Merging upstream version 1.72.1+dfsg1.

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

9 files changed, 261 insertions, 671 deletions

diff --git a/compiler/rustc_middle/src/traits/chalk.rs b/compiler/rustc_middle/src/traits/chalk.rs
deleted file mode 100644
index fcc8f457a..000000000
--- a/compiler/rustc_middle/src/traits/chalk.rs
+++ /dev/null
@@ -1,396 +0,0 @@
-//! Types required for Chalk-related queries
-//!
-//! The primary purpose of this file is defining an implementation for the
-//! `chalk_ir::interner::Interner` trait. The primary purpose of this trait, as
-//! its name suggest, is to provide an abstraction boundary for creating
-//! interned Chalk types.
-
-use rustc_middle::ty::{self, AdtDef, TyCtxt};
-
-use rustc_hir::def_id::DefId;
-use rustc_target::spec::abi::Abi;
-
-use std::cmp::Ordering;
-use std::fmt;
-use std::hash::{Hash, Hasher};
-
-#[derive(Copy, Clone)]
-pub struct RustInterner<'tcx> {
-    pub tcx: TyCtxt<'tcx>,
-}
-
-/// We don't ever actually need this. It's only required for derives.
-impl<'tcx> Hash for RustInterner<'tcx> {
-    fn hash<H: Hasher>(&self, _state: &mut H) {}
-}
-
-/// We don't ever actually need this. It's only required for derives.
-impl<'tcx> Ord for RustInterner<'tcx> {
-    fn cmp(&self, _other: &Self) -> Ordering {
-        Ordering::Equal
-    }
-}
-
-/// We don't ever actually need this. It's only required for derives.
-impl<'tcx> PartialOrd for RustInterner<'tcx> {
-    fn partial_cmp(&self, _other: &Self) -> Option<Ordering> {
-        None
-    }
-}
-
-/// We don't ever actually need this. It's only required for derives.
-impl<'tcx> PartialEq for RustInterner<'tcx> {
-    fn eq(&self, _other: &Self) -> bool {
-        false
-    }
-}
-
-/// We don't ever actually need this. It's only required for derives.
-impl<'tcx> Eq for RustInterner<'tcx> {}
-
-impl fmt::Debug for RustInterner<'_> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "RustInterner")
-    }
-}
-
-// Right now, there is no interning at all. I was running into problems with
-// adding interning in `ty/context.rs` for Chalk types with
-// `parallel-compiler = true`. -jackh726
-impl<'tcx> chalk_ir::interner::Interner for RustInterner<'tcx> {
-    type InternedType = Box<chalk_ir::TyData<Self>>;
-    type InternedLifetime = Box<chalk_ir::LifetimeData<Self>>;
-    type InternedConst = Box<chalk_ir::ConstData<Self>>;
-    type InternedConcreteConst = ty::ValTree<'tcx>;
-    type InternedGenericArg = Box<chalk_ir::GenericArgData<Self>>;
-    type InternedGoal = Box<chalk_ir::GoalData<Self>>;
-    type InternedGoals = Vec<chalk_ir::Goal<Self>>;
-    type InternedSubstitution = Vec<chalk_ir::GenericArg<Self>>;
-    type InternedProgramClause = Box<chalk_ir::ProgramClauseData<Self>>;
-    type InternedProgramClauses = Vec<chalk_ir::ProgramClause<Self>>;
-    type InternedQuantifiedWhereClauses = Vec<chalk_ir::QuantifiedWhereClause<Self>>;
-    type InternedVariableKinds = Vec<chalk_ir::VariableKind<Self>>;
-    type InternedCanonicalVarKinds = Vec<chalk_ir::CanonicalVarKind<Self>>;
-    type InternedVariances = Vec<chalk_ir::Variance>;
-    type InternedConstraints = Vec<chalk_ir::InEnvironment<chalk_ir::Constraint<Self>>>;
-    type DefId = DefId;
-    type InternedAdtId = AdtDef<'tcx>;
-    type Identifier = ();
-    type FnAbi = Abi;
-
-    fn debug_program_clause_implication(
-        pci: &chalk_ir::ProgramClauseImplication<Self>,
-        fmt: &mut fmt::Formatter<'_>,
-    ) -> Option<fmt::Result> {
-        let mut write = || {
-            write!(fmt, "{:?}", pci.consequence)?;
-
-            let conditions = pci.conditions.interned();
-            let constraints = pci.constraints.interned();
-
-            let conds = conditions.len();
-            let consts = constraints.len();
-            if conds == 0 && consts == 0 {
-                return Ok(());
-            }
-
-            write!(fmt, " :- ")?;
-
-            if conds != 0 {
-                for cond in &conditions[..conds - 1] {
-                    write!(fmt, "{:?}, ", cond)?;
-                }
-                write!(fmt, "{:?}", conditions[conds - 1])?;
-            }
-
-            if conds != 0 && consts != 0 {
-                write!(fmt, " ; ")?;
-            }
-
-            if consts != 0 {
-                for constraint in &constraints[..consts - 1] {
-                    write!(fmt, "{:?}, ", constraint)?;
-                }
-                write!(fmt, "{:?}", constraints[consts - 1])?;
-            }
-
-            Ok(())
-        };
-        Some(write())
-    }
-
-    fn debug_substitution(
-        substitution: &chalk_ir::Substitution<Self>,
-        fmt: &mut fmt::Formatter<'_>,
-    ) -> Option<fmt::Result> {
-        Some(write!(fmt, "{:?}", substitution.interned()))
-    }
-
-    fn debug_separator_trait_ref(
-        separator_trait_ref: &chalk_ir::SeparatorTraitRef<'_, Self>,
-        fmt: &mut fmt::Formatter<'_>,
-    ) -> Option<fmt::Result> {
-        let substitution = &separator_trait_ref.trait_ref.substitution;
-        let parameters = substitution.interned();
-        Some(write!(
-            fmt,
-            "{:?}{}{:?}{:?}",
-            parameters[0],
-            separator_trait_ref.separator,
-            separator_trait_ref.trait_ref.trait_id,
-            chalk_ir::debug::Angle(&parameters[1..])
-        ))
-    }
-
-    fn debug_quantified_where_clauses(
-        clauses: &chalk_ir::QuantifiedWhereClauses<Self>,
-        fmt: &mut fmt::Formatter<'_>,
-    ) -> Option<fmt::Result> {
-        Some(write!(fmt, "{:?}", clauses.interned()))
-    }
-
-    fn debug_ty(ty: &chalk_ir::Ty<Self>, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
-        match &ty.interned().kind {
-            chalk_ir::TyKind::Ref(chalk_ir::Mutability::Not, lifetime, ty) => {
-                Some(write!(fmt, "(&{:?} {:?})", lifetime, ty))
-            }
-            chalk_ir::TyKind::Ref(chalk_ir::Mutability::Mut, lifetime, ty) => {
-                Some(write!(fmt, "(&{:?} mut {:?})", lifetime, ty))
-            }
-            chalk_ir::TyKind::Array(ty, len) => Some(write!(fmt, "[{:?}; {:?}]", ty, len)),
-            chalk_ir::TyKind::Slice(ty) => Some(write!(fmt, "[{:?}]", ty)),
-            chalk_ir::TyKind::Tuple(len, substs) => Some(
-                try {
-                    write!(fmt, "(")?;
-                    for (idx, substitution) in substs.interned().iter().enumerate() {
-                        if idx == *len && *len != 1 {
-                            // Don't add a trailing comma if the tuple has more than one element
-                            write!(fmt, "{:?}", substitution)?;
-                        } else {
-                            write!(fmt, "{:?},", substitution)?;
-                        }
-                    }
-                    write!(fmt, ")")?;
-                },
-            ),
-            _ => None,
-        }
-    }
-
-    fn debug_alias(
-        alias_ty: &chalk_ir::AliasTy<Self>,
-        fmt: &mut fmt::Formatter<'_>,
-    ) -> Option<fmt::Result> {
-        match alias_ty {
-            chalk_ir::AliasTy::Projection(projection_ty) => {
-                Self::debug_projection_ty(projection_ty, fmt)
-            }
-            chalk_ir::AliasTy::Opaque(opaque_ty) => Self::debug_opaque_ty(opaque_ty, fmt),
-        }
-    }
-
-    fn debug_projection_ty(
-        projection_ty: &chalk_ir::ProjectionTy<Self>,
-        fmt: &mut fmt::Formatter<'_>,
-    ) -> Option<fmt::Result> {
-        Some(write!(
-            fmt,
-            "projection: {:?} {:?}",
-            projection_ty.associated_ty_id, projection_ty.substitution,
-        ))
-    }
-
-    fn debug_opaque_ty(
-        opaque_ty: &chalk_ir::OpaqueTy<Self>,
-        fmt: &mut fmt::Formatter<'_>,
-    ) -> Option<fmt::Result> {
-        Some(write!(fmt, "{:?}", opaque_ty.opaque_ty_id))
-    }
-
-    fn intern_ty(self, ty: chalk_ir::TyKind<Self>) -> Self::InternedType {
-        let flags = ty.compute_flags(self);
-        Box::new(chalk_ir::TyData { kind: ty, flags: flags })
-    }
-
-    fn ty_data(self, ty: &Self::InternedType) -> &chalk_ir::TyData<Self> {
-        ty
-    }
-
-    fn intern_lifetime(self, lifetime: chalk_ir::LifetimeData<Self>) -> Self::InternedLifetime {
-        Box::new(lifetime)
-    }
-
-    fn lifetime_data(self, lifetime: &Self::InternedLifetime) -> &chalk_ir::LifetimeData<Self> {
-        &lifetime
-    }
-
-    fn intern_const(self, constant: chalk_ir::ConstData<Self>) -> Self::InternedConst {
-        Box::new(constant)
-    }
-
-    fn const_data(self, constant: &Self::InternedConst) -> &chalk_ir::ConstData<Self> {
-        &constant
-    }
-
-    fn const_eq(
-        self,
-        _ty: &Self::InternedType,
-        c1: &Self::InternedConcreteConst,
-        c2: &Self::InternedConcreteConst,
-    ) -> bool {
-        c1 == c2
-    }
-
-    fn intern_generic_arg(self, data: chalk_ir::GenericArgData<Self>) -> Self::InternedGenericArg {
-        Box::new(data)
-    }
-
-    fn generic_arg_data(self, data: &Self::InternedGenericArg) -> &chalk_ir::GenericArgData<Self> {
-        &data
-    }
-
-    fn intern_goal(self, goal: chalk_ir::GoalData<Self>) -> Self::InternedGoal {
-        Box::new(goal)
-    }
-
-    fn goal_data(self, goal: &Self::InternedGoal) -> &chalk_ir::GoalData<Self> {
-        &goal
-    }
-
-    fn intern_goals<E>(
-        self,
-        data: impl IntoIterator<Item = Result<chalk_ir::Goal<Self>, E>>,
-    ) -> Result<Self::InternedGoals, E> {
-        data.into_iter().collect::<Result<Vec<_>, _>>()
-    }
-
-    fn goals_data(self, goals: &Self::InternedGoals) -> &[chalk_ir::Goal<Self>] {
-        goals
-    }
-
-    fn intern_substitution<E>(
-        self,
-        data: impl IntoIterator<Item = Result<chalk_ir::GenericArg<Self>, E>>,
-    ) -> Result<Self::InternedSubstitution, E> {
-        data.into_iter().collect::<Result<Vec<_>, _>>()
-    }
-
-    fn substitution_data(
-        self,
-        substitution: &Self::InternedSubstitution,
-    ) -> &[chalk_ir::GenericArg<Self>] {
-        substitution
-    }
-
-    fn intern_program_clause(
-        self,
-        data: chalk_ir::ProgramClauseData<Self>,
-    ) -> Self::InternedProgramClause {
-        Box::new(data)
-    }
-
-    fn program_clause_data(
-        self,
-        clause: &Self::InternedProgramClause,
-    ) -> &chalk_ir::ProgramClauseData<Self> {
-        &clause
-    }
-
-    fn intern_program_clauses<E>(
-        self,
-        data: impl IntoIterator<Item = Result<chalk_ir::ProgramClause<Self>, E>>,
-    ) -> Result<Self::InternedProgramClauses, E> {
-        data.into_iter().collect::<Result<Vec<_>, _>>()
-    }
-
-    fn program_clauses_data(
-        self,
-        clauses: &Self::InternedProgramClauses,
-    ) -> &[chalk_ir::ProgramClause<Self>] {
-        clauses
-    }
-
-    fn intern_quantified_where_clauses<E>(
-        self,
-        data: impl IntoIterator<Item = Result<chalk_ir::QuantifiedWhereClause<Self>, E>>,
-    ) -> Result<Self::InternedQuantifiedWhereClauses, E> {
-        data.into_iter().collect::<Result<Vec<_>, _>>()
-    }
-
-    fn quantified_where_clauses_data(
-        self,
-        clauses: &Self::InternedQuantifiedWhereClauses,
-    ) -> &[chalk_ir::QuantifiedWhereClause<Self>] {
-        clauses
-    }
-
-    fn intern_generic_arg_kinds<E>(
-        self,
-        data: impl IntoIterator<Item = Result<chalk_ir::VariableKind<Self>, E>>,
-    ) -> Result<Self::InternedVariableKinds, E> {
-        data.into_iter().collect::<Result<Vec<_>, _>>()
-    }
-
-    fn variable_kinds_data(
-        self,
-        parameter_kinds: &Self::InternedVariableKinds,
-    ) -> &[chalk_ir::VariableKind<Self>] {
-        parameter_kinds
-    }
-
-    fn intern_canonical_var_kinds<E>(
-        self,
-        data: impl IntoIterator<Item = Result<chalk_ir::CanonicalVarKind<Self>, E>>,
-    ) -> Result<Self::InternedCanonicalVarKinds, E> {
-        data.into_iter().collect::<Result<Vec<_>, _>>()
-    }
-
-    fn canonical_var_kinds_data(
-        self,
-        canonical_var_kinds: &Self::InternedCanonicalVarKinds,
-    ) -> &[chalk_ir::CanonicalVarKind<Self>] {
-        canonical_var_kinds
-    }
-
-    fn intern_constraints<E>(
-        self,
-        data: impl IntoIterator<Item = Result<chalk_ir::InEnvironment<chalk_ir::Constraint<Self>>, E>>,
-    ) -> Result<Self::InternedConstraints, E> {
-        data.into_iter().collect::<Result<Vec<_>, _>>()
-    }
-
-    fn constraints_data(
-        self,
-        constraints: &Self::InternedConstraints,
-    ) -> &[chalk_ir::InEnvironment<chalk_ir::Constraint<Self>>] {
-        constraints
-    }
-
-    fn intern_variances<E>(
-        self,
-        data: impl IntoIterator<Item = Result<chalk_ir::Variance, E>>,
-    ) -> Result<Self::InternedVariances, E> {
-        data.into_iter().collect::<Result<Vec<_>, _>>()
-    }
-
-    fn variances_data(self, variances: &Self::InternedVariances) -> &[chalk_ir::Variance] {
-        variances
-    }
-}
-
-impl<'tcx> chalk_ir::interner::HasInterner for RustInterner<'tcx> {
-    type Interner = Self;
-}
-
-/// A chalk environment and goal.
-#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, HashStable, TypeFoldable, TypeVisitable)]
-pub struct ChalkEnvironmentAndGoal<'tcx> {
-    pub environment: &'tcx ty::List<ty::Predicate<'tcx>>,
-    pub goal: ty::Predicate<'tcx>,
-}
-
-impl<'tcx> fmt::Display for ChalkEnvironmentAndGoal<'tcx> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "environment: {:?}, goal: {}", self.environment, self.goal)
-    }
-}
diff --git a/compiler/rustc_middle/src/traits/mod.rs b/compiler/rustc_middle/src/traits/mod.rs
index 0a903a769..c7d2e4c22 100644
--- a/compiler/rustc_middle/src/traits/mod.rs
+++ b/compiler/rustc_middle/src/traits/mod.rs
@@ -2,7 +2,6 @@
 //!
 //! [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/traits/resolution.html
 
-mod chalk;
 pub mod query;
 pub mod select;
 pub mod solve;
@@ -30,12 +29,8 @@ use std::hash::{Hash, Hasher};
 
 pub use self::select::{EvaluationCache, EvaluationResult, OverflowError, SelectionCache};
 
-pub type CanonicalChalkEnvironmentAndGoal<'tcx> = Canonical<'tcx, ChalkEnvironmentAndGoal<'tcx>>;
-
 pub use self::ObligationCauseCode::*;
 
-pub use self::chalk::{ChalkEnvironmentAndGoal, RustInterner as ChalkRustInterner};
-
 /// Depending on the stage of compilation, we want projection to be
 /// more or less conservative.
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash, HashStable, Encodable, Decodable)]
@@ -445,6 +440,12 @@ pub enum ObligationCauseCode<'tcx> {
     /// Obligations to prove that a `std::ops::Drop` impl is not stronger than
     /// the ADT it's being implemented for.
     DropImpl,
+
+    /// Requirement for a `const N: Ty` to implement `Ty: ConstParamTy`
+    ConstParam(Ty<'tcx>),
+
+    /// Obligations emitted during the normalization of a weak type alias.
+    TypeAlias(InternedObligationCauseCode<'tcx>, Span, DefId),
 }
 
 /// The 'location' at which we try to perform HIR-based wf checking.
@@ -587,6 +588,10 @@ pub enum SelectionError<'tcx> {
     /// Signaling that an error has already been emitted, to avoid
     /// multiple errors being shown.
     ErrorReporting,
+    /// Computing an opaque type's hidden type caused an error (e.g. a cycle error).
+    /// We can thus not know whether the hidden type implements an auto trait, so
+    /// we should not presume anything about it.
+    OpaqueTypeAutoTraitLeakageUnknown(DefId),
 }
 
 #[derive(Clone, Debug, TypeVisitable, Lift)]
@@ -640,12 +645,6 @@ pub enum ImplSource<'tcx, N> {
     /// ImplSource identifying a particular impl.
     UserDefined(ImplSourceUserDefinedData<'tcx, N>),
 
-    /// ImplSource for auto trait implementations.
-    /// This carries the information and nested obligations with regards
-    /// to an auto implementation for a trait `Trait`. The nested obligations
-    /// ensure the trait implementation holds for all the constituent types.
-    AutoImpl(ImplSourceAutoImplData<N>),
-
     /// Successful resolution to an obligation provided by the caller
     /// for some type parameter. The `Vec<N>` represents the
     /// obligations incurred from normalizing the where-clause (if
@@ -653,84 +652,40 @@ pub enum ImplSource<'tcx, N> {
     Param(Vec<N>, ty::BoundConstness),
 
     /// Virtual calls through an object.
-    Object(ImplSourceObjectData<'tcx, N>),
+    Object(ImplSourceObjectData<N>),
 
     /// Successful resolution for a builtin trait.
-    Builtin(ImplSourceBuiltinData<N>),
+    Builtin(Vec<N>),
 
     /// ImplSource for trait upcasting coercion
-    TraitUpcasting(ImplSourceTraitUpcastingData<'tcx, N>),
-
-    /// ImplSource automatically generated for a closure. The `DefId` is the ID
-    /// of the closure expression. This is an `ImplSource::UserDefined` in spirit, but the
-    /// impl is generated by the compiler and does not appear in the source.
-    Closure(ImplSourceClosureData<'tcx, N>),
-
-    /// Same as above, but for a function pointer type with the given signature.
-    FnPointer(ImplSourceFnPointerData<'tcx, N>),
-
-    /// ImplSource automatically generated for a generator.
-    Generator(ImplSourceGeneratorData<'tcx, N>),
-
-    /// ImplSource automatically generated for a generator backing an async future.
-    Future(ImplSourceFutureData<'tcx, N>),
-
-    /// ImplSource for a trait alias.
-    TraitAlias(ImplSourceTraitAliasData<'tcx, N>),
-
-    /// ImplSource for a `const Drop` implementation.
-    ConstDestruct(ImplSourceConstDestructData<N>),
+    TraitUpcasting(ImplSourceTraitUpcastingData<N>),
 }
 
 impl<'tcx, N> ImplSource<'tcx, N> {
     pub fn nested_obligations(self) -> Vec<N> {
         match self {
             ImplSource::UserDefined(i) => i.nested,
-            ImplSource::Param(n, _) => n,
-            ImplSource::Builtin(i) => i.nested,
-            ImplSource::AutoImpl(d) => d.nested,
-            ImplSource::Closure(c) => c.nested,
-            ImplSource::Generator(c) => c.nested,
-            ImplSource::Future(c) => c.nested,
+            ImplSource::Param(n, _) | ImplSource::Builtin(n) => n,
             ImplSource::Object(d) => d.nested,
-            ImplSource::FnPointer(d) => d.nested,
-            ImplSource::TraitAlias(d) => d.nested,
             ImplSource::TraitUpcasting(d) => d.nested,
-            ImplSource::ConstDestruct(i) => i.nested,
         }
     }
 
     pub fn borrow_nested_obligations(&self) -> &[N] {
         match self {
             ImplSource::UserDefined(i) => &i.nested,
-            ImplSource::Param(n, _) => n,
-            ImplSource::Builtin(i) => &i.nested,
-            ImplSource::AutoImpl(d) => &d.nested,
-            ImplSource::Closure(c) => &c.nested,
-            ImplSource::Generator(c) => &c.nested,
-            ImplSource::Future(c) => &c.nested,
+            ImplSource::Param(n, _) | ImplSource::Builtin(n) => &n,
             ImplSource::Object(d) => &d.nested,
-            ImplSource::FnPointer(d) => &d.nested,
-            ImplSource::TraitAlias(d) => &d.nested,
             ImplSource::TraitUpcasting(d) => &d.nested,
-            ImplSource::ConstDestruct(i) => &i.nested,
         }
     }
 
     pub fn borrow_nested_obligations_mut(&mut self) -> &mut [N] {
         match self {
             ImplSource::UserDefined(i) => &mut i.nested,
-            ImplSource::Param(n, _) => n,
-            ImplSource::Builtin(i) => &mut i.nested,
-            ImplSource::AutoImpl(d) => &mut d.nested,
-            ImplSource::Closure(c) => &mut c.nested,
-            ImplSource::Generator(c) => &mut c.nested,
-            ImplSource::Future(c) => &mut c.nested,
+            ImplSource::Param(n, _) | ImplSource::Builtin(n) => n,
             ImplSource::Object(d) => &mut d.nested,
-            ImplSource::FnPointer(d) => &mut d.nested,
-            ImplSource::TraitAlias(d) => &mut d.nested,
             ImplSource::TraitUpcasting(d) => &mut d.nested,
-            ImplSource::ConstDestruct(i) => &mut i.nested,
         }
     }
 
@@ -745,54 +700,17 @@ impl<'tcx, N> ImplSource<'tcx, N> {
                 nested: i.nested.into_iter().map(f).collect(),
             }),
             ImplSource::Param(n, ct) => ImplSource::Param(n.into_iter().map(f).collect(), ct),
-            ImplSource::Builtin(i) => ImplSource::Builtin(ImplSourceBuiltinData {
-                nested: i.nested.into_iter().map(f).collect(),
-            }),
+            ImplSource::Builtin(n) => ImplSource::Builtin(n.into_iter().map(f).collect()),
             ImplSource::Object(o) => ImplSource::Object(ImplSourceObjectData {
-                upcast_trait_ref: o.upcast_trait_ref,
                 vtable_base: o.vtable_base,
                 nested: o.nested.into_iter().map(f).collect(),
             }),
-            ImplSource::AutoImpl(d) => ImplSource::AutoImpl(ImplSourceAutoImplData {
-                trait_def_id: d.trait_def_id,
-                nested: d.nested.into_iter().map(f).collect(),
-            }),
-            ImplSource::Closure(c) => ImplSource::Closure(ImplSourceClosureData {
-                closure_def_id: c.closure_def_id,
-                substs: c.substs,
-                nested: c.nested.into_iter().map(f).collect(),
-            }),
-            ImplSource::Generator(c) => ImplSource::Generator(ImplSourceGeneratorData {
-                generator_def_id: c.generator_def_id,
-                substs: c.substs,
-                nested: c.nested.into_iter().map(f).collect(),
-            }),
-            ImplSource::Future(c) => ImplSource::Future(ImplSourceFutureData {
-                generator_def_id: c.generator_def_id,
-                substs: c.substs,
-                nested: c.nested.into_iter().map(f).collect(),
-            }),
-            ImplSource::FnPointer(p) => ImplSource::FnPointer(ImplSourceFnPointerData {
-                fn_ty: p.fn_ty,
-                nested: p.nested.into_iter().map(f).collect(),
-            }),
-            ImplSource::TraitAlias(d) => ImplSource::TraitAlias(ImplSourceTraitAliasData {
-                alias_def_id: d.alias_def_id,
-                substs: d.substs,
-                nested: d.nested.into_iter().map(f).collect(),
-            }),
             ImplSource::TraitUpcasting(d) => {
                 ImplSource::TraitUpcasting(ImplSourceTraitUpcastingData {
-                    upcast_trait_ref: d.upcast_trait_ref,
                     vtable_vptr_slot: d.vtable_vptr_slot,
                     nested: d.nested.into_iter().map(f).collect(),
                 })
             }
-            ImplSource::ConstDestruct(i) => {
-                ImplSource::ConstDestruct(ImplSourceConstDestructData {
-                    nested: i.nested.into_iter().map(f).collect(),
-                })
-            }
         }
     }
 }
@@ -817,47 +735,7 @@ pub struct ImplSourceUserDefinedData<'tcx, N> {
 
 #[derive(Clone, PartialEq, Eq, TyEncodable, TyDecodable, HashStable, Lift)]
 #[derive(TypeFoldable, TypeVisitable)]
-pub struct ImplSourceGeneratorData<'tcx, N> {
-    pub generator_def_id: DefId,
-    pub substs: SubstsRef<'tcx>,
-    /// Nested obligations. This can be non-empty if the generator
-    /// signature contains associated types.
-    pub nested: Vec<N>,
-}
-
-#[derive(Clone, PartialEq, Eq, TyEncodable, TyDecodable, HashStable, Lift)]
-#[derive(TypeFoldable, TypeVisitable)]
-pub struct ImplSourceFutureData<'tcx, N> {
-    pub generator_def_id: DefId,
-    pub substs: SubstsRef<'tcx>,
-    /// Nested obligations. This can be non-empty if the generator
-    /// signature contains associated types.
-    pub nested: Vec<N>,
-}
-
-#[derive(Clone, PartialEq, Eq, TyEncodable, TyDecodable, HashStable, Lift)]
-#[derive(TypeFoldable, TypeVisitable)]
-pub struct ImplSourceClosureData<'tcx, N> {
-    pub closure_def_id: DefId,
-    pub substs: SubstsRef<'tcx>,
-    /// Nested obligations. This can be non-empty if the closure
-    /// signature contains associated types.
-    pub nested: Vec<N>,
-}
-
-#[derive(Clone, PartialEq, Eq, TyEncodable, TyDecodable, HashStable, Lift)]
-#[derive(TypeFoldable, TypeVisitable)]
-pub struct ImplSourceAutoImplData<N> {
-    pub trait_def_id: DefId,
-    pub nested: Vec<N>,
-}
-
-#[derive(Clone, PartialEq, Eq, TyEncodable, TyDecodable, HashStable, Lift)]
-#[derive(TypeFoldable, TypeVisitable)]
-pub struct ImplSourceTraitUpcastingData<'tcx, N> {
-    /// `Foo` upcast to the obligation trait. This will be some supertrait of `Foo`.
-    pub upcast_trait_ref: ty::PolyTraitRef<'tcx>,
-
+pub struct ImplSourceTraitUpcastingData<N> {
     /// The vtable is formed by concatenating together the method lists of
     /// the base object trait and all supertraits, pointers to supertrait vtable will
     /// be provided when necessary; this is the position of `upcast_trait_ref`'s vtable
@@ -867,18 +745,9 @@ pub struct ImplSourceTraitUpcastingData<'tcx, N> {
     pub nested: Vec<N>,
 }
 
-#[derive(Clone, PartialEq, Eq, TyEncodable, TyDecodable, HashStable, Lift)]
-#[derive(TypeFoldable, TypeVisitable)]
-pub struct ImplSourceBuiltinData<N> {
-    pub nested: Vec<N>,
-}
-
 #[derive(PartialEq, Eq, Clone, TyEncodable, TyDecodable, HashStable, Lift)]
 #[derive(TypeFoldable, TypeVisitable)]
-pub struct ImplSourceObjectData<'tcx, N> {
-    /// `Foo` upcast to the obligation trait. This will be some supertrait of `Foo`.
-    pub upcast_trait_ref: ty::PolyTraitRef<'tcx>,
-
+pub struct ImplSourceObjectData<N> {
     /// The vtable is formed by concatenating together the method lists of
     /// the base object trait and all supertraits, pointers to supertrait vtable will
     /// be provided when necessary; this is the start of `upcast_trait_ref`'s methods
@@ -888,27 +757,6 @@ pub struct ImplSourceObjectData<'tcx, N> {
     pub nested: Vec<N>,
 }
 
-#[derive(Clone, PartialEq, Eq, TyEncodable, TyDecodable, HashStable, Lift)]
-#[derive(TypeFoldable, TypeVisitable)]
-pub struct ImplSourceFnPointerData<'tcx, N> {
-    pub fn_ty: Ty<'tcx>,
-    pub nested: Vec<N>,
-}
-
-#[derive(Clone, PartialEq, Eq, TyEncodable, TyDecodable, HashStable, Lift)]
-#[derive(TypeFoldable, TypeVisitable)]
-pub struct ImplSourceConstDestructData<N> {
-    pub nested: Vec<N>,
-}
-
-#[derive(Clone, PartialEq, Eq, TyEncodable, TyDecodable, HashStable, Lift)]
-#[derive(TypeFoldable, TypeVisitable)]
-pub struct ImplSourceTraitAliasData<'tcx, N> {
-    pub alias_def_id: DefId,
-    pub substs: SubstsRef<'tcx>,
-    pub nested: Vec<N>,
-}
-
 #[derive(Clone, Debug, PartialEq, Eq, Hash, HashStable, PartialOrd, Ord)]
 pub enum ObjectSafetyViolation {
     /// `Self: Sized` declared on the trait.
@@ -1109,7 +957,7 @@ pub enum CodegenObligationError {
     FulfillmentError,
 }
 
-#[derive(Debug, PartialEq, Eq, Clone, Copy, Hash, TypeFoldable, TypeVisitable)]
+#[derive(Debug, PartialEq, Eq, Clone, Copy, Hash, HashStable, TypeFoldable, TypeVisitable)]
 pub enum DefiningAnchor {
     /// `DefId` of the item.
     Bind(LocalDefId),
diff --git a/compiler/rustc_middle/src/traits/query.rs b/compiler/rustc_middle/src/traits/query.rs
index eae5a280e..60a38747f 100644
--- a/compiler/rustc_middle/src/traits/query.rs
+++ b/compiler/rustc_middle/src/traits/query.rs
@@ -92,7 +92,7 @@ pub type CanonicalTypeOpProvePredicateGoal<'tcx> =
 pub type CanonicalTypeOpNormalizeGoal<'tcx, T> =
     Canonical<'tcx, ty::ParamEnvAnd<'tcx, type_op::Normalize<T>>>;
 
-#[derive(Copy, Clone, Debug, HashStable, PartialEq, Eq)]
+#[derive(Copy, Clone, Debug, Hash, HashStable, PartialEq, Eq)]
 pub struct NoSolution;
 
 impl<'tcx> From<TypeError<'tcx>> for NoSolution {
diff --git a/compiler/rustc_middle/src/traits/solve.rs b/compiler/rustc_middle/src/traits/solve.rs
index 2c5b64a59..73b332fd8 100644
--- a/compiler/rustc_middle/src/traits/solve.rs
+++ b/compiler/rustc_middle/src/traits/solve.rs
@@ -11,6 +11,8 @@ use crate::ty::{
     TypeVisitor,
 };
 
+pub mod inspect;
+
 pub type EvaluationCache<'tcx> = Cache<CanonicalInput<'tcx>, QueryResult<'tcx>>;
 
 /// A goal is a statement, i.e. `predicate`, we want to prove
@@ -18,7 +20,7 @@ pub type EvaluationCache<'tcx> = Cache<CanonicalInput<'tcx>, QueryResult<'tcx>>;
 ///
 /// Most of the time the `param_env` contains the `where`-bounds of the function
 /// we're currently typechecking while the `predicate` is some trait bound.
-#[derive(Debug, PartialEq, Eq, Clone, Copy, Hash, TypeFoldable, TypeVisitable)]
+#[derive(Debug, PartialEq, Eq, Clone, Copy, Hash, HashStable, TypeFoldable, TypeVisitable)]
 pub struct Goal<'tcx, P> {
     pub predicate: P,
     pub param_env: ty::ParamEnv<'tcx>,
@@ -39,7 +41,7 @@ impl<'tcx, P> Goal<'tcx, P> {
     }
 }
 
-#[derive(Debug, PartialEq, Eq, Clone, Copy, Hash, TypeFoldable, TypeVisitable)]
+#[derive(Debug, PartialEq, Eq, Clone, Copy, Hash, HashStable, TypeFoldable, TypeVisitable)]
 pub struct Response<'tcx> {
     pub certainty: Certainty,
     pub var_values: CanonicalVarValues<'tcx>,
@@ -47,7 +49,7 @@ pub struct Response<'tcx> {
     pub external_constraints: ExternalConstraints<'tcx>,
 }
 
-#[derive(Debug, PartialEq, Eq, Clone, Copy, Hash, TypeFoldable, TypeVisitable)]
+#[derive(Debug, PartialEq, Eq, Clone, Copy, Hash, HashStable, TypeFoldable, TypeVisitable)]
 pub enum Certainty {
     Yes,
     Maybe(MaybeCause),
@@ -86,7 +88,7 @@ impl Certainty {
 }
 
 /// Why we failed to evaluate a goal.
-#[derive(Debug, PartialEq, Eq, Clone, Copy, Hash, TypeFoldable, TypeVisitable)]
+#[derive(Debug, PartialEq, Eq, Clone, Copy, Hash, HashStable, TypeFoldable, TypeVisitable)]
 pub enum MaybeCause {
     /// We failed due to ambiguity. This ambiguity can either
     /// be a true ambiguity, i.e. there are multiple different answers,
@@ -96,7 +98,7 @@ pub enum MaybeCause {
     Overflow,
 }
 
-#[derive(Debug, PartialEq, Eq, Clone, Copy, Hash, TypeFoldable, TypeVisitable)]
+#[derive(Debug, PartialEq, Eq, Clone, Copy, Hash, HashStable, TypeFoldable, TypeVisitable)]
 pub struct QueryInput<'tcx, T> {
     pub goal: Goal<'tcx, T>,
     pub anchor: DefiningAnchor,
@@ -104,12 +106,12 @@ pub struct QueryInput<'tcx, T> {
 }
 
 /// Additional constraints returned on success.
-#[derive(Debug, PartialEq, Eq, Clone, Hash, Default)]
+#[derive(Debug, PartialEq, Eq, Clone, Hash, HashStable, Default)]
 pub struct PredefinedOpaquesData<'tcx> {
     pub opaque_types: Vec<(ty::OpaqueTypeKey<'tcx>, Ty<'tcx>)>,
 }
 
-#[derive(Debug, PartialEq, Eq, Copy, Clone, Hash)]
+#[derive(Debug, PartialEq, Eq, Copy, Clone, Hash, HashStable)]
 pub struct PredefinedOpaques<'tcx>(pub(crate) Interned<'tcx, PredefinedOpaquesData<'tcx>>);
 
 impl<'tcx> std::ops::Deref for PredefinedOpaques<'tcx> {
@@ -132,7 +134,7 @@ pub type CanonicalResponse<'tcx> = Canonical<'tcx, Response<'tcx>>;
 /// solver, merge the two responses again.
 pub type QueryResult<'tcx> = Result<CanonicalResponse<'tcx>, NoSolution>;
 
-#[derive(Debug, PartialEq, Eq, Copy, Clone, Hash)]
+#[derive(Debug, PartialEq, Eq, Copy, Clone, Hash, HashStable)]
 pub struct ExternalConstraints<'tcx>(pub(crate) Interned<'tcx, ExternalConstraintsData<'tcx>>);
 
 impl<'tcx> std::ops::Deref for ExternalConstraints<'tcx> {
@@ -144,7 +146,7 @@ impl<'tcx> std::ops::Deref for ExternalConstraints<'tcx> {
 }
 
 /// Additional constraints returned on success.
-#[derive(Debug, PartialEq, Eq, Clone, Hash, Default)]
+#[derive(Debug, PartialEq, Eq, Clone, Hash, HashStable, Default)]
 pub struct ExternalConstraintsData<'tcx> {
     // FIXME: implement this.
     pub region_constraints: QueryRegionConstraints<'tcx>,
@@ -226,3 +228,9 @@ impl<'tcx> TypeVisitable<TyCtxt<'tcx>> for PredefinedOpaques<'tcx> {
         self.opaque_types.visit_with(visitor)
     }
 }
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash, HashStable)]
+pub enum IsNormalizesToHack {
+    Yes,
+    No,
+}
diff --git a/compiler/rustc_middle/src/traits/solve/inspect.rs b/compiler/rustc_middle/src/traits/solve/inspect.rs
new file mode 100644
index 000000000..527afa005
--- /dev/null
+++ b/compiler/rustc_middle/src/traits/solve/inspect.rs
@@ -0,0 +1,83 @@
+use super::{
+    CanonicalInput, Certainty, Goal, IsNormalizesToHack, NoSolution, QueryInput, QueryResult,
+};
+use crate::ty;
+use format::ProofTreeFormatter;
+use std::fmt::{Debug, Write};
+
+mod format;
+
+#[derive(Eq, PartialEq, Debug, Hash, HashStable)]
+pub enum CacheHit {
+    Provisional,
+    Global,
+}
+
+#[derive(Eq, PartialEq, Hash, HashStable)]
+pub struct GoalEvaluation<'tcx> {
+    pub uncanonicalized_goal: Goal<'tcx, ty::Predicate<'tcx>>,
+    pub canonicalized_goal: CanonicalInput<'tcx>,
+
+    pub kind: GoalEvaluationKind<'tcx>,
+    pub is_normalizes_to_hack: IsNormalizesToHack,
+    pub returned_goals: Vec<Goal<'tcx, ty::Predicate<'tcx>>>,
+
+    pub result: QueryResult<'tcx>,
+}
+
+#[derive(Eq, PartialEq, Hash, HashStable)]
+pub enum GoalEvaluationKind<'tcx> {
+    CacheHit(CacheHit),
+    Uncached { revisions: Vec<GoalEvaluationStep<'tcx>> },
+}
+impl Debug for GoalEvaluation<'_> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        ProofTreeFormatter { f, on_newline: true }.format_goal_evaluation(self)
+    }
+}
+
+#[derive(Eq, PartialEq, Hash, HashStable)]
+pub struct AddedGoalsEvaluation<'tcx> {
+    pub evaluations: Vec<Vec<GoalEvaluation<'tcx>>>,
+    pub result: Result<Certainty, NoSolution>,
+}
+impl Debug for AddedGoalsEvaluation<'_> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        ProofTreeFormatter { f, on_newline: true }.format_nested_goal_evaluation(self)
+    }
+}
+
+#[derive(Eq, PartialEq, Hash, HashStable)]
+pub struct GoalEvaluationStep<'tcx> {
+    pub instantiated_goal: QueryInput<'tcx, ty::Predicate<'tcx>>,
+
+    pub nested_goal_evaluations: Vec<AddedGoalsEvaluation<'tcx>>,
+    pub candidates: Vec<GoalCandidate<'tcx>>,
+
+    pub result: QueryResult<'tcx>,
+}
+impl Debug for GoalEvaluationStep<'_> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        ProofTreeFormatter { f, on_newline: true }.format_evaluation_step(self)
+    }
+}
+
+#[derive(Eq, PartialEq, Hash, HashStable)]
+pub struct GoalCandidate<'tcx> {
+    pub nested_goal_evaluations: Vec<AddedGoalsEvaluation<'tcx>>,
+    pub candidates: Vec<GoalCandidate<'tcx>>,
+    pub kind: CandidateKind<'tcx>,
+}
+
+#[derive(Eq, PartialEq, Debug, Hash, HashStable)]
+pub enum CandidateKind<'tcx> {
+    /// Probe entered when normalizing the self ty during candidate assembly
+    NormalizedSelfTyAssembly,
+    /// A normal candidate for proving a goal
+    Candidate { name: String, result: QueryResult<'tcx> },
+}
+impl Debug for GoalCandidate<'_> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        ProofTreeFormatter { f, on_newline: true }.format_candidate(self)
+    }
+}
diff --git a/compiler/rustc_middle/src/traits/solve/inspect/format.rs b/compiler/rustc_middle/src/traits/solve/inspect/format.rs
new file mode 100644
index 000000000..2ee625674
--- /dev/null
+++ b/compiler/rustc_middle/src/traits/solve/inspect/format.rs
@@ -0,0 +1,131 @@
+use super::*;
+
+pub(super) struct ProofTreeFormatter<'a, 'b> {
+    pub(super) f: &'a mut (dyn Write + 'b),
+    pub(super) on_newline: bool,
+}
+
+impl Write for ProofTreeFormatter<'_, '_> {
+    fn write_str(&mut self, s: &str) -> std::fmt::Result {
+        for line in s.split_inclusive("\n") {
+            if self.on_newline {
+                self.f.write_str("    ")?;
+            }
+            self.on_newline = line.ends_with("\n");
+            self.f.write_str(line)?;
+        }
+
+        Ok(())
+    }
+}
+
+impl ProofTreeFormatter<'_, '_> {
+    fn nested(&mut self) -> ProofTreeFormatter<'_, '_> {
+        ProofTreeFormatter { f: self, on_newline: true }
+    }
+
+    pub(super) fn format_goal_evaluation(&mut self, goal: &GoalEvaluation<'_>) -> std::fmt::Result {
+        let f = &mut *self.f;
+
+        let goal_text = match goal.is_normalizes_to_hack {
+            IsNormalizesToHack::Yes => "NORMALIZES-TO HACK GOAL",
+            IsNormalizesToHack::No => "GOAL",
+        };
+
+        writeln!(f, "{}: {:?}", goal_text, goal.uncanonicalized_goal,)?;
+        writeln!(f, "CANONICALIZED: {:?}", goal.canonicalized_goal)?;
+
+        match &goal.kind {
+            GoalEvaluationKind::CacheHit(CacheHit::Global) => {
+                writeln!(f, "GLOBAL CACHE HIT: {:?}", goal.result)
+            }
+            GoalEvaluationKind::CacheHit(CacheHit::Provisional) => {
+                writeln!(f, "PROVISIONAL CACHE HIT: {:?}", goal.result)
+            }
+            GoalEvaluationKind::Uncached { revisions } => {
+                for (n, step) in revisions.iter().enumerate() {
+                    let f = &mut *self.f;
+                    writeln!(f, "REVISION {n}: {:?}", step.result)?;
+                    let mut f = self.nested();
+                    f.format_evaluation_step(step)?;
+                }
+
+                let f = &mut *self.f;
+                writeln!(f, "RESULT: {:?}", goal.result)
+            }
+        }?;
+
+        if goal.returned_goals.len() > 0 {
+            let f = &mut *self.f;
+            writeln!(f, "NESTED GOALS ADDED TO CALLER: [")?;
+            let mut f = self.nested();
+            for goal in goal.returned_goals.iter() {
+                writeln!(f, "ADDED GOAL: {:?},", goal)?;
+            }
+            writeln!(self.f, "]")?;
+        }
+
+        Ok(())
+    }
+
+    pub(super) fn format_evaluation_step(
+        &mut self,
+        evaluation_step: &GoalEvaluationStep<'_>,
+    ) -> std::fmt::Result {
+        let f = &mut *self.f;
+        writeln!(f, "INSTANTIATED: {:?}", evaluation_step.instantiated_goal)?;
+
+        for candidate in &evaluation_step.candidates {
+            let mut f = self.nested();
+            f.format_candidate(candidate)?;
+        }
+        for nested_goal_evaluation in &evaluation_step.nested_goal_evaluations {
+            let mut f = self.nested();
+            f.format_nested_goal_evaluation(nested_goal_evaluation)?;
+        }
+
+        Ok(())
+    }
+
+    pub(super) fn format_candidate(&mut self, candidate: &GoalCandidate<'_>) -> std::fmt::Result {
+        let f = &mut *self.f;
+
+        match &candidate.kind {
+            CandidateKind::NormalizedSelfTyAssembly => {
+                writeln!(f, "NORMALIZING SELF TY FOR ASSEMBLY:")
+            }
+            CandidateKind::Candidate { name, result } => {
+                writeln!(f, "CANDIDATE {}: {:?}", name, result)
+            }
+        }?;
+
+        let mut f = self.nested();
+        for candidate in &candidate.candidates {
+            f.format_candidate(candidate)?;
+        }
+        for nested_evaluations in &candidate.nested_goal_evaluations {
+            f.format_nested_goal_evaluation(nested_evaluations)?;
+        }
+
+        Ok(())
+    }
+
+    pub(super) fn format_nested_goal_evaluation(
+        &mut self,
+        nested_goal_evaluation: &AddedGoalsEvaluation<'_>,
+    ) -> std::fmt::Result {
+        let f = &mut *self.f;
+        writeln!(f, "TRY_EVALUATE_ADDED_GOALS: {:?}", nested_goal_evaluation.result)?;
+
+        for (n, revision) in nested_goal_evaluation.evaluations.iter().enumerate() {
+            let f = &mut *self.f;
+            writeln!(f, "REVISION {n}")?;
+            let mut f = self.nested();
+            for goal_evaluation in revision {
+                f.format_goal_evaluation(goal_evaluation)?;
+            }
+        }
+
+        Ok(())
+    }
+}
diff --git a/compiler/rustc_middle/src/traits/specialization_graph.rs b/compiler/rustc_middle/src/traits/specialization_graph.rs
index c016f7227..dc2cd2035 100644
--- a/compiler/rustc_middle/src/traits/specialization_graph.rs
+++ b/compiler/rustc_middle/src/traits/specialization_graph.rs
@@ -228,7 +228,7 @@ impl<'tcx> Ancestors<'tcx> {
             if let Some(item) = node.item(tcx, trait_item_def_id) {
                 if finalizing_node.is_none() {
                     let is_specializable = item.defaultness(tcx).is_default()
-                        || tcx.impl_defaultness(node.def_id()).is_default();
+                        || tcx.defaultness(node.def_id()).is_default();
 
                     if !is_specializable {
                         finalizing_node = Some(node);
diff --git a/compiler/rustc_middle/src/traits/structural_impls.rs b/compiler/rustc_middle/src/traits/structural_impls.rs
index 6acb7745d..a703e3c95 100644
--- a/compiler/rustc_middle/src/traits/structural_impls.rs
+++ b/compiler/rustc_middle/src/traits/structural_impls.rs
@@ -9,15 +9,7 @@ impl<'tcx, N: fmt::Debug> fmt::Debug for traits::ImplSource<'tcx, N> {
         match *self {
             super::ImplSource::UserDefined(ref v) => write!(f, "{:?}", v),
 
-            super::ImplSource::AutoImpl(ref t) => write!(f, "{:?}", t),
-
-            super::ImplSource::Closure(ref d) => write!(f, "{:?}", d),
-
-            super::ImplSource::Generator(ref d) => write!(f, "{:?}", d),
-
-            super::ImplSource::Future(ref d) => write!(f, "{:?}", d),
-
-            super::ImplSource::FnPointer(ref d) => write!(f, "({:?})", d),
+            super::ImplSource::Builtin(ref d) => write!(f, "{:?}", d),
 
             super::ImplSource::Object(ref d) => write!(f, "{:?}", d),
 
@@ -25,13 +17,7 @@ impl<'tcx, N: fmt::Debug> fmt::Debug for traits::ImplSource<'tcx, N> {
                 write!(f, "ImplSourceParamData({:?}, {:?})", n, ct)
             }
 
-            super::ImplSource::Builtin(ref d) => write!(f, "{:?}", d),
-
-            super::ImplSource::TraitAlias(ref d) => write!(f, "{:?}", d),
-
             super::ImplSource::TraitUpcasting(ref d) => write!(f, "{:?}", d),
-
-            super::ImplSource::ConstDestruct(ref d) => write!(f, "{:?}", d),
         }
     }
 }
@@ -46,90 +32,22 @@ impl<'tcx, N: fmt::Debug> fmt::Debug for traits::ImplSourceUserDefinedData<'tcx,
     }
 }
 
-impl<'tcx, N: fmt::Debug> fmt::Debug for traits::ImplSourceGeneratorData<'tcx, N> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(
-            f,
-            "ImplSourceGeneratorData(generator_def_id={:?}, substs={:?}, nested={:?})",
-            self.generator_def_id, self.substs, self.nested
-        )
-    }
-}
-
-impl<'tcx, N: fmt::Debug> fmt::Debug for traits::ImplSourceFutureData<'tcx, N> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(
-            f,
-            "ImplSourceFutureData(generator_def_id={:?}, substs={:?}, nested={:?})",
-            self.generator_def_id, self.substs, self.nested
-        )
-    }
-}
-
-impl<'tcx, N: fmt::Debug> fmt::Debug for traits::ImplSourceClosureData<'tcx, N> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(
-            f,
-            "ImplSourceClosureData(closure_def_id={:?}, substs={:?}, nested={:?})",
-            self.closure_def_id, self.substs, self.nested
-        )
-    }
-}
-
-impl<N: fmt::Debug> fmt::Debug for traits::ImplSourceBuiltinData<N> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "ImplSourceBuiltinData(nested={:?})", self.nested)
-    }
-}
-
-impl<'tcx, N: fmt::Debug> fmt::Debug for traits::ImplSourceTraitUpcastingData<'tcx, N> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(
-            f,
-            "ImplSourceTraitUpcastingData(upcast={:?}, vtable_vptr_slot={:?}, nested={:?})",
-            self.upcast_trait_ref, self.vtable_vptr_slot, self.nested
-        )
-    }
-}
-
-impl<N: fmt::Debug> fmt::Debug for traits::ImplSourceAutoImplData<N> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(
-            f,
-            "ImplSourceAutoImplData(trait_def_id={:?}, nested={:?})",
-            self.trait_def_id, self.nested
-        )
-    }
-}
-
-impl<'tcx, N: fmt::Debug> fmt::Debug for traits::ImplSourceObjectData<'tcx, N> {
+impl<N: fmt::Debug> fmt::Debug for traits::ImplSourceTraitUpcastingData<N> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(
             f,
-            "ImplSourceObjectData(upcast={:?}, vtable_base={}, nested={:?})",
-            self.upcast_trait_ref, self.vtable_base, self.nested
+            "ImplSourceTraitUpcastingData(vtable_vptr_slot={:?}, nested={:?})",
+            self.vtable_vptr_slot, self.nested
         )
     }
 }
 
-impl<'tcx, N: fmt::Debug> fmt::Debug for traits::ImplSourceFnPointerData<'tcx, N> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "ImplSourceFnPointerData(fn_ty={:?}, nested={:?})", self.fn_ty, self.nested)
-    }
-}
-
-impl<'tcx, N: fmt::Debug> fmt::Debug for traits::ImplSourceTraitAliasData<'tcx, N> {
+impl<N: fmt::Debug> fmt::Debug for traits::ImplSourceObjectData<N> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(
             f,
-            "ImplSourceTraitAliasData(alias_def_id={:?}, substs={:?}, nested={:?})",
-            self.alias_def_id, self.substs, self.nested
+            "ImplSourceObjectData(vtable_base={}, nested={:?})",
+            self.vtable_base, self.nested
         )
     }
 }
-
-impl<N: fmt::Debug> fmt::Debug for traits::ImplSourceConstDestructData<N> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "ImplSourceConstDestructData(nested={:?})", self.nested)
-    }
-}
diff --git a/compiler/rustc_middle/src/traits/util.rs b/compiler/rustc_middle/src/traits/util.rs
index d54b8c599..05c06efaf 100644
--- a/compiler/rustc_middle/src/traits/util.rs
+++ b/compiler/rustc_middle/src/traits/util.rs
@@ -25,9 +25,7 @@ impl<'tcx> Elaborator<'tcx> {
             .super_predicates_of(trait_ref.def_id())
             .predicates
             .into_iter()
-            .flat_map(|(pred, _)| {
-                pred.subst_supertrait(self.tcx, &trait_ref).to_opt_poly_trait_pred()
-            })
+            .flat_map(|(pred, _)| pred.subst_supertrait(self.tcx, &trait_ref).as_trait_clause())
             .map(|t| t.map_bound(|pred| pred.trait_ref))
             .filter(|supertrait_ref| self.visited.insert(*supertrait_ref));