _ => bug!(
+                "no built-in definition for `{trait_ref}::{}` for non-fn type",
+                tcx.item_name(trait_item_id)
+            ),
+        },
+        traits::ImplSource::Object(ref data) => {
+            traits::get_vtable_index_of_object_method(tcx, data, trait_item_id).map(|index| {
+                Instance {
+                    def: ty::InstanceDef::Virtual(trait_item_id, index),
+                    substs: rcvr_substs,
+                }
+            })
         }
         traits::ImplSource::Builtin(..) => {
             let lang_items = tcx.lang_items();
@@ -300,7 +320,6 @@ fn resolve_associated_item<'tcx>(
     })
 }
 
-pub fn provide(providers: &mut ty::query::Providers) {
-    *providers =
-        ty::query::Providers { resolve_instance, resolve_instance_of_const_arg, ..*providers };
+pub fn provide(providers: &mut Providers) {
+    *providers = Providers { resolve_instance, ..*providers };
 }
diff --git a/compiler/rustc_ty_utils/src/layout.rs b/compiler/rustc_ty_utils/src/layout.rs
index 63ef1c724..16cd8bc8e 100644
--- a/compiler/rustc_ty_utils/src/layout.rs
+++ b/compiler/rustc_ty_utils/src/layout.rs
@@ -1,8 +1,9 @@
 use hir::def_id::DefId;
 use rustc_hir as hir;
 use rustc_index::bit_set::BitSet;
-use rustc_index::vec::{IndexSlice, IndexVec};
+use rustc_index::{IndexSlice, IndexVec};
 use rustc_middle::mir::{GeneratorLayout, GeneratorSavedLocal};
+use rustc_middle::query::Providers;
 use rustc_middle::ty::layout::{
     IntegerExt, LayoutCx, LayoutError, LayoutOf, TyAndLayout, MAX_SIMD_LANES,
 };
@@ -22,8 +23,8 @@ use crate::errors::{
 };
 use crate::layout_sanity_check::sanity_check_layout;
 
-pub fn provide(providers: &mut ty::query::Providers) {
-    *providers = ty::query::Providers { layout_of, ..*providers };
+pub fn provide(providers: &mut Providers) {
+    *providers = Providers { layout_of, ..*providers };
 }
 
 #[instrument(skip(tcx, query), level = "debug")]
diff --git a/compiler/rustc_ty_utils/src/layout_sanity_check.rs b/compiler/rustc_ty_utils/src/layout_sanity_check.rs
index a5311dbd1..c4a4cda68 100644
--- a/compiler/rustc_ty_utils/src/layout_sanity_check.rs
+++ b/compiler/rustc_ty_utils/src/layout_sanity_check.rs
@@ -4,7 +4,7 @@ use rustc_middle::ty::{
 };
 use rustc_target::abi::*;
 
-use std::cmp;
+use std::assert_matches::assert_matches;
 
 /// Enforce some basic invariants on layouts.
 pub(super) fn sanity_check_layout<'tcx>(
@@ -68,21 +68,31 @@ pub(super) fn sanity_check_layout<'tcx>(
     }
 
     fn check_layout_abi<'tcx>(cx: &LayoutCx<'tcx, TyCtxt<'tcx>>, layout: &TyAndLayout<'tcx>) {
+        // Verify the ABI mandated alignment and size.
+        let align = layout.abi.inherent_align(cx).map(|align| align.abi);
+        let size = layout.abi.inherent_size(cx);
+        let Some((align, size)) = align.zip(size) else {
+            assert_matches!(
+                layout.layout.abi(),
+                Abi::Uninhabited | Abi::Aggregate { .. },
+                "ABI unexpectedly missing alignment and/or size in {layout:#?}"
+            );
+            return
+        };
+        assert_eq!(
+            layout.layout.align().abi,
+            align,
+            "alignment mismatch between ABI and layout in {layout:#?}"
+        );
+        assert_eq!(
+            layout.layout.size(),
+            size,
+            "size mismatch between ABI and layout in {layout:#?}"
+        );
+
+        // Verify per-ABI invariants
         match layout.layout.abi() {
-            Abi::Scalar(scalar) => {
-                // No padding in scalars.
-                let size = scalar.size(cx);
-                let align = scalar.align(cx).abi;
-                assert_eq!(
-                    layout.layout.size(),
-                    size,
-                    "size mismatch between ABI and layout in {layout:#?}"
-                );
-                assert_eq!(
-                    layout.layout.align().abi,
-                    align,
-                    "alignment mismatch between ABI and layout in {layout:#?}"
-                );
+            Abi::Scalar(_) => {
                 // Check that this matches the underlying field.
                 let inner = skip_newtypes(cx, layout);
                 assert!(
@@ -135,24 +145,6 @@ pub(super) fn sanity_check_layout<'tcx>(
                 }
             }
             Abi::ScalarPair(scalar1, scalar2) => {
-                // Sanity-check scalar pairs. Computing the expected size and alignment is a bit of work.
-                let size1 = scalar1.size(cx);
-                let align1 = scalar1.align(cx).abi;
-                let size2 = scalar2.size(cx);
-                let align2 = scalar2.align(cx).abi;
-                let align = cmp::max(align1, align2);
-                let field2_offset = size1.align_to(align2);
-                let size = (field2_offset + size2).align_to(align);
-                assert_eq!(
-                    layout.layout.size(),
-                    size,
-                    "size mismatch between ABI and layout in {layout:#?}"
-                );
-                assert_eq!(
-                    layout.layout.align().abi,
-                    align,
-                    "alignment mismatch between ABI and layout in {layout:#?}",
-                );
                 // Check that the underlying pair of fields matches.
                 let inner = skip_newtypes(cx, layout);
                 assert!(
@@ -189,8 +181,9 @@ pub(super) fn sanity_check_layout<'tcx>(
                         "`ScalarPair` layout for type with less than two non-ZST fields: {inner:#?}"
                     )
                 });
-                assert!(
-                    fields.next().is_none(),
+                assert_matches!(
+                    fields.next(),
+                    None,
                     "`ScalarPair` layout for type with at least three non-ZST fields: {inner:#?}"
                 );
                 // The fields might be in opposite order.
@@ -200,6 +193,10 @@ pub(super) fn sanity_check_layout<'tcx>(
                     (offset2, field2, offset1, field1)
                 };
                 // The fields should be at the right offset, and match the `scalar` layout.
+                let size1 = scalar1.size(cx);
+                let align1 = scalar1.align(cx).abi;
+                let size2 = scalar2.size(cx);
+                let align2 = scalar2.align(cx).abi;
                 assert_eq!(
                     offset1,
                     Size::ZERO,
@@ -213,10 +210,12 @@ pub(super) fn sanity_check_layout<'tcx>(
                     field1.align.abi, align1,
                     "`ScalarPair` first field with bad align in {inner:#?}",
                 );
-                assert!(
-                    matches!(field1.abi, Abi::Scalar(_)),
+                assert_matches!(
+                    field1.abi,
+                    Abi::Scalar(_),
                     "`ScalarPair` first field with bad ABI in {inner:#?}",
                 );
+                let field2_offset = size1.align_to(align2);
                 assert_eq!(
                     offset2, field2_offset,
                     "`ScalarPair` second field at bad offset in {inner:#?}",
@@ -229,27 +228,14 @@ pub(super) fn sanity_check_layout<'tcx>(
                     field2.align.abi, align2,
                     "`ScalarPair` second field with bad align in {inner:#?}",
                 );
-                assert!(
-                    matches!(field2.abi, Abi::Scalar(_)),
+                assert_matches!(
+                    field2.abi,
+                    Abi::Scalar(_),
                     "`ScalarPair` second field with bad ABI in {inner:#?}",
                 );
             }
-            Abi::Vector { count, element } => {
-                // No padding in vectors, except possibly for trailing padding to make the size a multiple of align.
-                let size = element.size(cx) * count;
-                let align = cx.data_layout().vector_align(size).abi;
-                let size = size.align_to(align); // needed e.g. for vectors of size 3
+            Abi::Vector { element, .. } => {
                 assert!(align >= element.align(cx).abi); // just sanity-checking `vector_align`.
-                assert_eq!(
-                    layout.layout.size(),
-                    size,
-                    "size mismatch between ABI and layout in {layout:#?}"
-                );
-                assert_eq!(
-                    layout.layout.align().abi,
-                    align,
-                    "alignment mismatch between ABI and layout in {layout:#?}"
-                );
                 // FIXME: Do some kind of check of the inner type, like for Scalar and ScalarPair.
             }
             Abi::Uninhabited | Abi::Aggregate { .. } => {} // Nothing to check.
@@ -285,7 +271,7 @@ pub(super) fn sanity_check_layout<'tcx>(
             {
                 // These are never actually accessed anyway, so we can skip the coherence check
                 // for them. They also fail that check, since they have
-                // `Aggregate`/`Uninhbaited` ABI even when the main type is
+                // `Aggregate`/`Uninhabited` ABI even when the main type is
                 // `Scalar`/`ScalarPair`. (Note that sometimes, variants with fields have size
                 // 0, and sometimes, variants without fields have non-0 size.)
                 continue;
diff --git a/compiler/rustc_ty_utils/src/lib.rs b/compiler/rustc_ty_utils/src/lib.rs
index 2613445f3..55b8857ed 100644
--- a/compiler/rustc_ty_utils/src/lib.rs
+++ b/compiler/rustc_ty_utils/src/lib.rs
@@ -5,6 +5,7 @@
 //! This API is completely unstable and subject to change.
 
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
+#![feature(assert_matches)]
 #![feature(iterator_try_collect)]
 #![feature(let_chains)]
 #![feature(never_type)]
@@ -19,8 +20,8 @@ extern crate rustc_middle;
 extern crate tracing;
 
 use rustc_errors::{DiagnosticMessage, SubdiagnosticMessage};
-use rustc_macros::fluent_messages;
-use rustc_middle::ty::query::Providers;
+use rustc_fluent_macro::fluent_messages;
+use rustc_middle::query::Providers;
 
 mod abi;
 mod assoc;
@@ -32,6 +33,7 @@ pub mod instance;
 mod layout;
 mod layout_sanity_check;
 mod needs_drop;
+mod opaque_types;
 pub mod representability;
 mod structural_match;
 mod ty;
@@ -46,6 +48,7 @@ pub fn provide(providers: &mut Providers) {
     implied_bounds::provide(providers);
     layout::provide(providers);
     needs_drop::provide(providers);
+    opaque_types::provide(providers);
     representability::provide(providers);
     ty::provide(providers);
     instance::provide(providers);
diff --git a/compiler/rustc_ty_utils/src/needs_drop.rs b/compiler/rustc_ty_utils/src/needs_drop.rs
index de7fd0031..1f9701b93 100644
--- a/compiler/rustc_ty_utils/src/needs_drop.rs
+++ b/compiler/rustc_ty_utils/src/needs_drop.rs
@@ -2,6 +2,7 @@
 
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir::def_id::DefId;
+use rustc_middle::query::Providers;
 use rustc_middle::ty::subst::SubstsRef;
 use rustc_middle::ty::util::{needs_drop_components, AlwaysRequiresDrop};
 use rustc_middle::ty::{self, EarlyBinder, Ty, TyCtxt};
@@ -132,7 +133,7 @@ where
                             _ => {
                                 tcx.sess.delay_span_bug(
                                     tcx.hir().span_if_local(def_id).unwrap_or(DUMMY_SP),
-                                    &format!("unexpected generator witness type {:?}", witness),
+                                    format!("unexpected generator witness type {:?}", witness),
                                 );
                                 return Some(Err(AlwaysRequiresDrop));
                             }
@@ -243,7 +244,7 @@ fn drop_tys_helper<'tcx>(
         } else {
             let field_tys = adt_def.all_fields().map(|field| {
                 let r = tcx.type_of(field.did).subst(tcx, substs);
-                debug!("drop_tys_helper: Subst into {:?} with {:?} gettng {:?}", field, substs, r);
+                debug!("drop_tys_helper: Subst into {:?} with {:?} getting {:?}", field, substs, r);
                 r
             });
             if only_significant {
@@ -323,8 +324,8 @@ fn adt_significant_drop_tys(
     .map(|components| tcx.mk_type_list(&components))
 }
 
-pub(crate) fn provide(providers: &mut ty::query::Providers) {
-    *providers = ty::query::Providers {
+pub(crate) fn provide(providers: &mut Providers) {
+    *providers = Providers {
         needs_drop_raw,
         has_significant_drop_raw,
         adt_drop_tys,
diff --git a/compiler/rustc_ty_utils/src/opaque_types.rs b/compiler/rustc_ty_utils/src/opaque_types.rs
new file mode 100644
index 000000000..4e91dd380
--- /dev/null
+++ b/compiler/rustc_ty_utils/src/opaque_types.rs
@@ -0,0 +1,198 @@
+use rustc_data_structures::fx::FxHashSet;
+use rustc_errors::ErrorGuaranteed;
+use rustc_hir::{def::DefKind, def_id::LocalDefId};
+use rustc_middle::query::Providers;
+use rustc_middle::ty::util::{CheckRegions, NotUniqueParam};
+use rustc_middle::ty::{self, Ty, TyCtxt};
+use rustc_middle::ty::{TypeSuperVisitable, TypeVisitable, TypeVisitor};
+use rustc_span::Span;
+use rustc_type_ir::AliasKind;
+use std::ops::ControlFlow;
+
+use crate::errors::{DuplicateArg, NotParam};
+
+struct OpaqueTypeCollector<'tcx> {
+    tcx: TyCtxt<'tcx>,
+    opaques: Vec<LocalDefId>,
+    /// The `DefId` of the item which we are collecting opaque types for.
+    item: LocalDefId,
+
+    /// Avoid infinite recursion due to recursive declarations.
+    seen: FxHashSet<LocalDefId>,
+}
+
+impl<'tcx> OpaqueTypeCollector<'tcx> {
+    fn collect(
+        tcx: TyCtxt<'tcx>,
+        item: LocalDefId,
+        val: ty::Binder<'tcx, impl TypeVisitable<TyCtxt<'tcx>>>,
+    ) -> Vec<LocalDefId> {
+        let mut collector = Self { tcx, opaques: Vec::new(), item, seen: Default::default() };
+        val.skip_binder().visit_with(&mut collector);
+        collector.opaques
+    }
+
+    fn span(&self) -> Span {
+        self.tcx.def_span(self.item)
+    }
+
+    fn parent(&self) -> Option<LocalDefId> {
+        match self.tcx.def_kind(self.item) {
+            DefKind::Fn => None,
+            DefKind::AssocFn | DefKind::AssocTy | DefKind::AssocConst => {
+                Some(self.tcx.local_parent(self.item))
+            }
+            other => span_bug!(
+                self.tcx.def_span(self.item),
+                "unhandled item with opaque types: {other:?}"
+            ),
+        }
+    }
+}
+
+impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for OpaqueTypeCollector<'tcx> {
+    type BreakTy = ErrorGuaranteed;
+
+    #[instrument(skip(self), ret, level = "trace")]
+    fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<ErrorGuaranteed> {
+        match t.kind() {
+            ty::Alias(AliasKind::Opaque, alias_ty) if alias_ty.def_id.is_local() => {
+                if !self.seen.insert(alias_ty.def_id.expect_local()) {
+                    return ControlFlow::Continue(());
+                }
+                match self.tcx.uses_unique_generic_params(alias_ty.substs, CheckRegions::Bound) {
+                    Ok(()) => {
+                        // FIXME: implement higher kinded lifetime bounds on nested opaque types. They are not
+                        // supported at all, so this is sound to do, but once we want to support them, you'll
+                        // start seeing the error below.
+
+                        self.opaques.push(alias_ty.def_id.expect_local());
+
+                        // Collect opaque types nested within the associated type bounds of this opaque type.
+                        for (pred, _span) in self
+                            .tcx
+                            .explicit_item_bounds(alias_ty.def_id)
+                            .subst_iter_copied(self.tcx, alias_ty.substs)
+                        {
+                            trace!(?pred);
+                            pred.visit_with(self)?;
+                        }
+
+                        ControlFlow::Continue(())
+                    }
+                    Err(NotUniqueParam::NotParam(arg)) => {
+                        let err = self.tcx.sess.emit_err(NotParam {
+                            arg,
+                            span: self.span(),
+                            opaque_span: self.tcx.def_span(alias_ty.def_id),
+                        });
+                        ControlFlow::Break(err)
+                    }
+                    Err(NotUniqueParam::DuplicateParam(arg)) => {
+                        let err = self.tcx.sess.emit_err(DuplicateArg {
+                            arg,
+                            span: self.span(),
+                            opaque_span: self.tcx.def_span(alias_ty.def_id),
+                        });
+                        ControlFlow::Break(err)
+                    }
+                }
+            }
+            ty::Alias(AliasKind::Projection, alias_ty) => {
+                if let Some(parent) = self.parent() {
+                    trace!(?alias_ty);
+                    let (trait_ref, own_substs) = alias_ty.trait_ref_and_own_substs(self.tcx);
+
+                    trace!(?trait_ref, ?own_substs);
+                    // This avoids having to do normalization of `Self::AssocTy` by only
+                    // supporting the case of a method defining opaque types from assoc types
+                    // in the same impl block.
+                    if trait_ref.self_ty() == self.tcx.type_of(parent).subst_identity() {
+                        for assoc in self.tcx.associated_items(parent).in_definition_order() {
+                            trace!(?assoc);
+                            if assoc.trait_item_def_id == Some(alias_ty.def_id) {
+                                // We reconstruct the generic args of the associated type within the impl
+                                // from the impl's generics and the generic args passed to the type via the
+                                // projection.
+                                let substs = ty::InternalSubsts::identity_for_item(
+                                    self.tcx,
+                                    parent.to_def_id(),
+                                );
+                                trace!(?substs);
+                                let substs: Vec<_> =
+                                    substs.iter().chain(own_substs.iter().copied()).collect();
+                                trace!(?substs);
+                                // Find opaque types in this associated type.
+                                return self
+                                    .tcx
+                                    .type_of(assoc.def_id)
+                                    .subst(self.tcx, &substs)
+                                    .visit_with(self);
+                            }
+                        }
+                    }
+                }
+                t.super_visit_with(self)
+            }
+            _ => t.super_visit_with(self),
+        }
+    }
+}
+
+fn opaque_types_defined_by<'tcx>(tcx: TyCtxt<'tcx>, item: LocalDefId) -> &'tcx [LocalDefId] {
+    let kind = tcx.def_kind(item);
+    trace!(?kind);
+    // FIXME(type_alias_impl_trait): This is definitely still wrong except for RPIT and impl trait in assoc types.
+    match kind {
+        // We're also doing this for `AssocTy` for the wf checks in `check_opaque_meets_bounds`
+        DefKind::Fn | DefKind::AssocFn | DefKind::AssocTy | DefKind::AssocConst => {
+            let defined_opaques = match kind {
+                DefKind::Fn => {
+                    OpaqueTypeCollector::collect(tcx, item, tcx.fn_sig(item).subst_identity())
+                }
+                DefKind::AssocFn => {
+                    OpaqueTypeCollector::collect(tcx, item, tcx.fn_sig(item).subst_identity())
+                }
+                DefKind::AssocTy | DefKind::AssocConst => OpaqueTypeCollector::collect(
+                    tcx,
+                    item,
+                    ty::Binder::dummy(tcx.type_of(item).subst_identity()),
+                ),
+                _ => unreachable!(),
+            };
+            tcx.arena.alloc_from_iter(defined_opaques)
+        }
+        DefKind::Mod
+        | DefKind::Struct
+        | DefKind::Union
+        | DefKind::Enum
+        | DefKind::Variant
+        | DefKind::Trait
+        | DefKind::TyAlias
+        | DefKind::ForeignTy
+        | DefKind::TraitAlias
+        | DefKind::TyParam
+        | DefKind::Const
+        | DefKind::ConstParam
+        | DefKind::Static(_)
+        | DefKind::Ctor(_, _)
+        | DefKind::Macro(_)
+        | DefKind::ExternCrate
+        | DefKind::Use
+        | DefKind::ForeignMod
+        | DefKind::AnonConst
+        | DefKind::InlineConst
+        | DefKind::OpaqueTy
+        | DefKind::ImplTraitPlaceholder
+        | DefKind::Field
+        | DefKind::LifetimeParam
+        | DefKind::GlobalAsm
+        | DefKind::Impl { .. }
+        | DefKind::Closure
+        | DefKind::Generator => &[],
+    }
+}
+
+pub(super) fn provide(providers: &mut Providers) {
+    *providers = Providers { opaque_types_defined_by, ..*providers };
+}
diff --git a/compiler/rustc_ty_utils/src/representability.rs b/compiler/rustc_ty_utils/src/representability.rs
index 26d6deab8..0b5e27c2c 100644
--- a/compiler/rustc_ty_utils/src/representability.rs
+++ b/compiler/rustc_ty_utils/src/representability.rs
@@ -2,7 +2,7 @@
 
 use rustc_hir::def::DefKind;
 use rustc_index::bit_set::BitSet;
-use rustc_middle::ty::query::Providers;
+use rustc_middle::query::Providers;
 use rustc_middle::ty::{self, Representability, Ty, TyCtxt};
 use rustc_span::def_id::LocalDefId;
 
diff --git a/compiler/rustc_ty_utils/src/structural_match.rs b/compiler/rustc_ty_utils/src/structural_match.rs
index a55bb7e7e..215acbe2c 100644
--- a/compiler/rustc_ty_utils/src/structural_match.rs
+++ b/compiler/rustc_ty_utils/src/structural_match.rs
@@ -1,5 +1,5 @@
 use rustc_hir::lang_items::LangItem;
-use rustc_middle::ty::query::Providers;
+use rustc_middle::query::Providers;
 use rustc_middle::ty::{self, Ty, TyCtxt};
 
 use rustc_infer::infer::TyCtxtInferExt;
@@ -13,7 +13,7 @@ use rustc_trait_selection::traits::{ObligationCause, ObligationCtxt};
 /// Note that this does *not* recursively check if the substructure of `adt_ty`
 /// implements the traits.
 fn has_structural_eq_impls<'tcx>(tcx: TyCtxt<'tcx>, adt_ty: Ty<'tcx>) -> bool {
-    let ref infcx = tcx.infer_ctxt().build();
+    let infcx = &tcx.infer_ctxt().build();
     let cause = ObligationCause::dummy();
 
     let ocx = ObligationCtxt::new(infcx);
diff --git a/compiler/rustc_ty_utils/src/ty.rs b/compiler/rustc_ty_utils/src/ty.rs
index cb06c7acf..65dc3c39c 100644
--- a/compiler/rustc_ty_utils/src/ty.rs
+++ b/compiler/rustc_ty_utils/src/ty.rs
@@ -2,6 +2,7 @@ use rustc_data_structures::fx::{FxHashSet, FxIndexSet};
 use rustc_hir as hir;
 use rustc_hir::def::DefKind;
 use rustc_index::bit_set::BitSet;
+use rustc_middle::query::Providers;
 use rustc_middle::ty::{
     self, Binder, EarlyBinder, ImplTraitInTraitData, Predicate, PredicateKind, ToPredicate, Ty,
     TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitor,
@@ -62,9 +63,8 @@ fn sized_constraint_for_ty<'tcx>(
             // it on the impl.
 
             let Some(sized_trait) = tcx.lang_items().sized_trait() else { return vec![ty] };
-            let sized_predicate = ty::Binder::dummy(tcx.mk_trait_ref(sized_trait, [ty]))
-                .without_const()
-                .to_predicate(tcx);
+            let sized_predicate =
+                ty::TraitRef::new(tcx, sized_trait, [ty]).without_const().to_predicate(tcx);
             let predicates = tcx.predicates_of(adtdef.did()).predicates;
             if predicates.iter().any(|(p, _)| *p == sized_predicate) { vec![] } else { vec![ty] }
         }
@@ -567,8 +567,8 @@ fn unsizing_params_for_adt<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> BitSet<u32
     unsizing_params
 }
 
-pub fn provide(providers: &mut ty::query::Providers) {
-    *providers = ty::query::Providers {
+pub fn provide(providers: &mut Providers) {
+    *providers = Providers {
         asyncness,
         adt_sized_constraint,
         param_env,