diff --git a/compiler/rustc_error_messages/locales/en-US/monomorphize.ftl b/compiler/rustc_error_messages/locales/en-US/monomorphize.ftl
index 48ddb54b79e79..243d10bfa0621 100644
--- a/compiler/rustc_error_messages/locales/en-US/monomorphize.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/monomorphize.ftl
@@ -21,3 +21,6 @@ monomorphize_large_assignments =
     moving {$size} bytes
     .label = value moved from here
     .note = The current maximum size is {$limit}, but it can be customized with the move_size_limit attribute: `#![move_size_limit = "..."]`
+
+monomorphize_couldnt_dump_mono_stats =
+    unexpected error occurred while dumping monomorphization stats: {$error}
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
index 719f44f9f665a..407d6ac8544c2 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
@@ -13,7 +13,9 @@ 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, Ty};
+use rustc_middle::ty::{
+    self, suggest_constraining_type_params, Binder, DefIdTree, IsSuggestable, ToPredicate, Ty,
+};
 use rustc_session::errors::ExprParenthesesNeeded;
 use rustc_span::symbol::sym;
 use rustc_span::Span;
@@ -1276,15 +1278,13 @@ 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::new(
                 self.tcx,
                 traits::ObligationCause::dummy(),
                 self.param_env,
-                ty::Binder::dummy(self.tcx.mk_trait_ref(
-                    clone_trait_did,
-                    [expected_ty],
-                )),
+                trait_ref,
             ))
         {
             diag.span_note(
@@ -1293,6 +1293,19 @@ 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)]);
+            }
         }
     }
 
diff --git a/compiler/rustc_hir_typeck/src/method/suggest.rs b/compiler/rustc_hir_typeck/src/method/suggest.rs
index 5c0d5f32f0fd0..63cec9216eb89 100644
--- a/compiler/rustc_hir_typeck/src/method/suggest.rs
+++ b/compiler/rustc_hir_typeck/src/method/suggest.rs
@@ -25,7 +25,7 @@ use rustc_middle::infer::unify_key::{ConstVariableOrigin, ConstVariableOriginKin
 use rustc_middle::traits::util::supertraits;
 use rustc_middle::ty::fast_reject::DeepRejectCtxt;
 use rustc_middle::ty::fast_reject::{simplify_type, TreatParams};
-use rustc_middle::ty::print::with_crate_prefix;
+use rustc_middle::ty::print::{with_crate_prefix, with_forced_trimmed_paths};
 use rustc_middle::ty::{self, DefIdTree, GenericArgKind, Ty, TyCtxt, TypeVisitable};
 use rustc_middle::ty::{IsSuggestable, ToPolyTraitRef};
 use rustc_span::symbol::{kw, sym, Ident};
@@ -270,7 +270,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 let tcx = self.tcx;
 
                 let rcvr_ty = self.resolve_vars_if_possible(rcvr_ty);
-                let ty_str = self.ty_to_string(rcvr_ty);
+                let ty_str = with_forced_trimmed_paths!(self.ty_to_string(rcvr_ty));
                 let is_method = mode == Mode::MethodCall;
                 let item_kind = if is_method {
                     "method"
@@ -563,7 +563,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                                 let term = pred.skip_binder().term;
 
                                 let obligation = format!("{} = {}", projection_ty, term);
-                                let quiet = format!("{} = {}", quiet_projection_ty, term);
+                                let quiet = with_forced_trimmed_paths!(format!(
+                                    "{} = {}",
+                                    quiet_projection_ty, term
+                                ));
 
                                 bound_span_label(projection_ty.self_ty(), &obligation, &quiet);
                                 Some((obligation, projection_ty.self_ty()))
@@ -573,7 +576,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                                 let self_ty = p.self_ty();
                                 let path = p.print_only_trait_path();
                                 let obligation = format!("{}: {}", self_ty, path);
-                                let quiet = format!("_: {}", path);
+                                let quiet = with_forced_trimmed_paths!(format!("_: {}", path));
                                 bound_span_label(self_ty, &obligation, &quiet);
                                 Some((obligation, self_ty))
                             }
@@ -796,7 +799,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                                 (None, None)
                             };
                         let primary_message = primary_message.unwrap_or_else(|| format!(
-                            "the {item_kind} `{item_name}` exists for {actual_prefix} `{ty_str}`, but its trait bounds were not satisfied"
+                            "the {item_kind} `{item_name}` exists for {actual_prefix} `{ty_str}`, \
+                             but its trait bounds were not satisfied"
                         ));
                         err.set_primary_message(&primary_message);
                         if let Some(label) = label {
@@ -1848,7 +1852,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         self.suggest_derive(err, &preds);
     }
 
-    fn suggest_derive(
+    pub fn suggest_derive(
         &self,
         err: &mut Diagnostic,
         unsatisfied_predicates: &[(
diff --git a/compiler/rustc_middle/src/mir/mono.rs b/compiler/rustc_middle/src/mir/mono.rs
index 15a24aa4ace51..1e8d5f7eae87a 100644
--- a/compiler/rustc_middle/src/mir/mono.rs
+++ b/compiler/rustc_middle/src/mir/mono.rs
@@ -200,6 +200,15 @@ impl<'tcx> MonoItem<'tcx> {
             MonoItem::GlobalAsm(..) => LOCAL_CRATE,
         }
     }
+
+    /// Returns the item's `DefId`
+    pub fn def_id(&self) -> DefId {
+        match *self {
+            MonoItem::Fn(Instance { def, .. }) => def.def_id(),
+            MonoItem::Static(def_id) => def_id,
+            MonoItem::GlobalAsm(item_id) => item_id.owner_id.to_def_id(),
+        }
+    }
 }
 
 impl<'tcx> fmt::Display for MonoItem<'tcx> {
diff --git a/compiler/rustc_middle/src/ty/context.rs b/compiler/rustc_middle/src/ty/context.rs
index 70ac5acb40ead..173c5ed4feef0 100644
--- a/compiler/rustc_middle/src/ty/context.rs
+++ b/compiler/rustc_middle/src/ty/context.rs
@@ -4,8 +4,7 @@
 
 use crate::arena::Arena;
 use crate::dep_graph::{DepGraph, DepKindStruct};
-use crate::hir::place::Place as HirPlace;
-use crate::infer::canonical::{Canonical, CanonicalVarInfo, CanonicalVarInfos};
+use crate::infer::canonical::{CanonicalVarInfo, CanonicalVarInfos};
 use crate::lint::struct_lint_level;
 use crate::middle::codegen_fn_attrs::CodegenFnAttrs;
 use crate::middle::resolve_lifetime;
@@ -18,13 +17,13 @@ use crate::thir::Thir;
 use crate::traits;
 use crate::ty::query::{self, TyCtxtAt};
 use crate::ty::{
-    self, AdtDef, AdtDefData, AdtKind, Binder, BindingMode, BoundVar, CanonicalPolyFnSig,
-    ClosureSizeProfileData, Const, ConstS, DefIdTree, FloatTy, FloatVar, FloatVid,
-    GenericParamDefKind, InferTy, IntTy, IntVar, IntVid, List, ParamConst, ParamTy,
-    PolyExistentialPredicate, PolyFnSig, Predicate, PredicateKind, Region, RegionKind, ReprOptions,
-    TraitObjectVisitor, Ty, TyKind, TyVar, TyVid, TypeAndMut, UintTy, Visibility,
+    self, AdtDef, AdtDefData, AdtKind, Binder, Const, ConstS, DefIdTree, FloatTy, FloatVar,
+    FloatVid, GenericParamDefKind, ImplPolarity, InferTy, IntTy, IntVar, IntVid, List, ParamConst,
+    ParamTy, PolyExistentialPredicate, PolyFnSig, Predicate, PredicateKind, Region, RegionKind,
+    ReprOptions, TraitObjectVisitor, Ty, TyKind, TyVar, TyVid, TypeAndMut, TypeckResults, UintTy,
+    Visibility,
 };
-use crate::ty::{GenericArg, GenericArgKind, InternalSubsts, SubstsRef, UserSubsts};
+use crate::ty::{GenericArg, InternalSubsts, SubstsRef};
 use rustc_ast as ast;
 use rustc_data_structures::fingerprint::Fingerprint;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
@@ -35,25 +34,20 @@ use rustc_data_structures::sharded::{IntoPointer, ShardedHashMap};
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_data_structures::steal::Steal;
 use rustc_data_structures::sync::{self, Lock, Lrc, ReadGuard, WorkerLocal};
-use rustc_data_structures::unord::UnordSet;
-use rustc_data_structures::vec_map::VecMap;
 use rustc_errors::{
     DecorateLint, DiagnosticBuilder, DiagnosticMessage, ErrorGuaranteed, MultiSpan,
 };
 use rustc_hir as hir;
-use rustc_hir::def::{DefKind, Res};
-use rustc_hir::def_id::{CrateNum, DefId, LocalDefId, LocalDefIdMap, LOCAL_CRATE};
+use rustc_hir::def::DefKind;
+use rustc_hir::def_id::{CrateNum, DefId, LocalDefId, LOCAL_CRATE};
 use rustc_hir::definitions::Definitions;
-use rustc_hir::hir_id::OwnerId;
 use rustc_hir::intravisit::Visitor;
 use rustc_hir::lang_items::LangItem;
 use rustc_hir::{
-    Constness, ExprKind, HirId, ImplItemKind, ItemKind, ItemLocalId, ItemLocalMap, ItemLocalSet,
-    Node, TraitCandidate, TraitItemKind,
+    Constness, ExprKind, HirId, ImplItemKind, ItemKind, Node, TraitCandidate, TraitItemKind,
 };
-use rustc_index::vec::{Idx, IndexVec};
+use rustc_index::vec::IndexVec;
 use rustc_macros::HashStable;
-use rustc_middle::mir::FakeReadCause;
 use rustc_query_system::dep_graph::DepNodeIndex;
 use rustc_query_system::ich::StableHashingContext;
 use rustc_serialize::opaque::{FileEncodeResult, FileEncoder};
@@ -75,7 +69,6 @@ use rustc_type_ir::{DynKind, InternAs, InternIteratorElement, Interner, TypeFlag
 use std::any::Any;
 use std::borrow::Borrow;
 use std::cmp::Ordering;
-use std::collections::hash_map::{self, Entry};
 use std::fmt;
 use std::hash::{Hash, Hasher};
 use std::iter;
@@ -83,8 +76,6 @@ use std::mem;
 use std::ops::{Bound, Deref};
 use std::sync::Arc;
 
-use super::{ImplPolarity, RvalueScopes};
-
 pub trait OnDiskCache<'tcx>: rustc_data_structures::sync::Sync {
     /// Creates a new `OnDiskCache` instance from the serialized data in `data`.
     fn new(sess: &'tcx Session, data: Mmap, start_pos: usize) -> Self
@@ -284,666 +275,6 @@ pub struct CommonConsts<'tcx> {
     pub unit: Const<'tcx>,
 }
 
-pub struct LocalTableInContext<'a, V> {
-    hir_owner: OwnerId,
-    data: &'a ItemLocalMap<V>,
-}
-
-/// Validate that the given HirId (respectively its `local_id` part) can be
-/// safely used as a key in the maps of a TypeckResults. For that to be
-/// the case, the HirId must have the same `owner` as all the other IDs in
-/// this table (signified by `hir_owner`). Otherwise the HirId
-/// would be in a different frame of reference and using its `local_id`
-/// would result in lookup errors, or worse, in silently wrong data being
-/// stored/returned.
-#[inline]
-fn validate_hir_id_for_typeck_results(hir_owner: OwnerId, hir_id: hir::HirId) {
-    if hir_id.owner != hir_owner {
-        invalid_hir_id_for_typeck_results(hir_owner, hir_id);
-    }
-}
-
-#[cold]
-#[inline(never)]
-fn invalid_hir_id_for_typeck_results(hir_owner: OwnerId, hir_id: hir::HirId) {
-    ty::tls::with(|tcx| {
-        bug!(
-            "node {} with HirId::owner {:?} cannot be placed in TypeckResults with hir_owner {:?}",
-            tcx.hir().node_to_string(hir_id),
-            hir_id.owner,
-            hir_owner
-        )
-    });
-}
-
-impl<'a, V> LocalTableInContext<'a, V> {
-    pub fn contains_key(&self, id: hir::HirId) -> bool {
-        validate_hir_id_for_typeck_results(self.hir_owner, id);
-        self.data.contains_key(&id.local_id)
-    }
-
-    pub fn get(&self, id: hir::HirId) -> Option<&V> {
-        validate_hir_id_for_typeck_results(self.hir_owner, id);
-        self.data.get(&id.local_id)
-    }
-
-    pub fn iter(&self) -> hash_map::Iter<'_, hir::ItemLocalId, V> {
-        self.data.iter()
-    }
-}
-
-impl<'a, V> ::std::ops::Index<hir::HirId> for LocalTableInContext<'a, V> {
-    type Output = V;
-
-    fn index(&self, key: hir::HirId) -> &V {
-        self.get(key).expect("LocalTableInContext: key not found")
-    }
-}
-
-pub struct LocalTableInContextMut<'a, V> {
-    hir_owner: OwnerId,
-    data: &'a mut ItemLocalMap<V>,
-}
-
-impl<'a, V> LocalTableInContextMut<'a, V> {
-    pub fn get_mut(&mut self, id: hir::HirId) -> Option<&mut V> {
-        validate_hir_id_for_typeck_results(self.hir_owner, id);
-        self.data.get_mut(&id.local_id)
-    }
-
-    pub fn entry(&mut self, id: hir::HirId) -> Entry<'_, hir::ItemLocalId, V> {
-        validate_hir_id_for_typeck_results(self.hir_owner, id);
-        self.data.entry(id.local_id)
-    }
-
-    pub fn insert(&mut self, id: hir::HirId, val: V) -> Option<V> {
-        validate_hir_id_for_typeck_results(self.hir_owner, id);
-        self.data.insert(id.local_id, val)
-    }
-
-    pub fn remove(&mut self, id: hir::HirId) -> Option<V> {
-        validate_hir_id_for_typeck_results(self.hir_owner, id);
-        self.data.remove(&id.local_id)
-    }
-}
-
-/// Whenever a value may be live across a generator yield, the type of that value winds up in the
-/// `GeneratorInteriorTypeCause` struct. This struct adds additional information about such
-/// captured types that can be useful for diagnostics. In particular, it stores the span that
-/// caused a given type to be recorded, along with the scope that enclosed the value (which can
-/// be used to find the await that the value is live across).
-///
-/// For example:
-///
-/// ```ignore (pseudo-Rust)
-/// async move {
-///     let x: T = expr;
-///     foo.await
-///     ...
-/// }
-/// ```
-///
-/// Here, we would store the type `T`, the span of the value `x`, the "scope-span" for
-/// the scope that contains `x`, the expr `T` evaluated from, and the span of `foo.await`.
-#[derive(TyEncodable, TyDecodable, Clone, Debug, Eq, Hash, PartialEq, HashStable)]
-#[derive(TypeFoldable, TypeVisitable)]
-pub struct GeneratorInteriorTypeCause<'tcx> {
-    /// Type of the captured binding.
-    pub ty: Ty<'tcx>,
-    /// Span of the binding that was captured.
-    pub span: Span,
-    /// Span of the scope of the captured binding.
-    pub scope_span: Option<Span>,
-    /// Span of `.await` or `yield` expression.
-    pub yield_span: Span,
-    /// Expr which the type evaluated from.
-    pub expr: Option<hir::HirId>,
-}
-
-// This type holds diagnostic information on generators and async functions across crate boundaries
-// and is used to provide better error messages
-#[derive(TyEncodable, TyDecodable, Clone, Debug, HashStable)]
-pub struct GeneratorDiagnosticData<'tcx> {
-    pub generator_interior_types: ty::Binder<'tcx, Vec<GeneratorInteriorTypeCause<'tcx>>>,
-    pub hir_owner: DefId,
-    pub nodes_types: ItemLocalMap<Ty<'tcx>>,
-    pub adjustments: ItemLocalMap<Vec<ty::adjustment::Adjustment<'tcx>>>,
-}
-
-#[derive(TyEncodable, TyDecodable, Debug, HashStable)]
-pub struct TypeckResults<'tcx> {
-    /// The `HirId::owner` all `ItemLocalId`s in this table are relative to.
-    pub hir_owner: OwnerId,
-
-    /// Resolved definitions for `<T>::X` associated paths and
-    /// method calls, including those of overloaded operators.
-    type_dependent_defs: ItemLocalMap<Result<(DefKind, DefId), ErrorGuaranteed>>,
-
-    /// Resolved field indices for field accesses in expressions (`S { field }`, `obj.field`)
-    /// or patterns (`S { field }`). The index is often useful by itself, but to learn more
-    /// about the field you also need definition of the variant to which the field
-    /// belongs, but it may not exist if it's a tuple field (`tuple.0`).
-    field_indices: ItemLocalMap<usize>,
-
-    /// Stores the types for various nodes in the AST. Note that this table
-    /// is not guaranteed to be populated outside inference. See
-    /// typeck::check::fn_ctxt for details.
-    node_types: ItemLocalMap<Ty<'tcx>>,
-
-    /// Stores the type parameters which were substituted to obtain the type
-    /// of this node. This only applies to nodes that refer to entities
-    /// parameterized by type parameters, such as generic fns, types, or
-    /// other items.
-    node_substs: ItemLocalMap<SubstsRef<'tcx>>,
-
-    /// This will either store the canonicalized types provided by the user
-    /// or the substitutions that the user explicitly gave (if any) attached
-    /// to `id`. These will not include any inferred values. The canonical form
-    /// is used to capture things like `_` or other unspecified values.
-    ///
-    /// For example, if the user wrote `foo.collect::<Vec<_>>()`, then the
-    /// canonical substitutions would include only `for<X> { Vec<X> }`.
-    ///
-    /// See also `AscribeUserType` statement in MIR.
-    user_provided_types: ItemLocalMap<CanonicalUserType<'tcx>>,
-
-    /// Stores the canonicalized types provided by the user. See also
-    /// `AscribeUserType` statement in MIR.
-    pub user_provided_sigs: LocalDefIdMap<CanonicalPolyFnSig<'tcx>>,
-
-    adjustments: ItemLocalMap<Vec<ty::adjustment::Adjustment<'tcx>>>,
-
-    /// Stores the actual binding mode for all instances of hir::BindingAnnotation.
-    pat_binding_modes: ItemLocalMap<BindingMode>,
-
-    /// Stores the types which were implicitly dereferenced in pattern binding modes
-    /// for later usage in THIR lowering. For example,
-    ///
-    /// ```
-    /// match &&Some(5i32) {
-    ///     Some(n) => {},
-    ///     _ => {},
-    /// }
-    /// ```
-    /// leads to a `vec![&&Option<i32>, &Option<i32>]`. Empty vectors are not stored.
-    ///
-    /// See:
-    /// <https://github.com/rust-lang/rfcs/blob/master/text/2005-match-ergonomics.md#definitions>
-    pat_adjustments: ItemLocalMap<Vec<Ty<'tcx>>>,
-
-    /// Records the reasons that we picked the kind of each closure;
-    /// not all closures are present in the map.
-    closure_kind_origins: ItemLocalMap<(Span, HirPlace<'tcx>)>,
-
-    /// For each fn, records the "liberated" types of its arguments
-    /// and return type. Liberated means that all bound regions
-    /// (including late-bound regions) are replaced with free
-    /// equivalents. This table is not used in codegen (since regions
-    /// are erased there) and hence is not serialized to metadata.
-    ///
-    /// This table also contains the "revealed" values for any `impl Trait`
-    /// that appear in the signature and whose values are being inferred
-    /// by this function.
-    ///
-    /// # Example
-    ///
-    /// ```rust
-    /// # use std::fmt::Debug;
-    /// fn foo(x: &u32) -> impl Debug { *x }
-    /// ```
-    ///
-    /// The function signature here would be:
-    ///
-    /// ```ignore (illustrative)
-    /// for<'a> fn(&'a u32) -> Foo
-    /// ```
-    ///
-    /// where `Foo` is an opaque type created for this function.
-    ///
-    ///
-    /// The *liberated* form of this would be
-    ///
-    /// ```ignore (illustrative)
-    /// fn(&'a u32) -> u32
-    /// ```
-    ///
-    /// Note that `'a` is not bound (it would be an `ReFree`) and
-    /// that the `Foo` opaque type is replaced by its hidden type.
-    liberated_fn_sigs: ItemLocalMap<ty::FnSig<'tcx>>,
-
-    /// For each FRU expression, record the normalized types of the fields
-    /// of the struct - this is needed because it is non-trivial to
-    /// normalize while preserving regions. This table is used only in
-    /// MIR construction and hence is not serialized to metadata.
-    fru_field_types: ItemLocalMap<Vec<Ty<'tcx>>>,
-
-    /// For every coercion cast we add the HIR node ID of the cast
-    /// expression to this set.
-    coercion_casts: ItemLocalSet,
-
-    /// Set of trait imports actually used in the method resolution.
-    /// This is used for warning unused imports. During type
-    /// checking, this `Lrc` should not be cloned: it must have a ref-count
-    /// of 1 so that we can insert things into the set mutably.
-    pub used_trait_imports: Lrc<UnordSet<LocalDefId>>,
-
-    /// If any errors occurred while type-checking this body,
-    /// this field will be set to `Some(ErrorGuaranteed)`.
-    pub tainted_by_errors: Option<ErrorGuaranteed>,
-
-    /// All the opaque types that have hidden types set
-    /// by this function. We also store the
-    /// type here, so that mir-borrowck can use it as a hint for figuring out hidden types,
-    /// even if they are only set in dead code (which doesn't show up in MIR).
-    pub concrete_opaque_types: VecMap<LocalDefId, ty::OpaqueHiddenType<'tcx>>,
-
-    /// Tracks the minimum captures required for a closure;
-    /// see `MinCaptureInformationMap` for more details.
-    pub closure_min_captures: ty::MinCaptureInformationMap<'tcx>,
-
-    /// Tracks the fake reads required for a closure and the reason for the fake read.
-    /// When performing pattern matching for closures, there are times we don't end up
-    /// reading places that are mentioned in a closure (because of _ patterns). However,
-    /// to ensure the places are initialized, we introduce fake reads.
-    /// Consider these two examples:
-    /// ``` (discriminant matching with only wildcard arm)
-    /// let x: u8;
-    /// let c = || match x { _ => () };
-    /// ```
-    /// In this example, we don't need to actually read/borrow `x` in `c`, and so we don't
-    /// want to capture it. However, we do still want an error here, because `x` should have
-    /// to be initialized at the point where c is created. Therefore, we add a "fake read"
-    /// instead.
-    /// ``` (destructured assignments)
-    /// let c = || {
-    ///     let (t1, t2) = t;
-    /// }
-    /// ```
-    /// In the second example, we capture the disjoint fields of `t` (`t.0` & `t.1`), but
-    /// we never capture `t`. This becomes an issue when we build MIR as we require
-    /// information on `t` in order to create place `t.0` and `t.1`. We can solve this
-    /// issue by fake reading `t`.
-    pub closure_fake_reads: FxHashMap<LocalDefId, Vec<(HirPlace<'tcx>, FakeReadCause, hir::HirId)>>,
-
-    /// Tracks the rvalue scoping rules which defines finer scoping for rvalue expressions
-    /// by applying extended parameter rules.
-    /// Details may be find in `rustc_hir_analysis::check::rvalue_scopes`.
-    pub rvalue_scopes: RvalueScopes,
-
-    /// Stores the type, expression, span and optional scope span of all types
-    /// that are live across the yield of this generator (if a generator).
-    pub generator_interior_types: ty::Binder<'tcx, Vec<GeneratorInteriorTypeCause<'tcx>>>,
-
-    /// We sometimes treat byte string literals (which are of type `&[u8; N]`)
-    /// as `&[u8]`, depending on the pattern  in which they are used.
-    /// This hashset records all instances where we behave
-    /// like this to allow `const_to_pat` to reliably handle this situation.
-    pub treat_byte_string_as_slice: ItemLocalSet,
-
-    /// Contains the data for evaluating the effect of feature `capture_disjoint_fields`
-    /// on closure size.
-    pub closure_size_eval: FxHashMap<LocalDefId, ClosureSizeProfileData<'tcx>>,
-}
-
-impl<'tcx> TypeckResults<'tcx> {
-    pub fn new(hir_owner: OwnerId) -> TypeckResults<'tcx> {
-        TypeckResults {
-            hir_owner,
-            type_dependent_defs: Default::default(),
-            field_indices: Default::default(),
-            user_provided_types: Default::default(),
-            user_provided_sigs: Default::default(),
-            node_types: Default::default(),
-            node_substs: Default::default(),
-            adjustments: Default::default(),
-            pat_binding_modes: Default::default(),
-            pat_adjustments: Default::default(),
-            closure_kind_origins: Default::default(),
-            liberated_fn_sigs: Default::default(),
-            fru_field_types: Default::default(),
-            coercion_casts: Default::default(),
-            used_trait_imports: Lrc::new(Default::default()),
-            tainted_by_errors: None,
-            concrete_opaque_types: Default::default(),
-            closure_min_captures: Default::default(),
-            closure_fake_reads: Default::default(),
-            rvalue_scopes: Default::default(),
-            generator_interior_types: ty::Binder::dummy(Default::default()),
-            treat_byte_string_as_slice: Default::default(),
-            closure_size_eval: Default::default(),
-        }
-    }
-
-    /// Returns the final resolution of a `QPath` in an `Expr` or `Pat` node.
-    pub fn qpath_res(&self, qpath: &hir::QPath<'_>, id: hir::HirId) -> Res {
-        match *qpath {
-            hir::QPath::Resolved(_, ref path) => path.res,
-            hir::QPath::TypeRelative(..) | hir::QPath::LangItem(..) => self
-                .type_dependent_def(id)
-                .map_or(Res::Err, |(kind, def_id)| Res::Def(kind, def_id)),
-        }
-    }
-
-    pub fn type_dependent_defs(
-        &self,
-    ) -> LocalTableInContext<'_, Result<(DefKind, DefId), ErrorGuaranteed>> {
-        LocalTableInContext { hir_owner: self.hir_owner, data: &self.type_dependent_defs }
-    }
-
-    pub fn type_dependent_def(&self, id: HirId) -> Option<(DefKind, DefId)> {
-        validate_hir_id_for_typeck_results(self.hir_owner, id);
-        self.type_dependent_defs.get(&id.local_id).cloned().and_then(|r| r.ok())
-    }
-
-    pub fn type_dependent_def_id(&self, id: HirId) -> Option<DefId> {
-        self.type_dependent_def(id).map(|(_, def_id)| def_id)
-    }
-
-    pub fn type_dependent_defs_mut(
-        &mut self,
-    ) -> LocalTableInContextMut<'_, Result<(DefKind, DefId), ErrorGuaranteed>> {
-        LocalTableInContextMut { hir_owner: self.hir_owner, data: &mut self.type_dependent_defs }
-    }
-
-    pub fn field_indices(&self) -> LocalTableInContext<'_, usize> {
-        LocalTableInContext { hir_owner: self.hir_owner, data: &self.field_indices }
-    }
-
-    pub fn field_indices_mut(&mut self) -> LocalTableInContextMut<'_, usize> {
-        LocalTableInContextMut { hir_owner: self.hir_owner, data: &mut self.field_indices }
-    }
-
-    pub fn field_index(&self, id: hir::HirId) -> usize {
-        self.field_indices().get(id).cloned().expect("no index for a field")
-    }
-
-    pub fn opt_field_index(&self, id: hir::HirId) -> Option<usize> {
-        self.field_indices().get(id).cloned()
-    }
-
-    pub fn user_provided_types(&self) -> LocalTableInContext<'_, CanonicalUserType<'tcx>> {
-        LocalTableInContext { hir_owner: self.hir_owner, data: &self.user_provided_types }
-    }
-
-    pub fn user_provided_types_mut(
-        &mut self,
-    ) -> LocalTableInContextMut<'_, CanonicalUserType<'tcx>> {
-        LocalTableInContextMut { hir_owner: self.hir_owner, data: &mut self.user_provided_types }
-    }
-
-    pub fn node_types(&self) -> LocalTableInContext<'_, Ty<'tcx>> {
-        LocalTableInContext { hir_owner: self.hir_owner, data: &self.node_types }
-    }
-
-    pub fn node_types_mut(&mut self) -> LocalTableInContextMut<'_, Ty<'tcx>> {
-        LocalTableInContextMut { hir_owner: self.hir_owner, data: &mut self.node_types }
-    }
-
-    pub fn get_generator_diagnostic_data(&self) -> GeneratorDiagnosticData<'tcx> {
-        let generator_interior_type = self.generator_interior_types.map_bound_ref(|vec| {
-            vec.iter()
-                .map(|item| {
-                    GeneratorInteriorTypeCause {
-                        ty: item.ty,
-                        span: item.span,
-                        scope_span: item.scope_span,
-                        yield_span: item.yield_span,
-                        expr: None, //FIXME: Passing expression over crate boundaries is impossible at the moment
-                    }
-                })
-                .collect::<Vec<_>>()
-        });
-        GeneratorDiagnosticData {
-            generator_interior_types: generator_interior_type,
-            hir_owner: self.hir_owner.to_def_id(),
-            nodes_types: self.node_types.clone(),
-            adjustments: self.adjustments.clone(),
-        }
-    }
-
-    pub fn node_type(&self, id: hir::HirId) -> Ty<'tcx> {
-        self.node_type_opt(id).unwrap_or_else(|| {
-            bug!("node_type: no type for node `{}`", tls::with(|tcx| tcx.hir().node_to_string(id)))
-        })
-    }
-
-    pub fn node_type_opt(&self, id: hir::HirId) -> Option<Ty<'tcx>> {
-        validate_hir_id_for_typeck_results(self.hir_owner, id);
-        self.node_types.get(&id.local_id).cloned()
-    }
-
-    pub fn node_substs_mut(&mut self) -> LocalTableInContextMut<'_, SubstsRef<'tcx>> {
-        LocalTableInContextMut { hir_owner: self.hir_owner, data: &mut self.node_substs }
-    }
-
-    pub fn node_substs(&self, id: hir::HirId) -> SubstsRef<'tcx> {
-        validate_hir_id_for_typeck_results(self.hir_owner, id);
-        self.node_substs.get(&id.local_id).cloned().unwrap_or_else(|| InternalSubsts::empty())
-    }
-
-    pub fn node_substs_opt(&self, id: hir::HirId) -> Option<SubstsRef<'tcx>> {
-        validate_hir_id_for_typeck_results(self.hir_owner, id);
-        self.node_substs.get(&id.local_id).cloned()
-    }
-
-    /// Returns the type of a pattern as a monotype. Like [`expr_ty`], this function
-    /// doesn't provide type parameter substitutions.
-    ///
-    /// [`expr_ty`]: TypeckResults::expr_ty
-    pub fn pat_ty(&self, pat: &hir::Pat<'_>) -> Ty<'tcx> {
-        self.node_type(pat.hir_id)
-    }
-
-    /// Returns the type of an expression as a monotype.
-    ///
-    /// NB (1): This is the PRE-ADJUSTMENT TYPE for the expression.  That is, in
-    /// some cases, we insert `Adjustment` annotations such as auto-deref or
-    /// auto-ref.  The type returned by this function does not consider such
-    /// adjustments.  See `expr_ty_adjusted()` instead.
-    ///
-    /// NB (2): This type doesn't provide type parameter substitutions; e.g., if you
-    /// ask for the type of `id` in `id(3)`, it will return `fn(&isize) -> isize`
-    /// instead of `fn(ty) -> T with T = isize`.
-    pub fn expr_ty(&self, expr: &hir::Expr<'_>) -> Ty<'tcx> {
-        self.node_type(expr.hir_id)
-    }
-
-    pub fn expr_ty_opt(&self, expr: &hir::Expr<'_>) -> Option<Ty<'tcx>> {
-        self.node_type_opt(expr.hir_id)
-    }
-
-    pub fn adjustments(&self) -> LocalTableInContext<'_, Vec<ty::adjustment::Adjustment<'tcx>>> {
-        LocalTableInContext { hir_owner: self.hir_owner, data: &self.adjustments }
-    }
-
-    pub fn adjustments_mut(
-        &mut self,
-    ) -> LocalTableInContextMut<'_, Vec<ty::adjustment::Adjustment<'tcx>>> {
-        LocalTableInContextMut { hir_owner: self.hir_owner, data: &mut self.adjustments }
-    }
-
-    pub fn expr_adjustments(&self, expr: &hir::Expr<'_>) -> &[ty::adjustment::Adjustment<'tcx>] {
-        validate_hir_id_for_typeck_results(self.hir_owner, expr.hir_id);
-        self.adjustments.get(&expr.hir_id.local_id).map_or(&[], |a| &a[..])
-    }
-
-    /// Returns the type of `expr`, considering any `Adjustment`
-    /// entry recorded for that expression.
-    pub fn expr_ty_adjusted(&self, expr: &hir::Expr<'_>) -> Ty<'tcx> {
-        self.expr_adjustments(expr).last().map_or_else(|| self.expr_ty(expr), |adj| adj.target)
-    }
-
-    pub fn expr_ty_adjusted_opt(&self, expr: &hir::Expr<'_>) -> Option<Ty<'tcx>> {
-        self.expr_adjustments(expr).last().map(|adj| adj.target).or_else(|| self.expr_ty_opt(expr))
-    }
-
-    pub fn is_method_call(&self, expr: &hir::Expr<'_>) -> bool {
-        // Only paths and method calls/overloaded operators have
-        // entries in type_dependent_defs, ignore the former here.
-        if let hir::ExprKind::Path(_) = expr.kind {
-            return false;
-        }
-
-        matches!(self.type_dependent_defs().get(expr.hir_id), Some(Ok((DefKind::AssocFn, _))))
-    }
-
-    pub fn extract_binding_mode(&self, s: &Session, id: HirId, sp: Span) -> Option<BindingMode> {
-        self.pat_binding_modes().get(id).copied().or_else(|| {
-            s.delay_span_bug(sp, "missing binding mode");
-            None
-        })
-    }
-
-    pub fn pat_binding_modes(&self) -> LocalTableInContext<'_, BindingMode> {
-        LocalTableInContext { hir_owner: self.hir_owner, data: &self.pat_binding_modes }
-    }
-
-    pub fn pat_binding_modes_mut(&mut self) -> LocalTableInContextMut<'_, BindingMode> {
-        LocalTableInContextMut { hir_owner: self.hir_owner, data: &mut self.pat_binding_modes }
-    }
-
-    pub fn pat_adjustments(&self) -> LocalTableInContext<'_, Vec<Ty<'tcx>>> {
-        LocalTableInContext { hir_owner: self.hir_owner, data: &self.pat_adjustments }
-    }
-
-    pub fn pat_adjustments_mut(&mut self) -> LocalTableInContextMut<'_, Vec<Ty<'tcx>>> {
-        LocalTableInContextMut { hir_owner: self.hir_owner, data: &mut self.pat_adjustments }
-    }
-
-    /// For a given closure, returns the iterator of `ty::CapturedPlace`s that are captured
-    /// by the closure.
-    pub fn closure_min_captures_flattened(
-        &self,
-        closure_def_id: LocalDefId,
-    ) -> impl Iterator<Item = &ty::CapturedPlace<'tcx>> {
-        self.closure_min_captures
-            .get(&closure_def_id)
-            .map(|closure_min_captures| closure_min_captures.values().flat_map(|v| v.iter()))
-            .into_iter()
-            .flatten()
-    }
-
-    pub fn closure_kind_origins(&self) -> LocalTableInContext<'_, (Span, HirPlace<'tcx>)> {
-        LocalTableInContext { hir_owner: self.hir_owner, data: &self.closure_kind_origins }
-    }
-
-    pub fn closure_kind_origins_mut(
-        &mut self,
-    ) -> LocalTableInContextMut<'_, (Span, HirPlace<'tcx>)> {
-        LocalTableInContextMut { hir_owner: self.hir_owner, data: &mut self.closure_kind_origins }
-    }
-
-    pub fn liberated_fn_sigs(&self) -> LocalTableInContext<'_, ty::FnSig<'tcx>> {
-        LocalTableInContext { hir_owner: self.hir_owner, data: &self.liberated_fn_sigs }
-    }
-
-    pub fn liberated_fn_sigs_mut(&mut self) -> LocalTableInContextMut<'_, ty::FnSig<'tcx>> {
-        LocalTableInContextMut { hir_owner: self.hir_owner, data: &mut self.liberated_fn_sigs }
-    }
-
-    pub fn fru_field_types(&self) -> LocalTableInContext<'_, Vec<Ty<'tcx>>> {
-        LocalTableInContext { hir_owner: self.hir_owner, data: &self.fru_field_types }
-    }
-
-    pub fn fru_field_types_mut(&mut self) -> LocalTableInContextMut<'_, Vec<Ty<'tcx>>> {
-        LocalTableInContextMut { hir_owner: self.hir_owner, data: &mut self.fru_field_types }
-    }
-
-    pub fn is_coercion_cast(&self, hir_id: hir::HirId) -> bool {
-        validate_hir_id_for_typeck_results(self.hir_owner, hir_id);
-        self.coercion_casts.contains(&hir_id.local_id)
-    }
-
-    pub fn set_coercion_cast(&mut self, id: ItemLocalId) {
-        self.coercion_casts.insert(id);
-    }
-
-    pub fn coercion_casts(&self) -> &ItemLocalSet {
-        &self.coercion_casts
-    }
-}
-
-rustc_index::newtype_index! {
-    pub struct UserTypeAnnotationIndex {
-        derive [HashStable]
-        DEBUG_FORMAT = "UserType({})",
-        const START_INDEX = 0,
-    }
-}
-
-/// Mapping of type annotation indices to canonical user type annotations.
-pub type CanonicalUserTypeAnnotations<'tcx> =
-    IndexVec<UserTypeAnnotationIndex, CanonicalUserTypeAnnotation<'tcx>>;
-
-#[derive(Clone, Debug, TyEncodable, TyDecodable, HashStable, TypeFoldable, TypeVisitable, Lift)]
-pub struct CanonicalUserTypeAnnotation<'tcx> {
-    pub user_ty: Box<CanonicalUserType<'tcx>>,
-    pub span: Span,
-    pub inferred_ty: Ty<'tcx>,
-}
-
-/// Canonicalized user type annotation.
-pub type CanonicalUserType<'tcx> = Canonical<'tcx, UserType<'tcx>>;
-
-impl<'tcx> CanonicalUserType<'tcx> {
-    /// Returns `true` if this represents a substitution of the form `[?0, ?1, ?2]`,
-    /// i.e., each thing is mapped to a canonical variable with the same index.
-    pub fn is_identity(&self) -> bool {
-        match self.value {
-            UserType::Ty(_) => false,
-            UserType::TypeOf(_, user_substs) => {
-                if user_substs.user_self_ty.is_some() {
-                    return false;
-                }
-
-                iter::zip(user_substs.substs, BoundVar::new(0)..).all(|(kind, cvar)| {
-                    match kind.unpack() {
-                        GenericArgKind::Type(ty) => match ty.kind() {
-                            ty::Bound(debruijn, b) => {
-                                // We only allow a `ty::INNERMOST` index in substitutions.
-                                assert_eq!(*debruijn, ty::INNERMOST);
-                                cvar == b.var
-                            }
-                            _ => false,
-                        },
-
-                        GenericArgKind::Lifetime(r) => match *r {
-                            ty::ReLateBound(debruijn, br) => {
-                                // We only allow a `ty::INNERMOST` index in substitutions.
-                                assert_eq!(debruijn, ty::INNERMOST);
-                                cvar == br.var
-                            }
-                            _ => false,
-                        },
-
-                        GenericArgKind::Const(ct) => match ct.kind() {
-                            ty::ConstKind::Bound(debruijn, b) => {
-                                // We only allow a `ty::INNERMOST` index in substitutions.
-                                assert_eq!(debruijn, ty::INNERMOST);
-                                cvar == b
-                            }
-                            _ => false,
-                        },
-                    }
-                })
-            }
-        }
-    }
-}
-
-/// A user-given type annotation attached to a constant. These arise
-/// from constants that are named via paths, like `Foo::<A>::new` and
-/// so forth.
-#[derive(Copy, Clone, Debug, PartialEq, TyEncodable, TyDecodable)]
-#[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
-pub enum UserType<'tcx> {
-    Ty(Ty<'tcx>),
-
-    /// The canonical type is the result of `type_of(def_id)` with the
-    /// given substitutions applied.
-    TypeOf(DefId, UserSubsts<'tcx>),
-}
-
 impl<'tcx> CommonTypes<'tcx> {
     fn new(
         interners: &CtxtInterners<'tcx>,
diff --git a/compiler/rustc_middle/src/ty/fast_reject.rs b/compiler/rustc_middle/src/ty/fast_reject.rs
index 44650827810ab..f785fb5c4b9be 100644
--- a/compiler/rustc_middle/src/ty/fast_reject.rs
+++ b/compiler/rustc_middle/src/ty/fast_reject.rs
@@ -6,28 +6,18 @@ use std::fmt::Debug;
 use std::hash::Hash;
 use std::iter;
 
-use self::SimplifiedTypeGen::*;
+use self::SimplifiedType::*;
 
-pub type SimplifiedType = SimplifiedTypeGen<DefId>;
-
-/// See `simplify_type`
-///
-/// Note that we keep this type generic over the type of identifier it uses
-/// because we sometimes need to use SimplifiedTypeGen values as stable sorting
-/// keys (in which case we use a DefPathHash as id-type) but in the general case
-/// the non-stable but fast to construct DefId-version is the better choice.
+/// See `simplify_type`.
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, TyEncodable, TyDecodable, HashStable)]
-pub enum SimplifiedTypeGen<D>
-where
-    D: Copy + Debug + Eq,
-{
+pub enum SimplifiedType {
     BoolSimplifiedType,
     CharSimplifiedType,
     IntSimplifiedType(ty::IntTy),
     UintSimplifiedType(ty::UintTy),
     FloatSimplifiedType(ty::FloatTy),
-    AdtSimplifiedType(D),
-    ForeignSimplifiedType(D),
+    AdtSimplifiedType(DefId),
+    ForeignSimplifiedType(DefId),
     StrSimplifiedType,
     ArraySimplifiedType,
     SliceSimplifiedType,
@@ -38,9 +28,9 @@ where
     /// A trait object, all of whose components are markers
     /// (e.g., `dyn Send + Sync`).
     MarkerTraitObjectSimplifiedType,
-    TraitSimplifiedType(D),
-    ClosureSimplifiedType(D),
-    GeneratorSimplifiedType(D),
+    TraitSimplifiedType(DefId),
+    ClosureSimplifiedType(DefId),
+    GeneratorSimplifiedType(DefId),
     GeneratorWitnessSimplifiedType(usize),
     FunctionSimplifiedType(usize),
     PlaceholderSimplifiedType,
@@ -142,8 +132,8 @@ pub fn simplify_type<'tcx>(
     }
 }
 
-impl<D: Copy + Debug + Eq> SimplifiedTypeGen<D> {
-    pub fn def(self) -> Option<D> {
+impl SimplifiedType {
+    pub fn def(self) -> Option<DefId> {
         match self {
             AdtSimplifiedType(d)
             | ForeignSimplifiedType(d)
@@ -153,36 +143,6 @@ impl<D: Copy + Debug + Eq> SimplifiedTypeGen<D> {
             _ => None,
         }
     }
-
-    pub fn map_def<U, F>(self, map: F) -> SimplifiedTypeGen<U>
-    where
-        F: Fn(D) -> U,
-        U: Copy + Debug + Eq,
-    {
-        match self {
-            BoolSimplifiedType => BoolSimplifiedType,
-            CharSimplifiedType => CharSimplifiedType,
-            IntSimplifiedType(t) => IntSimplifiedType(t),
-            UintSimplifiedType(t) => UintSimplifiedType(t),
-            FloatSimplifiedType(t) => FloatSimplifiedType(t),
-            AdtSimplifiedType(d) => AdtSimplifiedType(map(d)),
-            ForeignSimplifiedType(d) => ForeignSimplifiedType(map(d)),
-            StrSimplifiedType => StrSimplifiedType,
-            ArraySimplifiedType => ArraySimplifiedType,
-            SliceSimplifiedType => SliceSimplifiedType,
-            RefSimplifiedType(m) => RefSimplifiedType(m),
-            PtrSimplifiedType(m) => PtrSimplifiedType(m),
-            NeverSimplifiedType => NeverSimplifiedType,
-            MarkerTraitObjectSimplifiedType => MarkerTraitObjectSimplifiedType,
-            TupleSimplifiedType(n) => TupleSimplifiedType(n),
-            TraitSimplifiedType(d) => TraitSimplifiedType(map(d)),
-            ClosureSimplifiedType(d) => ClosureSimplifiedType(map(d)),
-            GeneratorSimplifiedType(d) => GeneratorSimplifiedType(map(d)),
-            GeneratorWitnessSimplifiedType(n) => GeneratorWitnessSimplifiedType(n),
-            FunctionSimplifiedType(n) => FunctionSimplifiedType(n),
-            PlaceholderSimplifiedType => PlaceholderSimplifiedType,
-        }
-    }
 }
 
 /// Given generic arguments from an obligation and an impl,
diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs
index 5232c1e1cc0f8..7290f0ae7c035 100644
--- a/compiler/rustc_middle/src/ty/mod.rs
+++ b/compiler/rustc_middle/src/ty/mod.rs
@@ -83,10 +83,8 @@ pub use self::consts::{
     Const, ConstInt, ConstKind, ConstS, Expr, InferConst, ScalarInt, UnevaluatedConst, ValTree,
 };
 pub use self::context::{
-    tls, CanonicalUserType, CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations,
-    CtxtInterners, DeducedParamAttrs, FreeRegionInfo, GeneratorDiagnosticData,
-    GeneratorInteriorTypeCause, GlobalCtxt, Lift, OnDiskCache, TyCtxt, TyCtxtFeed, TypeckResults,
-    UserType, UserTypeAnnotationIndex,
+    tls, CtxtInterners, DeducedParamAttrs, FreeRegionInfo, GlobalCtxt, Lift, OnDiskCache, TyCtxt,
+    TyCtxtFeed,
 };
 pub use self::instance::{Instance, InstanceDef, ShortInstance};
 pub use self::list::List;
@@ -103,6 +101,11 @@ pub use self::sty::{
     Region, RegionKind, RegionVid, TraitRef, TyKind, TypeAndMut, UpvarSubsts, VarianceDiagInfo,
 };
 pub use self::trait_def::TraitDef;
+pub use self::typeck_results::{
+    CanonicalUserType, CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations,
+    GeneratorDiagnosticData, GeneratorInteriorTypeCause, TypeckResults, UserType,
+    UserTypeAnnotationIndex,
+};
 
 pub mod _match;
 pub mod abstract_const;
@@ -143,6 +146,7 @@ mod parameterized;
 mod rvalue_scopes;
 mod structural_impls;
 mod sty;
+mod typeck_results;
 
 // Data types
 
diff --git a/compiler/rustc_middle/src/ty/parameterized.rs b/compiler/rustc_middle/src/ty/parameterized.rs
index c7d6c6abd1c22..a21e3961cb627 100644
--- a/compiler/rustc_middle/src/ty/parameterized.rs
+++ b/compiler/rustc_middle/src/ty/parameterized.rs
@@ -1,15 +1,10 @@
 use rustc_data_structures::fx::FxHashMap;
-use rustc_hir::def_id::{DefId, DefIndex};
+use rustc_hir::def_id::DefIndex;
 use rustc_index::vec::{Idx, IndexVec};
 
-use crate::middle::exported_symbols::ExportedSymbol;
-use crate::mir::Body;
-use crate::ty::{
-    self, Clause, Const, FnSig, GeneratorDiagnosticData, GenericPredicates, Predicate, TraitRef, Ty,
-};
+use crate::ty;
 
 pub trait ParameterizedOverTcx: 'static {
-    #[allow(unused_lifetimes)]
     type Value<'tcx>;
 }
 
@@ -67,7 +62,7 @@ trivially_parameterized_over_tcx! {
     ty::TraitDef,
     ty::Visibility<DefIndex>,
     ty::adjustment::CoerceUnsizedInfo,
-    ty::fast_reject::SimplifiedTypeGen<DefId>,
+    ty::fast_reject::SimplifiedType,
     rustc_ast::Attribute,
     rustc_ast::DelimArgs,
     rustc_attr::ConstStability,
@@ -100,29 +95,28 @@ trivially_parameterized_over_tcx! {
     rustc_type_ir::Variance,
 }
 
-// HACK(compiler-errors): This macro rule can only take an ident,
-// not a path, due to parsing ambiguity reasons. That means we gotta
-// import all of these types above.
+// HACK(compiler-errors): This macro rule can only take a fake path,
+// not a real, due to parsing ambiguity reasons.
 #[macro_export]
 macro_rules! parameterized_over_tcx {
-    ($($ident:ident),+ $(,)?) => {
+    ($($($fake_path:ident)::+),+ $(,)?) => {
         $(
-            impl $crate::ty::ParameterizedOverTcx for $ident<'static> {
-                type Value<'tcx> = $ident<'tcx>;
+            impl $crate::ty::ParameterizedOverTcx for $($fake_path)::+<'static> {
+                type Value<'tcx> = $($fake_path)::+<'tcx>;
             }
         )*
     }
 }
 
 parameterized_over_tcx! {
-    Ty,
-    FnSig,
-    GenericPredicates,
-    TraitRef,
-    Const,
-    Predicate,
-    Clause,
-    GeneratorDiagnosticData,
-    Body,
-    ExportedSymbol,
+    crate::middle::exported_symbols::ExportedSymbol,
+    crate::mir::Body,
+    ty::Ty,
+    ty::FnSig,
+    ty::GenericPredicates,
+    ty::TraitRef,
+    ty::Const,
+    ty::Predicate,
+    ty::Clause,
+    ty::GeneratorDiagnosticData,
 }
diff --git a/compiler/rustc_middle/src/ty/print/pretty.rs b/compiler/rustc_middle/src/ty/print/pretty.rs
index b1bc6eb8b81c5..a1d53506707c9 100644
--- a/compiler/rustc_middle/src/ty/print/pretty.rs
+++ b/compiler/rustc_middle/src/ty/print/pretty.rs
@@ -16,6 +16,7 @@ use rustc_session::config::TrimmedDefPaths;
 use rustc_session::cstore::{ExternCrate, ExternCrateSource};
 use rustc_session::Limit;
 use rustc_span::symbol::{kw, Ident, Symbol};
+use rustc_span::FileNameDisplayPreference;
 use rustc_target::abi::Size;
 use rustc_target::spec::abi::Abi;
 use smallvec::SmallVec;
@@ -818,11 +819,16 @@ pub trait PrettyPrinter<'tcx>:
                             p!("@", print_def_path(did.to_def_id(), substs));
                         } else {
                             let span = self.tcx().def_span(did);
+                            let preference = if FORCE_TRIMMED_PATH.with(|flag| flag.get()) {
+                                FileNameDisplayPreference::Short
+                            } else {
+                                FileNameDisplayPreference::Remapped
+                            };
                             p!(write(
                                 "@{}",
                                 // This may end up in stderr diagnostics but it may also be emitted
                                 // into MIR. Hence we use the remapped path if available
-                                self.tcx().sess.source_map().span_to_embeddable_string(span)
+                                self.tcx().sess.source_map().span_to_string(span, preference)
                             ));
                         }
                     } else {
diff --git a/compiler/rustc_middle/src/ty/typeck_results.rs b/compiler/rustc_middle/src/ty/typeck_results.rs
new file mode 100644
index 0000000000000..4fe85d4366f3e
--- /dev/null
+++ b/compiler/rustc_middle/src/ty/typeck_results.rs
@@ -0,0 +1,689 @@
+use crate::{
+    hir::place::Place as HirPlace,
+    infer::canonical::Canonical,
+    ty::{
+        self, tls, BindingMode, BoundVar, CanonicalPolyFnSig, ClosureSizeProfileData,
+        GenericArgKind, InternalSubsts, SubstsRef, Ty, UserSubsts,
+    },
+};
+use rustc_data_structures::{fx::FxHashMap, sync::Lrc, unord::UnordSet, vec_map::VecMap};
+use rustc_errors::ErrorGuaranteed;
+use rustc_hir as hir;
+use rustc_hir::{
+    def::{DefKind, Res},
+    def_id::{DefId, LocalDefId, LocalDefIdMap},
+    hir_id::OwnerId,
+    HirId, ItemLocalId, ItemLocalMap, ItemLocalSet,
+};
+use rustc_index::vec::{Idx, IndexVec};
+use rustc_macros::HashStable;
+use rustc_middle::mir::FakeReadCause;
+use rustc_session::Session;
+use rustc_span::Span;
+use std::{
+    collections::hash_map::{self, Entry},
+    hash::Hash,
+    iter,
+};
+
+use super::RvalueScopes;
+
+#[derive(TyEncodable, TyDecodable, Debug, HashStable)]
+pub struct TypeckResults<'tcx> {
+    /// The `HirId::owner` all `ItemLocalId`s in this table are relative to.
+    pub hir_owner: OwnerId,
+
+    /// Resolved definitions for `<T>::X` associated paths and
+    /// method calls, including those of overloaded operators.
+    type_dependent_defs: ItemLocalMap<Result<(DefKind, DefId), ErrorGuaranteed>>,
+
+    /// Resolved field indices for field accesses in expressions (`S { field }`, `obj.field`)
+    /// or patterns (`S { field }`). The index is often useful by itself, but to learn more
+    /// about the field you also need definition of the variant to which the field
+    /// belongs, but it may not exist if it's a tuple field (`tuple.0`).
+    field_indices: ItemLocalMap<usize>,
+
+    /// Stores the types for various nodes in the AST. Note that this table
+    /// is not guaranteed to be populated outside inference. See
+    /// typeck::check::fn_ctxt for details.
+    node_types: ItemLocalMap<Ty<'tcx>>,
+
+    /// Stores the type parameters which were substituted to obtain the type
+    /// of this node. This only applies to nodes that refer to entities
+    /// parameterized by type parameters, such as generic fns, types, or
+    /// other items.
+    node_substs: ItemLocalMap<SubstsRef<'tcx>>,
+
+    /// This will either store the canonicalized types provided by the user
+    /// or the substitutions that the user explicitly gave (if any) attached
+    /// to `id`. These will not include any inferred values. The canonical form
+    /// is used to capture things like `_` or other unspecified values.
+    ///
+    /// For example, if the user wrote `foo.collect::<Vec<_>>()`, then the
+    /// canonical substitutions would include only `for<X> { Vec<X> }`.
+    ///
+    /// See also `AscribeUserType` statement in MIR.
+    user_provided_types: ItemLocalMap<CanonicalUserType<'tcx>>,
+
+    /// Stores the canonicalized types provided by the user. See also
+    /// `AscribeUserType` statement in MIR.
+    pub user_provided_sigs: LocalDefIdMap<CanonicalPolyFnSig<'tcx>>,
+
+    adjustments: ItemLocalMap<Vec<ty::adjustment::Adjustment<'tcx>>>,
+
+    /// Stores the actual binding mode for all instances of hir::BindingAnnotation.
+    pat_binding_modes: ItemLocalMap<BindingMode>,
+
+    /// Stores the types which were implicitly dereferenced in pattern binding modes
+    /// for later usage in THIR lowering. For example,
+    ///
+    /// ```
+    /// match &&Some(5i32) {
+    ///     Some(n) => {},
+    ///     _ => {},
+    /// }
+    /// ```
+    /// leads to a `vec![&&Option<i32>, &Option<i32>]`. Empty vectors are not stored.
+    ///
+    /// See:
+    /// <https://github.com/rust-lang/rfcs/blob/master/text/2005-match-ergonomics.md#definitions>
+    pat_adjustments: ItemLocalMap<Vec<Ty<'tcx>>>,
+
+    /// Records the reasons that we picked the kind of each closure;
+    /// not all closures are present in the map.
+    closure_kind_origins: ItemLocalMap<(Span, HirPlace<'tcx>)>,
+
+    /// For each fn, records the "liberated" types of its arguments
+    /// and return type. Liberated means that all bound regions
+    /// (including late-bound regions) are replaced with free
+    /// equivalents. This table is not used in codegen (since regions
+    /// are erased there) and hence is not serialized to metadata.
+    ///
+    /// This table also contains the "revealed" values for any `impl Trait`
+    /// that appear in the signature and whose values are being inferred
+    /// by this function.
+    ///
+    /// # Example
+    ///
+    /// ```rust
+    /// # use std::fmt::Debug;
+    /// fn foo(x: &u32) -> impl Debug { *x }
+    /// ```
+    ///
+    /// The function signature here would be:
+    ///
+    /// ```ignore (illustrative)
+    /// for<'a> fn(&'a u32) -> Foo
+    /// ```
+    ///
+    /// where `Foo` is an opaque type created for this function.
+    ///
+    ///
+    /// The *liberated* form of this would be
+    ///
+    /// ```ignore (illustrative)
+    /// fn(&'a u32) -> u32
+    /// ```
+    ///
+    /// Note that `'a` is not bound (it would be an `ReFree`) and
+    /// that the `Foo` opaque type is replaced by its hidden type.
+    liberated_fn_sigs: ItemLocalMap<ty::FnSig<'tcx>>,
+
+    /// For each FRU expression, record the normalized types of the fields
+    /// of the struct - this is needed because it is non-trivial to
+    /// normalize while preserving regions. This table is used only in
+    /// MIR construction and hence is not serialized to metadata.
+    fru_field_types: ItemLocalMap<Vec<Ty<'tcx>>>,
+
+    /// For every coercion cast we add the HIR node ID of the cast
+    /// expression to this set.
+    coercion_casts: ItemLocalSet,
+
+    /// Set of trait imports actually used in the method resolution.
+    /// This is used for warning unused imports. During type
+    /// checking, this `Lrc` should not be cloned: it must have a ref-count
+    /// of 1 so that we can insert things into the set mutably.
+    pub used_trait_imports: Lrc<UnordSet<LocalDefId>>,
+
+    /// If any errors occurred while type-checking this body,
+    /// this field will be set to `Some(ErrorGuaranteed)`.
+    pub tainted_by_errors: Option<ErrorGuaranteed>,
+
+    /// All the opaque types that have hidden types set
+    /// by this function. We also store the
+    /// type here, so that mir-borrowck can use it as a hint for figuring out hidden types,
+    /// even if they are only set in dead code (which doesn't show up in MIR).
+    pub concrete_opaque_types: VecMap<LocalDefId, ty::OpaqueHiddenType<'tcx>>,
+
+    /// Tracks the minimum captures required for a closure;
+    /// see `MinCaptureInformationMap` for more details.
+    pub closure_min_captures: ty::MinCaptureInformationMap<'tcx>,
+
+    /// Tracks the fake reads required for a closure and the reason for the fake read.
+    /// When performing pattern matching for closures, there are times we don't end up
+    /// reading places that are mentioned in a closure (because of _ patterns). However,
+    /// to ensure the places are initialized, we introduce fake reads.
+    /// Consider these two examples:
+    /// ``` (discriminant matching with only wildcard arm)
+    /// let x: u8;
+    /// let c = || match x { _ => () };
+    /// ```
+    /// In this example, we don't need to actually read/borrow `x` in `c`, and so we don't
+    /// want to capture it. However, we do still want an error here, because `x` should have
+    /// to be initialized at the point where c is created. Therefore, we add a "fake read"
+    /// instead.
+    /// ``` (destructured assignments)
+    /// let c = || {
+    ///     let (t1, t2) = t;
+    /// }
+    /// ```
+    /// In the second example, we capture the disjoint fields of `t` (`t.0` & `t.1`), but
+    /// we never capture `t`. This becomes an issue when we build MIR as we require
+    /// information on `t` in order to create place `t.0` and `t.1`. We can solve this
+    /// issue by fake reading `t`.
+    pub closure_fake_reads: FxHashMap<LocalDefId, Vec<(HirPlace<'tcx>, FakeReadCause, hir::HirId)>>,
+
+    /// Tracks the rvalue scoping rules which defines finer scoping for rvalue expressions
+    /// by applying extended parameter rules.
+    /// Details may be find in `rustc_hir_analysis::check::rvalue_scopes`.
+    pub rvalue_scopes: RvalueScopes,
+
+    /// Stores the type, expression, span and optional scope span of all types
+    /// that are live across the yield of this generator (if a generator).
+    pub generator_interior_types: ty::Binder<'tcx, Vec<GeneratorInteriorTypeCause<'tcx>>>,
+
+    /// We sometimes treat byte string literals (which are of type `&[u8; N]`)
+    /// as `&[u8]`, depending on the pattern  in which they are used.
+    /// This hashset records all instances where we behave
+    /// like this to allow `const_to_pat` to reliably handle this situation.
+    pub treat_byte_string_as_slice: ItemLocalSet,
+
+    /// Contains the data for evaluating the effect of feature `capture_disjoint_fields`
+    /// on closure size.
+    pub closure_size_eval: FxHashMap<LocalDefId, ClosureSizeProfileData<'tcx>>,
+}
+
+/// Whenever a value may be live across a generator yield, the type of that value winds up in the
+/// `GeneratorInteriorTypeCause` struct. This struct adds additional information about such
+/// captured types that can be useful for diagnostics. In particular, it stores the span that
+/// caused a given type to be recorded, along with the scope that enclosed the value (which can
+/// be used to find the await that the value is live across).
+///
+/// For example:
+///
+/// ```ignore (pseudo-Rust)
+/// async move {
+///     let x: T = expr;
+///     foo.await
+///     ...
+/// }
+/// ```
+///
+/// Here, we would store the type `T`, the span of the value `x`, the "scope-span" for
+/// the scope that contains `x`, the expr `T` evaluated from, and the span of `foo.await`.
+#[derive(TyEncodable, TyDecodable, Clone, Debug, Eq, Hash, PartialEq, HashStable)]
+#[derive(TypeFoldable, TypeVisitable)]
+pub struct GeneratorInteriorTypeCause<'tcx> {
+    /// Type of the captured binding.
+    pub ty: Ty<'tcx>,
+    /// Span of the binding that was captured.
+    pub span: Span,
+    /// Span of the scope of the captured binding.
+    pub scope_span: Option<Span>,
+    /// Span of `.await` or `yield` expression.
+    pub yield_span: Span,
+    /// Expr which the type evaluated from.
+    pub expr: Option<hir::HirId>,
+}
+
+// This type holds diagnostic information on generators and async functions across crate boundaries
+// and is used to provide better error messages
+#[derive(TyEncodable, TyDecodable, Clone, Debug, HashStable)]
+pub struct GeneratorDiagnosticData<'tcx> {
+    pub generator_interior_types: ty::Binder<'tcx, Vec<GeneratorInteriorTypeCause<'tcx>>>,
+    pub hir_owner: DefId,
+    pub nodes_types: ItemLocalMap<Ty<'tcx>>,
+    pub adjustments: ItemLocalMap<Vec<ty::adjustment::Adjustment<'tcx>>>,
+}
+
+impl<'tcx> TypeckResults<'tcx> {
+    pub fn new(hir_owner: OwnerId) -> TypeckResults<'tcx> {
+        TypeckResults {
+            hir_owner,
+            type_dependent_defs: Default::default(),
+            field_indices: Default::default(),
+            user_provided_types: Default::default(),
+            user_provided_sigs: Default::default(),
+            node_types: Default::default(),
+            node_substs: Default::default(),
+            adjustments: Default::default(),
+            pat_binding_modes: Default::default(),
+            pat_adjustments: Default::default(),
+            closure_kind_origins: Default::default(),
+            liberated_fn_sigs: Default::default(),
+            fru_field_types: Default::default(),
+            coercion_casts: Default::default(),
+            used_trait_imports: Lrc::new(Default::default()),
+            tainted_by_errors: None,
+            concrete_opaque_types: Default::default(),
+            closure_min_captures: Default::default(),
+            closure_fake_reads: Default::default(),
+            rvalue_scopes: Default::default(),
+            generator_interior_types: ty::Binder::dummy(Default::default()),
+            treat_byte_string_as_slice: Default::default(),
+            closure_size_eval: Default::default(),
+        }
+    }
+
+    /// Returns the final resolution of a `QPath` in an `Expr` or `Pat` node.
+    pub fn qpath_res(&self, qpath: &hir::QPath<'_>, id: hir::HirId) -> Res {
+        match *qpath {
+            hir::QPath::Resolved(_, ref path) => path.res,
+            hir::QPath::TypeRelative(..) | hir::QPath::LangItem(..) => self
+                .type_dependent_def(id)
+                .map_or(Res::Err, |(kind, def_id)| Res::Def(kind, def_id)),
+        }
+    }
+
+    pub fn type_dependent_defs(
+        &self,
+    ) -> LocalTableInContext<'_, Result<(DefKind, DefId), ErrorGuaranteed>> {
+        LocalTableInContext { hir_owner: self.hir_owner, data: &self.type_dependent_defs }
+    }
+
+    pub fn type_dependent_def(&self, id: HirId) -> Option<(DefKind, DefId)> {
+        validate_hir_id_for_typeck_results(self.hir_owner, id);
+        self.type_dependent_defs.get(&id.local_id).cloned().and_then(|r| r.ok())
+    }
+
+    pub fn type_dependent_def_id(&self, id: HirId) -> Option<DefId> {
+        self.type_dependent_def(id).map(|(_, def_id)| def_id)
+    }
+
+    pub fn type_dependent_defs_mut(
+        &mut self,
+    ) -> LocalTableInContextMut<'_, Result<(DefKind, DefId), ErrorGuaranteed>> {
+        LocalTableInContextMut { hir_owner: self.hir_owner, data: &mut self.type_dependent_defs }
+    }
+
+    pub fn field_indices(&self) -> LocalTableInContext<'_, usize> {
+        LocalTableInContext { hir_owner: self.hir_owner, data: &self.field_indices }
+    }
+
+    pub fn field_indices_mut(&mut self) -> LocalTableInContextMut<'_, usize> {
+        LocalTableInContextMut { hir_owner: self.hir_owner, data: &mut self.field_indices }
+    }
+
+    pub fn field_index(&self, id: hir::HirId) -> usize {
+        self.field_indices().get(id).cloned().expect("no index for a field")
+    }
+
+    pub fn opt_field_index(&self, id: hir::HirId) -> Option<usize> {
+        self.field_indices().get(id).cloned()
+    }
+
+    pub fn user_provided_types(&self) -> LocalTableInContext<'_, CanonicalUserType<'tcx>> {
+        LocalTableInContext { hir_owner: self.hir_owner, data: &self.user_provided_types }
+    }
+
+    pub fn user_provided_types_mut(
+        &mut self,
+    ) -> LocalTableInContextMut<'_, CanonicalUserType<'tcx>> {
+        LocalTableInContextMut { hir_owner: self.hir_owner, data: &mut self.user_provided_types }
+    }
+
+    pub fn node_types(&self) -> LocalTableInContext<'_, Ty<'tcx>> {
+        LocalTableInContext { hir_owner: self.hir_owner, data: &self.node_types }
+    }
+
+    pub fn node_types_mut(&mut self) -> LocalTableInContextMut<'_, Ty<'tcx>> {
+        LocalTableInContextMut { hir_owner: self.hir_owner, data: &mut self.node_types }
+    }
+
+    pub fn get_generator_diagnostic_data(&self) -> GeneratorDiagnosticData<'tcx> {
+        let generator_interior_type = self.generator_interior_types.map_bound_ref(|vec| {
+            vec.iter()
+                .map(|item| {
+                    GeneratorInteriorTypeCause {
+                        ty: item.ty,
+                        span: item.span,
+                        scope_span: item.scope_span,
+                        yield_span: item.yield_span,
+                        expr: None, //FIXME: Passing expression over crate boundaries is impossible at the moment
+                    }
+                })
+                .collect::<Vec<_>>()
+        });
+        GeneratorDiagnosticData {
+            generator_interior_types: generator_interior_type,
+            hir_owner: self.hir_owner.to_def_id(),
+            nodes_types: self.node_types.clone(),
+            adjustments: self.adjustments.clone(),
+        }
+    }
+
+    pub fn node_type(&self, id: hir::HirId) -> Ty<'tcx> {
+        self.node_type_opt(id).unwrap_or_else(|| {
+            bug!("node_type: no type for node `{}`", tls::with(|tcx| tcx.hir().node_to_string(id)))
+        })
+    }
+
+    pub fn node_type_opt(&self, id: hir::HirId) -> Option<Ty<'tcx>> {
+        validate_hir_id_for_typeck_results(self.hir_owner, id);
+        self.node_types.get(&id.local_id).cloned()
+    }
+
+    pub fn node_substs_mut(&mut self) -> LocalTableInContextMut<'_, SubstsRef<'tcx>> {
+        LocalTableInContextMut { hir_owner: self.hir_owner, data: &mut self.node_substs }
+    }
+
+    pub fn node_substs(&self, id: hir::HirId) -> SubstsRef<'tcx> {
+        validate_hir_id_for_typeck_results(self.hir_owner, id);
+        self.node_substs.get(&id.local_id).cloned().unwrap_or_else(|| InternalSubsts::empty())
+    }
+
+    pub fn node_substs_opt(&self, id: hir::HirId) -> Option<SubstsRef<'tcx>> {
+        validate_hir_id_for_typeck_results(self.hir_owner, id);
+        self.node_substs.get(&id.local_id).cloned()
+    }
+
+    /// Returns the type of a pattern as a monotype. Like [`expr_ty`], this function
+    /// doesn't provide type parameter substitutions.
+    ///
+    /// [`expr_ty`]: TypeckResults::expr_ty
+    pub fn pat_ty(&self, pat: &hir::Pat<'_>) -> Ty<'tcx> {
+        self.node_type(pat.hir_id)
+    }
+
+    /// Returns the type of an expression as a monotype.
+    ///
+    /// NB (1): This is the PRE-ADJUSTMENT TYPE for the expression.  That is, in
+    /// some cases, we insert `Adjustment` annotations such as auto-deref or
+    /// auto-ref.  The type returned by this function does not consider such
+    /// adjustments.  See `expr_ty_adjusted()` instead.
+    ///
+    /// NB (2): This type doesn't provide type parameter substitutions; e.g., if you
+    /// ask for the type of `id` in `id(3)`, it will return `fn(&isize) -> isize`
+    /// instead of `fn(ty) -> T with T = isize`.
+    pub fn expr_ty(&self, expr: &hir::Expr<'_>) -> Ty<'tcx> {
+        self.node_type(expr.hir_id)
+    }
+
+    pub fn expr_ty_opt(&self, expr: &hir::Expr<'_>) -> Option<Ty<'tcx>> {
+        self.node_type_opt(expr.hir_id)
+    }
+
+    pub fn adjustments(&self) -> LocalTableInContext<'_, Vec<ty::adjustment::Adjustment<'tcx>>> {
+        LocalTableInContext { hir_owner: self.hir_owner, data: &self.adjustments }
+    }
+
+    pub fn adjustments_mut(
+        &mut self,
+    ) -> LocalTableInContextMut<'_, Vec<ty::adjustment::Adjustment<'tcx>>> {
+        LocalTableInContextMut { hir_owner: self.hir_owner, data: &mut self.adjustments }
+    }
+
+    pub fn expr_adjustments(&self, expr: &hir::Expr<'_>) -> &[ty::adjustment::Adjustment<'tcx>] {
+        validate_hir_id_for_typeck_results(self.hir_owner, expr.hir_id);
+        self.adjustments.get(&expr.hir_id.local_id).map_or(&[], |a| &a[..])
+    }
+
+    /// Returns the type of `expr`, considering any `Adjustment`
+    /// entry recorded for that expression.
+    pub fn expr_ty_adjusted(&self, expr: &hir::Expr<'_>) -> Ty<'tcx> {
+        self.expr_adjustments(expr).last().map_or_else(|| self.expr_ty(expr), |adj| adj.target)
+    }
+
+    pub fn expr_ty_adjusted_opt(&self, expr: &hir::Expr<'_>) -> Option<Ty<'tcx>> {
+        self.expr_adjustments(expr).last().map(|adj| adj.target).or_else(|| self.expr_ty_opt(expr))
+    }
+
+    pub fn is_method_call(&self, expr: &hir::Expr<'_>) -> bool {
+        // Only paths and method calls/overloaded operators have
+        // entries in type_dependent_defs, ignore the former here.
+        if let hir::ExprKind::Path(_) = expr.kind {
+            return false;
+        }
+
+        matches!(self.type_dependent_defs().get(expr.hir_id), Some(Ok((DefKind::AssocFn, _))))
+    }
+
+    pub fn extract_binding_mode(&self, s: &Session, id: HirId, sp: Span) -> Option<BindingMode> {
+        self.pat_binding_modes().get(id).copied().or_else(|| {
+            s.delay_span_bug(sp, "missing binding mode");
+            None
+        })
+    }
+
+    pub fn pat_binding_modes(&self) -> LocalTableInContext<'_, BindingMode> {
+        LocalTableInContext { hir_owner: self.hir_owner, data: &self.pat_binding_modes }
+    }
+
+    pub fn pat_binding_modes_mut(&mut self) -> LocalTableInContextMut<'_, BindingMode> {
+        LocalTableInContextMut { hir_owner: self.hir_owner, data: &mut self.pat_binding_modes }
+    }
+
+    pub fn pat_adjustments(&self) -> LocalTableInContext<'_, Vec<Ty<'tcx>>> {
+        LocalTableInContext { hir_owner: self.hir_owner, data: &self.pat_adjustments }
+    }
+
+    pub fn pat_adjustments_mut(&mut self) -> LocalTableInContextMut<'_, Vec<Ty<'tcx>>> {
+        LocalTableInContextMut { hir_owner: self.hir_owner, data: &mut self.pat_adjustments }
+    }
+
+    /// For a given closure, returns the iterator of `ty::CapturedPlace`s that are captured
+    /// by the closure.
+    pub fn closure_min_captures_flattened(
+        &self,
+        closure_def_id: LocalDefId,
+    ) -> impl Iterator<Item = &ty::CapturedPlace<'tcx>> {
+        self.closure_min_captures
+            .get(&closure_def_id)
+            .map(|closure_min_captures| closure_min_captures.values().flat_map(|v| v.iter()))
+            .into_iter()
+            .flatten()
+    }
+
+    pub fn closure_kind_origins(&self) -> LocalTableInContext<'_, (Span, HirPlace<'tcx>)> {
+        LocalTableInContext { hir_owner: self.hir_owner, data: &self.closure_kind_origins }
+    }
+
+    pub fn closure_kind_origins_mut(
+        &mut self,
+    ) -> LocalTableInContextMut<'_, (Span, HirPlace<'tcx>)> {
+        LocalTableInContextMut { hir_owner: self.hir_owner, data: &mut self.closure_kind_origins }
+    }
+
+    pub fn liberated_fn_sigs(&self) -> LocalTableInContext<'_, ty::FnSig<'tcx>> {
+        LocalTableInContext { hir_owner: self.hir_owner, data: &self.liberated_fn_sigs }
+    }
+
+    pub fn liberated_fn_sigs_mut(&mut self) -> LocalTableInContextMut<'_, ty::FnSig<'tcx>> {
+        LocalTableInContextMut { hir_owner: self.hir_owner, data: &mut self.liberated_fn_sigs }
+    }
+
+    pub fn fru_field_types(&self) -> LocalTableInContext<'_, Vec<Ty<'tcx>>> {
+        LocalTableInContext { hir_owner: self.hir_owner, data: &self.fru_field_types }
+    }
+
+    pub fn fru_field_types_mut(&mut self) -> LocalTableInContextMut<'_, Vec<Ty<'tcx>>> {
+        LocalTableInContextMut { hir_owner: self.hir_owner, data: &mut self.fru_field_types }
+    }
+
+    pub fn is_coercion_cast(&self, hir_id: hir::HirId) -> bool {
+        validate_hir_id_for_typeck_results(self.hir_owner, hir_id);
+        self.coercion_casts.contains(&hir_id.local_id)
+    }
+
+    pub fn set_coercion_cast(&mut self, id: ItemLocalId) {
+        self.coercion_casts.insert(id);
+    }
+
+    pub fn coercion_casts(&self) -> &ItemLocalSet {
+        &self.coercion_casts
+    }
+}
+
+/// Validate that the given HirId (respectively its `local_id` part) can be
+/// safely used as a key in the maps of a TypeckResults. For that to be
+/// the case, the HirId must have the same `owner` as all the other IDs in
+/// this table (signified by `hir_owner`). Otherwise the HirId
+/// would be in a different frame of reference and using its `local_id`
+/// would result in lookup errors, or worse, in silently wrong data being
+/// stored/returned.
+#[inline]
+fn validate_hir_id_for_typeck_results(hir_owner: OwnerId, hir_id: hir::HirId) {
+    if hir_id.owner != hir_owner {
+        invalid_hir_id_for_typeck_results(hir_owner, hir_id);
+    }
+}
+
+#[cold]
+#[inline(never)]
+fn invalid_hir_id_for_typeck_results(hir_owner: OwnerId, hir_id: hir::HirId) {
+    ty::tls::with(|tcx| {
+        bug!(
+            "node {} with HirId::owner {:?} cannot be placed in TypeckResults with hir_owner {:?}",
+            tcx.hir().node_to_string(hir_id),
+            hir_id.owner,
+            hir_owner
+        )
+    });
+}
+
+pub struct LocalTableInContext<'a, V> {
+    hir_owner: OwnerId,
+    data: &'a ItemLocalMap<V>,
+}
+
+impl<'a, V> LocalTableInContext<'a, V> {
+    pub fn contains_key(&self, id: hir::HirId) -> bool {
+        validate_hir_id_for_typeck_results(self.hir_owner, id);
+        self.data.contains_key(&id.local_id)
+    }
+
+    pub fn get(&self, id: hir::HirId) -> Option<&V> {
+        validate_hir_id_for_typeck_results(self.hir_owner, id);
+        self.data.get(&id.local_id)
+    }
+
+    pub fn iter(&self) -> hash_map::Iter<'_, hir::ItemLocalId, V> {
+        self.data.iter()
+    }
+}
+
+impl<'a, V> ::std::ops::Index<hir::HirId> for LocalTableInContext<'a, V> {
+    type Output = V;
+
+    fn index(&self, key: hir::HirId) -> &V {
+        self.get(key).expect("LocalTableInContext: key not found")
+    }
+}
+
+pub struct LocalTableInContextMut<'a, V> {
+    hir_owner: OwnerId,
+    data: &'a mut ItemLocalMap<V>,
+}
+
+impl<'a, V> LocalTableInContextMut<'a, V> {
+    pub fn get_mut(&mut self, id: hir::HirId) -> Option<&mut V> {
+        validate_hir_id_for_typeck_results(self.hir_owner, id);
+        self.data.get_mut(&id.local_id)
+    }
+
+    pub fn entry(&mut self, id: hir::HirId) -> Entry<'_, hir::ItemLocalId, V> {
+        validate_hir_id_for_typeck_results(self.hir_owner, id);
+        self.data.entry(id.local_id)
+    }
+
+    pub fn insert(&mut self, id: hir::HirId, val: V) -> Option<V> {
+        validate_hir_id_for_typeck_results(self.hir_owner, id);
+        self.data.insert(id.local_id, val)
+    }
+
+    pub fn remove(&mut self, id: hir::HirId) -> Option<V> {
+        validate_hir_id_for_typeck_results(self.hir_owner, id);
+        self.data.remove(&id.local_id)
+    }
+}
+
+rustc_index::newtype_index! {
+    pub struct UserTypeAnnotationIndex {
+        derive [HashStable]
+        DEBUG_FORMAT = "UserType({})",
+        const START_INDEX = 0,
+    }
+}
+
+/// Mapping of type annotation indices to canonical user type annotations.
+pub type CanonicalUserTypeAnnotations<'tcx> =
+    IndexVec<UserTypeAnnotationIndex, CanonicalUserTypeAnnotation<'tcx>>;
+
+#[derive(Clone, Debug, TyEncodable, TyDecodable, HashStable, TypeFoldable, TypeVisitable, Lift)]
+pub struct CanonicalUserTypeAnnotation<'tcx> {
+    pub user_ty: Box<CanonicalUserType<'tcx>>,
+    pub span: Span,
+    pub inferred_ty: Ty<'tcx>,
+}
+
+/// Canonicalized user type annotation.
+pub type CanonicalUserType<'tcx> = Canonical<'tcx, UserType<'tcx>>;
+
+impl<'tcx> CanonicalUserType<'tcx> {
+    /// Returns `true` if this represents a substitution of the form `[?0, ?1, ?2]`,
+    /// i.e., each thing is mapped to a canonical variable with the same index.
+    pub fn is_identity(&self) -> bool {
+        match self.value {
+            UserType::Ty(_) => false,
+            UserType::TypeOf(_, user_substs) => {
+                if user_substs.user_self_ty.is_some() {
+                    return false;
+                }
+
+                iter::zip(user_substs.substs, BoundVar::new(0)..).all(|(kind, cvar)| {
+                    match kind.unpack() {
+                        GenericArgKind::Type(ty) => match ty.kind() {
+                            ty::Bound(debruijn, b) => {
+                                // We only allow a `ty::INNERMOST` index in substitutions.
+                                assert_eq!(*debruijn, ty::INNERMOST);
+                                cvar == b.var
+                            }
+                            _ => false,
+                        },
+
+                        GenericArgKind::Lifetime(r) => match *r {
+                            ty::ReLateBound(debruijn, br) => {
+                                // We only allow a `ty::INNERMOST` index in substitutions.
+                                assert_eq!(debruijn, ty::INNERMOST);
+                                cvar == br.var
+                            }
+                            _ => false,
+                        },
+
+                        GenericArgKind::Const(ct) => match ct.kind() {
+                            ty::ConstKind::Bound(debruijn, b) => {
+                                // We only allow a `ty::INNERMOST` index in substitutions.
+                                assert_eq!(debruijn, ty::INNERMOST);
+                                cvar == b
+                            }
+                            _ => false,
+                        },
+                    }
+                })
+            }
+        }
+    }
+}
+
+/// A user-given type annotation attached to a constant. These arise
+/// from constants that are named via paths, like `Foo::<A>::new` and
+/// so forth.
+#[derive(Copy, Clone, Debug, PartialEq, TyEncodable, TyDecodable)]
+#[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
+pub enum UserType<'tcx> {
+    Ty(Ty<'tcx>),
+
+    /// The canonical type is the result of `type_of(def_id)` with the
+    /// given substitutions applied.
+    TypeOf(DefId, UserSubsts<'tcx>),
+}
diff --git a/compiler/rustc_monomorphize/src/errors.rs b/compiler/rustc_monomorphize/src/errors.rs
index f1ca72de8dbe4..f15cf54718e2b 100644
--- a/compiler/rustc_monomorphize/src/errors.rs
+++ b/compiler/rustc_monomorphize/src/errors.rs
@@ -77,3 +77,9 @@ pub struct SymbolAlreadyDefined {
     pub span: Option<Span>,
     pub symbol: String,
 }
+
+#[derive(Diagnostic)]
+#[diag(monomorphize_couldnt_dump_mono_stats)]
+pub struct CouldntDumpMonoStats {
+    pub error: String,
+}
diff --git a/compiler/rustc_monomorphize/src/partitioning/mod.rs b/compiler/rustc_monomorphize/src/partitioning/mod.rs
index 932edc6675f59..38e1d98e44e13 100644
--- a/compiler/rustc_monomorphize/src/partitioning/mod.rs
+++ b/compiler/rustc_monomorphize/src/partitioning/mod.rs
@@ -95,6 +95,11 @@
 mod default;
 mod merging;
 
+use std::cmp;
+use std::fs::{self, File};
+use std::io::{BufWriter, Write};
+use std::path::{Path, PathBuf};
+
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::sync;
 use rustc_hir::def_id::DefIdSet;
@@ -104,11 +109,12 @@ use rustc_middle::mir::mono::{CodegenUnit, Linkage};
 use rustc_middle::ty::print::with_no_trimmed_paths;
 use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::TyCtxt;
+use rustc_session::config::SwitchWithOptPath;
 use rustc_span::symbol::Symbol;
 
 use crate::collector::InliningMap;
 use crate::collector::{self, MonoItemCollectionMode};
-use crate::errors::{SymbolAlreadyDefined, UnknownPartitionStrategy};
+use crate::errors::{CouldntDumpMonoStats, SymbolAlreadyDefined, UnknownPartitionStrategy};
 
 pub struct PartitioningCx<'a, 'tcx> {
     tcx: TyCtxt<'tcx>,
@@ -411,6 +417,15 @@ fn collect_and_partition_mono_items<'tcx>(
         })
         .collect();
 
+    // Output monomorphization stats per def_id
+    if let SwitchWithOptPath::Enabled(ref path) = tcx.sess.opts.unstable_opts.dump_mono_stats {
+        if let Err(err) =
+            dump_mono_items_stats(tcx, &codegen_units, path, tcx.sess.opts.crate_name.as_deref())
+        {
+            tcx.sess.emit_fatal(CouldntDumpMonoStats { error: err.to_string() });
+        }
+    }
+
     if tcx.sess.opts.unstable_opts.print_mono_items.is_some() {
         let mut item_to_cgus: FxHashMap<_, Vec<_>> = Default::default();
 
@@ -465,6 +480,67 @@ fn collect_and_partition_mono_items<'tcx>(
     (tcx.arena.alloc(mono_items), codegen_units)
 }
 
+/// Outputs stats about instantation counts and estimated size, per `MonoItem`'s
+/// def, to a file in the given output directory.
+fn dump_mono_items_stats<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    codegen_units: &[CodegenUnit<'tcx>],
+    output_directory: &Option<PathBuf>,
+    crate_name: Option<&str>,
+) -> Result<(), Box<dyn std::error::Error>> {
+    let output_directory = if let Some(ref directory) = output_directory {
+        fs::create_dir_all(directory)?;
+        directory
+    } else {
+        Path::new(".")
+    };
+
+    let filename = format!("{}.mono_items.md", crate_name.unwrap_or("unknown-crate"));
+    let output_path = output_directory.join(&filename);
+    let file = File::create(output_path)?;
+    let mut file = BufWriter::new(file);
+
+    // Gather instantiated mono items grouped by def_id
+    let mut items_per_def_id: FxHashMap<_, Vec<_>> = Default::default();
+    for cgu in codegen_units {
+        for (&mono_item, _) in cgu.items() {
+            // Avoid variable-sized compiler-generated shims
+            if mono_item.is_user_defined() {
+                items_per_def_id.entry(mono_item.def_id()).or_default().push(mono_item);
+            }
+        }
+    }
+
+    // Output stats sorted by total instantiated size, from heaviest to lightest
+    let mut stats: Vec<_> = items_per_def_id
+        .into_iter()
+        .map(|(def_id, items)| {
+            let instantiation_count = items.len();
+            let size_estimate = items[0].size_estimate(tcx);
+            let total_estimate = instantiation_count * size_estimate;
+            (def_id, instantiation_count, size_estimate, total_estimate)
+        })
+        .collect();
+    stats.sort_unstable_by_key(|(_, _, _, total_estimate)| cmp::Reverse(*total_estimate));
+
+    if !stats.is_empty() {
+        writeln!(
+            file,
+            "| Item | Instantiation count | Estimated Cost Per Instantiation | Total Estimated Cost |"
+        )?;
+        writeln!(file, "| --- | ---: | ---: | ---: |")?;
+        for (def_id, instantiation_count, size_estimate, total_estimate) in stats {
+            let item = with_no_trimmed_paths!(tcx.def_path_str(def_id));
+            writeln!(
+                file,
+                "| {item} | {instantiation_count} | {size_estimate} | {total_estimate} |"
+            )?;
+        }
+    }
+
+    Ok(())
+}
+
 fn codegened_and_inlined_items<'tcx>(tcx: TyCtxt<'tcx>, (): ()) -> &'tcx DefIdSet {
     let (items, cgus) = tcx.collect_and_partition_mono_items(());
     let mut visited = DefIdSet::default();
diff --git a/compiler/rustc_session/src/options.rs b/compiler/rustc_session/src/options.rs
index dab9c736d14d5..9e130287104f9 100644
--- a/compiler/rustc_session/src/options.rs
+++ b/compiler/rustc_session/src/options.rs
@@ -1294,6 +1294,9 @@ options! {
         computed `block` spans (one span encompassing a block's terminator and \
         all statements). If `-Z instrument-coverage` is also enabled, create \
         an additional `.html` file showing the computed coverage spans."),
+    dump_mono_stats: SwitchWithOptPath = (SwitchWithOptPath::Disabled,
+        parse_switch_with_opt_path, [UNTRACKED],
+        "output statistics about monomorphization collection (format: markdown)"),
     dwarf_version: Option<u32> = (None, parse_opt_number, [TRACKED],
         "version of DWARF debug information to emit (default: 2 or 4, depending on platform)"),
     dylib_lto: bool = (false, parse_bool, [UNTRACKED],
diff --git a/compiler/rustc_span/src/lib.rs b/compiler/rustc_span/src/lib.rs
index 5525eb5331c27..2181c090027b5 100644
--- a/compiler/rustc_span/src/lib.rs
+++ b/compiler/rustc_span/src/lib.rs
@@ -259,6 +259,10 @@ impl RealFileName {
             FileNameDisplayPreference::Remapped => {
                 self.remapped_path_if_available().to_string_lossy()
             }
+            FileNameDisplayPreference::Short => self
+                .local_path_if_available()
+                .file_name()
+                .map_or_else(|| "".into(), |f| f.to_string_lossy()),
         }
     }
 }
@@ -302,6 +306,9 @@ pub enum FileNameDisplayPreference {
     /// Display the path before the application of rewrite rules provided via `--remap-path-prefix`.
     /// This is appropriate for use in user-facing output (such as diagnostics).
     Local,
+    /// Display only the filename, as a way to reduce the verbosity of the output.
+    /// This is appropriate for use in user-facing output (such as diagnostics).
+    Short,
 }
 
 pub struct FileNameDisplay<'a> {
diff --git a/compiler/rustc_span/src/source_map.rs b/compiler/rustc_span/src/source_map.rs
index fb3e4a6c083f8..d9c87ac0ba82b 100644
--- a/compiler/rustc_span/src/source_map.rs
+++ b/compiler/rustc_span/src/source_map.rs
@@ -438,7 +438,11 @@ impl SourceMap {
         }
     }
 
-    fn span_to_string(&self, sp: Span, filename_display_pref: FileNameDisplayPreference) -> String {
+    pub fn span_to_string(
+        &self,
+        sp: Span,
+        filename_display_pref: FileNameDisplayPreference,
+    ) -> String {
         if self.files.borrow().source_files.is_empty() || sp.is_dummy() {
             return "no-location".to_string();
         }
@@ -446,12 +450,15 @@ impl SourceMap {
         let lo = self.lookup_char_pos(sp.lo());
         let hi = self.lookup_char_pos(sp.hi());
         format!(
-            "{}:{}:{}: {}:{}",
+            "{}:{}:{}{}",
             lo.file.name.display(filename_display_pref),
             lo.line,
             lo.col.to_usize() + 1,
-            hi.line,
-            hi.col.to_usize() + 1,
+            if let FileNameDisplayPreference::Short = filename_display_pref {
+                String::new()
+            } else {
+                format!(": {}:{}", hi.line, hi.col.to_usize() + 1)
+            }
         )
     }
 
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
index 3c5e36123ecf5..181316427609e 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
@@ -35,7 +35,7 @@ use rustc_middle::traits::select::OverflowError;
 use rustc_middle::ty::abstract_const::NotConstEvaluatable;
 use rustc_middle::ty::error::ExpectedFound;
 use rustc_middle::ty::fold::{TypeFolder, TypeSuperFoldable};
-use rustc_middle::ty::print::{FmtPrinter, Print};
+use rustc_middle::ty::print::{with_forced_trimmed_paths, FmtPrinter, Print};
 use rustc_middle::ty::{
     self, SubtypePredicate, ToPolyTraitRef, ToPredicate, TraitRef, Ty, TyCtxt, TypeFoldable,
     TypeVisitable,
@@ -1757,21 +1757,26 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         let trait_def_id = pred.projection_ty.trait_def_id(self.tcx);
         let self_ty = pred.projection_ty.self_ty();
 
-        if Some(pred.projection_ty.def_id) == self.tcx.lang_items().fn_once_output() {
-            Some(format!(
-                "expected `{self_ty}` to be a {fn_kind} that returns `{expected_ty}`, but it returns `{normalized_ty}`",
-                fn_kind = self_ty.prefix_string(self.tcx)
-            ))
-        } else if Some(trait_def_id) == self.tcx.lang_items().future_trait() {
-            Some(format!(
-                "expected `{self_ty}` to be a future that resolves to `{expected_ty}`, but it resolves to `{normalized_ty}`"
-            ))
-        } else if Some(trait_def_id) == self.tcx.get_diagnostic_item(sym::Iterator) {
-            Some(format!(
-                "expected `{self_ty}` to be an iterator that yields `{expected_ty}`, but it yields `{normalized_ty}`"
-            ))
-        } else {
-            None
+        with_forced_trimmed_paths! {
+            if Some(pred.projection_ty.def_id) == self.tcx.lang_items().fn_once_output() {
+                Some(format!(
+                    "expected `{self_ty}` to be a {fn_kind} that returns `{expected_ty}`, but it \
+                     returns `{normalized_ty}`",
+                    fn_kind = self_ty.prefix_string(self.tcx)
+                ))
+            } else if Some(trait_def_id) == self.tcx.lang_items().future_trait() {
+                Some(format!(
+                    "expected `{self_ty}` to be a future that resolves to `{expected_ty}`, but it \
+                     resolves to `{normalized_ty}`"
+                ))
+            } else if Some(trait_def_id) == self.tcx.get_diagnostic_item(sym::Iterator) {
+                Some(format!(
+                    "expected `{self_ty}` to be an iterator that yields `{expected_ty}`, but it \
+                     yields `{normalized_ty}`"
+                ))
+            } else {
+                None
+            }
         }
     }
 
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
index dd5085bf4f300..057b0a368bf9b 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
@@ -352,6 +352,14 @@ pub trait TypeErrCtxtExt<'tcx> {
         param_env: ty::ParamEnv<'tcx>,
         err: &mut Diagnostic,
     );
+    fn probe_assoc_types_at_expr(
+        &self,
+        type_diffs: &[TypeError<'tcx>],
+        span: Span,
+        prev_ty: Ty<'tcx>,
+        body_id: hir::HirId,
+        param_env: ty::ParamEnv<'tcx>,
+    ) -> Vec<Option<(Span, (DefId, Ty<'tcx>))>>;
 }
 
 fn predicate_constraint(generics: &hir::Generics<'_>, pred: ty::Predicate<'_>) -> (Span, String) {
@@ -1618,7 +1626,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         let trait_obj = if has_dyn { &snippet[4..] } else { &snippet };
         if only_never_return {
             // No return paths, probably using `panic!()` or similar.
-            // Suggest `-> T`, `-> impl Trait`, and if `Trait` is object safe, `-> Box<dyn Trait>`.
+            // Suggest `-> impl Trait`, and if `Trait` is object safe, `-> Box<dyn Trait>`.
             suggest_trait_object_return_type_alternatives(
                 err,
                 ret_ty.span,
@@ -2540,6 +2548,25 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             }
             ObligationCauseCode::SizedArgumentType(sp) => {
                 if let Some(span) = sp {
+                    if let ty::PredicateKind::Clause(clause) = predicate.kind().skip_binder()
+                        && let ty::Clause::Trait(trait_pred) = clause
+                        && let ty::Dynamic(..) = trait_pred.self_ty().kind()
+                    {
+                        let span = if let Ok(snippet) = self.tcx.sess.source_map().span_to_snippet(span)
+                            && snippet.starts_with("dyn ")
+                        {
+                            let pos = snippet.len() - snippet[3..].trim_start().len();
+                            span.with_hi(span.lo() + BytePos(pos as u32))
+                        } else {
+                            span.shrink_to_lo()
+                        };
+                        err.span_suggestion_verbose(
+                            span,
+                            "you can use `impl Trait` as the argument type",
+                            "impl ".to_string(),
+                            Applicability::MaybeIncorrect,
+                        );
+                    }
                     err.span_suggestion_verbose(
                         span.shrink_to_lo(),
                         "function arguments must have a statically known size, borrowed types \
@@ -3152,23 +3179,37 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             if let ObligationCauseCode::ExprBindingObligation(def_id, _, _, idx) = parent_code.deref()
                 && let predicates = self.tcx.predicates_of(def_id).instantiate_identity(self.tcx)
                 && let Some(pred) = predicates.predicates.get(*idx)
-                && let Ok(trait_pred) = pred.kind().try_map_bound(|pred| match pred {
-                    ty::PredicateKind::Clause(ty::Clause::Trait(trait_pred)) => Ok(trait_pred),
-                    _ => Err(()),
-                })
             {
-                let mut c = CollectAllMismatches {
-                    infcx: self.infcx,
-                    param_env,
-                    errors: vec![],
-                };
-                if let Ok(trait_predicate) = predicate.kind().try_map_bound(|pred| match pred {
+                if let Ok(trait_pred) = pred.kind().try_map_bound(|pred| match pred {
                     ty::PredicateKind::Clause(ty::Clause::Trait(trait_pred)) => Ok(trait_pred),
                     _ => Err(()),
-                }) {
+                })
+                    && let Ok(trait_predicate) = predicate.kind().try_map_bound(|pred| match pred {
+                        ty::PredicateKind::Clause(ty::Clause::Trait(trait_pred)) => Ok(trait_pred),
+                        _ => Err(()),
+                    })
+                {
+                    let mut c = CollectAllMismatches {
+                        infcx: self.infcx,
+                        param_env,
+                        errors: vec![],
+                    };
                     if let Ok(_) = c.relate(trait_pred, trait_predicate) {
                         type_diffs = c.errors;
                     }
+                } else if let ty::PredicateKind::Clause(
+                    ty::Clause::Projection(proj)
+                ) = pred.kind().skip_binder()
+                    && let ty::PredicateKind::Clause(
+                        ty::Clause::Projection(projection)
+                    ) = predicate.kind().skip_binder()
+                {
+                    type_diffs = vec![
+                        Sorts(ty::error::ExpectedFound {
+                            expected: self.tcx.mk_ty(ty::Alias(ty::Projection, proj.projection_ty)),
+                            found: projection.term.ty().unwrap(),
+                        }),
+                    ];
                 }
             }
             if let hir::ExprKind::Path(hir::QPath::Resolved(None, path)) = expr.kind
@@ -3221,10 +3262,8 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
 
         let tcx = self.tcx;
 
+        let mut print_root_expr = true;
         let mut assocs = vec![];
-        // We still want to point at the different methods even if there hasn't
-        // been a change of assoc type.
-        let mut call_spans = vec![];
         let mut expr = expr;
         let mut prev_ty = self.resolve_vars_if_possible(
             typeck_results.expr_ty_adjusted_opt(expr).unwrap_or(tcx.ty_error()),
@@ -3234,63 +3273,8 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             // vec![1, 2, 3].iter().map(mapper).sum<i32>()
             //               ^^^^^^ ^^^^^^^^^^^
             expr = rcvr_expr;
-            let mut assocs_in_this_method = Vec::with_capacity(type_diffs.len());
-            call_spans.push(span);
-
-            let ocx = ObligationCtxt::new_in_snapshot(self.infcx);
-            for diff in &type_diffs {
-                let Sorts(expected_found) = diff else { continue; };
-                let ty::Alias(ty::Projection, proj) = expected_found.expected.kind() else { continue; };
-
-                let origin =
-                    TypeVariableOrigin { kind: TypeVariableOriginKind::TypeInference, span };
-                let trait_def_id = proj.trait_def_id(self.tcx);
-                // Make `Self` be equivalent to the type of the call chain
-                // expression we're looking at now, so that we can tell what
-                // for example `Iterator::Item` is at this point in the chain.
-                let substs = InternalSubsts::for_item(self.tcx, trait_def_id, |param, _| {
-                    match param.kind {
-                        ty::GenericParamDefKind::Type { .. } => {
-                            if param.index == 0 {
-                                return prev_ty.into();
-                            }
-                        }
-                        ty::GenericParamDefKind::Lifetime
-                        | ty::GenericParamDefKind::Const { .. } => {}
-                    }
-                    self.var_for_def(span, param)
-                });
-                // This will hold the resolved type of the associated type, if the
-                // current expression implements the trait that associated type is
-                // in. For example, this would be what `Iterator::Item` is here.
-                let ty_var = self.infcx.next_ty_var(origin);
-                // This corresponds to `<ExprTy as Iterator>::Item = _`.
-                let projection = ty::Binder::dummy(ty::PredicateKind::Clause(
-                    ty::Clause::Projection(ty::ProjectionPredicate {
-                        projection_ty: tcx.mk_alias_ty(proj.def_id, substs),
-                        term: ty_var.into(),
-                    }),
-                ));
-                // Add `<ExprTy as Iterator>::Item = _` obligation.
-                ocx.register_obligation(Obligation::misc(
-                    self.tcx,
-                    span,
-                    expr.hir_id,
-                    param_env,
-                    projection,
-                ));
-                if ocx.select_where_possible().is_empty() {
-                    // `ty_var` now holds the type that `Item` is for `ExprTy`.
-                    let ty_var = self.resolve_vars_if_possible(ty_var);
-                    assocs_in_this_method.push(Some((span, (proj.def_id, ty_var))));
-                } else {
-                    // `<ExprTy as Iterator>` didn't select, so likely we've
-                    // reached the end of the iterator chain, like the originating
-                    // `Vec<_>`.
-                    // Keep the space consistent for later zipping.
-                    assocs_in_this_method.push(None);
-                }
-            }
+            let assocs_in_this_method =
+                self.probe_assoc_types_at_expr(&type_diffs, span, prev_ty, expr.hir_id, param_env);
             assocs.push(assocs_in_this_method);
             prev_ty = self.resolve_vars_if_possible(
                 typeck_results.expr_ty_adjusted_opt(expr).unwrap_or(tcx.ty_error()),
@@ -3300,17 +3284,32 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                 && let hir::Path { res: hir::def::Res::Local(hir_id), .. } = path
                 && let Some(hir::Node::Pat(binding)) = self.tcx.hir().find(*hir_id)
                 && let parent_hir_id = self.tcx.hir().get_parent_node(binding.hir_id)
-                && let Some(hir::Node::Local(local)) = self.tcx.hir().find(parent_hir_id)
-                && let Some(binding_expr) = local.init
+                && let Some(parent) = self.tcx.hir().find(parent_hir_id)
             {
-                // We've reached the root of the method call chain and it is a
-                // binding. Get the binding creation and try to continue the chain.
-                expr = binding_expr;
+                // We've reached the root of the method call chain...
+                if let hir::Node::Local(local) = parent
+                    && let Some(binding_expr) = local.init
+                {
+                    // ...and it is a binding. Get the binding creation and continue the chain.
+                    expr = binding_expr;
+                }
+                if let hir::Node::Param(param) = parent {
+                    // ...and it is a an fn argument.
+                    let prev_ty = self.resolve_vars_if_possible(
+                        typeck_results.node_type_opt(param.hir_id).unwrap_or(tcx.ty_error()),
+                    );
+                    let assocs_in_this_method = self.probe_assoc_types_at_expr(&type_diffs, param.ty_span, prev_ty, param.hir_id, param_env);
+                    if assocs_in_this_method.iter().any(|a| a.is_some()) {
+                        assocs.push(assocs_in_this_method);
+                        print_root_expr = false;
+                    }
+                    break;
+                }
             }
         }
         // We want the type before deref coercions, otherwise we talk about `&[_]`
         // instead of `Vec<_>`.
-        if let Some(ty) = typeck_results.expr_ty_opt(expr) {
+        if let Some(ty) = typeck_results.expr_ty_opt(expr) && print_root_expr {
             let ty = with_forced_trimmed_paths!(self.ty_to_string(ty));
             // Point at the root expression
             // vec![1, 2, 3].iter().map(mapper).sum<i32>()
@@ -3324,7 +3323,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             let Some(prev_assoc_in_method) = assocs.peek() else {
                 for entry in assocs_in_method {
                     let Some((span, (assoc, ty))) = entry else { continue; };
-                    if type_diffs.iter().any(|diff| {
+                    if primary_spans.is_empty() || type_diffs.iter().any(|diff| {
                         let Sorts(expected_found) = diff else { return false; };
                         self.can_eq(param_env, expected_found.found, ty).is_ok()
                     }) {
@@ -3353,7 +3352,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                         let ty_str = with_forced_trimmed_paths!(self.ty_to_string(ty));
 
                         let assoc = with_forced_trimmed_paths!(self.tcx.def_path_str(assoc));
-                        if ty != *prev_ty {
+                        if self.can_eq(param_env, ty, *prev_ty).is_err() {
                             if type_diffs.iter().any(|diff| {
                                 let Sorts(expected_found) = diff else { return false; };
                                 self.can_eq(param_env, expected_found.found, ty).is_ok()
@@ -3380,13 +3379,6 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                 }
             }
         }
-        for span in call_spans {
-            if span_labels.iter().find(|(s, _)| *s == span).is_none() {
-                // Ensure we are showing the entire chain, even if the assoc types
-                // haven't changed.
-                span_labels.push((span, String::new()));
-            }
-        }
         if !primary_spans.is_empty() {
             let mut multi_span: MultiSpan = primary_spans.into();
             for (span, label) in span_labels {
@@ -3394,13 +3386,70 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             }
             err.span_note(
                 multi_span,
-                format!(
-                    "the method call chain might not have had the expected \
-                                     associated types",
-                ),
+                format!("the method call chain might not have had the expected associated types"),
             );
         }
     }
+
+    fn probe_assoc_types_at_expr(
+        &self,
+        type_diffs: &[TypeError<'tcx>],
+        span: Span,
+        prev_ty: Ty<'tcx>,
+        body_id: hir::HirId,
+        param_env: ty::ParamEnv<'tcx>,
+    ) -> Vec<Option<(Span, (DefId, Ty<'tcx>))>> {
+        let ocx = ObligationCtxt::new_in_snapshot(self.infcx);
+        let mut assocs_in_this_method = Vec::with_capacity(type_diffs.len());
+        for diff in type_diffs {
+            let Sorts(expected_found) = diff else { continue; };
+            let ty::Alias(ty::Projection, proj) = expected_found.expected.kind() else { continue; };
+
+            let origin = TypeVariableOrigin { kind: TypeVariableOriginKind::TypeInference, span };
+            let trait_def_id = proj.trait_def_id(self.tcx);
+            // Make `Self` be equivalent to the type of the call chain
+            // expression we're looking at now, so that we can tell what
+            // for example `Iterator::Item` is at this point in the chain.
+            let substs = InternalSubsts::for_item(self.tcx, trait_def_id, |param, _| {
+                match param.kind {
+                    ty::GenericParamDefKind::Type { .. } => {
+                        if param.index == 0 {
+                            return prev_ty.into();
+                        }
+                    }
+                    ty::GenericParamDefKind::Lifetime | ty::GenericParamDefKind::Const { .. } => {}
+                }
+                self.var_for_def(span, param)
+            });
+            // This will hold the resolved type of the associated type, if the
+            // current expression implements the trait that associated type is
+            // in. For example, this would be what `Iterator::Item` is here.
+            let ty_var = self.infcx.next_ty_var(origin);
+            // This corresponds to `<ExprTy as Iterator>::Item = _`.
+            let projection = ty::Binder::dummy(ty::PredicateKind::Clause(ty::Clause::Projection(
+                ty::ProjectionPredicate {
+                    projection_ty: self.tcx.mk_alias_ty(proj.def_id, substs),
+                    term: ty_var.into(),
+                },
+            )));
+            // Add `<ExprTy as Iterator>::Item = _` obligation.
+            ocx.register_obligation(Obligation::misc(
+                self.tcx, span, body_id, param_env, projection,
+            ));
+            if ocx.select_where_possible().is_empty() {
+                // `ty_var` now holds the type that `Item` is for `ExprTy`.
+                let ty_var = self.resolve_vars_if_possible(ty_var);
+                assocs_in_this_method.push(Some((span, (proj.def_id, ty_var))));
+            } else {
+                // `<ExprTy as Iterator>` didn't select, so likely we've
+                // reached the end of the iterator chain, like the originating
+                // `Vec<_>`.
+                // Keep the space consistent for later zipping.
+                assocs_in_this_method.push(None);
+            }
+        }
+        assocs_in_this_method
+    }
 }
 
 /// Add a hint to add a missing borrow or remove an unnecessary one.
@@ -3580,13 +3629,6 @@ fn suggest_trait_object_return_type_alternatives(
     trait_obj: &str,
     is_object_safe: bool,
 ) {
-    err.span_suggestion(
-        ret_ty,
-        "use some type `T` that is `T: Sized` as the return type if all return paths have the \
-            same type",
-        "T",
-        Applicability::MaybeIncorrect,
-    );
     err.span_suggestion(
         ret_ty,
         &format!(
diff --git a/compiler/rustc_trait_selection/src/traits/wf.rs b/compiler/rustc_trait_selection/src/traits/wf.rs
index a995eeb9a7afb..0e0a883d9f590 100644
--- a/compiler/rustc_trait_selection/src/traits/wf.rs
+++ b/compiler/rustc_trait_selection/src/traits/wf.rs
@@ -451,19 +451,21 @@ impl<'tcx> WfPredicates<'tcx> {
                 GenericArgKind::Const(ct) => {
                     match ct.kind() {
                         ty::ConstKind::Unevaluated(uv) => {
-                            let obligations = self.nominal_obligations(uv.def.did, uv.substs);
-                            self.out.extend(obligations);
-
-                            let predicate =
-                                ty::Binder::dummy(ty::PredicateKind::ConstEvaluatable(ct));
-                            let cause = self.cause(traits::WellFormed(None));
-                            self.out.push(traits::Obligation::with_depth(
-                                self.tcx(),
-                                cause,
-                                self.recursion_depth,
-                                self.param_env,
-                                predicate,
-                            ));
+                            if !ct.has_escaping_bound_vars() {
+                                let obligations = self.nominal_obligations(uv.def.did, uv.substs);
+                                self.out.extend(obligations);
+
+                                let predicate =
+                                    ty::Binder::dummy(ty::PredicateKind::ConstEvaluatable(ct));
+                                let cause = self.cause(traits::WellFormed(None));
+                                self.out.push(traits::Obligation::with_depth(
+                                    self.tcx(),
+                                    cause,
+                                    self.recursion_depth,
+                                    self.param_env,
+                                    predicate,
+                                ));
+                            }
                         }
                         ty::ConstKind::Infer(_) => {
                             let cause = self.cause(traits::WellFormed(None));
diff --git a/src/librustdoc/clean/inline.rs b/src/librustdoc/clean/inline.rs
index 50caef3553fda..d1601272af759 100644
--- a/src/librustdoc/clean/inline.rs
+++ b/src/librustdoc/clean/inline.rs
@@ -325,7 +325,7 @@ pub(crate) fn build_impls(
     // * https://github.com/rust-lang/rust/pull/99917 — where the feature got used
     // * https://github.com/rust-lang/rust/issues/53487 — overall tracking issue for Error
     if tcx.has_attr(did, sym::rustc_has_incoherent_inherent_impls) {
-        use rustc_middle::ty::fast_reject::SimplifiedTypeGen::*;
+        use rustc_middle::ty::fast_reject::SimplifiedType::*;
         let type_ =
             if tcx.is_trait(did) { TraitSimplifiedType(did) } else { AdtSimplifiedType(did) };
         for &did in tcx.incoherent_impls(type_) {
diff --git a/src/librustdoc/clean/types.rs b/src/librustdoc/clean/types.rs
index 7a7313c4bc99d..7a13e7e36d169 100644
--- a/src/librustdoc/clean/types.rs
+++ b/src/librustdoc/clean/types.rs
@@ -1870,7 +1870,7 @@ impl PrimitiveType {
     }
 
     pub(crate) fn simplified_types() -> &'static SimplifiedTypes {
-        use ty::fast_reject::SimplifiedTypeGen::*;
+        use ty::fast_reject::SimplifiedType::*;
         use ty::{FloatTy, IntTy, UintTy};
         use PrimitiveType::*;
         static CELL: OnceCell<SimplifiedTypes> = OnceCell::new();
diff --git a/src/librustdoc/html/static/css/rustdoc.css b/src/librustdoc/html/static/css/rustdoc.css
index bc1e15b359371..a527e9feaec37 100644
--- a/src/librustdoc/html/static/css/rustdoc.css
+++ b/src/librustdoc/html/static/css/rustdoc.css
@@ -1071,6 +1071,10 @@ pre.rust .doccomment {
 	color: var(--code-highlight-doc-comment-color);
 }
 
+.rustdoc.source .example-wrap pre.rust a {
+	background: var(--codeblock-link-background);
+}
+
 .example-wrap.compile_fail,
 .example-wrap.should_panic {
 	border-left: 2px solid var(--codeblock-error-color);
diff --git a/src/librustdoc/html/static/css/themes/ayu.css b/src/librustdoc/html/static/css/themes/ayu.css
index a4097c456135d..de0dfcd469045 100644
--- a/src/librustdoc/html/static/css/themes/ayu.css
+++ b/src/librustdoc/html/static/css/themes/ayu.css
@@ -88,6 +88,7 @@ Original by Dempfi (https://github.com/dempfi/ayu)
 	--source-sidebar-background-selected: #14191f;
 	--source-sidebar-background-hover: #14191f;
 	--table-alt-row-background-color: #191f26;
+	--codeblock-link-background: #333;
 }
 
 h1, h2, h3, h4 {
@@ -154,9 +155,6 @@ pre, .rustdoc.source .example-wrap {
 .sidebar h3 a {
 	color: white;
 }
-body.source .example-wrap pre.rust a {
-	background: #333;
-}
 
 .result-name .primitive > i, .result-name .keyword > i {
 	color: #788797;
diff --git a/src/librustdoc/html/static/css/themes/dark.css b/src/librustdoc/html/static/css/themes/dark.css
index a11aba12e0ac7..dd7fc6892537c 100644
--- a/src/librustdoc/html/static/css/themes/dark.css
+++ b/src/librustdoc/html/static/css/themes/dark.css
@@ -83,10 +83,7 @@
 	--source-sidebar-background-selected: #333;
 	--source-sidebar-background-hover: #444;
 	--table-alt-row-background-color: #2A2A2A;
-}
-
-body.source .example-wrap pre.rust a {
-	background: #333;
+	--codeblock-link-background: #333;
 }
 
 #titles > button:not(.selected) {
diff --git a/src/librustdoc/html/static/css/themes/light.css b/src/librustdoc/html/static/css/themes/light.css
index f697724468fb3..b69d8a1cff957 100644
--- a/src/librustdoc/html/static/css/themes/light.css
+++ b/src/librustdoc/html/static/css/themes/light.css
@@ -80,10 +80,7 @@
 	--source-sidebar-background-selected: #fff;
 	--source-sidebar-background-hover: #e0e0e0;
 	--table-alt-row-background-color: #F5F5F5;
-}
-
-body.source .example-wrap pre.rust a {
-	background: #eee;
+	--codeblock-link-background: #eee;
 }
 
 #titles > button:not(.selected) {
diff --git a/src/test/rustdoc-ui/z-help.stdout b/src/test/rustdoc-ui/z-help.stdout
index 94cf7b94241df..3537e669608d1 100644
--- a/src/test/rustdoc-ui/z-help.stdout
+++ b/src/test/rustdoc-ui/z-help.stdout
@@ -35,6 +35,7 @@
     -Z            dump-mir-exclude-pass-number=val -- exclude the pass number when dumping MIR (used in tests) (default: no)
     -Z                       dump-mir-graphviz=val -- in addition to `.mir` files, create graphviz `.dot` files (and with `-Z instrument-coverage`, also create a `.dot` file for the MIR-derived coverage graph) (default: no)
     -Z                       dump-mir-spanview=val -- in addition to `.mir` files, create `.html` files to view spans for all `statement`s (including terminators), only `terminator` spans, or computed `block` spans (one span encompassing a block's terminator and all statements). If `-Z instrument-coverage` is also enabled, create an additional `.html` file showing the computed coverage spans.
+    -Z                         dump-mono-stats=val -- output statistics about monomorphization collection (format: markdown)
     -Z                           dwarf-version=val -- version of DWARF debug information to emit (default: 2 or 4, depending on platform)
     -Z                               dylib-lto=val -- enables LTO for dylib crate type
     -Z                        emit-stack-sizes=val -- emit a section containing stack size metadata (default: no)
diff --git a/src/test/ui/associated-types/associated-types-overridden-binding-2.rs b/src/test/ui/associated-types/associated-types-overridden-binding-2.rs
index 26b9f4b3a9266..fed60ccf089d0 100644
--- a/src/test/ui/associated-types/associated-types-overridden-binding-2.rs
+++ b/src/test/ui/associated-types/associated-types-overridden-binding-2.rs
@@ -4,5 +4,5 @@ trait I32Iterator = Iterator<Item = i32>;
 
 fn main() {
     let _: &dyn I32Iterator<Item = u32> = &vec![42].into_iter();
-    //~^ ERROR expected `std::vec::IntoIter<u32>` to be an iterator that yields `i32`, but it yields `u32`
+    //~^ ERROR expected `IntoIter<u32>` to be an iterator that yields `i32`, but it yields `u32`
 }
diff --git a/src/test/ui/associated-types/associated-types-overridden-binding-2.stderr b/src/test/ui/associated-types/associated-types-overridden-binding-2.stderr
index 2d25f68de44ad..a28a0b74e4acc 100644
--- a/src/test/ui/associated-types/associated-types-overridden-binding-2.stderr
+++ b/src/test/ui/associated-types/associated-types-overridden-binding-2.stderr
@@ -1,4 +1,4 @@
-error[E0271]: expected `std::vec::IntoIter<u32>` to be an iterator that yields `i32`, but it yields `u32`
+error[E0271]: expected `IntoIter<u32>` to be an iterator that yields `i32`, but it yields `u32`
   --> $DIR/associated-types-overridden-binding-2.rs:6:43
    |
 LL |     let _: &dyn I32Iterator<Item = u32> = &vec![42].into_iter();
diff --git a/src/test/ui/confuse-field-and-method/issue-33784.stderr b/src/test/ui/confuse-field-and-method/issue-33784.stderr
index 34debb6831734..3906d64c94624 100644
--- a/src/test/ui/confuse-field-and-method/issue-33784.stderr
+++ b/src/test/ui/confuse-field-and-method/issue-33784.stderr
@@ -1,4 +1,4 @@
-error[E0599]: no method named `closure` found for reference `&Obj<[closure@$DIR/issue-33784.rs:25:43: 25:45]>` in the current scope
+error[E0599]: no method named `closure` found for reference `&Obj<[closure@issue-33784.rs:25:43]>` in the current scope
   --> $DIR/issue-33784.rs:27:7
    |
 LL |     p.closure();
@@ -9,7 +9,7 @@ help: to call the function stored in `closure`, surround the field access with p
 LL |     (p.closure)();
    |     +         +
 
-error[E0599]: no method named `fn_ptr` found for reference `&&Obj<[closure@$DIR/issue-33784.rs:25:43: 25:45]>` in the current scope
+error[E0599]: no method named `fn_ptr` found for reference `&&Obj<[closure@issue-33784.rs:25:43]>` in the current scope
   --> $DIR/issue-33784.rs:29:7
    |
 LL |     q.fn_ptr();
diff --git a/src/test/ui/const-generics/issue-105689.rs b/src/test/ui/const-generics/issue-105689.rs
new file mode 100644
index 0000000000000..4237b3cad8e7f
--- /dev/null
+++ b/src/test/ui/const-generics/issue-105689.rs
@@ -0,0 +1,14 @@
+// check-pass
+// edition:2021
+#![feature(generic_const_exprs)]
+#![allow(incomplete_features)]
+
+#[allow(unused)]
+async fn foo<'a>() {
+    let _data = &mut [0u8; { 1 + 4 }];
+    bar().await
+}
+
+async fn bar() {}
+
+fn main() {}
diff --git a/src/test/ui/empty/empty-struct-braces-expr.stderr b/src/test/ui/empty/empty-struct-braces-expr.stderr
index e1a7a02a56869..0e580aedeaa92 100644
--- a/src/test/ui/empty/empty-struct-braces-expr.stderr
+++ b/src/test/ui/empty/empty-struct-braces-expr.stderr
@@ -100,22 +100,22 @@ help: a unit struct with a similar name exists
 LL |     let xe1 = XEmpty2();
    |               ~~~~~~~
 
-error[E0599]: no variant or associated item named `Empty3` found for enum `empty_struct::XE` in the current scope
+error[E0599]: no variant or associated item named `Empty3` found for enum `XE` in the current scope
   --> $DIR/empty-struct-braces-expr.rs:25:19
    |
 LL |     let xe3 = XE::Empty3;
    |                   ^^^^^^
    |                   |
-   |                   variant or associated item not found in `empty_struct::XE`
+   |                   variant or associated item not found in `XE`
    |                   help: there is a variant with a similar name: `XEmpty3`
 
-error[E0599]: no variant or associated item named `Empty3` found for enum `empty_struct::XE` in the current scope
+error[E0599]: no variant or associated item named `Empty3` found for enum `XE` in the current scope
   --> $DIR/empty-struct-braces-expr.rs:26:19
    |
 LL |     let xe3 = XE::Empty3();
    |                   ^^^^^^
    |                   |
-   |                   variant or associated item not found in `empty_struct::XE`
+   |                   variant or associated item not found in `XE`
    |                   help: there is a variant with a similar name: `XEmpty3`
 
 error[E0599]: no variant named `Empty1` found for enum `empty_struct::XE`
diff --git a/src/test/ui/feature-gates/feature-gate-unsized_fn_params.rs b/src/test/ui/feature-gates/feature-gate-unsized_fn_params.rs
index 9b868ed7a9e93..c04e57843d4b2 100644
--- a/src/test/ui/feature-gates/feature-gate-unsized_fn_params.rs
+++ b/src/test/ui/feature-gates/feature-gate-unsized_fn_params.rs
@@ -1,5 +1,5 @@
+#![allow(unused, bare_trait_objects)]
 #[repr(align(256))]
-#[allow(dead_code)]
 struct A {
     v: u8,
 }
@@ -14,13 +14,17 @@ impl Foo for A {
     }
 }
 
-fn foo(x: dyn Foo) {
-    //~^ ERROR [E0277]
+fn foo(x: dyn Foo) { //~ ERROR [E0277]
     x.foo()
 }
 
+fn bar(x: Foo) { //~ ERROR [E0277]
+    x.foo()
+}
+
+fn qux(_: [()]) {} //~ ERROR [E0277]
+
 fn main() {
     let x: Box<dyn Foo> = Box::new(A { v: 22 });
-    foo(*x);
-    //~^ ERROR [E0277]
+    foo(*x); //~ ERROR [E0277]
 }
diff --git a/src/test/ui/feature-gates/feature-gate-unsized_fn_params.stderr b/src/test/ui/feature-gates/feature-gate-unsized_fn_params.stderr
index 0f7520ef7f8a9..92c71392672e1 100644
--- a/src/test/ui/feature-gates/feature-gate-unsized_fn_params.stderr
+++ b/src/test/ui/feature-gates/feature-gate-unsized_fn_params.stderr
@@ -6,13 +6,47 @@ LL | fn foo(x: dyn Foo) {
    |
    = help: the trait `Sized` is not implemented for `(dyn Foo + 'static)`
    = help: unsized fn params are gated as an unstable feature
+help: you can use `impl Trait` as the argument type
+   |
+LL | fn foo(x: impl Foo) {
+   |           ~~~~
 help: function arguments must have a statically known size, borrowed types always have a known size
    |
 LL | fn foo(x: &dyn Foo) {
    |           +
 
 error[E0277]: the size for values of type `(dyn Foo + 'static)` cannot be known at compilation time
-  --> $DIR/feature-gate-unsized_fn_params.rs:24:9
+  --> $DIR/feature-gate-unsized_fn_params.rs:21:8
+   |
+LL | fn bar(x: Foo) {
+   |        ^ doesn't have a size known at compile-time
+   |
+   = help: the trait `Sized` is not implemented for `(dyn Foo + 'static)`
+   = help: unsized fn params are gated as an unstable feature
+help: you can use `impl Trait` as the argument type
+   |
+LL | fn bar(x: impl Foo) {
+   |           ++++
+help: function arguments must have a statically known size, borrowed types always have a known size
+   |
+LL | fn bar(x: &Foo) {
+   |           +
+
+error[E0277]: the size for values of type `[()]` cannot be known at compilation time
+  --> $DIR/feature-gate-unsized_fn_params.rs:25:8
+   |
+LL | fn qux(_: [()]) {}
+   |        ^ doesn't have a size known at compile-time
+   |
+   = help: the trait `Sized` is not implemented for `[()]`
+   = help: unsized fn params are gated as an unstable feature
+help: function arguments must have a statically known size, borrowed types always have a known size
+   |
+LL | fn qux(_: &[()]) {}
+   |           +
+
+error[E0277]: the size for values of type `(dyn Foo + 'static)` cannot be known at compilation time
+  --> $DIR/feature-gate-unsized_fn_params.rs:29:9
    |
 LL |     foo(*x);
    |         ^^ doesn't have a size known at compile-time
@@ -21,6 +55,6 @@ LL |     foo(*x);
    = note: all function arguments must have a statically known size
    = help: unsized fn params are gated as an unstable feature
 
-error: aborting due to 2 previous errors
+error: aborting due to 4 previous errors
 
 For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/feature-gates/feature-gate-unsized_locals.stderr b/src/test/ui/feature-gates/feature-gate-unsized_locals.stderr
index c4507843e366e..9aeeb88cf04f2 100644
--- a/src/test/ui/feature-gates/feature-gate-unsized_locals.stderr
+++ b/src/test/ui/feature-gates/feature-gate-unsized_locals.stderr
@@ -6,6 +6,10 @@ LL | fn f(f: dyn FnOnce()) {}
    |
    = help: the trait `Sized` is not implemented for `(dyn FnOnce() + 'static)`
    = help: unsized fn params are gated as an unstable feature
+help: you can use `impl Trait` as the argument type
+   |
+LL | fn f(f: impl FnOnce()) {}
+   |         ~~~~
 help: function arguments must have a statically known size, borrowed types always have a known size
    |
 LL | fn f(f: &dyn FnOnce()) {}
diff --git a/src/test/ui/functions-closures/fn-help-with-err.stderr b/src/test/ui/functions-closures/fn-help-with-err.stderr
index 2296666219eef..463ac7684ecdf 100644
--- a/src/test/ui/functions-closures/fn-help-with-err.stderr
+++ b/src/test/ui/functions-closures/fn-help-with-err.stderr
@@ -17,11 +17,11 @@ note: `Bar` defines an item `bar`, perhaps you need to implement it
 LL | trait Bar {
    | ^^^^^^^^^
 
-error[E0599]: no method named `bar` found for struct `Arc<[closure@$DIR/fn-help-with-err.rs:22:36: 22:38]>` in the current scope
+error[E0599]: no method named `bar` found for struct `Arc<[closure@fn-help-with-err.rs:22:36]>` in the current scope
   --> $DIR/fn-help-with-err.rs:23:10
    |
 LL |     arc2.bar();
-   |          ^^^ method not found in `Arc<[closure@$DIR/fn-help-with-err.rs:22:36: 22:38]>`
+   |          ^^^ method not found in `Arc<[closure@fn-help-with-err.rs:22:36]>`
    |
    = help: items from traits can only be used if the trait is implemented and in scope
 note: `Bar` defines an item `bar`, perhaps you need to implement it
diff --git a/src/test/ui/higher-rank-trait-bounds/issue-30786.stderr b/src/test/ui/higher-rank-trait-bounds/issue-30786.stderr
index d1d76916b2639..0458d2535f2f5 100644
--- a/src/test/ui/higher-rank-trait-bounds/issue-30786.stderr
+++ b/src/test/ui/higher-rank-trait-bounds/issue-30786.stderr
@@ -1,4 +1,4 @@
-error[E0599]: the method `filterx` exists for struct `Map<Repeat, [closure@$DIR/issue-30786.rs:117:27: 117:34]>`, but its trait bounds were not satisfied
+error[E0599]: the method `filterx` exists for struct `Map<Repeat, [closure@issue-30786.rs:117:27]>`, but its trait bounds were not satisfied
   --> $DIR/issue-30786.rs:118:22
    |
 LL | pub struct Map<S, F> {
@@ -8,7 +8,7 @@ LL | pub struct Map<S, F> {
    | doesn't satisfy `_: StreamExt`
 ...
 LL |     let filter = map.filterx(|x: &_| true);
-   |                      ^^^^^^^ method cannot be called due to unsatisfied trait bounds
+   |                      ^^^^^^^ method cannot be called on `Map<Repeat, [closure@issue-30786.rs:117:27]>` due to unsatisfied trait bounds
    |
 note: the following trait bounds were not satisfied:
       `&'a mut &Map<Repeat, [closure@$DIR/issue-30786.rs:117:27: 117:34]>: Stream`
@@ -19,7 +19,7 @@ note: the following trait bounds were not satisfied:
 LL | impl<T> StreamExt for T where for<'a> &'a mut T: Stream {}
    |         ---------     -                          ^^^^^^ unsatisfied trait bound introduced here
 
-error[E0599]: the method `countx` exists for struct `Filter<Map<Repeat, for<'a> fn(&'a u64) -> &'a u64 {identity::<u64>}>, [closure@$DIR/issue-30786.rs:129:30: 129:37]>`, but its trait bounds were not satisfied
+error[E0599]: the method `countx` exists for struct `Filter<Map<Repeat, for<'a> fn(&'a u64) -> &'a u64 {identity::<u64>}>, [closure@issue-30786.rs:129:30]>`, but its trait bounds were not satisfied
   --> $DIR/issue-30786.rs:130:24
    |
 LL | pub struct Filter<S, F> {
diff --git a/src/test/ui/higher-rank-trait-bounds/issue-62203-hrtb-ice.stderr b/src/test/ui/higher-rank-trait-bounds/issue-62203-hrtb-ice.stderr
index ab5598e364fc4..fdd192f431370 100644
--- a/src/test/ui/higher-rank-trait-bounds/issue-62203-hrtb-ice.stderr
+++ b/src/test/ui/higher-rank-trait-bounds/issue-62203-hrtb-ice.stderr
@@ -30,7 +30,7 @@ LL |     where
 LL |         F: for<'r> T0<'r, (<Self as Ty<'r>>::V,), O = <B as Ty<'r>>::V>,
    |                                                   ^^^^^^^^^^^^^^^^^^^^ required by this bound in `T1::m`
 
-error[E0271]: expected `[closure@$DIR/issue-62203-hrtb-ice.rs:42:16: 42:19]` to be a closure that returns `Unit3`, but it returns `Unit4`
+error[E0271]: expected `[closure@issue-62203-hrtb-ice.rs:42:16]` to be a closure that returns `Unit3`, but it returns `Unit4`
   --> $DIR/issue-62203-hrtb-ice.rs:39:9
    |
 LL |       let v = Unit2.m(
diff --git a/src/test/ui/impl-trait/dyn-trait-return-should-be-impl-trait.stderr b/src/test/ui/impl-trait/dyn-trait-return-should-be-impl-trait.stderr
index f90399b6b9458..7f73d5e12d196 100644
--- a/src/test/ui/impl-trait/dyn-trait-return-should-be-impl-trait.stderr
+++ b/src/test/ui/impl-trait/dyn-trait-return-should-be-impl-trait.stderr
@@ -70,10 +70,6 @@ error[E0746]: return type cannot have an unboxed trait object
 LL | fn bak() -> dyn Trait { unimplemented!() }
    |             ^^^^^^^^^ doesn't have a size known at compile-time
    |
-help: use some type `T` that is `T: Sized` as the return type if all return paths have the same type
-   |
-LL | fn bak() -> T { unimplemented!() }
-   |             ~
 help: use `impl Trait` as the return type if all return paths have the same type but you want to expose only the trait in the signature
    |
 LL | fn bak() -> impl Trait { unimplemented!() }
diff --git a/src/test/ui/impl-trait/no-method-suggested-traits.stderr b/src/test/ui/impl-trait/no-method-suggested-traits.stderr
index 3d4ae11e57670..548c89d0a3871 100644
--- a/src/test/ui/impl-trait/no-method-suggested-traits.stderr
+++ b/src/test/ui/impl-trait/no-method-suggested-traits.stderr
@@ -145,11 +145,11 @@ note: `foo::Bar` defines an item `method2`, perhaps you need to implement it
 LL |     pub trait Bar {
    |     ^^^^^^^^^^^^^
 
-error[E0599]: no method named `method2` found for struct `no_method_suggested_traits::Foo` in the current scope
+error[E0599]: no method named `method2` found for struct `Foo` in the current scope
   --> $DIR/no-method-suggested-traits.rs:50:37
    |
 LL |     no_method_suggested_traits::Foo.method2();
-   |                                     ^^^^^^^ method not found in `no_method_suggested_traits::Foo`
+   |                                     ^^^^^^^ method not found in `Foo`
    |
    = help: items from traits can only be used if the trait is implemented and in scope
 note: `foo::Bar` defines an item `method2`, perhaps you need to implement it
@@ -158,11 +158,11 @@ note: `foo::Bar` defines an item `method2`, perhaps you need to implement it
 LL |     pub trait Bar {
    |     ^^^^^^^^^^^^^
 
-error[E0599]: no method named `method2` found for struct `Rc<&mut Box<&no_method_suggested_traits::Foo>>` in the current scope
+error[E0599]: no method named `method2` found for struct `Rc<&mut Box<&Foo>>` in the current scope
   --> $DIR/no-method-suggested-traits.rs:52:71
    |
 LL |     std::rc::Rc::new(&mut Box::new(&no_method_suggested_traits::Foo)).method2();
-   |                                                                       ^^^^^^^ method not found in `Rc<&mut Box<&no_method_suggested_traits::Foo>>`
+   |                                                                       ^^^^^^^ method not found in `Rc<&mut Box<&Foo>>`
    |
    = help: items from traits can only be used if the trait is implemented and in scope
 note: `foo::Bar` defines an item `method2`, perhaps you need to implement it
@@ -171,11 +171,11 @@ note: `foo::Bar` defines an item `method2`, perhaps you need to implement it
 LL |     pub trait Bar {
    |     ^^^^^^^^^^^^^
 
-error[E0599]: no method named `method2` found for enum `no_method_suggested_traits::Bar` in the current scope
+error[E0599]: no method named `method2` found for enum `Bar` in the current scope
   --> $DIR/no-method-suggested-traits.rs:54:40
    |
 LL |     no_method_suggested_traits::Bar::X.method2();
-   |                                        ^^^^^^^ method not found in `no_method_suggested_traits::Bar`
+   |                                        ^^^^^^^ method not found in `Bar`
    |
    = help: items from traits can only be used if the trait is implemented and in scope
 note: `foo::Bar` defines an item `method2`, perhaps you need to implement it
@@ -184,11 +184,11 @@ note: `foo::Bar` defines an item `method2`, perhaps you need to implement it
 LL |     pub trait Bar {
    |     ^^^^^^^^^^^^^
 
-error[E0599]: no method named `method2` found for struct `Rc<&mut Box<&no_method_suggested_traits::Bar>>` in the current scope
+error[E0599]: no method named `method2` found for struct `Rc<&mut Box<&Bar>>` in the current scope
   --> $DIR/no-method-suggested-traits.rs:56:74
    |
 LL |     std::rc::Rc::new(&mut Box::new(&no_method_suggested_traits::Bar::X)).method2();
-   |                                                                          ^^^^^^^ method not found in `Rc<&mut Box<&no_method_suggested_traits::Bar>>`
+   |                                                                          ^^^^^^^ method not found in `Rc<&mut Box<&Bar>>`
    |
    = help: items from traits can only be used if the trait is implemented and in scope
 note: `foo::Bar` defines an item `method2`, perhaps you need to implement it
@@ -255,29 +255,29 @@ error[E0599]: no method named `method3` found for struct `Rc<&mut Box<&usize>>`
 LL |     std::rc::Rc::new(&mut Box::new(&1_usize)).method3();
    |                                               ^^^^^^^ method not found in `Rc<&mut Box<&usize>>`
 
-error[E0599]: no method named `method3` found for struct `no_method_suggested_traits::Foo` in the current scope
+error[E0599]: no method named `method3` found for struct `Foo` in the current scope
   --> $DIR/no-method-suggested-traits.rs:71:37
    |
 LL |     no_method_suggested_traits::Foo.method3();
-   |                                     ^^^^^^^ method not found in `no_method_suggested_traits::Foo`
+   |                                     ^^^^^^^ method not found in `Foo`
 
-error[E0599]: no method named `method3` found for struct `Rc<&mut Box<&no_method_suggested_traits::Foo>>` in the current scope
+error[E0599]: no method named `method3` found for struct `Rc<&mut Box<&Foo>>` in the current scope
   --> $DIR/no-method-suggested-traits.rs:72:71
    |
 LL |     std::rc::Rc::new(&mut Box::new(&no_method_suggested_traits::Foo)).method3();
-   |                                                                       ^^^^^^^ method not found in `Rc<&mut Box<&no_method_suggested_traits::Foo>>`
+   |                                                                       ^^^^^^^ method not found in `Rc<&mut Box<&Foo>>`
 
-error[E0599]: no method named `method3` found for enum `no_method_suggested_traits::Bar` in the current scope
+error[E0599]: no method named `method3` found for enum `Bar` in the current scope
   --> $DIR/no-method-suggested-traits.rs:74:40
    |
 LL |     no_method_suggested_traits::Bar::X.method3();
-   |                                        ^^^^^^^ method not found in `no_method_suggested_traits::Bar`
+   |                                        ^^^^^^^ method not found in `Bar`
 
-error[E0599]: no method named `method3` found for struct `Rc<&mut Box<&no_method_suggested_traits::Bar>>` in the current scope
+error[E0599]: no method named `method3` found for struct `Rc<&mut Box<&Bar>>` in the current scope
   --> $DIR/no-method-suggested-traits.rs:75:74
    |
 LL |     std::rc::Rc::new(&mut Box::new(&no_method_suggested_traits::Bar::X)).method3();
-   |                                                                          ^^^^^^^ method not found in `Rc<&mut Box<&no_method_suggested_traits::Bar>>`
+   |                                                                          ^^^^^^^ method not found in `Rc<&mut Box<&Bar>>`
 
 error: aborting due to 24 previous errors
 
diff --git a/src/test/ui/issues/issue-18107.stderr b/src/test/ui/issues/issue-18107.stderr
index 28478457b296d..1669b550a9baf 100644
--- a/src/test/ui/issues/issue-18107.stderr
+++ b/src/test/ui/issues/issue-18107.stderr
@@ -4,10 +4,6 @@ error[E0746]: return type cannot have an unboxed trait object
 LL |     dyn AbstractRenderer
    |     ^^^^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time
    |
-help: use some type `T` that is `T: Sized` as the return type if all return paths have the same type
-   |
-LL |     T
-   |
 help: use `impl AbstractRenderer` as the return type if all return paths have the same type but you want to expose only the trait in the signature
    |
 LL |     impl AbstractRenderer
diff --git a/src/test/ui/issues/issue-30123.stderr b/src/test/ui/issues/issue-30123.stderr
index e9d934332f171..7808cbf8aa108 100644
--- a/src/test/ui/issues/issue-30123.stderr
+++ b/src/test/ui/issues/issue-30123.stderr
@@ -1,8 +1,8 @@
-error[E0599]: no function or associated item named `new_undirected` found for struct `issue_30123_aux::Graph<i32, i32>` in the current scope
+error[E0599]: no function or associated item named `new_undirected` found for struct `Graph<i32, i32>` in the current scope
   --> $DIR/issue-30123.rs:7:33
    |
 LL |     let ug = Graph::<i32, i32>::new_undirected();
-   |                                 ^^^^^^^^^^^^^^ function or associated item not found in `issue_30123_aux::Graph<i32, i32>`
+   |                                 ^^^^^^^^^^^^^^ function or associated item not found in `Graph<i32, i32>`
    |
    = note: the function or associated item was found for
            - `issue_30123_aux::Graph<N, E, Undirected>`
diff --git a/src/test/ui/issues/issue-31173.stderr b/src/test/ui/issues/issue-31173.stderr
index a32359c2b9f79..f3be99f9bcb4b 100644
--- a/src/test/ui/issues/issue-31173.stderr
+++ b/src/test/ui/issues/issue-31173.stderr
@@ -1,4 +1,4 @@
-error[E0271]: expected `TakeWhile<&mut std::vec::IntoIter<u8>, [closure@$DIR/issue-31173.rs:7:21: 7:25]>` to be an iterator that yields `&_`, but it yields `u8`
+error[E0271]: expected `TakeWhile<&mut IntoIter<u8>, [closure@issue-31173.rs:7:21]>` to be an iterator that yields `&_`, but it yields `u8`
   --> $DIR/issue-31173.rs:11:10
    |
 LL |         .cloned()
@@ -6,10 +6,22 @@ LL |         .cloned()
    |
    = note: expected reference `&_`
                    found type `u8`
+note: the method call chain might not have had the expected associated types
+  --> $DIR/issue-31173.rs:3:20
+   |
+LL |   pub fn get_tok(it: &mut IntoIter<u8>) {
+   |                      ^^^^^^^^^^^^^^^^^ `Iterator::Item` is `u8` here
+...
+LL |           .take_while(|&x| {
+   |  __________-
+LL | |             found_e = true;
+LL | |             false
+LL | |         })
+   | |__________- `Iterator::Item` remains `u8` here
 note: required by a bound in `cloned`
   --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
 
-error[E0599]: the method `collect` exists for struct `Cloned<TakeWhile<&mut std::vec::IntoIter<u8>, [closure@$DIR/issue-31173.rs:7:21: 7:25]>>`, but its trait bounds were not satisfied
+error[E0599]: the method `collect` exists for struct `Cloned<TakeWhile<&mut IntoIter<u8>, [closure@issue-31173.rs:7:21]>>`, but its trait bounds were not satisfied
   --> $DIR/issue-31173.rs:12:10
    |
 LL |         .collect();
diff --git a/src/test/ui/issues/issue-33941.rs b/src/test/ui/issues/issue-33941.rs
index 8430e85df8715..e3b6dcf55a744 100644
--- a/src/test/ui/issues/issue-33941.rs
+++ b/src/test/ui/issues/issue-33941.rs
@@ -3,7 +3,7 @@
 use std::collections::HashMap;
 
 fn main() {
-    for _ in HashMap::new().iter().cloned() {} //~ ERROR expected `std::collections::hash_map::Iter<'_, _, _>` to be an iterator that yields `&_`, but it yields `(&_, &_)`
-    //~^ ERROR expected `std::collections::hash_map::Iter<'_, _, _>` to be an iterator that yields `&_`, but it yields `(&_, &_)`
-    //~| ERROR expected `std::collections::hash_map::Iter<'_, _, _>` to be an iterator that yields `&_`, but it yields `(&_, &_)`
+    for _ in HashMap::new().iter().cloned() {} //~ ERROR expected `Iter<'_, _, _>` to be an iterator that yields `&_`, but it yields `(&_, &_)`
+    //~^ ERROR expected `Iter<'_, _, _>` to be an iterator that yields `&_`, but it yields `(&_, &_)`
+    //~| ERROR expected `Iter<'_, _, _>` to be an iterator that yields `&_`, but it yields `(&_, &_)`
 }
diff --git a/src/test/ui/issues/issue-33941.stderr b/src/test/ui/issues/issue-33941.stderr
index 49702c4765863..668eaabca4c46 100644
--- a/src/test/ui/issues/issue-33941.stderr
+++ b/src/test/ui/issues/issue-33941.stderr
@@ -1,4 +1,4 @@
-error[E0271]: expected `std::collections::hash_map::Iter<'_, _, _>` to be an iterator that yields `&_`, but it yields `(&_, &_)`
+error[E0271]: expected `Iter<'_, _, _>` to be an iterator that yields `&_`, but it yields `(&_, &_)`
   --> $DIR/issue-33941.rs:6:36
    |
 LL |     for _ in HashMap::new().iter().cloned() {}
@@ -6,10 +6,17 @@ LL |     for _ in HashMap::new().iter().cloned() {}
    |
    = note: expected reference `&_`
                   found tuple `(&_, &_)`
+note: the method call chain might not have had the expected associated types
+  --> $DIR/issue-33941.rs:6:29
+   |
+LL |     for _ in HashMap::new().iter().cloned() {}
+   |              -------------- ^^^^^^ `Iterator::Item` is `(&_, &_)` here
+   |              |
+   |              this expression has type `HashMap<_, _>`
 note: required by a bound in `cloned`
   --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
 
-error[E0271]: expected `std::collections::hash_map::Iter<'_, _, _>` to be an iterator that yields `&_`, but it yields `(&_, &_)`
+error[E0271]: expected `Iter<'_, _, _>` to be an iterator that yields `&_`, but it yields `(&_, &_)`
   --> $DIR/issue-33941.rs:6:14
    |
 LL |     for _ in HashMap::new().iter().cloned() {}
@@ -20,7 +27,7 @@ LL |     for _ in HashMap::new().iter().cloned() {}
    = note: required for `Cloned<std::collections::hash_map::Iter<'_, _, _>>` to implement `Iterator`
    = note: required for `Cloned<std::collections::hash_map::Iter<'_, _, _>>` to implement `IntoIterator`
 
-error[E0271]: expected `std::collections::hash_map::Iter<'_, _, _>` to be an iterator that yields `&_`, but it yields `(&_, &_)`
+error[E0271]: expected `Iter<'_, _, _>` to be an iterator that yields `&_`, but it yields `(&_, &_)`
   --> $DIR/issue-33941.rs:6:14
    |
 LL |     for _ in HashMap::new().iter().cloned() {}
diff --git a/src/test/ui/issues/issue-41880.stderr b/src/test/ui/issues/issue-41880.stderr
index fd694df30457e..00c375f8d2acf 100644
--- a/src/test/ui/issues/issue-41880.stderr
+++ b/src/test/ui/issues/issue-41880.stderr
@@ -5,7 +5,7 @@ LL | pub struct Iterate<T, F> {
    | ------------------------ method `iter` not found for this struct
 ...
 LL |     println!("{:?}", a.iter().take(10).collect::<Vec<usize>>());
-   |                        ^^^^ method not found in `Iterate<{integer}, [closure@$DIR/issue-41880.rs:26:24: 26:27]>`
+   |                        ^^^^ method not found in `Iterate<{integer}, [closure@issue-41880.rs:26:24]>`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-42312.stderr b/src/test/ui/issues/issue-42312.stderr
index 6fe151622433a..3ca6a2957e14b 100644
--- a/src/test/ui/issues/issue-42312.stderr
+++ b/src/test/ui/issues/issue-42312.stderr
@@ -23,6 +23,10 @@ LL | pub fn f(_: dyn ToString) {}
    |
    = help: the trait `Sized` is not implemented for `(dyn ToString + 'static)`
    = help: unsized fn params are gated as an unstable feature
+help: you can use `impl Trait` as the argument type
+   |
+LL | pub fn f(_: impl ToString) {}
+   |             ~~~~
 help: function arguments must have a statically known size, borrowed types always have a known size
    |
 LL | pub fn f(_: &dyn ToString) {}
diff --git a/src/test/ui/issues/issue-5883.stderr b/src/test/ui/issues/issue-5883.stderr
index 8a20a60853a63..ffff403e0d465 100644
--- a/src/test/ui/issues/issue-5883.stderr
+++ b/src/test/ui/issues/issue-5883.stderr
@@ -6,6 +6,10 @@ LL |     r: dyn A + 'static
    |
    = help: the trait `Sized` is not implemented for `(dyn A + 'static)`
    = help: unsized fn params are gated as an unstable feature
+help: you can use `impl Trait` as the argument type
+   |
+LL |     r: impl A + 'static
+   |        ~~~~
 help: function arguments must have a statically known size, borrowed types always have a known size
    |
 LL |     r: &dyn A + 'static
diff --git a/src/test/ui/iterators/invalid-iterator-chain.rs b/src/test/ui/iterators/invalid-iterator-chain.rs
index 87116e4924570..ebdf33303c982 100644
--- a/src/test/ui/iterators/invalid-iterator-chain.rs
+++ b/src/test/ui/iterators/invalid-iterator-chain.rs
@@ -1,3 +1,11 @@
+use std::collections::hash_set::Iter;
+use std::collections::HashSet;
+
+fn iter_to_vec<'b, X>(i: Iter<'b, X>) -> Vec<X> {
+    let i = i.map(|x| x.clone());
+    i.collect() //~ ERROR E0277
+}
+
 fn main() {
     let scores = vec![(0, 0)]
         .iter()
@@ -38,4 +46,8 @@ fn main() {
     });
     let f = e.filter(|_| false);
     let g: Vec<i32> = f.collect(); //~ ERROR E0277
+
+    let mut s = HashSet::new();
+    s.insert(1u8);
+    println!("{:?}", iter_to_vec(s.iter()));
 }
diff --git a/src/test/ui/iterators/invalid-iterator-chain.stderr b/src/test/ui/iterators/invalid-iterator-chain.stderr
index 84bac7833f67b..d76a4bfb7b3ea 100644
--- a/src/test/ui/iterators/invalid-iterator-chain.stderr
+++ b/src/test/ui/iterators/invalid-iterator-chain.stderr
@@ -1,5 +1,23 @@
+error[E0277]: a value of type `Vec<X>` cannot be built from an iterator over elements of type `&X`
+  --> $DIR/invalid-iterator-chain.rs:6:7
+   |
+LL |     i.collect()
+   |       ^^^^^^^ value of type `Vec<X>` cannot be built from `std::iter::Iterator<Item=&X>`
+   |
+   = help: the trait `FromIterator<&X>` is not implemented for `Vec<X>`
+   = help: the trait `FromIterator<T>` is implemented for `Vec<T>`
+note: the method call chain might not have had the expected associated types
+  --> $DIR/invalid-iterator-chain.rs:4:26
+   |
+LL | fn iter_to_vec<'b, X>(i: Iter<'b, X>) -> Vec<X> {
+   |                          ^^^^^^^^^^^ `Iterator::Item` is `&X` here
+LL |     let i = i.map(|x| x.clone());
+   |               ------------------ `Iterator::Item` remains `&X` here
+note: required by a bound in `collect`
+  --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
+
 error[E0277]: a value of type `i32` cannot be made by summing an iterator over elements of type `()`
-  --> $DIR/invalid-iterator-chain.rs:7:27
+  --> $DIR/invalid-iterator-chain.rs:15:27
    |
 LL |     println!("{}", scores.sum::<i32>());
    |                           ^^^ value of type `i32` cannot be made by summing a `std::iter::Iterator<Item=()>`
@@ -9,7 +27,7 @@ LL |     println!("{}", scores.sum::<i32>());
              <i32 as Sum<&'a i32>>
              <i32 as Sum>
 note: the method call chain might not have had the expected associated types
-  --> $DIR/invalid-iterator-chain.rs:4:10
+  --> $DIR/invalid-iterator-chain.rs:12:10
    |
 LL |       let scores = vec![(0, 0)]
    |                    ------------ this expression has type `Vec<({integer}, {integer})>`
@@ -24,7 +42,7 @@ note: required by a bound in `std::iter::Iterator::sum`
   --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
 
 error[E0277]: a value of type `i32` cannot be made by summing an iterator over elements of type `()`
-  --> $DIR/invalid-iterator-chain.rs:18:14
+  --> $DIR/invalid-iterator-chain.rs:26:14
    |
 LL |             .sum::<i32>(),
    |              ^^^ value of type `i32` cannot be made by summing a `std::iter::Iterator<Item=()>`
@@ -34,7 +52,7 @@ LL |             .sum::<i32>(),
              <i32 as Sum<&'a i32>>
              <i32 as Sum>
 note: the method call chain might not have had the expected associated types
-  --> $DIR/invalid-iterator-chain.rs:12:14
+  --> $DIR/invalid-iterator-chain.rs:20:14
    |
 LL |         vec![0, 1]
    |         ---------- this expression has type `Vec<{integer}>`
@@ -56,7 +74,7 @@ note: required by a bound in `std::iter::Iterator::sum`
   --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
 
 error[E0277]: a value of type `i32` cannot be made by summing an iterator over elements of type `f64`
-  --> $DIR/invalid-iterator-chain.rs:28:14
+  --> $DIR/invalid-iterator-chain.rs:36:14
    |
 LL |             .sum::<i32>(),
    |              ^^^ value of type `i32` cannot be made by summing a `std::iter::Iterator<Item=f64>`
@@ -66,7 +84,7 @@ LL |             .sum::<i32>(),
              <i32 as Sum<&'a i32>>
              <i32 as Sum>
 note: the method call chain might not have had the expected associated types
-  --> $DIR/invalid-iterator-chain.rs:24:14
+  --> $DIR/invalid-iterator-chain.rs:32:14
    |
 LL |         vec![0, 1]
    |         ---------- this expression has type `Vec<{integer}>`
@@ -84,7 +102,7 @@ note: required by a bound in `std::iter::Iterator::sum`
   --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
 
 error[E0277]: a value of type `i32` cannot be made by summing an iterator over elements of type `()`
-  --> $DIR/invalid-iterator-chain.rs:30:54
+  --> $DIR/invalid-iterator-chain.rs:38:54
    |
 LL |     println!("{}", vec![0, 1].iter().map(|x| { x; }).sum::<i32>());
    |                                                      ^^^ value of type `i32` cannot be made by summing a `std::iter::Iterator<Item=()>`
@@ -94,7 +112,7 @@ LL |     println!("{}", vec![0, 1].iter().map(|x| { x; }).sum::<i32>());
              <i32 as Sum<&'a i32>>
              <i32 as Sum>
 note: the method call chain might not have had the expected associated types
-  --> $DIR/invalid-iterator-chain.rs:30:38
+  --> $DIR/invalid-iterator-chain.rs:38:38
    |
 LL |     println!("{}", vec![0, 1].iter().map(|x| { x; }).sum::<i32>());
    |                    ---------- ------ ^^^^^^^^^^^^^^^ `Iterator::Item` changed to `()` here
@@ -105,7 +123,7 @@ note: required by a bound in `std::iter::Iterator::sum`
   --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
 
 error[E0277]: a value of type `i32` cannot be made by summing an iterator over elements of type `&()`
-  --> $DIR/invalid-iterator-chain.rs:31:40
+  --> $DIR/invalid-iterator-chain.rs:39:40
    |
 LL |     println!("{}", vec![(), ()].iter().sum::<i32>());
    |                                        ^^^ value of type `i32` cannot be made by summing a `std::iter::Iterator<Item=&()>`
@@ -115,7 +133,7 @@ LL |     println!("{}", vec![(), ()].iter().sum::<i32>());
              <i32 as Sum<&'a i32>>
              <i32 as Sum>
 note: the method call chain might not have had the expected associated types
-  --> $DIR/invalid-iterator-chain.rs:31:33
+  --> $DIR/invalid-iterator-chain.rs:39:33
    |
 LL |     println!("{}", vec![(), ()].iter().sum::<i32>());
    |                    ------------ ^^^^^^ `Iterator::Item` is `&()` here
@@ -125,7 +143,7 @@ note: required by a bound in `std::iter::Iterator::sum`
   --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
 
 error[E0277]: a value of type `Vec<i32>` cannot be built from an iterator over elements of type `()`
-  --> $DIR/invalid-iterator-chain.rs:40:25
+  --> $DIR/invalid-iterator-chain.rs:48:25
    |
 LL |     let g: Vec<i32> = f.collect();
    |                         ^^^^^^^ value of type `Vec<i32>` cannot be built from `std::iter::Iterator<Item=()>`
@@ -133,7 +151,7 @@ LL |     let g: Vec<i32> = f.collect();
    = help: the trait `FromIterator<()>` is not implemented for `Vec<i32>`
    = help: the trait `FromIterator<T>` is implemented for `Vec<T>`
 note: the method call chain might not have had the expected associated types
-  --> $DIR/invalid-iterator-chain.rs:36:15
+  --> $DIR/invalid-iterator-chain.rs:44:15
    |
 LL |       let a = vec![0];
    |               ------- this expression has type `Vec<{integer}>`
@@ -153,6 +171,6 @@ LL |       let f = e.filter(|_| false);
 note: required by a bound in `collect`
   --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
 
-error: aborting due to 6 previous errors
+error: aborting due to 7 previous errors
 
 For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/methods/method-not-found-generic-arg-elision.stderr b/src/test/ui/methods/method-not-found-generic-arg-elision.stderr
index fc42d1a4dcd08..8846efba871b9 100644
--- a/src/test/ui/methods/method-not-found-generic-arg-elision.stderr
+++ b/src/test/ui/methods/method-not-found-generic-arg-elision.stderr
@@ -23,7 +23,7 @@ error[E0599]: no method named `extend` found for struct `Map` in the current sco
   --> $DIR/method-not-found-generic-arg-elision.rs:87:29
    |
 LL |     v.iter().map(|x| x * x).extend(std::iter::once(100));
-   |                             ^^^^^^ method not found in `Map<std::slice::Iter<'_, i32>, [closure@$DIR/method-not-found-generic-arg-elision.rs:87:18: 87:21]>`
+   |                             ^^^^^^ method not found in `Map<Iter<'_, i32>, [closure@method-not-found-generic-arg-elision.rs:87:18]>`
 
 error[E0599]: no method named `method` found for struct `Wrapper<bool>` in the current scope
   --> $DIR/method-not-found-generic-arg-elision.rs:90:13
diff --git a/src/test/ui/mismatched_types/issue-36053-2.stderr b/src/test/ui/mismatched_types/issue-36053-2.stderr
index 3151bc76891e4..72fb0e4d77431 100644
--- a/src/test/ui/mismatched_types/issue-36053-2.stderr
+++ b/src/test/ui/mismatched_types/issue-36053-2.stderr
@@ -13,7 +13,7 @@ LL |     once::<&str>("str").fuse().filter(|a: &str| true).count();
 note: required by a bound in `filter`
   --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
 
-error[E0599]: the method `count` exists for struct `Filter<Fuse<std::iter::Once<&str>>, [closure@$DIR/issue-36053-2.rs:7:39: 7:48]>`, but its trait bounds were not satisfied
+error[E0599]: the method `count` exists for struct `Filter<Fuse<Once<&str>>, [closure@issue-36053-2.rs:7:39]>`, but its trait bounds were not satisfied
   --> $DIR/issue-36053-2.rs:7:55
    |
 LL |     once::<&str>("str").fuse().filter(|a: &str| true).count();
diff --git a/src/test/ui/never_type/fallback-closure-wrap.fallback.stderr b/src/test/ui/never_type/fallback-closure-wrap.fallback.stderr
index 45cf3723483f3..a0f790dba15ed 100644
--- a/src/test/ui/never_type/fallback-closure-wrap.fallback.stderr
+++ b/src/test/ui/never_type/fallback-closure-wrap.fallback.stderr
@@ -1,4 +1,4 @@
-error[E0271]: expected `[closure@$DIR/fallback-closure-wrap.rs:18:40: 18:47]` to be a closure that returns `()`, but it returns `!`
+error[E0271]: expected `[closure@fallback-closure-wrap.rs:18:40]` to be a closure that returns `()`, but it returns `!`
   --> $DIR/fallback-closure-wrap.rs:18:31
    |
 LL |       let error = Closure::wrap(Box::new(move || {
diff --git a/src/test/ui/resolve/issue-5035-2.stderr b/src/test/ui/resolve/issue-5035-2.stderr
index 939392733f0e9..558e6b7b118d8 100644
--- a/src/test/ui/resolve/issue-5035-2.stderr
+++ b/src/test/ui/resolve/issue-5035-2.stderr
@@ -6,6 +6,10 @@ LL | fn foo(_x: K) {}
    |
    = help: the trait `Sized` is not implemented for `(dyn I + 'static)`
    = help: unsized fn params are gated as an unstable feature
+help: you can use `impl Trait` as the argument type
+   |
+LL | fn foo(_x: impl K) {}
+   |            ++++
 help: function arguments must have a statically known size, borrowed types always have a known size
    |
 LL | fn foo(_x: &K) {}
diff --git a/src/test/ui/suggestions/clone-on-unconstrained-borrowed-type-param.fixed b/src/test/ui/suggestions/clone-on-unconstrained-borrowed-type-param.fixed
new file mode 100644
index 0000000000000..4f9e93a47ed1c
--- /dev/null
+++ b/src/test/ui/suggestions/clone-on-unconstrained-borrowed-type-param.fixed
@@ -0,0 +1,16 @@
+// run-rustfix
+fn wat<T: Clone>(t: &T) -> T {
+    t.clone() //~ ERROR E0308
+}
+
+#[derive(Clone)]
+struct Foo;
+
+fn wut(t: &Foo) -> Foo {
+    t.clone() //~ ERROR E0308
+}
+
+fn main() {
+    wat(&42);
+    wut(&Foo);
+}
diff --git a/src/test/ui/suggestions/clone-on-unconstrained-borrowed-type-param.rs b/src/test/ui/suggestions/clone-on-unconstrained-borrowed-type-param.rs
new file mode 100644
index 0000000000000..89b077d671a51
--- /dev/null
+++ b/src/test/ui/suggestions/clone-on-unconstrained-borrowed-type-param.rs
@@ -0,0 +1,15 @@
+// run-rustfix
+fn wat<T>(t: &T) -> T {
+    t.clone() //~ ERROR E0308
+}
+
+struct Foo;
+
+fn wut(t: &Foo) -> Foo {
+    t.clone() //~ ERROR E0308
+}
+
+fn main() {
+    wat(&42);
+    wut(&Foo);
+}
diff --git a/src/test/ui/suggestions/clone-on-unconstrained-borrowed-type-param.stderr b/src/test/ui/suggestions/clone-on-unconstrained-borrowed-type-param.stderr
new file mode 100644
index 0000000000000..26ab515d9b4b6
--- /dev/null
+++ b/src/test/ui/suggestions/clone-on-unconstrained-borrowed-type-param.stderr
@@ -0,0 +1,43 @@
+error[E0308]: mismatched types
+  --> $DIR/clone-on-unconstrained-borrowed-type-param.rs:3:5
+   |
+LL | fn wat<T>(t: &T) -> T {
+   |        -            - expected `T` because of return type
+   |        |
+   |        this type parameter
+LL |     t.clone()
+   |     ^^^^^^^^^ expected type parameter `T`, found `&T`
+   |
+   = note: expected type parameter `T`
+                   found reference `&T`
+note: `T` does not implement `Clone`, so `&T` was cloned instead
+  --> $DIR/clone-on-unconstrained-borrowed-type-param.rs:3:5
+   |
+LL |     t.clone()
+   |     ^
+help: consider restricting type parameter `T`
+   |
+LL | fn wat<T: Clone>(t: &T) -> T {
+   |         +++++++
+
+error[E0308]: mismatched types
+  --> $DIR/clone-on-unconstrained-borrowed-type-param.rs:9:5
+   |
+LL | fn wut(t: &Foo) -> Foo {
+   |                    --- expected `Foo` because of return type
+LL |     t.clone()
+   |     ^^^^^^^^^ expected struct `Foo`, found `&Foo`
+   |
+note: `Foo` does not implement `Clone`, so `&Foo` was cloned instead
+  --> $DIR/clone-on-unconstrained-borrowed-type-param.rs:9:5
+   |
+LL |     t.clone()
+   |     ^
+help: consider annotating `Foo` with `#[derive(Clone)]`
+   |
+LL | #[derive(Clone)]
+   |
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/suggestions/mut-borrow-needed-by-trait.stderr b/src/test/ui/suggestions/mut-borrow-needed-by-trait.stderr
index 2cb53ecce1040..6910b77d9bc3f 100644
--- a/src/test/ui/suggestions/mut-borrow-needed-by-trait.stderr
+++ b/src/test/ui/suggestions/mut-borrow-needed-by-trait.stderr
@@ -20,11 +20,11 @@ LL |     let fp = BufWriter::new(fp);
 note: required by a bound in `BufWriter`
   --> $SRC_DIR/std/src/io/buffered/bufwriter.rs:LL:COL
 
-error[E0599]: the method `write_fmt` exists for struct `BufWriter<&dyn std::io::Write>`, but its trait bounds were not satisfied
+error[E0599]: the method `write_fmt` exists for struct `BufWriter<&dyn Write>`, but its trait bounds were not satisfied
   --> $DIR/mut-borrow-needed-by-trait.rs:21:5
    |
 LL |     writeln!(fp, "hello world").unwrap();
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^ method cannot be called on `BufWriter<&dyn std::io::Write>` due to unsatisfied trait bounds
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^ method cannot be called on `BufWriter<&dyn Write>` due to unsatisfied trait bounds
   --> $SRC_DIR/std/src/io/buffered/bufwriter.rs:LL:COL
    |
    = note: doesn't satisfy `BufWriter<&dyn std::io::Write>: std::io::Write`
diff --git a/src/test/ui/traits/assoc-type-in-superbad.rs b/src/test/ui/traits/assoc-type-in-superbad.rs
index d7d6241ef708c..65340b2a2092f 100644
--- a/src/test/ui/traits/assoc-type-in-superbad.rs
+++ b/src/test/ui/traits/assoc-type-in-superbad.rs
@@ -10,7 +10,7 @@ pub trait Foo: Iterator<Item = <Self as Foo>::Key> {
 
 impl Foo for IntoIter<i32> {
     type Key = u32;
-    //~^ ERROR expected `std::vec::IntoIter<i32>` to be an iterator that yields `u32`, but it yields `i32`
+    //~^ ERROR expected `IntoIter<i32>` to be an iterator that yields `u32`, but it yields `i32`
 }
 
 fn main() {}
diff --git a/src/test/ui/traits/assoc-type-in-superbad.stderr b/src/test/ui/traits/assoc-type-in-superbad.stderr
index 3e2d9d9038aa7..7fa1d2c2eed67 100644
--- a/src/test/ui/traits/assoc-type-in-superbad.stderr
+++ b/src/test/ui/traits/assoc-type-in-superbad.stderr
@@ -1,4 +1,4 @@
-error[E0271]: expected `std::vec::IntoIter<i32>` to be an iterator that yields `u32`, but it yields `i32`
+error[E0271]: expected `IntoIter<i32>` to be an iterator that yields `u32`, but it yields `i32`
   --> $DIR/assoc-type-in-superbad.rs:12:16
    |
 LL |     type Key = u32;
diff --git a/src/test/ui/traits/bound/not-on-bare-trait.stderr b/src/test/ui/traits/bound/not-on-bare-trait.stderr
index 8da0b6d6b8505..36b08a7d30931 100644
--- a/src/test/ui/traits/bound/not-on-bare-trait.stderr
+++ b/src/test/ui/traits/bound/not-on-bare-trait.stderr
@@ -20,6 +20,10 @@ LL | fn foo(_x: Foo + Send) {
    |
    = help: the trait `Sized` is not implemented for `(dyn Foo + Send + 'static)`
    = help: unsized fn params are gated as an unstable feature
+help: you can use `impl Trait` as the argument type
+   |
+LL | fn foo(_x: impl Foo + Send) {
+   |            ++++
 help: function arguments must have a statically known size, borrowed types always have a known size
    |
 LL | fn foo(_x: &Foo + Send) {
diff --git a/src/test/ui/type-alias-impl-trait/issue-57961.rs b/src/test/ui/type-alias-impl-trait/issue-57961.rs
index 24b3a045856a6..4aa5966ff25d4 100644
--- a/src/test/ui/type-alias-impl-trait/issue-57961.rs
+++ b/src/test/ui/type-alias-impl-trait/issue-57961.rs
@@ -8,7 +8,7 @@ trait Foo {
 
 impl Foo for () {
     type Bar = std::vec::IntoIter<u32>;
-    //~^ ERROR expected `std::vec::IntoIter<u32>` to be an iterator that yields `X`, but it yields `u32`
+    //~^ ERROR expected `IntoIter<u32>` to be an iterator that yields `X`, but it yields `u32`
 }
 
 fn incoherent() {
diff --git a/src/test/ui/type-alias-impl-trait/issue-57961.stderr b/src/test/ui/type-alias-impl-trait/issue-57961.stderr
index fb40895c49f15..8d11b48888947 100644
--- a/src/test/ui/type-alias-impl-trait/issue-57961.stderr
+++ b/src/test/ui/type-alias-impl-trait/issue-57961.stderr
@@ -1,4 +1,4 @@
-error[E0271]: expected `std::vec::IntoIter<u32>` to be an iterator that yields `X`, but it yields `u32`
+error[E0271]: expected `IntoIter<u32>` to be an iterator that yields `X`, but it yields `u32`
   --> $DIR/issue-57961.rs:10:16
    |
 LL | type X = impl Sized;
diff --git a/src/test/ui/typeck/explain_clone_autoref.stderr b/src/test/ui/typeck/explain_clone_autoref.stderr
index faac680ea1931..ff36e18d28301 100644
--- a/src/test/ui/typeck/explain_clone_autoref.stderr
+++ b/src/test/ui/typeck/explain_clone_autoref.stderr
@@ -12,6 +12,10 @@ note: `NotClone` does not implement `Clone`, so `&NotClone` was cloned instead
    |
 LL |     nc.clone()
    |     ^^
+help: consider annotating `NotClone` with `#[derive(Clone)]`
+   |
+LL | #[derive(Clone)]
+   |
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/unboxed-closures/unboxed-closures-static-call-wrong-trait.stderr b/src/test/ui/unboxed-closures/unboxed-closures-static-call-wrong-trait.stderr
index e5ca0edd7a91c..99ec517834003 100644
--- a/src/test/ui/unboxed-closures/unboxed-closures-static-call-wrong-trait.stderr
+++ b/src/test/ui/unboxed-closures/unboxed-closures-static-call-wrong-trait.stderr
@@ -1,8 +1,8 @@
-error[E0599]: no method named `call` found for closure `[closure@$DIR/unboxed-closures-static-call-wrong-trait.rs:6:26: 6:29]` in the current scope
+error[E0599]: no method named `call` found for closure `[closure@unboxed-closures-static-call-wrong-trait.rs:6:26]` in the current scope
   --> $DIR/unboxed-closures-static-call-wrong-trait.rs:7:10
    |
 LL |     mut_.call((0, ));
-   |          ^^^^ method not found in `[closure@$DIR/unboxed-closures-static-call-wrong-trait.rs:6:26: 6:29]`
+   |          ^^^^ method not found in `[closure@unboxed-closures-static-call-wrong-trait.rs:6:26]`
 
 error: aborting due to previous error
 
diff --git a/src/tools/clippy/clippy_utils/src/lib.rs b/src/tools/clippy/clippy_utils/src/lib.rs
index 90192f46cbfa0..652f8b4d3c56e 100644
--- a/src/tools/clippy/clippy_utils/src/lib.rs
+++ b/src/tools/clippy/clippy_utils/src/lib.rs
@@ -97,7 +97,7 @@ use rustc_middle::hir::place::PlaceBase;
 use rustc_middle::ty as rustc_ty;
 use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow};
 use rustc_middle::ty::binding::BindingMode;
-use rustc_middle::ty::fast_reject::SimplifiedTypeGen::{
+use rustc_middle::ty::fast_reject::SimplifiedType::{
     ArraySimplifiedType, BoolSimplifiedType, CharSimplifiedType, FloatSimplifiedType, IntSimplifiedType,
     PtrSimplifiedType, SliceSimplifiedType, StrSimplifiedType, UintSimplifiedType,
 };