Merging debian version 1.65.0+dfsg1-2.

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

8 files changed, 241 insertions, 228 deletions

diff --git a/compiler/rustc_ty_utils/Cargo.toml b/compiler/rustc_ty_utils/Cargo.toml
index caad2ed42..52fbd3ae0 100644
--- a/compiler/rustc_ty_utils/Cargo.toml
+++ b/compiler/rustc_ty_utils/Cargo.toml
@@ -10,6 +10,7 @@ rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_errors = { path = "../rustc_errors" }
 rustc_hir = { path = "../rustc_hir" }
 rustc_infer = { path = "../rustc_infer" }
+rustc_macros = { path = "../rustc_macros" }
 rustc_span = { path = "../rustc_span" }
 rustc_session = { path = "../rustc_session" }
 rustc_target = { path = "../rustc_target" }
diff --git a/compiler/rustc_ty_utils/src/consts.rs b/compiler/rustc_ty_utils/src/consts.rs
index 7c2f4db94..44c4fc48d 100644
--- a/compiler/rustc_ty_utils/src/consts.rs
+++ b/compiler/rustc_ty_utils/src/consts.rs
@@ -11,6 +11,8 @@ use rustc_target::abi::VariantIdx;
 
 use std::iter;
 
+use crate::errors::{GenericConstantTooComplex, GenericConstantTooComplexSub};
+
 /// Destructures array, ADT or tuple constants into the constants
 /// of their fields.
 pub(crate) fn destructure_const<'tcx>(
@@ -93,26 +95,25 @@ impl<'a, 'tcx> AbstractConstBuilder<'a, 'tcx> {
         self.body.exprs[self.body_id].span
     }
 
-    fn error(&mut self, span: Span, msg: &str) -> Result<!, ErrorGuaranteed> {
-        let reported = self
-            .tcx
-            .sess
-            .struct_span_err(self.root_span(), "overly complex generic constant")
-            .span_label(span, msg)
-            .help("consider moving this anonymous constant into a `const` function")
-            .emit();
+    fn error(&mut self, sub: GenericConstantTooComplexSub) -> Result<!, ErrorGuaranteed> {
+        let reported = self.tcx.sess.emit_err(GenericConstantTooComplex {
+            span: self.root_span(),
+            maybe_supported: None,
+            sub,
+        });
 
         Err(reported)
     }
-    fn maybe_supported_error(&mut self, span: Span, msg: &str) -> Result<!, ErrorGuaranteed> {
-        let reported = self
-            .tcx
-            .sess
-            .struct_span_err(self.root_span(), "overly complex generic constant")
-            .span_label(span, msg)
-            .help("consider moving this anonymous constant into a `const` function")
-            .note("this operation may be supported in the future")
-            .emit();
+
+    fn maybe_supported_error(
+        &mut self,
+        sub: GenericConstantTooComplexSub,
+    ) -> Result<!, ErrorGuaranteed> {
+        let reported = self.tcx.sess.emit_err(GenericConstantTooComplex {
+            span: self.root_span(),
+            maybe_supported: Some(()),
+            sub,
+        });
 
         Err(reported)
     }
@@ -154,9 +155,9 @@ impl<'a, 'tcx> AbstractConstBuilder<'a, 'tcx> {
                     return true;
                 }
 
-                match pat.kind.as_ref() {
+                match pat.kind {
                     thir::PatKind::Constant { value } => value.has_param_types_or_consts(),
-                    thir::PatKind::Range(thir::PatRange { lo, hi, .. }) => {
+                    thir::PatKind::Range(box thir::PatRange { lo, hi, .. }) => {
                         lo.has_param_types_or_consts() || hi.has_param_types_or_consts()
                     }
                     _ => false,
@@ -221,17 +222,6 @@ impl<'a, 'tcx> AbstractConstBuilder<'a, 'tcx> {
         debug!("AbstractConstBuilder::build: body={:?}", &*self.body);
         self.recurse_build(self.body_id)?;
 
-        for n in self.nodes.iter() {
-            if let Node::Leaf(ct) = n {
-                if let ty::ConstKind::Unevaluated(ct) = ct.kind() {
-                    // `AbstractConst`s should not contain any promoteds as they require references which
-                    // are not allowed.
-                    assert_eq!(ct.promoted, None);
-                    assert_eq!(ct, self.tcx.erase_regions(ct));
-                }
-            }
-        }
-
         Ok(self.tcx.arena.alloc_from_iter(self.nodes.into_iter()))
     }
 
@@ -243,22 +233,23 @@ impl<'a, 'tcx> AbstractConstBuilder<'a, 'tcx> {
             &ExprKind::Scope { value, .. } => self.recurse_build(value)?,
             &ExprKind::PlaceTypeAscription { source, .. }
             | &ExprKind::ValueTypeAscription { source, .. } => self.recurse_build(source)?,
-            &ExprKind::Literal { lit, neg} => {
+            &ExprKind::Literal { lit, neg } => {
                 let sp = node.span;
-                let constant =
-                    match self.tcx.at(sp).lit_to_const(LitToConstInput { lit: &lit.node, ty: node.ty, neg }) {
-                        Ok(c) => c,
-                        Err(LitToConstError::Reported) => {
-                            self.tcx.const_error(node.ty)
-                        }
-                        Err(LitToConstError::TypeError) => {
-                            bug!("encountered type error in lit_to_const")
-                        }
-                    };
+                let constant = match self.tcx.at(sp).lit_to_const(LitToConstInput {
+                    lit: &lit.node,
+                    ty: node.ty,
+                    neg,
+                }) {
+                    Ok(c) => c,
+                    Err(LitToConstError::Reported) => self.tcx.const_error(node.ty),
+                    Err(LitToConstError::TypeError) => {
+                        bug!("encountered type error in lit_to_const")
+                    }
+                };
 
                 self.nodes.push(Node::Leaf(constant))
             }
-            &ExprKind::NonHirLiteral { lit , user_ty: _} => {
+            &ExprKind::NonHirLiteral { lit, user_ty: _ } => {
                 let val = ty::ValTree::from_scalar_int(lit);
                 self.nodes.push(Node::Leaf(ty::Const::from_value(self.tcx, val, node.ty)))
             }
@@ -269,19 +260,17 @@ impl<'a, 'tcx> AbstractConstBuilder<'a, 'tcx> {
             &ExprKind::NamedConst { def_id, substs, user_ty: _ } => {
                 let uneval = ty::Unevaluated::new(ty::WithOptConstParam::unknown(def_id), substs);
 
-                let constant = self.tcx.mk_const(ty::ConstS {
-                                kind: ty::ConstKind::Unevaluated(uneval),
-                                ty: node.ty,
-                            });
+                let constant = self
+                    .tcx
+                    .mk_const(ty::ConstS { kind: ty::ConstKind::Unevaluated(uneval), ty: node.ty });
 
                 self.nodes.push(Node::Leaf(constant))
             }
 
-            ExprKind::ConstParam {param, ..} => {
-                let const_param = self.tcx.mk_const(ty::ConstS {
-                        kind: ty::ConstKind::Param(*param),
-                        ty: node.ty,
-                    });
+            ExprKind::ConstParam { param, .. } => {
+                let const_param = self
+                    .tcx
+                    .mk_const(ty::ConstS { kind: ty::ConstKind::Param(*param), ty: node.ty });
                 self.nodes.push(Node::Leaf(const_param))
             }
 
@@ -311,8 +300,15 @@ impl<'a, 'tcx> AbstractConstBuilder<'a, 'tcx> {
             //     bar::<{ N + 1 }>();
             // }
             // ```
-            ExprKind::Block { body: thir::Block { stmts: box [], expr: Some(e), .. } } => {
-                self.recurse_build(*e)?
+            ExprKind::Block { block } => {
+                if let thir::Block { stmts: box [], expr: Some(e), .. } = &self.body.blocks[*block]
+                {
+                    self.recurse_build(*e)?
+                } else {
+                    self.maybe_supported_error(GenericConstantTooComplexSub::BlockNotSupported(
+                        node.span,
+                    ))?
+                }
             }
             // `ExprKind::Use` happens when a `hir::ExprKind::Cast` is a
             // "coercion cast" i.e. using a coercion or is a no-op.
@@ -325,7 +321,7 @@ impl<'a, 'tcx> AbstractConstBuilder<'a, 'tcx> {
                 let arg = self.recurse_build(source)?;
                 self.nodes.push(Node::Cast(CastKind::As, arg, node.ty))
             }
-            ExprKind::Borrow{ arg, ..} => {
+            ExprKind::Borrow { arg, .. } => {
                 let arg_node = &self.body.exprs[*arg];
 
                 // Skip reborrows for now until we allow Deref/Borrow/AddressOf
@@ -334,80 +330,69 @@ impl<'a, 'tcx> AbstractConstBuilder<'a, 'tcx> {
                 if let ExprKind::Deref { arg } = arg_node.kind {
                     self.recurse_build(arg)?
                 } else {
-                    self.maybe_supported_error(
+                    self.maybe_supported_error(GenericConstantTooComplexSub::BorrowNotSupported(
                         node.span,
-                        "borrowing is not supported in generic constants",
-                    )?
+                    ))?
                 }
             }
             // FIXME(generic_const_exprs): We may want to support these.
-            ExprKind::AddressOf { .. } | ExprKind::Deref {..}=> self.maybe_supported_error(
-                node.span,
-                "dereferencing or taking the address is not supported in generic constants",
-            )?,
-            ExprKind::Repeat { .. } | ExprKind::Array { .. } =>  self.maybe_supported_error(
-                node.span,
-                "array construction is not supported in generic constants",
+            ExprKind::AddressOf { .. } | ExprKind::Deref { .. } => self.maybe_supported_error(
+                GenericConstantTooComplexSub::AddressAndDerefNotSupported(node.span),
             )?,
-            ExprKind::Block { .. } => self.maybe_supported_error(
-                node.span,
-                "blocks are not supported in generic constant",
+            ExprKind::Repeat { .. } | ExprKind::Array { .. } => self.maybe_supported_error(
+                GenericConstantTooComplexSub::ArrayNotSupported(node.span),
             )?,
             ExprKind::NeverToAny { .. } => self.maybe_supported_error(
-                node.span,
-                "converting nevers to any is not supported in generic constant",
+                GenericConstantTooComplexSub::NeverToAnyNotSupported(node.span),
             )?,
             ExprKind::Tuple { .. } => self.maybe_supported_error(
-                node.span,
-                "tuple construction is not supported in generic constants",
+                GenericConstantTooComplexSub::TupleNotSupported(node.span),
             )?,
             ExprKind::Index { .. } => self.maybe_supported_error(
-                node.span,
-                "indexing is not supported in generic constant",
+                GenericConstantTooComplexSub::IndexNotSupported(node.span),
             )?,
             ExprKind::Field { .. } => self.maybe_supported_error(
-                node.span,
-                "field access is not supported in generic constant",
+                GenericConstantTooComplexSub::FieldNotSupported(node.span),
             )?,
             ExprKind::ConstBlock { .. } => self.maybe_supported_error(
-                node.span,
-                "const blocks are not supported in generic constant",
-            )?,
-            ExprKind::Adt(_) => self.maybe_supported_error(
-                node.span,
-                "struct/enum construction is not supported in generic constants",
+                GenericConstantTooComplexSub::ConstBlockNotSupported(node.span),
             )?,
+            ExprKind::Adt(_) => self
+                .maybe_supported_error(GenericConstantTooComplexSub::AdtNotSupported(node.span))?,
             // dont know if this is correct
-            ExprKind::Pointer { .. } =>
-                self.error(node.span, "pointer casts are not allowed in generic constants")?,
-            ExprKind::Yield { .. } =>
-                self.error(node.span, "generator control flow is not allowed in generic constants")?,
-            ExprKind::Continue { .. } | ExprKind::Break { .. } | ExprKind::Loop { .. } => self
-                .error(
-                    node.span,
-                    "loops and loop control flow are not supported in generic constants",
-                )?,
-            ExprKind::Box { .. } =>
-                self.error(node.span, "allocations are not allowed in generic constants")?,
+            ExprKind::Pointer { .. } => {
+                self.error(GenericConstantTooComplexSub::PointerNotSupported(node.span))?
+            }
+            ExprKind::Yield { .. } => {
+                self.error(GenericConstantTooComplexSub::YieldNotSupported(node.span))?
+            }
+            ExprKind::Continue { .. } | ExprKind::Break { .. } | ExprKind::Loop { .. } => {
+                self.error(GenericConstantTooComplexSub::LoopNotSupported(node.span))?
+            }
+            ExprKind::Box { .. } => {
+                self.error(GenericConstantTooComplexSub::BoxNotSupported(node.span))?
+            }
 
             ExprKind::Unary { .. } => unreachable!(),
             // we handle valid unary/binary ops above
-            ExprKind::Binary { .. } =>
-                self.error(node.span, "unsupported binary operation in generic constants")?,
-            ExprKind::LogicalOp { .. } =>
-                self.error(node.span, "unsupported operation in generic constants, short-circuiting operations would imply control flow")?,
+            ExprKind::Binary { .. } => {
+                self.error(GenericConstantTooComplexSub::BinaryNotSupported(node.span))?
+            }
+            ExprKind::LogicalOp { .. } => {
+                self.error(GenericConstantTooComplexSub::LogicalOpNotSupported(node.span))?
+            }
             ExprKind::Assign { .. } | ExprKind::AssignOp { .. } => {
-                self.error(node.span, "assignment is not supported in generic constants")?
+                self.error(GenericConstantTooComplexSub::AssignNotSupported(node.span))?
+            }
+            ExprKind::Closure { .. } | ExprKind::Return { .. } => {
+                self.error(GenericConstantTooComplexSub::ClosureAndReturnNotSupported(node.span))?
             }
-            ExprKind::Closure { .. } | ExprKind::Return { .. } => self.error(
-                node.span,
-                "closures and function keywords are not supported in generic constants",
-            )?,
             // let expressions imply control flow
-            ExprKind::Match { .. } | ExprKind::If { .. } | ExprKind::Let { .. } =>
-                self.error(node.span, "control flow is not supported in generic constants")?,
+            ExprKind::Match { .. } | ExprKind::If { .. } | ExprKind::Let { .. } => {
+                self.error(GenericConstantTooComplexSub::ControlFlowNotSupported(node.span))?
+            }
             ExprKind::InlineAsm { .. } => {
-                self.error(node.span, "assembly is not supported in generic constants")?
+                self.error(GenericConstantTooComplexSub::InlineAsmNotSupported(node.span))?
             }
 
             // we dont permit let stmts so `VarRef` and `UpvarRef` cant happen
@@ -415,7 +400,7 @@ impl<'a, 'tcx> AbstractConstBuilder<'a, 'tcx> {
             | ExprKind::UpvarRef { .. }
             | ExprKind::StaticRef { .. }
             | ExprKind::ThreadLocalRef(_) => {
-                self.error(node.span, "unsupported operation in generic constant")?
+                self.error(GenericConstantTooComplexSub::OperationNotSupported(node.span))?
             }
         })
     }
diff --git a/compiler/rustc_ty_utils/src/errors.rs b/compiler/rustc_ty_utils/src/errors.rs
new file mode 100644
index 000000000..3a8ef96c9
--- /dev/null
+++ b/compiler/rustc_ty_utils/src/errors.rs
@@ -0,0 +1,69 @@
+//! Errors emitted by ty_utils
+
+use rustc_macros::{SessionDiagnostic, SessionSubdiagnostic};
+use rustc_middle::ty::Ty;
+use rustc_span::Span;
+
+#[derive(SessionDiagnostic)]
+#[diag(ty_utils::needs_drop_overflow)]
+pub struct NeedsDropOverflow<'tcx> {
+    pub query_ty: Ty<'tcx>,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(ty_utils::generic_constant_too_complex)]
+#[help]
+pub struct GenericConstantTooComplex {
+    #[primary_span]
+    pub span: Span,
+    #[note(ty_utils::maybe_supported)]
+    pub maybe_supported: Option<()>,
+    #[subdiagnostic]
+    pub sub: GenericConstantTooComplexSub,
+}
+
+#[derive(SessionSubdiagnostic)]
+pub enum GenericConstantTooComplexSub {
+    #[label(ty_utils::borrow_not_supported)]
+    BorrowNotSupported(#[primary_span] Span),
+    #[label(ty_utils::address_and_deref_not_supported)]
+    AddressAndDerefNotSupported(#[primary_span] Span),
+    #[label(ty_utils::array_not_supported)]
+    ArrayNotSupported(#[primary_span] Span),
+    #[label(ty_utils::block_not_supported)]
+    BlockNotSupported(#[primary_span] Span),
+    #[label(ty_utils::never_to_any_not_supported)]
+    NeverToAnyNotSupported(#[primary_span] Span),
+    #[label(ty_utils::tuple_not_supported)]
+    TupleNotSupported(#[primary_span] Span),
+    #[label(ty_utils::index_not_supported)]
+    IndexNotSupported(#[primary_span] Span),
+    #[label(ty_utils::field_not_supported)]
+    FieldNotSupported(#[primary_span] Span),
+    #[label(ty_utils::const_block_not_supported)]
+    ConstBlockNotSupported(#[primary_span] Span),
+    #[label(ty_utils::adt_not_supported)]
+    AdtNotSupported(#[primary_span] Span),
+    #[label(ty_utils::pointer_not_supported)]
+    PointerNotSupported(#[primary_span] Span),
+    #[label(ty_utils::yield_not_supported)]
+    YieldNotSupported(#[primary_span] Span),
+    #[label(ty_utils::loop_not_supported)]
+    LoopNotSupported(#[primary_span] Span),
+    #[label(ty_utils::box_not_supported)]
+    BoxNotSupported(#[primary_span] Span),
+    #[label(ty_utils::binary_not_supported)]
+    BinaryNotSupported(#[primary_span] Span),
+    #[label(ty_utils::logical_op_not_supported)]
+    LogicalOpNotSupported(#[primary_span] Span),
+    #[label(ty_utils::assign_not_supported)]
+    AssignNotSupported(#[primary_span] Span),
+    #[label(ty_utils::closure_and_return_not_supported)]
+    ClosureAndReturnNotSupported(#[primary_span] Span),
+    #[label(ty_utils::control_flow_not_supported)]
+    ControlFlowNotSupported(#[primary_span] Span),
+    #[label(ty_utils::inline_asm_not_supported)]
+    InlineAsmNotSupported(#[primary_span] Span),
+    #[label(ty_utils::operation_not_supported)]
+    OperationNotSupported(#[primary_span] Span),
+}
diff --git a/compiler/rustc_ty_utils/src/implied_bounds.rs b/compiler/rustc_ty_utils/src/implied_bounds.rs
new file mode 100644
index 000000000..f0d8c240e
--- /dev/null
+++ b/compiler/rustc_ty_utils/src/implied_bounds.rs
@@ -0,0 +1,61 @@
+use crate::rustc_middle::ty::DefIdTree;
+use rustc_hir::{def::DefKind, def_id::DefId};
+use rustc_middle::ty::{self, Ty, TyCtxt};
+
+pub fn provide(providers: &mut ty::query::Providers) {
+    *providers = ty::query::Providers { assumed_wf_types, ..*providers };
+}
+
+fn assumed_wf_types<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> &'tcx ty::List<Ty<'tcx>> {
+    match tcx.def_kind(def_id) {
+        DefKind::Fn => {
+            let sig = tcx.fn_sig(def_id);
+            let liberated_sig = tcx.liberate_late_bound_regions(def_id, sig);
+            liberated_sig.inputs_and_output
+        }
+        DefKind::AssocFn => {
+            let sig = tcx.fn_sig(def_id);
+            let liberated_sig = tcx.liberate_late_bound_regions(def_id, sig);
+            let mut assumed_wf_types: Vec<_> =
+                tcx.assumed_wf_types(tcx.parent(def_id)).as_slice().into();
+            assumed_wf_types.extend(liberated_sig.inputs_and_output);
+            tcx.intern_type_list(&assumed_wf_types)
+        }
+        DefKind::Impl => match tcx.impl_trait_ref(def_id) {
+            Some(trait_ref) => {
+                let types: Vec<_> = trait_ref.substs.types().collect();
+                tcx.intern_type_list(&types)
+            }
+            // Only the impl self type
+            None => tcx.intern_type_list(&[tcx.type_of(def_id)]),
+        },
+        DefKind::AssocConst | DefKind::AssocTy => tcx.assumed_wf_types(tcx.parent(def_id)),
+        DefKind::Mod
+        | DefKind::Struct
+        | DefKind::Union
+        | DefKind::Enum
+        | DefKind::Variant
+        | DefKind::Trait
+        | DefKind::TyAlias
+        | DefKind::ForeignTy
+        | DefKind::TraitAlias
+        | DefKind::TyParam
+        | DefKind::Const
+        | DefKind::ConstParam
+        | DefKind::Static(_)
+        | DefKind::Ctor(_, _)
+        | DefKind::Macro(_)
+        | DefKind::ExternCrate
+        | DefKind::Use
+        | DefKind::ForeignMod
+        | DefKind::AnonConst
+        | DefKind::InlineConst
+        | DefKind::OpaqueTy
+        | DefKind::ImplTraitPlaceholder
+        | DefKind::Field
+        | DefKind::LifetimeParam
+        | DefKind::GlobalAsm
+        | DefKind::Closure
+        | DefKind::Generator => ty::List::empty(),
+    }
+}
diff --git a/compiler/rustc_ty_utils/src/instance.rs b/compiler/rustc_ty_utils/src/instance.rs
index bd1d568cd..05738b6c4 100644
--- a/compiler/rustc_ty_utils/src/instance.rs
+++ b/compiler/rustc_ty_utils/src/instance.rs
@@ -3,115 +3,11 @@ use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_infer::infer::TyCtxtInferExt;
 use rustc_middle::traits::CodegenObligationError;
 use rustc_middle::ty::subst::SubstsRef;
-use rustc_middle::ty::{
-    self, Binder, Instance, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitor,
-};
+use rustc_middle::ty::{self, Instance, TyCtxt, TypeVisitable};
 use rustc_span::{sym, DUMMY_SP};
 use rustc_trait_selection::traits;
 use traits::{translate_substs, Reveal};
 
-use rustc_data_structures::sso::SsoHashSet;
-use std::collections::btree_map::Entry;
-use std::collections::BTreeMap;
-use std::ops::ControlFlow;
-
-use tracing::debug;
-
-// FIXME(#86795): `BoundVarsCollector` here should **NOT** be used
-// outside of `resolve_associated_item`. It's just to address #64494,
-// #83765, and #85848 which are creating bound types/regions that lose
-// their `Binder` *unintentionally*.
-// It's ideal to remove `BoundVarsCollector` and just use
-// `ty::Binder::*` methods but we use this stopgap until we figure out
-// the "real" fix.
-struct BoundVarsCollector<'tcx> {
-    binder_index: ty::DebruijnIndex,
-    vars: BTreeMap<u32, ty::BoundVariableKind>,
-    // We may encounter the same variable at different levels of binding, so
-    // this can't just be `Ty`
-    visited: SsoHashSet<(ty::DebruijnIndex, Ty<'tcx>)>,
-}
-
-impl<'tcx> BoundVarsCollector<'tcx> {
-    fn new() -> Self {
-        BoundVarsCollector {
-            binder_index: ty::INNERMOST,
-            vars: BTreeMap::new(),
-            visited: SsoHashSet::default(),
-        }
-    }
-
-    fn into_vars(self, tcx: TyCtxt<'tcx>) -> &'tcx ty::List<ty::BoundVariableKind> {
-        let max = self.vars.iter().map(|(k, _)| *k).max().unwrap_or(0);
-        for i in 0..max {
-            if let None = self.vars.get(&i) {
-                panic!("Unknown variable: {:?}", i);
-            }
-        }
-
-        tcx.mk_bound_variable_kinds(self.vars.into_iter().map(|(_, v)| v))
-    }
-}
-
-impl<'tcx> TypeVisitor<'tcx> for BoundVarsCollector<'tcx> {
-    type BreakTy = ();
-
-    fn visit_binder<T: TypeVisitable<'tcx>>(
-        &mut self,
-        t: &Binder<'tcx, T>,
-    ) -> ControlFlow<Self::BreakTy> {
-        self.binder_index.shift_in(1);
-        let result = t.super_visit_with(self);
-        self.binder_index.shift_out(1);
-        result
-    }
-
-    fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
-        if t.outer_exclusive_binder() < self.binder_index
-            || !self.visited.insert((self.binder_index, t))
-        {
-            return ControlFlow::CONTINUE;
-        }
-        match *t.kind() {
-            ty::Bound(debruijn, bound_ty) if debruijn == self.binder_index => {
-                match self.vars.entry(bound_ty.var.as_u32()) {
-                    Entry::Vacant(entry) => {
-                        entry.insert(ty::BoundVariableKind::Ty(bound_ty.kind));
-                    }
-                    Entry::Occupied(entry) => match entry.get() {
-                        ty::BoundVariableKind::Ty(_) => {}
-                        _ => bug!("Conflicting bound vars"),
-                    },
-                }
-            }
-
-            _ => (),
-        };
-
-        t.super_visit_with(self)
-    }
-
-    fn visit_region(&mut self, r: ty::Region<'tcx>) -> ControlFlow<Self::BreakTy> {
-        match *r {
-            ty::ReLateBound(index, br) if index == self.binder_index => {
-                match self.vars.entry(br.var.as_u32()) {
-                    Entry::Vacant(entry) => {
-                        entry.insert(ty::BoundVariableKind::Region(br.kind));
-                    }
-                    Entry::Occupied(entry) => match entry.get() {
-                        ty::BoundVariableKind::Region(_) => {}
-                        _ => bug!("Conflicting bound vars"),
-                    },
-                }
-            }
-
-            _ => (),
-        };
-
-        r.super_visit_with(self)
-    }
-}
-
 fn resolve_instance<'tcx>(
     tcx: TyCtxt<'tcx>,
     key: ty::ParamEnvAnd<'tcx, (DefId, SubstsRef<'tcx>)>,
@@ -203,19 +99,14 @@ fn resolve_associated_item<'tcx>(
 
     let trait_ref = ty::TraitRef::from_method(tcx, trait_id, rcvr_substs);
 
-    // See FIXME on `BoundVarsCollector`.
-    let mut bound_vars_collector = BoundVarsCollector::new();
-    trait_ref.visit_with(&mut bound_vars_collector);
-    let trait_binder = ty::Binder::bind_with_vars(trait_ref, bound_vars_collector.into_vars(tcx));
-    let vtbl = match tcx.codegen_fulfill_obligation((param_env, trait_binder)) {
+    let vtbl = match tcx.codegen_select_candidate((param_env, ty::Binder::dummy(trait_ref))) {
         Ok(vtbl) => vtbl,
         Err(CodegenObligationError::Ambiguity) => {
             let reported = tcx.sess.delay_span_bug(
                 tcx.def_span(trait_item_id),
                 &format!(
-                    "encountered ambiguity selecting `{:?}` during codegen, presuming due to \
+                    "encountered ambiguity selecting `{trait_ref:?}` during codegen, presuming due to \
                      overflow or prior type error",
-                    trait_binder
                 ),
             );
             return Err(reported);
@@ -372,7 +263,10 @@ fn resolve_associated_item<'tcx>(
                     let is_copy = self_ty.is_copy_modulo_regions(tcx.at(DUMMY_SP), param_env);
                     match self_ty.kind() {
                         _ if is_copy => (),
-                        ty::Closure(..) | ty::Tuple(..) => {}
+                        ty::Generator(..)
+                        | ty::GeneratorWitness(..)
+                        | ty::Closure(..)
+                        | ty::Tuple(..) => {}
                         _ => return Ok(None),
                     };
 
@@ -397,7 +291,8 @@ fn resolve_associated_item<'tcx>(
         | traits::ImplSource::DiscriminantKind(..)
         | traits::ImplSource::Pointee(..)
         | traits::ImplSource::TraitUpcasting(_)
-        | traits::ImplSource::ConstDestruct(_) => None,
+        | traits::ImplSource::ConstDestruct(_)
+        | traits::ImplSource::Tuple => None,
     })
 }
 
diff --git a/compiler/rustc_ty_utils/src/lib.rs b/compiler/rustc_ty_utils/src/lib.rs
index 09f5c2a11..8524e57cb 100644
--- a/compiler/rustc_ty_utils/src/lib.rs
+++ b/compiler/rustc_ty_utils/src/lib.rs
@@ -6,10 +6,12 @@
 
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(control_flow_enum)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(never_type)]
 #![feature(box_patterns)]
 #![recursion_limit = "256"]
+#![deny(rustc::untranslatable_diagnostic)]
+#![deny(rustc::diagnostic_outside_of_impl)]
 
 #[macro_use]
 extern crate rustc_middle;
@@ -21,6 +23,8 @@ use rustc_middle::ty::query::Providers;
 mod assoc;
 mod common_traits;
 mod consts;
+mod errors;
+mod implied_bounds;
 pub mod instance;
 mod needs_drop;
 pub mod representability;
@@ -30,6 +34,7 @@ pub fn provide(providers: &mut Providers) {
     assoc::provide(providers);
     common_traits::provide(providers);
     consts::provide(providers);
+    implied_bounds::provide(providers);
     needs_drop::provide(providers);
     ty::provide(providers);
     instance::provide(providers);
diff --git a/compiler/rustc_ty_utils/src/needs_drop.rs b/compiler/rustc_ty_utils/src/needs_drop.rs
index 9ad44d14d..ab5a3d8ae 100644
--- a/compiler/rustc_ty_utils/src/needs_drop.rs
+++ b/compiler/rustc_ty_utils/src/needs_drop.rs
@@ -9,6 +9,8 @@ use rustc_middle::ty::{self, EarlyBinder, Ty, TyCtxt};
 use rustc_session::Limit;
 use rustc_span::{sym, DUMMY_SP};
 
+use crate::errors::NeedsDropOverflow;
+
 type NeedsDropResult<T> = Result<T, AlwaysRequiresDrop>;
 
 fn needs_drop_raw<'tcx>(tcx: TyCtxt<'tcx>, query: ty::ParamEnvAnd<'tcx, Ty<'tcx>>) -> bool {
@@ -90,10 +92,7 @@ where
             if !self.recursion_limit.value_within_limit(level) {
                 // Not having a `Span` isn't great. But there's hopefully some other
                 // recursion limit error as well.
-                tcx.sess.span_err(
-                    DUMMY_SP,
-                    &format!("overflow while checking whether `{}` requires drop", self.query_ty),
-                );
+                tcx.sess.emit_err(NeedsDropOverflow { query_ty: self.query_ty });
                 return Some(Err(AlwaysRequiresDrop));
             }
 
diff --git a/compiler/rustc_ty_utils/src/ty.rs b/compiler/rustc_ty_utils/src/ty.rs
index db0d45b86..9266e4e3f 100644
--- a/compiler/rustc_ty_utils/src/ty.rs
+++ b/compiler/rustc_ty_utils/src/ty.rs
@@ -104,7 +104,6 @@ fn adt_sized_constraint(tcx: TyCtxt<'_>, def_id: DefId) -> ty::AdtSizedConstrain
 }
 
 /// See `ParamEnv` struct definition for details.
-#[instrument(level = "debug", skip(tcx))]
 fn param_env(tcx: TyCtxt<'_>, def_id: DefId) -> ty::ParamEnv<'_> {
     // The param_env of an impl Trait type is its defining function's param_env
     if let Some(parent) = ty::is_impl_trait_defn(tcx, def_id) {
@@ -348,7 +347,7 @@ fn instance_def_size_estimate<'tcx>(
     match instance_def {
         InstanceDef::Item(..) | InstanceDef::DropGlue(..) => {
             let mir = tcx.instance_mir(instance_def);
-            mir.basic_blocks().iter().map(|bb| bb.statements.len() + 1).sum()
+            mir.basic_blocks.iter().map(|bb| bb.statements.len() + 1).sum()
         }
         // Estimate the size of other compiler-generated shims to be 1.
         _ => 1,
@@ -390,7 +389,7 @@ fn issue33140_self_ty(tcx: TyCtxt<'_>, def_id: DefId) -> Option<Ty<'_>> {
 
     let self_ty = trait_ref.self_ty();
     let self_ty_matches = match self_ty.kind() {
-        ty::Dynamic(ref data, re) if re.is_static() => data.principal().is_none(),
+        ty::Dynamic(ref data, re, _) if re.is_static() => data.principal().is_none(),
         _ => false,
     };
 
@@ -410,7 +409,6 @@ fn asyncness(tcx: TyCtxt<'_>, def_id: DefId) -> hir::IsAsync {
 }
 
 /// Don't call this directly: use ``tcx.conservative_is_privately_uninhabited`` instead.
-#[instrument(level = "debug", skip(tcx))]
 pub fn conservative_is_privately_uninhabited_raw<'tcx>(
     tcx: TyCtxt<'tcx>,
     param_env_and: ty::ParamEnvAnd<'tcx, Ty<'tcx>>,