Merging upstream version 1.68.2+dfsg1.

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

5 files changed, 417 insertions, 331 deletions

diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs
index 952d27262..6ed8adb47 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs
@@ -1,7 +1,7 @@
 use crate::callee::{self, DeferredCallResolution};
 use crate::method::{self, MethodCallee, SelfSource};
 use crate::rvalue_scopes;
-use crate::{BreakableCtxt, Diverges, Expectation, FnCtxt, LocalTy};
+use crate::{BreakableCtxt, Diverges, Expectation, FnCtxt, LocalTy, RawTy};
 use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::{Applicability, Diagnostic, ErrorGuaranteed, MultiSpan};
@@ -10,6 +10,9 @@ use rustc_hir::def::{CtorOf, DefKind, Res};
 use rustc_hir::def_id::DefId;
 use rustc_hir::lang_items::LangItem;
 use rustc_hir::{ExprKind, GenericArg, Node, QPath};
+use rustc_hir_analysis::astconv::generics::{
+    check_generic_arg_count_for_call, create_substs_for_generic_args,
+};
 use rustc_hir_analysis::astconv::{
     AstConv, CreateSubstsForGenericArgsCtxt, ExplicitLateBound, GenericArgCountMismatch,
     GenericArgCountResult, IsMethodCall, PathSeg,
@@ -22,9 +25,9 @@ use rustc_middle::ty::error::TypeError;
 use rustc_middle::ty::fold::TypeFoldable;
 use rustc_middle::ty::visit::TypeVisitable;
 use rustc_middle::ty::{
-    self, AdtKind, CanonicalUserType, DefIdTree, EarlyBinder, GenericParamDefKind, Ty, UserType,
+    self, AdtKind, CanonicalUserType, DefIdTree, GenericParamDefKind, Ty, UserType,
 };
-use rustc_middle::ty::{GenericArgKind, InternalSubsts, SubstsRef, UserSelfTy, UserSubsts};
+use rustc_middle::ty::{GenericArgKind, SubstsRef, UserSelfTy, UserSubsts};
 use rustc_session::lint;
 use rustc_span::def_id::LocalDefId;
 use rustc_span::hygiene::DesugaringKind;
@@ -161,47 +164,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     pub fn write_method_call(&self, hir_id: hir::HirId, method: MethodCallee<'tcx>) {
         self.write_resolution(hir_id, Ok((DefKind::AssocFn, method.def_id)));
         self.write_substs(hir_id, method.substs);
-
-        // When the method is confirmed, the `method.substs` includes
-        // parameters from not just the method, but also the impl of
-        // the method -- in particular, the `Self` type will be fully
-        // resolved. However, those are not something that the "user
-        // specified" -- i.e., those types come from the inferred type
-        // of the receiver, not something the user wrote. So when we
-        // create the user-substs, we want to replace those earlier
-        // types with just the types that the user actually wrote --
-        // that is, those that appear on the *method itself*.
-        //
-        // As an example, if the user wrote something like
-        // `foo.bar::<u32>(...)` -- the `Self` type here will be the
-        // type of `foo` (possibly adjusted), but we don't want to
-        // include that. We want just the `[_, u32]` part.
-        if !method.substs.is_empty() {
-            let method_generics = self.tcx.generics_of(method.def_id);
-            if !method_generics.params.is_empty() {
-                let user_type_annotation = self.probe(|_| {
-                    let user_substs = UserSubsts {
-                        substs: InternalSubsts::for_item(self.tcx, method.def_id, |param, _| {
-                            let i = param.index as usize;
-                            if i < method_generics.parent_count {
-                                self.var_for_def(DUMMY_SP, param)
-                            } else {
-                                method.substs[i]
-                            }
-                        }),
-                        user_self_ty: None, // not relevant here
-                    };
-
-                    self.canonicalize_user_type_annotation(UserType::TypeOf(
-                        method.def_id,
-                        user_substs,
-                    ))
-                });
-
-                debug!("write_method_call: user_type_annotation={:?}", user_type_annotation);
-                self.write_user_type_annotation(hir_id, user_type_annotation);
-            }
-        }
     }
 
     pub fn write_substs(&self, node_id: hir::HirId, substs: SubstsRef<'tcx>) {
@@ -333,22 +295,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
     }
 
-    /// Basically whenever we are converting from a type scheme into
-    /// the fn body space, we always want to normalize associated
-    /// types as well. This function combines the two.
-    fn instantiate_type_scheme<T>(&self, span: Span, substs: SubstsRef<'tcx>, value: T) -> T
-    where
-        T: TypeFoldable<'tcx>,
-    {
-        debug!("instantiate_type_scheme(value={:?}, substs={:?})", value, substs);
-        let value = EarlyBinder(value).subst(self.tcx, substs);
-        let result = self.normalize(span, value);
-        debug!("instantiate_type_scheme = {:?}", result);
-        result
-    }
-
-    /// As `instantiate_type_scheme`, but for the bounds found in a
-    /// generic type scheme.
+    /// Instantiates and normalizes the bounds for a given item
     pub(in super::super) fn instantiate_bounds(
         &self,
         span: Span,
@@ -425,23 +372,38 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
     }
 
-    pub fn to_ty(&self, ast_t: &hir::Ty<'_>) -> Ty<'tcx> {
-        let t = <dyn AstConv<'_>>::ast_ty_to_ty(self, ast_t);
+    pub fn handle_raw_ty(&self, span: Span, ty: Ty<'tcx>) -> RawTy<'tcx> {
+        RawTy { raw: ty, normalized: self.normalize(span, ty) }
+    }
+
+    pub fn to_ty(&self, ast_t: &hir::Ty<'_>) -> RawTy<'tcx> {
+        let t = self.astconv().ast_ty_to_ty(ast_t);
         self.register_wf_obligation(t.into(), ast_t.span, traits::WellFormed(None));
-        t
+        self.handle_raw_ty(ast_t.span, t)
     }
 
     pub fn to_ty_saving_user_provided_ty(&self, ast_ty: &hir::Ty<'_>) -> Ty<'tcx> {
         let ty = self.to_ty(ast_ty);
         debug!("to_ty_saving_user_provided_ty: ty={:?}", ty);
 
-        if Self::can_contain_user_lifetime_bounds(ty) {
-            let c_ty = self.canonicalize_response(UserType::Ty(ty));
+        if Self::can_contain_user_lifetime_bounds(ty.raw) {
+            let c_ty = self.canonicalize_response(UserType::Ty(ty.raw));
             debug!("to_ty_saving_user_provided_ty: c_ty={:?}", c_ty);
             self.typeck_results.borrow_mut().user_provided_types_mut().insert(ast_ty.hir_id, c_ty);
         }
 
-        ty
+        ty.normalized
+    }
+
+    pub(super) fn user_substs_for_adt(ty: RawTy<'tcx>) -> UserSubsts<'tcx> {
+        match (ty.raw.kind(), ty.normalized.kind()) {
+            (ty::Adt(_, substs), _) => UserSubsts { substs, user_self_ty: None },
+            (_, ty::Adt(adt, substs)) => UserSubsts {
+                substs,
+                user_self_ty: Some(UserSelfTy { impl_def_id: adt.did(), self_ty: ty.raw }),
+            },
+            _ => bug!("non-adt type {:?}", ty),
+        }
     }
 
     pub fn array_length_to_const(&self, length: &hir::ArrayLen) -> ty::Const<'tcx> {
@@ -711,12 +673,12 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // Note: this check is pessimistic, as the inference type could be matched with something other
         // than the opaque type, but then we need a new `TypeRelation` just for this specific case and
         // can't re-use `sup` below.
-        // See src/test/ui/impl-trait/hidden-type-is-opaque.rs and
-        // src/test/ui/impl-trait/hidden-type-is-opaque-2.rs for examples that hit this path.
+        // See tests/ui/impl-trait/hidden-type-is-opaque.rs and
+        // tests/ui/impl-trait/hidden-type-is-opaque-2.rs for examples that hit this path.
         if formal_ret.has_infer_types() {
             for ty in ret_ty.walk() {
                 if let ty::subst::GenericArgKind::Type(ty) = ty.unpack()
-                    && let ty::Opaque(def_id, _) = *ty.kind()
+                    && let ty::Alias(ty::Opaque, ty::AliasTy { def_id, .. }) = *ty.kind()
                     && let Some(def_id) = def_id.as_local()
                     && self.opaque_type_origin(def_id, DUMMY_SP).is_some() {
                     return None;
@@ -795,7 +757,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         qpath: &'tcx QPath<'tcx>,
         hir_id: hir::HirId,
         span: Span,
-    ) -> (Res, Option<Ty<'tcx>>, &'tcx [hir::PathSegment<'tcx>]) {
+    ) -> (Res, Option<RawTy<'tcx>>, &'tcx [hir::PathSegment<'tcx>]) {
         debug!(
             "resolve_ty_and_res_fully_qualified_call: qpath={:?} hir_id={:?} span={:?}",
             qpath, hir_id, span
@@ -818,7 +780,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 // to be object-safe.
                 // We manually call `register_wf_obligation` in the success path
                 // below.
-                (<dyn AstConv<'_>>::ast_ty_to_ty_in_path(self, qself), qself, segment)
+                let ty = self.astconv().ast_ty_to_ty_in_path(qself);
+                (self.handle_raw_ty(span, ty), qself, segment)
             }
             QPath::LangItem(..) => {
                 bug!("`resolve_ty_and_res_fully_qualified_call` called on `LangItem`")
@@ -826,7 +789,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         };
         if let Some(&cached_result) = self.typeck_results.borrow().type_dependent_defs().get(hir_id)
         {
-            self.register_wf_obligation(ty.into(), qself.span, traits::WellFormed(None));
+            self.register_wf_obligation(ty.raw.into(), qself.span, traits::WellFormed(None));
             // Return directly on cache hit. This is useful to avoid doubly reporting
             // errors with default match binding modes. See #44614.
             let def = cached_result.map_or(Res::Err, |(kind, def_id)| Res::Def(kind, def_id));
@@ -834,7 +797,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
         let item_name = item_segment.ident;
         let result = self
-            .resolve_fully_qualified_call(span, item_name, ty, qself.span, hir_id)
+            .resolve_fully_qualified_call(span, item_name, ty.normalized, qself.span, hir_id)
             .or_else(|error| {
                 let result = match error {
                     method::MethodError::PrivateMatch(kind, def_id, _) => Ok((kind, def_id)),
@@ -845,17 +808,22 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 // a WF obligation for `dyn MyTrait` when method lookup fails. Otherwise,
                 // register a WF obligation so that we can detect any additional
                 // errors in the self type.
-                if !(matches!(error, method::MethodError::NoMatch(_)) && ty.is_trait()) {
-                    self.register_wf_obligation(ty.into(), qself.span, traits::WellFormed(None));
+                if !(matches!(error, method::MethodError::NoMatch(_)) && ty.normalized.is_trait()) {
+                    self.register_wf_obligation(
+                        ty.raw.into(),
+                        qself.span,
+                        traits::WellFormed(None),
+                    );
                 }
                 if item_name.name != kw::Empty {
                     if let Some(mut e) = self.report_method_error(
                         span,
-                        ty,
+                        ty.normalized,
                         item_name,
                         SelfSource::QPath(qself),
                         error,
                         None,
+                        Expectation::NoExpectation,
                     ) {
                         e.emit();
                     }
@@ -864,7 +832,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             });
 
         if result.is_ok() {
-            self.register_wf_obligation(ty.into(), qself.span, traits::WellFormed(None));
+            self.register_wf_obligation(ty.raw.into(), qself.span, traits::WellFormed(None));
         }
 
         // Write back the new resolution.
@@ -1001,7 +969,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     pub fn instantiate_value_path(
         &self,
         segments: &[hir::PathSegment<'_>],
-        self_ty: Option<Ty<'tcx>>,
+        self_ty: Option<RawTy<'tcx>>,
         res: Res,
         span: Span,
         hir_id: hir::HirId,
@@ -1010,8 +978,12 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         let path_segs = match res {
             Res::Local(_) | Res::SelfCtor(_) => vec![],
-            Res::Def(kind, def_id) => <dyn AstConv<'_>>::def_ids_for_value_path_segments(
-                self, segments, self_ty, kind, def_id,
+            Res::Def(kind, def_id) => self.astconv().def_ids_for_value_path_segments(
+                segments,
+                self_ty.map(|ty| ty.raw),
+                kind,
+                def_id,
+                span,
             ),
             _ => bug!("instantiate_value_path on {:?}", res),
         };
@@ -1022,8 +994,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             Res::Def(DefKind::Ctor(CtorOf::Variant, _), _)
                 if let Some(self_ty) = self_ty =>
             {
-                let adt_def = self_ty.ty_adt_def().unwrap();
-                user_self_ty = Some(UserSelfTy { impl_def_id: adt_def.did(), self_ty });
+                let adt_def = self_ty.normalized.ty_adt_def().unwrap();
+                user_self_ty = Some(UserSelfTy { impl_def_id: adt_def.did(), self_ty: self_ty.raw });
                 is_alias_variant_ctor = true;
             }
             Res::Def(DefKind::AssocFn | DefKind::AssocConst, def_id) => {
@@ -1042,7 +1014,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                             // inherent impl, we need to record the
                             // `T` for posterity (see `UserSelfTy` for
                             // details).
-                            let self_ty = self_ty.expect("UFCS sugared assoc missing Self");
+                            let self_ty = self_ty.expect("UFCS sugared assoc missing Self").raw;
                             user_self_ty = Some(UserSelfTy { impl_def_id: container_id, self_ty });
                         }
                     }
@@ -1057,8 +1029,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // errors if type parameters are provided in an inappropriate place.
 
         let generic_segs: FxHashSet<_> = path_segs.iter().map(|PathSeg(_, index)| index).collect();
-        let generics_has_err = <dyn AstConv<'_>>::prohibit_generics(
-            self,
+        let generics_has_err = self.astconv().prohibit_generics(
             segments.iter().enumerate().filter_map(|(index, seg)| {
                 if !generic_segs.contains(&index) || is_alias_variant_ctor {
                     Some(seg)
@@ -1099,7 +1070,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             // parameter internally, but we don't allow users to specify the
             // parameter's value explicitly, so we have to do some error-
             // checking here.
-            let arg_count = <dyn AstConv<'_>>::check_generic_arg_count_for_call(
+            let arg_count = check_generic_arg_count_for_call(
                 tcx,
                 span,
                 def_id,
@@ -1124,19 +1095,21 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             .unwrap_or(false);
 
         let (res, self_ctor_substs) = if let Res::SelfCtor(impl_def_id) = res {
-            let ty = self.normalize_ty(span, tcx.at(span).type_of(impl_def_id));
-            match *ty.kind() {
-                ty::Adt(adt_def, substs) if adt_def.has_ctor() => {
-                    let variant = adt_def.non_enum_variant();
-                    let (ctor_kind, ctor_def_id) = variant.ctor.unwrap();
-                    (Res::Def(DefKind::Ctor(CtorOf::Struct, ctor_kind), ctor_def_id), Some(substs))
+            let ty = self.handle_raw_ty(span, tcx.at(span).type_of(impl_def_id));
+            match ty.normalized.ty_adt_def() {
+                Some(adt_def) if adt_def.has_ctor() => {
+                    let (ctor_kind, ctor_def_id) = adt_def.non_enum_variant().ctor.unwrap();
+                    let new_res = Res::Def(DefKind::Ctor(CtorOf::Struct, ctor_kind), ctor_def_id);
+                    let user_substs = Self::user_substs_for_adt(ty);
+                    user_self_ty = user_substs.user_self_ty;
+                    (new_res, Some(user_substs.substs))
                 }
                 _ => {
                     let mut err = tcx.sess.struct_span_err(
                         span,
                         "the `Self` constructor can only be used with tuple or unit structs",
                     );
-                    if let Some(adt_def) = ty.ty_adt_def() {
+                    if let Some(adt_def) = ty.normalized.ty_adt_def() {
                         match adt_def.adt_kind() {
                             AdtKind::Enum => {
                                 err.help("did you mean to use one of the enum's variants?");
@@ -1160,10 +1133,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         };
         let def_id = res.def_id();
 
-        // The things we are substituting into the type should not contain
-        // escaping late-bound regions, and nor should the base type scheme.
-        let ty = tcx.type_of(def_id);
-
         let arg_count = GenericArgCountResult {
             explicit_late_bound,
             correct: if infer_args_for_err.is_empty() {
@@ -1209,10 +1178,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             ) -> ty::GenericArg<'tcx> {
                 match (&param.kind, arg) {
                     (GenericParamDefKind::Lifetime, GenericArg::Lifetime(lt)) => {
-                        <dyn AstConv<'_>>::ast_region_to_region(self.fcx, lt, Some(param)).into()
+                        self.fcx.astconv().ast_region_to_region(lt, Some(param)).into()
                     }
                     (GenericParamDefKind::Type { .. }, GenericArg::Type(ty)) => {
-                        self.fcx.to_ty(ty).into()
+                        self.fcx.to_ty(ty).raw.into()
                     }
                     (GenericParamDefKind::Const { .. }, GenericArg::Const(ct)) => {
                         self.fcx.const_arg_to_const(&ct.value, param.def_id).into()
@@ -1244,10 +1213,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                             // If we have a default, then we it doesn't matter that we're not
                             // inferring the type arguments: we provide the default where any
                             // is missing.
-                            let default = tcx.bound_type_of(param.def_id);
-                            self.fcx
-                                .normalize_ty(self.span, default.subst(tcx, substs.unwrap()))
-                                .into()
+                            tcx.bound_type_of(param.def_id).subst(tcx, substs.unwrap()).into()
                         } else {
                             // If no type arguments were provided, we have to infer them.
                             // This case also occurs as a result of some malformed input, e.g.
@@ -1258,9 +1224,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     }
                     GenericParamDefKind::Const { has_default } => {
                         if !infer_args && has_default {
-                            tcx.bound_const_param_default(param.def_id)
-                                .subst(tcx, substs.unwrap())
-                                .into()
+                            tcx.const_param_default(param.def_id).subst(tcx, substs.unwrap()).into()
                         } else {
                             self.fcx.var_for_def(self.span, param)
                         }
@@ -1269,13 +1233,13 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             }
         }
 
-        let substs = self_ctor_substs.unwrap_or_else(|| {
-            <dyn AstConv<'_>>::create_substs_for_generic_args(
+        let substs_raw = self_ctor_substs.unwrap_or_else(|| {
+            create_substs_for_generic_args(
                 tcx,
                 def_id,
                 &[],
                 has_self,
-                self_ty,
+                self_ty.map(|s| s.raw),
                 &arg_count,
                 &mut CreateCtorSubstsContext {
                     fcx: self,
@@ -1286,17 +1250,21 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 },
             )
         });
-        assert!(!substs.has_escaping_bound_vars());
-        assert!(!ty.has_escaping_bound_vars());
 
         // First, store the "user substs" for later.
-        self.write_user_type_annotation_from_substs(hir_id, def_id, substs, user_self_ty);
+        self.write_user_type_annotation_from_substs(hir_id, def_id, substs_raw, user_self_ty);
+
+        // Normalize only after registering type annotations.
+        let substs = self.normalize(span, substs_raw);
 
         self.add_required_obligations_for_hir(span, def_id, &substs, hir_id);
 
         // Substitute the values for the type parameters into the type of
         // the referenced item.
-        let ty_substituted = self.instantiate_type_scheme(span, &substs, ty);
+        let ty = tcx.bound_type_of(def_id);
+        assert!(!substs.has_escaping_bound_vars());
+        assert!(!ty.0.has_escaping_bound_vars());
+        let ty_substituted = self.normalize(span, ty.subst(tcx, substs));
 
         if let Some(UserSelfTy { impl_def_id, self_ty }) = user_self_ty {
             // In the case of `Foo<T>::method` and `<Foo<T>>::method`, if `method`
@@ -1304,9 +1272,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             // type parameters, which we can infer by unifying the provided `Self`
             // with the substituted impl type.
             // This also occurs for an enum variant on a type alias.
-            let ty = tcx.type_of(impl_def_id);
-
-            let impl_ty = self.instantiate_type_scheme(span, &substs, ty);
+            let impl_ty = self.normalize(span, tcx.bound_type_of(impl_def_id).subst(tcx, substs));
+            let self_ty = self.normalize(span, self_ty);
             match self.at(&self.misc(span), self.param_env).eq(impl_ty, self_ty) {
                 Ok(ok) => self.register_infer_ok_obligations(ok),
                 Err(_) => {
@@ -1455,9 +1422,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     pub(in super::super) fn expr_in_place(&self, mut expr_id: hir::HirId) -> bool {
         let mut contained_in_place = false;
 
-        while let hir::Node::Expr(parent_expr) =
-            self.tcx.hir().get(self.tcx.hir().get_parent_node(expr_id))
-        {
+        while let hir::Node::Expr(parent_expr) = self.tcx.hir().get_parent(expr_id) {
             match &parent_expr.kind {
                 hir::ExprKind::Assign(lhs, ..) | hir::ExprKind::AssignOp(_, lhs, ..) => {
                     if lhs.hir_id == expr_id {
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/arg_matrix.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/arg_matrix.rs
index fc83994ca..6f26afcaf 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/arg_matrix.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/arg_matrix.rs
@@ -4,15 +4,13 @@ use rustc_index::vec::IndexVec;
 use rustc_middle::ty::error::TypeError;
 
 rustc_index::newtype_index! {
-    pub(crate) struct ExpectedIdx {
-        DEBUG_FORMAT = "ExpectedIdx({})",
-    }
+    #[debug_format = "ExpectedIdx({})"]
+    pub(crate) struct ExpectedIdx {}
 }
 
 rustc_index::newtype_index! {
-    pub(crate) struct ProvidedIdx {
-        DEBUG_FORMAT = "ProvidedIdx({})",
-    }
+    #[debug_format = "ProvidedIdx({})"]
+    pub(crate) struct ProvidedIdx {}
 }
 
 impl ExpectedIdx {
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
index 60fec05d3..2d841d53f 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
@@ -5,11 +5,11 @@ use crate::method::MethodCallee;
 use crate::Expectation::*;
 use crate::TupleArgumentsFlag::*;
 use crate::{
-    struct_span_err, BreakableCtxt, Diverges, Expectation, FnCtxt, LocalTy, Needs,
+    struct_span_err, BreakableCtxt, Diverges, Expectation, FnCtxt, LocalTy, Needs, RawTy,
     TupleArgumentsFlag,
 };
 use rustc_ast as ast;
-use rustc_data_structures::fx::FxHashSet;
+use rustc_data_structures::fx::FxIndexSet;
 use rustc_errors::{pluralize, Applicability, Diagnostic, DiagnosticId, MultiSpan};
 use rustc_hir as hir;
 use rustc_hir::def::{CtorOf, DefKind, Res};
@@ -28,7 +28,7 @@ use rustc_middle::ty::adjustment::AllowTwoPhase;
 use rustc_middle::ty::visit::TypeVisitable;
 use rustc_middle::ty::{self, DefIdTree, IsSuggestable, Ty, TypeSuperVisitable, TypeVisitor};
 use rustc_session::Session;
-use rustc_span::symbol::Ident;
+use rustc_span::symbol::{kw, Ident};
 use rustc_span::{self, sym, Span};
 use rustc_trait_selection::traits::{self, ObligationCauseCode, SelectionContext};
 
@@ -214,7 +214,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         "cannot use call notation; the first type parameter \
                          for the function trait is neither a tuple nor unit"
                     )
-                    .delay_as_bug();
+                    .emit();
                     (self.err_args(provided_args.len()), None)
                 }
             }
@@ -473,7 +473,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         call_expr: &hir::Expr<'tcx>,
     ) {
         // Next, let's construct the error
-        let (error_span, full_call_span, ctor_of, is_method) = match &call_expr.kind {
+        let (error_span, full_call_span, call_name, is_method) = match &call_expr.kind {
             hir::ExprKind::Call(
                 hir::Expr { hir_id, span, kind: hir::ExprKind::Path(qpath), .. },
                 _,
@@ -481,12 +481,16 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 if let Res::Def(DefKind::Ctor(of, _), _) =
                     self.typeck_results.borrow().qpath_res(qpath, *hir_id)
                 {
-                    (call_span, *span, Some(of), false)
+                    let name = match of {
+                        CtorOf::Struct => "struct",
+                        CtorOf::Variant => "enum variant",
+                    };
+                    (call_span, *span, name, false)
                 } else {
-                    (call_span, *span, None, false)
+                    (call_span, *span, "function", false)
                 }
             }
-            hir::ExprKind::Call(hir::Expr { span, .. }, _) => (call_span, *span, None, false),
+            hir::ExprKind::Call(hir::Expr { span, .. }, _) => (call_span, *span, "function", false),
             hir::ExprKind::MethodCall(path_segment, _, _, span) => {
                 let ident_span = path_segment.ident.span;
                 let ident_span = if let Some(args) = path_segment.args {
@@ -494,17 +498,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 } else {
                     ident_span
                 };
-                // methods are never ctors
-                (*span, ident_span, None, true)
+                (*span, ident_span, "method", true)
             }
             k => span_bug!(call_span, "checking argument types on a non-call: `{:?}`", k),
         };
         let args_span = error_span.trim_start(full_call_span).unwrap_or(error_span);
-        let call_name = match ctor_of {
-            Some(CtorOf::Struct) => "struct",
-            Some(CtorOf::Variant) => "enum variant",
-            None => "function",
-        };
 
         // Don't print if it has error types or is just plain `_`
         fn has_error_or_infer<'tcx>(tys: impl IntoIterator<Item = Ty<'tcx>>) -> bool {
@@ -690,8 +688,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         err = tcx.sess.struct_span_err_with_code(
                             full_call_span,
                             &format!(
-                                "this {} takes {}{} but {} {} supplied",
-                                call_name,
+                                "{call_name} takes {}{} but {} {} supplied",
                                 if c_variadic { "at least " } else { "" },
                                 potentially_plural_count(
                                     formal_and_expected_inputs.len(),
@@ -1013,7 +1010,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                             } else {
                                 args_span
                             };
-                            labels.push((span, format!("multiple arguments are missing")));
+                            labels.push((span, "multiple arguments are missing".to_string()));
                             suggestion_text = match suggestion_text {
                                 SuggestionText::None | SuggestionText::Provide(_) => {
                                     SuggestionText::Provide(true)
@@ -1141,6 +1138,13 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         "()".to_string()
                     } else if expected_ty.is_suggestable(tcx, false) {
                         format!("/* {} */", expected_ty)
+                    } else if let Some(fn_def_id) = fn_def_id
+                        && self.tcx.def_kind(fn_def_id).is_fn_like()
+                        && let self_implicit = matches!(call_expr.kind, hir::ExprKind::MethodCall(..)) as usize
+                        && let Some(arg) = self.tcx.fn_arg_names(fn_def_id).get(expected_idx.as_usize() + self_implicit)
+                        && arg.name != kw::SelfLower
+                    {
+                        format!("/* {} */", arg.name)
                     } else {
                         "/* value */".to_string()
                     }
@@ -1169,7 +1173,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         match lit.node {
             ast::LitKind::Str(..) => tcx.mk_static_str(),
-            ast::LitKind::ByteStr(ref v) => {
+            ast::LitKind::ByteStr(ref v, _) => {
                 tcx.mk_imm_ref(tcx.lifetimes.re_static, tcx.mk_array(tcx.types.u8, v.len() as u64))
             }
             ast::LitKind::Byte(_) => tcx.types.u8,
@@ -1215,31 +1219,35 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 );
                 return None;
             }
-            Res::Def(DefKind::Variant, _) => match ty.kind() {
-                ty::Adt(adt, substs) => Some((adt.variant_of_res(def), adt.did(), substs)),
-                _ => bug!("unexpected type: {:?}", ty),
+            Res::Def(DefKind::Variant, _) => match ty.normalized.ty_adt_def() {
+                Some(adt) => {
+                    Some((adt.variant_of_res(def), adt.did(), Self::user_substs_for_adt(ty)))
+                }
+                _ => bug!("unexpected type: {:?}", ty.normalized),
             },
             Res::Def(DefKind::Struct | DefKind::Union | DefKind::TyAlias | DefKind::AssocTy, _)
             | Res::SelfTyParam { .. }
-            | Res::SelfTyAlias { .. } => match ty.kind() {
-                ty::Adt(adt, substs) if !adt.is_enum() => {
-                    Some((adt.non_enum_variant(), adt.did(), substs))
+            | Res::SelfTyAlias { .. } => match ty.normalized.ty_adt_def() {
+                Some(adt) if !adt.is_enum() => {
+                    Some((adt.non_enum_variant(), adt.did(), Self::user_substs_for_adt(ty)))
                 }
                 _ => None,
             },
             _ => bug!("unexpected definition: {:?}", def),
         };
 
-        if let Some((variant, did, substs)) = variant {
+        if let Some((variant, did, ty::UserSubsts { substs, user_self_ty })) = variant {
             debug!("check_struct_path: did={:?} substs={:?}", did, substs);
-            self.write_user_type_annotation_from_substs(hir_id, did, substs, None);
+
+            // Register type annotation.
+            self.write_user_type_annotation_from_substs(hir_id, did, substs, user_self_ty);
 
             // Check bounds on type arguments used in the path.
             self.add_required_obligations_for_hir(path_span, did, substs, hir_id);
 
-            Some((variant, ty))
+            Some((variant, ty.normalized))
         } else {
-            match ty.kind() {
+            match ty.normalized.kind() {
                 ty::Error(_) => {
                     // E0071 might be caused by a spelling error, which will have
                     // already caused an error message and probably a suggestion
@@ -1252,7 +1260,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         path_span,
                         E0071,
                         "expected struct, variant or union type, found {}",
-                        ty.sort_string(self.tcx)
+                        ty.normalized.sort_string(self.tcx)
                     )
                     .span_label(path_span, "not a struct")
                     .emit();
@@ -1300,7 +1308,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // Type check the initializer.
         if let Some(ref init) = decl.init {
             let init_ty = self.check_decl_initializer(decl.hir_id, decl.pat, &init);
-            self.overwrite_local_ty_if_err(decl.hir_id, decl.pat, decl_ty, init_ty);
+            self.overwrite_local_ty_if_err(decl.hir_id, decl.pat, init_ty);
         }
 
         // Does the expected pattern type originate from an expression and what is the span?
@@ -1315,7 +1323,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // Type check the pattern. Override if necessary to avoid knock-on errors.
         self.check_pat_top(&decl.pat, decl_ty, ty_span, origin_expr);
         let pat_ty = self.node_ty(decl.pat.hir_id);
-        self.overwrite_local_ty_if_err(decl.hir_id, decl.pat, decl_ty, pat_ty);
+        self.overwrite_local_ty_if_err(decl.hir_id, decl.pat, pat_ty);
 
         if let Some(blk) = decl.els {
             let previous_diverges = self.diverges.get();
@@ -1620,14 +1628,14 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         &self,
         hir_id: hir::HirId,
         pat: &'tcx hir::Pat<'tcx>,
-        decl_ty: Ty<'tcx>,
         ty: Ty<'tcx>,
     ) {
         if ty.references_error() {
             // Override the types everywhere with `err()` to avoid knock on errors.
-            self.write_ty(hir_id, ty);
-            self.write_ty(pat.hir_id, ty);
-            let local_ty = LocalTy { decl_ty, revealed_ty: ty };
+            let err = self.tcx.ty_error();
+            self.write_ty(hir_id, err);
+            self.write_ty(pat.hir_id, err);
+            let local_ty = LocalTy { decl_ty: err, revealed_ty: err };
             self.locals.borrow_mut().insert(hir_id, local_ty);
             self.locals.borrow_mut().insert(pat.hir_id, local_ty);
         }
@@ -1640,20 +1648,21 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         qpath: &QPath<'_>,
         path_span: Span,
         hir_id: hir::HirId,
-    ) -> (Res, Ty<'tcx>) {
+    ) -> (Res, RawTy<'tcx>) {
         match *qpath {
             QPath::Resolved(ref maybe_qself, ref path) => {
-                let self_ty = maybe_qself.as_ref().map(|qself| self.to_ty(qself));
-                let ty = <dyn AstConv<'_>>::res_to_ty(self, self_ty, path, true);
-                (path.res, ty)
+                let self_ty = maybe_qself.as_ref().map(|qself| self.to_ty(qself).raw);
+                let ty = self.astconv().res_to_ty(self_ty, path, true);
+                (path.res, self.handle_raw_ty(path_span, ty))
             }
             QPath::TypeRelative(ref qself, ref segment) => {
                 let ty = self.to_ty(qself);
 
-                let result = <dyn AstConv<'_>>::associated_path_to_ty(
-                    self, hir_id, path_span, ty, qself, segment, true,
-                );
+                let result = self
+                    .astconv()
+                    .associated_path_to_ty(hir_id, path_span, ty.raw, qself, segment, true);
                 let ty = result.map(|(ty, _, _)| ty).unwrap_or_else(|_| self.tcx().ty_error());
+                let ty = self.handle_raw_ty(path_span, ty);
                 let result = result.map(|(_, kind, def_id)| (kind, def_id));
 
                 // Write back the new resolution.
@@ -1662,7 +1671,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 (result.map_or(Res::Err, |(kind, def_id)| Res::Def(kind, def_id)), ty)
             }
             QPath::LangItem(lang_item, span, id) => {
-                self.resolve_lang_item_path(lang_item, span, hir_id, id)
+                let (res, ty) = self.resolve_lang_item_path(lang_item, span, hir_id, id);
+                (res, self.handle_raw_ty(path_span, ty))
             }
         }
     }
@@ -1682,7 +1692,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // even if their `ObligationCauseCode` isn't an `Expr*Obligation` kind.
         // This is important since if we adjust one span but not the other, then
         // we will have "duplicated" the error on the UI side.
-        let mut remap_cause = FxHashSet::default();
+        let mut remap_cause = FxIndexSet::default();
         let mut not_adjusted = vec![];
 
         for error in errors {
@@ -1710,6 +1720,13 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             }
         }
 
+        // Adjust any other errors that come from other cause codes, when these
+        // errors are of the same predicate as one we successfully adjusted, and
+        // when their spans overlap (suggesting they're due to the same root cause).
+        //
+        // This is because due to normalization, we often register duplicate
+        // obligations with misc obligations that are basically impossible to
+        // line back up with a useful ExprBindingObligation.
         for error in not_adjusted {
             for (span, predicate, cause) in &remap_cause {
                 if *predicate == error.obligation.predicate
@@ -1796,7 +1813,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     hir_id: call_hir_id,
                     span: call_span,
                     ..
-                }) = hir.get(hir.get_parent_node(expr.hir_id))
+                }) = hir.get_parent(expr.hir_id)
                     && callee.hir_id == expr.hir_id
                 {
                     if self.closure_span_overlaps_error(error, *call_span) {
@@ -2111,8 +2128,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         // FIXME(compiler-errors): This could be problematic if something has two
                         // fn-like predicates with different args, but callable types really never
                         // do that, so it's OK.
-                        for (predicate, span) in
-                            std::iter::zip(instantiated.predicates, instantiated.spans)
+                        for (predicate, span) in instantiated
                         {
                             if let ty::PredicateKind::Clause(ty::Clause::Trait(pred)) = predicate.kind().skip_binder()
                                 && pred.self_ty().peel_refs() == callee_ty
@@ -2124,7 +2140,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         }
                     }
                 }
-                ty::Opaque(new_def_id, _)
+                ty::Alias(ty::Opaque, ty::AliasTy { def_id: new_def_id, .. })
                 | ty::Closure(new_def_id, _)
                 | ty::FnDef(new_def_id, _) => {
                     def_id = new_def_id;
@@ -2132,19 +2148,15 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 _ => {
                     // Look for a user-provided impl of a `Fn` trait, and point to it.
                     let new_def_id = self.probe(|_| {
-                        let trait_ref = ty::TraitRef::new(
+                        let trait_ref = self.tcx.mk_trait_ref(
                             call_kind.to_def_id(self.tcx),
-                            self.tcx.mk_substs(
-                                [
-                                    ty::GenericArg::from(callee_ty),
-                                    self.next_ty_var(TypeVariableOrigin {
-                                        kind: TypeVariableOriginKind::MiscVariable,
-                                        span: rustc_span::DUMMY_SP,
-                                    })
-                                    .into(),
-                                ]
-                                .into_iter(),
-                            ),
+                            [
+                                callee_ty,
+                                self.next_ty_var(TypeVariableOrigin {
+                                    kind: TypeVariableOriginKind::MiscVariable,
+                                    span: rustc_span::DUMMY_SP,
+                                }),
+                            ],
                         );
                         let obligation = traits::Obligation::new(
                             self.tcx,
@@ -2217,7 +2229,7 @@ fn find_param_in_ty<'tcx>(ty: Ty<'tcx>, param_to_point_at: ty::GenericArg<'tcx>)
         if arg == param_to_point_at {
             return true;
         } else if let ty::GenericArgKind::Type(ty) = arg.unpack()
-            && let ty::Projection(..) = ty.kind()
+            && let ty::Alias(ty::Projection, ..) = ty.kind()
         {
             // This logic may seem a bit strange, but typically when
             // we have a projection type in a function signature, the
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs
index 30b59da78..428fde642 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs
@@ -17,11 +17,10 @@ use rustc_infer::infer::error_reporting::TypeErrCtxt;
 use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
 use rustc_middle::infer::unify_key::{ConstVariableOrigin, ConstVariableOriginKind};
 use rustc_middle::ty::subst::GenericArgKind;
-use rustc_middle::ty::visit::TypeVisitable;
-use rustc_middle::ty::{self, Const, Ty, TyCtxt};
+use rustc_middle::ty::{self, Const, Ty, TyCtxt, TypeVisitable};
 use rustc_session::Session;
 use rustc_span::symbol::Ident;
-use rustc_span::{self, Span};
+use rustc_span::{self, Span, DUMMY_SP};
 use rustc_trait_selection::traits::{ObligationCause, ObligationCauseCode, ObligationCtxt};
 
 use std::cell::{Cell, RefCell};
@@ -176,6 +175,14 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     fn_sig
                 })
             }),
+            autoderef_steps: Box::new(|ty| {
+                let mut autoderef = self.autoderef(DUMMY_SP, ty).silence_errors();
+                let mut steps = vec![];
+                while let Some((ty, _)) = autoderef.next() {
+                    steps.push((ty, autoderef.current_obligations()));
+                }
+                steps
+            }),
         }
     }
 
@@ -287,8 +294,7 @@ impl<'a, 'tcx> AstConv<'tcx> for FnCtxt<'a, 'tcx> {
             poly_trait_ref,
         );
 
-        let item_substs = <dyn AstConv<'tcx>>::create_substs_for_associated_item(
-            self,
+        let item_substs = self.astconv().create_substs_for_associated_item(
             span,
             item_def_id,
             item_segment,
@@ -298,11 +304,14 @@ impl<'a, 'tcx> AstConv<'tcx> for FnCtxt<'a, 'tcx> {
         self.tcx().mk_projection(item_def_id, item_substs)
     }
 
-    fn normalize_ty(&self, span: Span, ty: Ty<'tcx>) -> Ty<'tcx> {
-        if ty.has_escaping_bound_vars() {
-            ty // FIXME: normalization and escaping regions
-        } else {
-            self.normalize(span, ty)
+    fn probe_adt(&self, span: Span, ty: Ty<'tcx>) -> Option<ty::AdtDef<'tcx>> {
+        match ty.kind() {
+            ty::Adt(adt_def, _) => Some(*adt_def),
+            // FIXME(#104767): Should we handle bound regions here?
+            ty::Alias(ty::Projection, _) if !ty.has_escaping_bound_vars() => {
+                self.normalize(span, ty).ty_adt_def()
+            }
+            _ => None,
         }
     }
 
@@ -310,7 +319,21 @@ impl<'a, 'tcx> AstConv<'tcx> for FnCtxt<'a, 'tcx> {
         self.infcx.set_tainted_by_errors(e)
     }
 
-    fn record_ty(&self, hir_id: hir::HirId, ty: Ty<'tcx>, _span: Span) {
+    fn record_ty(&self, hir_id: hir::HirId, ty: Ty<'tcx>, span: Span) {
+        // FIXME: normalization and escaping regions
+        let ty = if !ty.has_escaping_bound_vars() { self.normalize(span, ty) } else { ty };
         self.write_ty(hir_id, ty)
     }
 }
+
+/// Represents a user-provided type in the raw form (never normalized).
+///
+/// This is a bridge between the interface of `AstConv`, which outputs a raw `Ty`,
+/// and the API in this module, which expect `Ty` to be fully normalized.
+#[derive(Clone, Copy, Debug)]
+pub struct RawTy<'tcx> {
+    pub raw: Ty<'tcx>,
+
+    /// The normalized form of `raw`, stored here for efficiency.
+    pub normalized: Ty<'tcx>,
+}
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
index 4f92477b5..4d673ac91 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
@@ -1,33 +1,37 @@
 use super::FnCtxt;
 
 use crate::errors::{AddReturnTypeSuggestion, ExpectedReturnTypeLabel};
+use crate::method::probe::{IsSuggestion, Mode, ProbeScope};
 use rustc_ast::util::parser::{ExprPrecedence, PREC_POSTFIX};
 use rustc_errors::{Applicability, Diagnostic, MultiSpan};
 use rustc_hir as hir;
-use rustc_hir::def::{CtorOf, DefKind};
+use rustc_hir::def::{CtorKind, CtorOf, DefKind};
 use rustc_hir::lang_items::LangItem;
 use rustc_hir::{
     Expr, ExprKind, GenericBound, Node, Path, QPath, Stmt, StmtKind, TyKind, WherePredicate,
 };
 use rustc_hir_analysis::astconv::AstConv;
-use rustc_infer::infer;
 use rustc_infer::traits::{self, StatementAsExpression};
 use rustc_middle::lint::in_external_macro;
-use rustc_middle::ty::{self, Binder, DefIdTree, IsSuggestable, ToPredicate, Ty};
+use rustc_middle::ty::{
+    self, suggest_constraining_type_params, Binder, DefIdTree, IsSuggestable, ToPredicate, Ty,
+    TypeVisitable,
+};
 use rustc_session::errors::ExprParenthesesNeeded;
-use rustc_span::symbol::sym;
-use rustc_span::Span;
+use rustc_span::source_map::Spanned;
+use rustc_span::symbol::{sym, Ident};
+use rustc_span::{Span, Symbol};
 use rustc_trait_selection::infer::InferCtxtExt;
+use rustc_trait_selection::traits::error_reporting::suggestions::TypeErrCtxtExt;
 use rustc_trait_selection::traits::error_reporting::DefIdOrName;
 use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt as _;
-use rustc_trait_selection::traits::NormalizeExt;
 
 impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     pub(crate) fn body_fn_sig(&self) -> Option<ty::FnSig<'tcx>> {
         self.typeck_results
             .borrow()
             .liberated_fn_sigs()
-            .get(self.tcx.hir().get_parent_node(self.body_id))
+            .get(self.tcx.hir().parent_id(self.body_id))
             .copied()
     }
 
@@ -89,7 +93,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         found: Ty<'tcx>,
         can_satisfy: impl FnOnce(Ty<'tcx>) -> bool,
     ) -> bool {
-        let Some((def_id_or_name, output, inputs)) = self.extract_callable_info(expr, found)
+        let Some((def_id_or_name, output, inputs)) = self.extract_callable_info(found)
             else { return false; };
         if can_satisfy(output) {
             let (sugg_call, mut applicability) = match inputs.len() {
@@ -158,99 +162,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     /// because the callable type must also be well-formed to be called.
     pub(in super::super) fn extract_callable_info(
         &self,
-        expr: &Expr<'_>,
-        found: Ty<'tcx>,
+        ty: Ty<'tcx>,
     ) -> Option<(DefIdOrName, Ty<'tcx>, Vec<Ty<'tcx>>)> {
-        // Autoderef is useful here because sometimes we box callables, etc.
-        let Some((def_id_or_name, output, inputs)) = self.autoderef(expr.span, found).silence_errors().find_map(|(found, _)| {
-            match *found.kind() {
-                ty::FnPtr(fn_sig) =>
-                    Some((DefIdOrName::Name("function pointer"), fn_sig.output(), fn_sig.inputs())),
-                ty::FnDef(def_id, _) => {
-                    let fn_sig = found.fn_sig(self.tcx);
-                    Some((DefIdOrName::DefId(def_id), fn_sig.output(), fn_sig.inputs()))
-                }
-                ty::Closure(def_id, substs) => {
-                    let fn_sig = substs.as_closure().sig();
-                    Some((DefIdOrName::DefId(def_id), fn_sig.output(), fn_sig.inputs().map_bound(|inputs| &inputs[1..])))
-                }
-                ty::Opaque(def_id, substs) => {
-                    self.tcx.bound_item_bounds(def_id).subst(self.tcx, substs).iter().find_map(|pred| {
-                        if let ty::PredicateKind::Clause(ty::Clause::Projection(proj)) = pred.kind().skip_binder()
-                        && Some(proj.projection_ty.item_def_id) == self.tcx.lang_items().fn_once_output()
-                        // args tuple will always be substs[1]
-                        && let ty::Tuple(args) = proj.projection_ty.substs.type_at(1).kind()
-                        {
-                            Some((
-                                DefIdOrName::DefId(def_id),
-                                pred.kind().rebind(proj.term.ty().unwrap()),
-                                pred.kind().rebind(args.as_slice()),
-                            ))
-                        } else {
-                            None
-                        }
-                    })
-                }
-                ty::Dynamic(data, _, ty::Dyn) => {
-                    data.iter().find_map(|pred| {
-                        if let ty::ExistentialPredicate::Projection(proj) = pred.skip_binder()
-                        && Some(proj.item_def_id) == self.tcx.lang_items().fn_once_output()
-                        // for existential projection, substs are shifted over by 1
-                        && let ty::Tuple(args) = proj.substs.type_at(0).kind()
-                        {
-                            Some((
-                                DefIdOrName::Name("trait object"),
-                                pred.rebind(proj.term.ty().unwrap()),
-                                pred.rebind(args.as_slice()),
-                            ))
-                        } else {
-                            None
-                        }
-                    })
-                }
-                ty::Param(param) => {
-                    let def_id = self.tcx.generics_of(self.body_id.owner).type_param(&param, self.tcx).def_id;
-                    self.tcx.predicates_of(self.body_id.owner).predicates.iter().find_map(|(pred, _)| {
-                        if let ty::PredicateKind::Clause(ty::Clause::Projection(proj)) = pred.kind().skip_binder()
-                        && Some(proj.projection_ty.item_def_id) == self.tcx.lang_items().fn_once_output()
-                        && proj.projection_ty.self_ty() == found
-                        // args tuple will always be substs[1]
-                        && let ty::Tuple(args) = proj.projection_ty.substs.type_at(1).kind()
-                        {
-                            Some((
-                                DefIdOrName::DefId(def_id),
-                                pred.kind().rebind(proj.term.ty().unwrap()),
-                                pred.kind().rebind(args.as_slice()),
-                            ))
-                        } else {
-                            None
-                        }
-                    })
-                }
-                _ => None,
-            }
-        }) else { return None; };
-
-        let output = self.replace_bound_vars_with_fresh_vars(expr.span, infer::FnCall, output);
-        let inputs = inputs
-            .skip_binder()
-            .iter()
-            .map(|ty| {
-                self.replace_bound_vars_with_fresh_vars(
-                    expr.span,
-                    infer::FnCall,
-                    inputs.rebind(*ty),
-                )
-            })
-            .collect();
-
-        // We don't want to register any extra obligations, which should be
-        // implied by wf, but also because that would possibly result in
-        // erroneous errors later on.
-        let infer::InferOk { value: output, obligations: _ } =
-            self.at(&self.misc(expr.span), self.param_env).normalize(output);
-
-        if output.is_ty_var() { None } else { Some((def_id_or_name, output, inputs)) }
+        self.err_ctxt().extract_callable_info(self.body_id, self.param_env, ty)
     }
 
     pub fn suggest_two_fn_call(
@@ -262,9 +176,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         rhs_ty: Ty<'tcx>,
         can_satisfy: impl FnOnce(Ty<'tcx>, Ty<'tcx>) -> bool,
     ) -> bool {
-        let Some((_, lhs_output_ty, lhs_inputs)) = self.extract_callable_info(lhs_expr, lhs_ty)
+        let Some((_, lhs_output_ty, lhs_inputs)) = self.extract_callable_info(lhs_ty)
             else { return false; };
-        let Some((_, rhs_output_ty, rhs_inputs)) = self.extract_callable_info(rhs_expr, rhs_ty)
+        let Some((_, rhs_output_ty, rhs_inputs)) = self.extract_callable_info(rhs_ty)
             else { return false; };
 
         if can_satisfy(lhs_output_ty, rhs_output_ty) {
@@ -317,11 +231,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 }
             }
 
-            err.multipart_suggestion_verbose(
-                format!("use parentheses to call these"),
-                sugg,
-                applicability,
-            );
+            err.multipart_suggestion_verbose("use parentheses to call these", sugg, applicability);
 
             true
         } else {
@@ -329,6 +239,31 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
     }
 
+    pub fn suggest_remove_last_method_call(
+        &self,
+        err: &mut Diagnostic,
+        expr: &hir::Expr<'tcx>,
+        expected: Ty<'tcx>,
+    ) -> bool {
+        if let hir::ExprKind::MethodCall(hir::PathSegment { ident: method, .. }, recv_expr, &[], _) = expr.kind &&
+            let Some(recv_ty) = self.typeck_results.borrow().expr_ty_opt(recv_expr) &&
+            self.can_coerce(recv_ty, expected) {
+                let span = if let Some(recv_span) = recv_expr.span.find_ancestor_inside(expr.span) {
+                    expr.span.with_lo(recv_span.hi())
+                } else {
+                    expr.span.with_lo(method.span.lo() - rustc_span::BytePos(1))
+                };
+                err.span_suggestion_verbose(
+                    span,
+                    "try removing the method call",
+                    "",
+                    Applicability::MachineApplicable,
+                );
+                return true;
+            }
+        false
+    }
+
     pub fn suggest_deref_ref_or_into(
         &self,
         err: &mut Diagnostic,
@@ -391,10 +326,20 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         } else if self.suggest_else_fn_with_closure(err, expr, found, expected) {
             return true;
         } else if self.suggest_fn_call(err, expr, found, |output| self.can_coerce(output, expected))
-            && let ty::FnDef(def_id, ..) = &found.kind()
-            && let Some(sp) = self.tcx.hir().span_if_local(*def_id)
+            && let ty::FnDef(def_id, ..) = *found.kind()
+            && let Some(sp) = self.tcx.hir().span_if_local(def_id)
         {
-            err.span_label(sp, format!("{found} defined here"));
+            let name = self.tcx.item_name(def_id);
+            let kind = self.tcx.def_kind(def_id);
+            if let DefKind::Ctor(of, CtorKind::Fn) = kind {
+                err.span_label(sp, format!("`{name}` defines {} constructor here, which should be called", match of {
+                    CtorOf::Struct => "a struct",
+                    CtorOf::Variant => "an enum variant",
+                }));
+            } else {
+                let descr = kind.descr(def_id);
+                err.span_label(sp, format!("{descr} `{name}` defined here"));
+            }
             return true;
         } else if self.check_for_cast(err, expr, found, expected, expected_ty_expr) {
             return true;
@@ -416,7 +361,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                             && method_call_list.contains(&conversion_method.name)
                             // If receiver is `.clone()` and found type has one of those methods,
                             // we guess that the user wants to convert from a slice type (`&[]` or `&str`)
-                            // to an owned type (`Vec` or `String`).  These conversions clone internally,
+                            // to an owned type (`Vec` or `String`). These conversions clone internally,
                             // so we remove the user's `clone` call.
                         {
                             vec![(
@@ -613,10 +558,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 }
             }
             ty::Adt(def, _) if def.is_box() && self.can_coerce(box_found, expected) => {
-                // Check if the parent expression is a call to Pin::new.  If it
+                // Check if the parent expression is a call to Pin::new. If it
                 // is and we were expecting a Box, ergo Pin<Box<expected>>, we
                 // can suggest Box::pin.
-                let parent = self.tcx.hir().get_parent_node(expr.hir_id);
+                let parent = self.tcx.hir().parent_id(expr.hir_id);
                 let Some(Node::Expr(Expr { kind: ExprKind::Call(fn_name, _), .. })) = self.tcx.hir().find(parent) else {
                     return false;
                 };
@@ -752,12 +697,12 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     return true
                 }
             }
-            &hir::FnRetTy::Return(ref ty) => {
+            hir::FnRetTy::Return(ty) => {
                 // Only point to return type if the expected type is the return type, as if they
                 // are not, the expectation must have been caused by something else.
                 debug!("suggest_missing_return_type: return type {:?} node {:?}", ty, ty.kind);
                 let span = ty.span;
-                let ty = <dyn AstConv<'_>>::ast_ty_to_ty(self, ty);
+                let ty = self.astconv().ast_ty_to_ty(ty);
                 debug!("suggest_missing_return_type: return type {:?}", ty);
                 debug!("suggest_missing_return_type: expected type {:?}", ty);
                 let bound_vars = self.tcx.late_bound_vars(fn_id);
@@ -828,7 +773,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     ..
                 }) => {
                     // FIXME: Maybe these calls to `ast_ty_to_ty` can be removed (and the ones below)
-                    let ty = <dyn AstConv<'_>>::ast_ty_to_ty(self, bounded_ty);
+                    let ty = self.astconv().ast_ty_to_ty(bounded_ty);
                     Some((ty, bounds))
                 }
                 _ => None,
@@ -866,7 +811,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let all_bounds_str = all_matching_bounds_strs.join(" + ");
 
         let ty_param_used_in_fn_params = fn_parameters.iter().any(|param| {
-                let ty = <dyn AstConv<'_>>::ast_ty_to_ty(self, param);
+                let ty = self.astconv().ast_ty_to_ty( param);
                 matches!(ty.kind(), ty::Param(fn_param_ty_param) if expected_ty_as_param == fn_param_ty_param)
             });
 
@@ -920,7 +865,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
 
         if let hir::FnRetTy::Return(ty) = fn_decl.output {
-            let ty = <dyn AstConv<'_>>::ast_ty_to_ty(self, ty);
+            let ty = self.astconv().ast_ty_to_ty(ty);
             let bound_vars = self.tcx.late_bound_vars(fn_id);
             let ty = self.tcx.erase_late_bound_regions(Binder::bind_with_vars(ty, bound_vars));
             let ty = match self.tcx.asyncness(fn_id.owner) {
@@ -948,7 +893,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         err: &mut Diagnostic,
         expr: &hir::Expr<'_>,
     ) -> bool {
-        let sp = self.tcx.sess.source_map().start_point(expr.span);
+        let sp = self.tcx.sess.source_map().start_point(expr.span).with_parent(None);
         if let Some(sp) = self.tcx.sess.parse_sess.ambiguous_block_expr_parse.borrow().get(&sp) {
             // `{ 42 } &&x` (#61475) or `{ 42 } && if x { 1 } else { 0 }`
             err.subdiagnostic(ExprParenthesesNeeded::surrounding(*sp));
@@ -988,6 +933,36 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
     }
 
+    pub(crate) fn suggest_clone_for_ref(
+        &self,
+        diag: &mut Diagnostic,
+        expr: &hir::Expr<'_>,
+        expr_ty: Ty<'tcx>,
+        expected_ty: Ty<'tcx>,
+    ) -> bool {
+        if let ty::Ref(_, inner_ty, hir::Mutability::Not) = expr_ty.kind()
+            && let Some(clone_trait_def) = self.tcx.lang_items().clone_trait()
+            && expected_ty == *inner_ty
+            && self
+                .infcx
+                .type_implements_trait(
+                    clone_trait_def,
+                    [self.tcx.erase_regions(expected_ty)],
+                    self.param_env
+                )
+                .must_apply_modulo_regions()
+          {
+              diag.span_suggestion_verbose(
+                  expr.span.shrink_to_hi(),
+                  "consider using clone here",
+                  ".clone()",
+                  Applicability::MachineApplicable,
+              );
+              return true;
+          }
+        false
+    }
+
     pub(crate) fn suggest_copied_or_cloned(
         &self,
         diag: &mut Diagnostic,
@@ -1126,9 +1101,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
 
         let hir = self.tcx.hir();
-        let cond_parent = hir.parent_iter(expr.hir_id).skip_while(|(_, node)| {
-            matches!(node, hir::Node::Expr(hir::Expr { kind: hir::ExprKind::Binary(op, _, _), .. }) if op.node == hir::BinOpKind::And)
-        }).next();
+        let cond_parent = hir.parent_iter(expr.hir_id).find(|(_, node)| {
+            !matches!(node, hir::Node::Expr(hir::Expr { kind: hir::ExprKind::Binary(op, _, _), .. }) if op.node == hir::BinOpKind::And)
+        });
         // Don't suggest:
         //     `let Some(_) = a.is_some() && b`
         //                     ++++++++++
@@ -1234,10 +1209,114 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 );
                 true
             }
+            ExprKind::Lit(Spanned {
+                node: rustc_ast::LitKind::Int(lit, rustc_ast::LitIntType::Unsuffixed),
+                span,
+            }) => {
+                let Ok(snippet) = self.tcx.sess.source_map().span_to_snippet(span) else { return false; };
+                if !(snippet.starts_with("0x") || snippet.starts_with("0X")) {
+                    return false;
+                }
+                if snippet.len() <= 5 || !snippet.is_char_boundary(snippet.len() - 3) {
+                    return false;
+                }
+                let (_, suffix) = snippet.split_at(snippet.len() - 3);
+                let value = match suffix {
+                    "f32" => (lit - 0xf32) / (16 * 16 * 16),
+                    "f64" => (lit - 0xf64) / (16 * 16 * 16),
+                    _ => return false,
+                };
+                err.span_suggestions(
+                    expr.span,
+                    "rewrite this as a decimal floating point literal, or use `as` to turn a hex literal into a float",
+                    [format!("0x{value:X} as {suffix}"), format!("{value}_{suffix}")],
+                    Applicability::MaybeIncorrect,
+                );
+                true
+            }
             _ => false,
         }
     }
 
+    pub(crate) fn suggest_associated_const(
+        &self,
+        err: &mut Diagnostic,
+        expr: &hir::Expr<'_>,
+        expected_ty: Ty<'tcx>,
+    ) -> bool {
+        let Some((DefKind::AssocFn, old_def_id)) = self.typeck_results.borrow().type_dependent_def(expr.hir_id) else {
+            return false;
+        };
+        let old_item_name = self.tcx.item_name(old_def_id);
+        let capitalized_name = Symbol::intern(&old_item_name.as_str().to_uppercase());
+        if old_item_name == capitalized_name {
+            return false;
+        }
+        let (item, segment) = match expr.kind {
+            hir::ExprKind::Path(QPath::Resolved(
+                Some(ty),
+                hir::Path { segments: [segment], .. },
+            ))
+            | hir::ExprKind::Path(QPath::TypeRelative(ty, segment)) => {
+                let self_ty = self.astconv().ast_ty_to_ty(ty);
+                if let Ok(pick) = self.probe_for_name(
+                    Mode::Path,
+                    Ident::new(capitalized_name, segment.ident.span),
+                    Some(expected_ty),
+                    IsSuggestion(true),
+                    self_ty,
+                    expr.hir_id,
+                    ProbeScope::TraitsInScope,
+                ) {
+                    (pick.item, segment)
+                } else {
+                    return false;
+                }
+            }
+            hir::ExprKind::Path(QPath::Resolved(
+                None,
+                hir::Path { segments: [.., segment], .. },
+            )) => {
+                // we resolved through some path that doesn't end in the item name,
+                // better not do a bad suggestion by accident.
+                if old_item_name != segment.ident.name {
+                    return false;
+                }
+                if let Some(item) = self
+                    .tcx
+                    .associated_items(self.tcx.parent(old_def_id))
+                    .filter_by_name_unhygienic(capitalized_name)
+                    .next()
+                {
+                    (*item, segment)
+                } else {
+                    return false;
+                }
+            }
+            _ => return false,
+        };
+        if item.def_id == old_def_id || self.tcx.def_kind(item.def_id) != DefKind::AssocConst {
+            // Same item
+            return false;
+        }
+        let item_ty = self.tcx.type_of(item.def_id);
+        // FIXME(compiler-errors): This check is *so* rudimentary
+        if item_ty.needs_subst() {
+            return false;
+        }
+        if self.can_coerce(item_ty, expected_ty) {
+            err.span_suggestion_verbose(
+                segment.ident.span,
+                format!("try referring to the associated const `{capitalized_name}` instead",),
+                capitalized_name,
+                Applicability::MachineApplicable,
+            );
+            true
+        } else {
+            false
+        }
+    }
+
     fn is_loop(&self, id: hir::HirId) -> bool {
         let node = self.tcx.hir().get(id);
         matches!(node, Node::Expr(Expr { kind: ExprKind::Loop(..), .. }))
@@ -1276,18 +1355,14 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             && !results.expr_adjustments(callee_expr).iter().any(|adj| matches!(adj.kind, ty::adjustment::Adjust::Deref(..)))
             // Check that we're in fact trying to clone into the expected type
             && self.can_coerce(*pointee_ty, expected_ty)
+            && let trait_ref = ty::Binder::dummy(self.tcx.mk_trait_ref(clone_trait_did, [expected_ty]))
             // And the expected type doesn't implement `Clone`
-            && !self.predicate_must_hold_considering_regions(&traits::Obligation {
-                cause: traits::ObligationCause::dummy(),
-                param_env: self.param_env,
-                recursion_depth: 0,
-                predicate: ty::Binder::dummy(ty::TraitRef {
-                    def_id: clone_trait_did,
-                    substs: self.tcx.mk_substs([expected_ty.into()].iter()),
-                })
-                .without_const()
-                .to_predicate(self.tcx),
-            })
+            && !self.predicate_must_hold_considering_regions(&traits::Obligation::new(
+                self.tcx,
+                traits::ObligationCause::dummy(),
+                self.param_env,
+                trait_ref,
+            ))
         {
             diag.span_note(
                 callee_expr.span,
@@ -1295,6 +1370,19 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     "`{expected_ty}` does not implement `Clone`, so `{found_ty}` was cloned instead"
                 ),
             );
+            let owner = self.tcx.hir().enclosing_body_owner(expr.hir_id);
+            if let ty::Param(param) = expected_ty.kind()
+                && let Some(generics) = self.tcx.hir().get_generics(owner)
+            {
+                suggest_constraining_type_params(
+                    self.tcx,
+                    generics,
+                    diag,
+                    vec![(param.name.as_str(), "Clone", Some(clone_trait_did))].into_iter(),
+                );
+            } else {
+                self.suggest_derive(diag, &[(trait_ref.to_predicate(self.tcx), None, None)]);
+            }
         }
     }