Rollup merge of #112667 - compiler-errors:wf-goal-is-clause, r=lcnr

Move WF/ConstEvaluatable goal to clause

It can show up in a param-env, so I think it needs to be a clause kind.

r? ```@lcnr``` or ```@oli-obk```

compiler/rustc_borrowck/src/region_infer/opaque_types.rs

@@ -330,7 +330,8 @@ fn check_opaque_type_well_formed<'tcx>(
     // Require the hidden type to be well-formed with only the generics of the opaque type.
     // Defining use functions may have more bounds than the opaque type, which is ok, as long as the
     // hidden type is well formed even without those bounds.
-    let predicate = ty::Binder::dummy(ty::PredicateKind::WellFormed(definition_ty.into()));
+    let predicate =
+        ty::Binder::dummy(ty::PredicateKind::Clause(ty::Clause::WellFormed(definition_ty.into())));
     ocx.register_obligation(Obligation::misc(tcx, definition_span, def_id, param_env, predicate));
 
     // Check that all obligations are satisfied by the implementation's

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -1419,9 +1419,11 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                 //
                 // See #91068 for an example.
                 self.prove_predicates(
-                    sig.inputs_and_output
+                    sig.inputs_and_output.iter().map(|ty| {
-                        .iter()
+                        ty::Binder::dummy(ty::PredicateKind::Clause(ty::Clause::WellFormed(
-                        .map(|ty| ty::Binder::dummy(ty::PredicateKind::WellFormed(ty.into()))),
+                            ty.into(),
+                        )))
+                    }),
                     term_location.to_locations(),
                     ConstraintCategory::Boring,
                 );
@@ -1850,7 +1852,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
 
                 let array_ty = rvalue.ty(body.local_decls(), tcx);
                 self.prove_predicate(
-                    ty::PredicateKind::WellFormed(array_ty.into()),
+                    ty::PredicateKind::Clause(ty::Clause::WellFormed(array_ty.into())),
                     Locations::Single(location),
                     ConstraintCategory::Boring,
                 );

compiler/rustc_hir_analysis/src/astconv/bounds.rs

@@ -0,0 +1,583 @@
+use rustc_data_structures::fx::FxHashMap;
+use rustc_errors::struct_span_err;
+use rustc_hir as hir;
+use rustc_hir::def::{DefKind, Res};
+use rustc_hir::def_id::{DefId, LocalDefId};
+use rustc_lint_defs::Applicability;
+use rustc_middle::ty::{self as ty, Ty, TypeVisitableExt};
+use rustc_span::symbol::Ident;
+use rustc_span::{ErrorGuaranteed, Span};
+use rustc_trait_selection::traits;
+
+use crate::astconv::{AstConv, ConvertedBinding, ConvertedBindingKind};
+use crate::bounds::Bounds;
+use crate::errors::{MultipleRelaxedDefaultBounds, ValueOfAssociatedStructAlreadySpecified};
+
+use super::OnlySelfBounds;
+
+impl<'tcx> dyn AstConv<'tcx> + '_ {
+    /// Sets `implicitly_sized` to true on `Bounds` if necessary
+    pub(crate) fn add_implicitly_sized(
+        &self,
+        bounds: &mut Bounds<'tcx>,
+        self_ty: Ty<'tcx>,
+        ast_bounds: &'tcx [hir::GenericBound<'tcx>],
+        self_ty_where_predicates: Option<(LocalDefId, &'tcx [hir::WherePredicate<'tcx>])>,
+        span: Span,
+    ) {
+        let tcx = self.tcx();
+
+        // Try to find an unbound in bounds.
+        let mut unbound = None;
+        let mut search_bounds = |ast_bounds: &'tcx [hir::GenericBound<'tcx>]| {
+            for ab in ast_bounds {
+                if let hir::GenericBound::Trait(ptr, hir::TraitBoundModifier::Maybe) = ab {
+                    if unbound.is_none() {
+                        unbound = Some(&ptr.trait_ref);
+                    } else {
+                        tcx.sess.emit_err(MultipleRelaxedDefaultBounds { span });
+                    }
+                }
+            }
+        };
+        search_bounds(ast_bounds);
+        if let Some((self_ty, where_clause)) = self_ty_where_predicates {
+            for clause in where_clause {
+                if let hir::WherePredicate::BoundPredicate(pred) = clause {
+                    if pred.is_param_bound(self_ty.to_def_id()) {
+                        search_bounds(pred.bounds);
+                    }
+                }
+            }
+        }
+
+        let sized_def_id = tcx.lang_items().sized_trait();
+        match (&sized_def_id, unbound) {
+            (Some(sized_def_id), Some(tpb))
+                if tpb.path.res == Res::Def(DefKind::Trait, *sized_def_id) =>
+            {
+                // There was in fact a `?Sized` bound, return without doing anything
+                return;
+            }
+            (_, Some(_)) => {
+                // There was a `?Trait` bound, but it was not `?Sized`; warn.
+                tcx.sess.span_warn(
+                    span,
+                    "default bound relaxed for a type parameter, but \
+                        this does nothing because the given bound is not \
+                        a default; only `?Sized` is supported",
+                );
+                // Otherwise, add implicitly sized if `Sized` is available.
+            }
+            _ => {
+                // There was no `?Sized` bound; add implicitly sized if `Sized` is available.
+            }
+        }
+        if sized_def_id.is_none() {
+            // No lang item for `Sized`, so we can't add it as a bound.
+            return;
+        }
+        bounds.push_sized(tcx, self_ty, span);
+    }
+
+    /// This helper takes a *converted* parameter type (`param_ty`)
+    /// and an *unconverted* list of bounds:
+    ///
+    /// ```text
+    /// fn foo<T: Debug>
+    ///        ^  ^^^^^ `ast_bounds` parameter, in HIR form
+    ///        |
+    ///        `param_ty`, in ty form
+    /// ```
+    ///
+    /// It adds these `ast_bounds` into the `bounds` structure.
+    ///
+    /// **A note on binders:** there is an implied binder around
+    /// `param_ty` and `ast_bounds`. See `instantiate_poly_trait_ref`
+    /// for more details.
+    #[instrument(level = "debug", skip(self, ast_bounds, bounds))]
+    pub(crate) fn add_bounds<'hir, I: Iterator<Item = &'hir hir::GenericBound<'hir>>>(
+        &self,
+        param_ty: Ty<'tcx>,
+        ast_bounds: I,
+        bounds: &mut Bounds<'tcx>,
+        bound_vars: &'tcx ty::List<ty::BoundVariableKind>,
+        only_self_bounds: OnlySelfBounds,
+    ) {
+        for ast_bound in ast_bounds {
+            match ast_bound {
+                hir::GenericBound::Trait(poly_trait_ref, modifier) => {
+                    let (constness, polarity) = match modifier {
+                        hir::TraitBoundModifier::MaybeConst => {
+                            (ty::BoundConstness::ConstIfConst, ty::ImplPolarity::Positive)
+                        }
+                        hir::TraitBoundModifier::None => {
+                            (ty::BoundConstness::NotConst, ty::ImplPolarity::Positive)
+                        }
+                        hir::TraitBoundModifier::Negative => {
+                            (ty::BoundConstness::NotConst, ty::ImplPolarity::Negative)
+                        }
+                        hir::TraitBoundModifier::Maybe => continue,
+                    };
+                    let _ = self.instantiate_poly_trait_ref(
+                        &poly_trait_ref.trait_ref,
+                        poly_trait_ref.span,
+                        constness,
+                        polarity,
+                        param_ty,
+                        bounds,
+                        false,
+                        only_self_bounds,
+                    );
+                }
+                &hir::GenericBound::LangItemTrait(lang_item, span, hir_id, args) => {
+                    self.instantiate_lang_item_trait_ref(
+                        lang_item,
+                        span,
+                        hir_id,
+                        args,
+                        param_ty,
+                        bounds,
+                        only_self_bounds,
+                    );
+                }
+                hir::GenericBound::Outlives(lifetime) => {
+                    let region = self.ast_region_to_region(lifetime, None);
+                    bounds.push_region_bound(
+                        self.tcx(),
+                        ty::Binder::bind_with_vars(
+                            ty::OutlivesPredicate(param_ty, region),
+                            bound_vars,
+                        ),
+                        lifetime.ident.span,
+                    );
+                }
+            }
+        }
+    }
+
+    /// Translates a list of bounds from the HIR into the `Bounds` data structure.
+    /// The self-type for the bounds is given by `param_ty`.
+    ///
+    /// Example:
+    ///
+    /// ```ignore (illustrative)
+    /// fn foo<T: Bar + Baz>() { }
+    /// //     ^  ^^^^^^^^^ ast_bounds
+    /// //     param_ty
+    /// ```
+    ///
+    /// The `sized_by_default` parameter indicates if, in this context, the `param_ty` should be
+    /// considered `Sized` unless there is an explicit `?Sized` bound. This would be true in the
+    /// example above, but is not true in supertrait listings like `trait Foo: Bar + Baz`.
+    ///
+    /// `span` should be the declaration size of the parameter.
+    pub(crate) fn compute_bounds(
+        &self,
+        param_ty: Ty<'tcx>,
+        ast_bounds: &[hir::GenericBound<'_>],
+        only_self_bounds: OnlySelfBounds,
+    ) -> Bounds<'tcx> {
+        let mut bounds = Bounds::default();
+        self.add_bounds(
+            param_ty,
+            ast_bounds.iter(),
+            &mut bounds,
+            ty::List::empty(),
+            only_self_bounds,
+        );
+        debug!(?bounds);
+
+        bounds
+    }
+
+    /// Convert the bounds in `ast_bounds` that refer to traits which define an associated type
+    /// named `assoc_name` into ty::Bounds. Ignore the rest.
+    pub(crate) fn compute_bounds_that_match_assoc_item(
+        &self,
+        param_ty: Ty<'tcx>,
+        ast_bounds: &[hir::GenericBound<'_>],
+        assoc_name: Ident,
+    ) -> Bounds<'tcx> {
+        let mut result = Vec::new();
+
+        for ast_bound in ast_bounds {
+            if let Some(trait_ref) = ast_bound.trait_ref()
+                && let Some(trait_did) = trait_ref.trait_def_id()
+                && self.tcx().trait_may_define_assoc_item(trait_did, assoc_name)
+            {
+                result.push(ast_bound.clone());
+            }
+        }
+
+        let mut bounds = Bounds::default();
+        self.add_bounds(
+            param_ty,
+            result.iter(),
+            &mut bounds,
+            ty::List::empty(),
+            OnlySelfBounds(true),
+        );
+        debug!(?bounds);
+
+        bounds
+    }
+
+    /// Given an HIR binding like `Item = Foo` or `Item: Foo`, pushes the corresponding predicates
+    /// onto `bounds`.
+    ///
+    /// **A note on binders:** given something like `T: for<'a> Iterator<Item = &'a u32>`, the
+    /// `trait_ref` here will be `for<'a> T: Iterator`. The `binding` data however is from *inside*
+    /// the binder (e.g., `&'a u32`) and hence may reference bound regions.
+    #[instrument(level = "debug", skip(self, bounds, speculative, dup_bindings, path_span))]
+    pub(super) fn add_predicates_for_ast_type_binding(
+        &self,
+        hir_ref_id: hir::HirId,
+        trait_ref: ty::PolyTraitRef<'tcx>,
+        binding: &ConvertedBinding<'_, 'tcx>,
+        bounds: &mut Bounds<'tcx>,
+        speculative: bool,
+        dup_bindings: &mut FxHashMap<DefId, Span>,
+        path_span: Span,
+        constness: ty::BoundConstness,
+        only_self_bounds: OnlySelfBounds,
+        polarity: ty::ImplPolarity,
+    ) -> Result<(), ErrorGuaranteed> {
+        // Given something like `U: SomeTrait<T = X>`, we want to produce a
+        // predicate like `<U as SomeTrait>::T = X`. This is somewhat
+        // subtle in the event that `T` is defined in a supertrait of
+        // `SomeTrait`, because in that case we need to upcast.
+        //
+        // That is, consider this case:
+        //
+        // ```
+        // trait SubTrait: SuperTrait<i32> { }
+        // trait SuperTrait<A> { type T; }
+        //
+        // ... B: SubTrait<T = foo> ...
+        // ```
+        //
+        // We want to produce `<B as SuperTrait<i32>>::T == foo`.
+
+        let tcx = self.tcx();
+
+        let return_type_notation =
+            binding.gen_args.parenthesized == hir::GenericArgsParentheses::ReturnTypeNotation;
+
+        let candidate = if return_type_notation {
+            if self.trait_defines_associated_item_named(
+                trait_ref.def_id(),
+                ty::AssocKind::Fn,
+                binding.item_name,
+            ) {
+                trait_ref
+            } else {
+                self.one_bound_for_assoc_method(
+                    traits::supertraits(tcx, trait_ref),
+                    trait_ref.print_only_trait_path(),
+                    binding.item_name,
+                    path_span,
+                )?
+            }
+        } else if self.trait_defines_associated_item_named(
+            trait_ref.def_id(),
+            ty::AssocKind::Type,
+            binding.item_name,
+        ) {
+            // Simple case: X is defined in the current trait.
+            trait_ref
+        } else {
+            // Otherwise, we have to walk through the supertraits to find
+            // those that do.
+            self.one_bound_for_assoc_type(
+                || traits::supertraits(tcx, trait_ref),
+                trait_ref.skip_binder().print_only_trait_name(),
+                binding.item_name,
+                path_span,
+                match binding.kind {
+                    ConvertedBindingKind::Equality(term) => Some(term),
+                    _ => None,
+                },
+            )?
+        };
+
+        let (assoc_ident, def_scope) =
+            tcx.adjust_ident_and_get_scope(binding.item_name, candidate.def_id(), hir_ref_id);
+
+        // We have already adjusted the item name above, so compare with `ident.normalize_to_macros_2_0()` instead
+        // of calling `filter_by_name_and_kind`.
+        let find_item_of_kind = |kind| {
+            tcx.associated_items(candidate.def_id())
+                .filter_by_name_unhygienic(assoc_ident.name)
+                .find(|i| i.kind == kind && i.ident(tcx).normalize_to_macros_2_0() == assoc_ident)
+        };
+        let assoc_item = if return_type_notation {
+            find_item_of_kind(ty::AssocKind::Fn)
+        } else {
+            find_item_of_kind(ty::AssocKind::Type)
+                .or_else(|| find_item_of_kind(ty::AssocKind::Const))
+        }
+        .expect("missing associated type");
+
+        if !assoc_item.visibility(tcx).is_accessible_from(def_scope, tcx) {
+            tcx.sess
+                .struct_span_err(
+                    binding.span,
+                    format!("{} `{}` is private", assoc_item.kind, binding.item_name),
+                )
+                .span_label(binding.span, format!("private {}", assoc_item.kind))
+                .emit();
+        }
+        tcx.check_stability(assoc_item.def_id, Some(hir_ref_id), binding.span, None);
+
+        if !speculative {
+            dup_bindings
+                .entry(assoc_item.def_id)
+                .and_modify(|prev_span| {
+                    tcx.sess.emit_err(ValueOfAssociatedStructAlreadySpecified {
+                        span: binding.span,
+                        prev_span: *prev_span,
+                        item_name: binding.item_name,
+                        def_path: tcx.def_path_str(assoc_item.container_id(tcx)),
+                    });
+                })
+                .or_insert(binding.span);
+        }
+
+        let projection_ty = if return_type_notation {
+            let mut emitted_bad_param_err = false;
+            // If we have an method return type bound, then we need to substitute
+            // the method's early bound params with suitable late-bound params.
+            let mut num_bound_vars = candidate.bound_vars().len();
+            let substs =
+                candidate.skip_binder().substs.extend_to(tcx, assoc_item.def_id, |param, _| {
+                    let subst = match param.kind {
+                        ty::GenericParamDefKind::Lifetime => ty::Region::new_late_bound(
+                            tcx,
+                            ty::INNERMOST,
+                            ty::BoundRegion {
+                                var: ty::BoundVar::from_usize(num_bound_vars),
+                                kind: ty::BoundRegionKind::BrNamed(param.def_id, param.name),
+                            },
+                        )
+                        .into(),
+                        ty::GenericParamDefKind::Type { .. } => {
+                            if !emitted_bad_param_err {
+                                tcx.sess.emit_err(
+                                    crate::errors::ReturnTypeNotationIllegalParam::Type {
+                                        span: path_span,
+                                        param_span: tcx.def_span(param.def_id),
+                                    },
+                                );
+                                emitted_bad_param_err = true;
+                            }
+                            tcx.mk_bound(
+                                ty::INNERMOST,
+                                ty::BoundTy {
+                                    var: ty::BoundVar::from_usize(num_bound_vars),
+                                    kind: ty::BoundTyKind::Param(param.def_id, param.name),
+                                },
+                            )
+                            .into()
+                        }
+                        ty::GenericParamDefKind::Const { .. } => {
+                            if !emitted_bad_param_err {
+                                tcx.sess.emit_err(
+                                    crate::errors::ReturnTypeNotationIllegalParam::Const {
+                                        span: path_span,
+                                        param_span: tcx.def_span(param.def_id),
+                                    },
+                                );
+                                emitted_bad_param_err = true;
+                            }
+                            let ty = tcx
+                                .type_of(param.def_id)
+                                .no_bound_vars()
+                                .expect("ct params cannot have early bound vars");
+                            tcx.mk_const(
+                                ty::ConstKind::Bound(
+                                    ty::INNERMOST,
+                                    ty::BoundVar::from_usize(num_bound_vars),
+                                ),
+                                ty,
+                            )
+                            .into()
+                        }
+                    };
+                    num_bound_vars += 1;
+                    subst
+                });
+
+            // Next, we need to check that the return-type notation is being used on
+            // an RPITIT (return-position impl trait in trait) or AFIT (async fn in trait).
+            let output = tcx.fn_sig(assoc_item.def_id).skip_binder().output();
+            let output = if let ty::Alias(ty::Projection, alias_ty) = *output.skip_binder().kind()
+                && tcx.def_kind(alias_ty.def_id) == DefKind::ImplTraitPlaceholder
+            {
+                alias_ty
+            } else {
+                return Err(self.tcx().sess.emit_err(
+                    crate::errors::ReturnTypeNotationOnNonRpitit {
+                        span: binding.span,
+                        ty: tcx.liberate_late_bound_regions(assoc_item.def_id, output),
+                        fn_span: tcx.hir().span_if_local(assoc_item.def_id),
+                        note: (),
+                    },
+                ));
+            };
+
+            // Finally, move the fn return type's bound vars over to account for the early bound
+            // params (and trait ref's late bound params). This logic is very similar to
+            // `Predicate::subst_supertrait`, and it's no coincidence why.
+            let shifted_output = tcx.shift_bound_var_indices(num_bound_vars, output);
+            let subst_output = ty::EarlyBinder::bind(shifted_output).subst(tcx, substs);
+
+            let bound_vars = tcx.late_bound_vars(binding.hir_id);
+            ty::Binder::bind_with_vars(subst_output, bound_vars)
+        } else {
+            // Include substitutions for generic parameters of associated types
+            candidate.map_bound(|trait_ref| {
+                let ident = Ident::new(assoc_item.name, binding.item_name.span);
+                let item_segment = hir::PathSegment {
+                    ident,
+                    hir_id: binding.hir_id,
+                    res: Res::Err,
+                    args: Some(binding.gen_args),
+                    infer_args: false,
+                };
+
+                let substs_trait_ref_and_assoc_item = self.create_substs_for_associated_item(
+                    path_span,
+                    assoc_item.def_id,
+                    &item_segment,
+                    trait_ref.substs,
+                );
+
+                debug!(?substs_trait_ref_and_assoc_item);
+
+                tcx.mk_alias_ty(assoc_item.def_id, substs_trait_ref_and_assoc_item)
+            })
+        };
+
+        if !speculative {
+            // Find any late-bound regions declared in `ty` that are not
+            // declared in the trait-ref or assoc_item. These are not well-formed.
+            //
+            // Example:
+            //
+            //     for<'a> <T as Iterator>::Item = &'a str // <-- 'a is bad
+            //     for<'a> <T as FnMut<(&'a u32,)>>::Output = &'a str // <-- 'a is ok
+            if let ConvertedBindingKind::Equality(ty) = binding.kind {
+                let late_bound_in_trait_ref =
+                    tcx.collect_constrained_late_bound_regions(&projection_ty);
+                let late_bound_in_ty =
+                    tcx.collect_referenced_late_bound_regions(&trait_ref.rebind(ty));
+                debug!(?late_bound_in_trait_ref);
+                debug!(?late_bound_in_ty);
+
+                // FIXME: point at the type params that don't have appropriate lifetimes:
+                // struct S1<F: for<'a> Fn(&i32, &i32) -> &'a i32>(F);
+                //                         ----  ----     ^^^^^^^
+                self.validate_late_bound_regions(
+                    late_bound_in_trait_ref,
+                    late_bound_in_ty,
+                    |br_name| {
+                        struct_span_err!(
+                            tcx.sess,
+                            binding.span,
+                            E0582,
+                            "binding for associated type `{}` references {}, \
+                             which does not appear in the trait input types",
+                            binding.item_name,
+                            br_name
+                        )
+                    },
+                );
+            }
+        }
+
+        match binding.kind {
+            ConvertedBindingKind::Equality(..) if return_type_notation => {
+                return Err(self.tcx().sess.emit_err(
+                    crate::errors::ReturnTypeNotationEqualityBound { span: binding.span },
+                ));
+            }
+            ConvertedBindingKind::Equality(mut term) => {
+                // "Desugar" a constraint like `T: Iterator<Item = u32>` this to
+                // the "projection predicate" for:
+                //
+                // `<T as Iterator>::Item = u32`
+                let assoc_item_def_id = projection_ty.skip_binder().def_id;
+                let def_kind = tcx.def_kind(assoc_item_def_id);
+                match (def_kind, term.unpack()) {
+                    (hir::def::DefKind::AssocTy, ty::TermKind::Ty(_))
+                    | (hir::def::DefKind::AssocConst, ty::TermKind::Const(_)) => (),
+                    (_, _) => {
+                        let got = if let Some(_) = term.ty() { "type" } else { "constant" };
+                        let expected = tcx.def_descr(assoc_item_def_id);
+                        let mut err = tcx.sess.struct_span_err(
+                            binding.span,
+                            format!("expected {expected} bound, found {got}"),
+                        );
+                        err.span_note(
+                            tcx.def_span(assoc_item_def_id),
+                            format!("{expected} defined here"),
+                        );
+
+                        if let hir::def::DefKind::AssocConst = def_kind
+                          && let Some(t) = term.ty() && (t.is_enum() || t.references_error())
+                          && tcx.features().associated_const_equality {
+                            err.span_suggestion(
+                                binding.span,
+                                "if equating a const, try wrapping with braces",
+                                format!("{} = {{ const }}", binding.item_name),
+                                Applicability::HasPlaceholders,
+                            );
+                        }
+                        let reported = err.emit();
+                        term = match def_kind {
+                            hir::def::DefKind::AssocTy => tcx.ty_error(reported).into(),
+                            hir::def::DefKind::AssocConst => tcx
+                                .const_error(
+                                    tcx.type_of(assoc_item_def_id)
+                                        .subst(tcx, projection_ty.skip_binder().substs),
+                                    reported,
+                                )
+                                .into(),
+                            _ => unreachable!(),
+                        };
+                    }
+                }
+                bounds.push_projection_bound(
+                    tcx,
+                    projection_ty
+                        .map_bound(|projection_ty| ty::ProjectionPredicate { projection_ty, term }),
+                    binding.span,
+                );
+            }
+            ConvertedBindingKind::Constraint(ast_bounds) => {
+                // "Desugar" a constraint like `T: Iterator<Item: Debug>` to
+                //
+                // `<T as Iterator>::Item: Debug`
+                //
+                // Calling `skip_binder` is okay, because `add_bounds` expects the `param_ty`
+                // parameter to have a skipped binder.
+                //
+                // NOTE: If `only_self_bounds` is true, do NOT expand this associated
+                // type bound into a trait predicate, since we only want to add predicates
+                // for the `Self` type.
+                if !only_self_bounds.0 {
+                    let param_ty = tcx.mk_alias(ty::Projection, projection_ty.skip_binder());
+                    self.add_bounds(
+                        param_ty,
+                        ast_bounds.iter(),
+                        bounds,
+                        projection_ty.bound_vars(),
+                        only_self_bounds,
+                    );
+                }
+            }
+        }
+        Ok(())
+    }
+}

compiler/rustc_hir_analysis/src/astconv/mod.rs

@@ -2,6 +2,7 @@
 //! The main routine here is `ast_ty_to_ty()`; each use is parameterized by an
 //! instance of `AstConv`.
 
+mod bounds;
 mod errors;
 pub mod generics;
 mod lint;
@@ -11,8 +12,7 @@ use crate::astconv::generics::{check_generic_arg_count, create_substs_for_generi
 use crate::bounds::Bounds;
 use crate::collect::HirPlaceholderCollector;
 use crate::errors::{
-    AmbiguousLifetimeBound, MultipleRelaxedDefaultBounds, TraitObjectDeclaredWithNoTraits,
+    AmbiguousLifetimeBound, TraitObjectDeclaredWithNoTraits, TypeofReservedKeywordUsed,
-    TypeofReservedKeywordUsed, ValueOfAssociatedStructAlreadySpecified,
 };
 use crate::middle::resolve_bound_vars as rbv;
 use crate::require_c_abi_if_c_variadic;
@@ -885,571 +885,6 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             .is_some()
     }
 
-    /// Sets `implicitly_sized` to true on `Bounds` if necessary
-    pub(crate) fn add_implicitly_sized(
-        &self,
-        bounds: &mut Bounds<'tcx>,
-        self_ty: Ty<'tcx>,
-        ast_bounds: &'tcx [hir::GenericBound<'tcx>],
-        self_ty_where_predicates: Option<(LocalDefId, &'tcx [hir::WherePredicate<'tcx>])>,
-        span: Span,
-    ) {
-        let tcx = self.tcx();
-
-        // Try to find an unbound in bounds.
-        let mut unbound = None;
-        let mut search_bounds = |ast_bounds: &'tcx [hir::GenericBound<'tcx>]| {
-            for ab in ast_bounds {
-                if let hir::GenericBound::Trait(ptr, hir::TraitBoundModifier::Maybe) = ab {
-                    if unbound.is_none() {
-                        unbound = Some(&ptr.trait_ref);
-                    } else {
-                        tcx.sess.emit_err(MultipleRelaxedDefaultBounds { span });
-                    }
-                }
-            }
-        };
-        search_bounds(ast_bounds);
-        if let Some((self_ty, where_clause)) = self_ty_where_predicates {
-            for clause in where_clause {
-                if let hir::WherePredicate::BoundPredicate(pred) = clause {
-                    if pred.is_param_bound(self_ty.to_def_id()) {
-                        search_bounds(pred.bounds);
-                    }
-                }
-            }
-        }
-
-        let sized_def_id = tcx.lang_items().sized_trait();
-        match (&sized_def_id, unbound) {
-            (Some(sized_def_id), Some(tpb))
-                if tpb.path.res == Res::Def(DefKind::Trait, *sized_def_id) =>
-            {
-                // There was in fact a `?Sized` bound, return without doing anything
-                return;
-            }
-            (_, Some(_)) => {
-                // There was a `?Trait` bound, but it was not `?Sized`; warn.
-                tcx.sess.span_warn(
-                    span,
-                    "default bound relaxed for a type parameter, but \
-                        this does nothing because the given bound is not \
-                        a default; only `?Sized` is supported",
-                );
-                // Otherwise, add implicitly sized if `Sized` is available.
-            }
-            _ => {
-                // There was no `?Sized` bound; add implicitly sized if `Sized` is available.
-            }
-        }
-        if sized_def_id.is_none() {
-            // No lang item for `Sized`, so we can't add it as a bound.
-            return;
-        }
-        bounds.push_sized(tcx, self_ty, span);
-    }
-
-    /// This helper takes a *converted* parameter type (`param_ty`)
-    /// and an *unconverted* list of bounds:
-    ///
-    /// ```text
-    /// fn foo<T: Debug>
-    ///        ^  ^^^^^ `ast_bounds` parameter, in HIR form
-    ///        |
-    ///        `param_ty`, in ty form
-    /// ```
-    ///
-    /// It adds these `ast_bounds` into the `bounds` structure.
-    ///
-    /// **A note on binders:** there is an implied binder around
-    /// `param_ty` and `ast_bounds`. See `instantiate_poly_trait_ref`
-    /// for more details.
-    #[instrument(level = "debug", skip(self, ast_bounds, bounds))]
-    pub(crate) fn add_bounds<'hir, I: Iterator<Item = &'hir hir::GenericBound<'hir>>>(
-        &self,
-        param_ty: Ty<'tcx>,
-        ast_bounds: I,
-        bounds: &mut Bounds<'tcx>,
-        bound_vars: &'tcx ty::List<ty::BoundVariableKind>,
-        only_self_bounds: OnlySelfBounds,
-    ) {
-        for ast_bound in ast_bounds {
-            match ast_bound {
-                hir::GenericBound::Trait(poly_trait_ref, modifier) => {
-                    let (constness, polarity) = match modifier {
-                        hir::TraitBoundModifier::MaybeConst => {
-                            (ty::BoundConstness::ConstIfConst, ty::ImplPolarity::Positive)
-                        }
-                        hir::TraitBoundModifier::None => {
-                            (ty::BoundConstness::NotConst, ty::ImplPolarity::Positive)
-                        }
-                        hir::TraitBoundModifier::Negative => {
-                            (ty::BoundConstness::NotConst, ty::ImplPolarity::Negative)
-                        }
-                        hir::TraitBoundModifier::Maybe => continue,
-                    };
-                    let _ = self.instantiate_poly_trait_ref(
-                        &poly_trait_ref.trait_ref,
-                        poly_trait_ref.span,
-                        constness,
-                        polarity,
-                        param_ty,
-                        bounds,
-                        false,
-                        only_self_bounds,
-                    );
-                }
-                &hir::GenericBound::LangItemTrait(lang_item, span, hir_id, args) => {
-                    self.instantiate_lang_item_trait_ref(
-                        lang_item,
-                        span,
-                        hir_id,
-                        args,
-                        param_ty,
-                        bounds,
-                        only_self_bounds,
-                    );
-                }
-                hir::GenericBound::Outlives(lifetime) => {
-                    let region = self.ast_region_to_region(lifetime, None);
-                    bounds.push_region_bound(
-                        self.tcx(),
-                        ty::Binder::bind_with_vars(
-                            ty::OutlivesPredicate(param_ty, region),
-                            bound_vars,
-                        ),
-                        lifetime.ident.span,
-                    );
-                }
-            }
-        }
-    }
-
-    /// Translates a list of bounds from the HIR into the `Bounds` data structure.
-    /// The self-type for the bounds is given by `param_ty`.
-    ///
-    /// Example:
-    ///
-    /// ```ignore (illustrative)
-    /// fn foo<T: Bar + Baz>() { }
-    /// //     ^  ^^^^^^^^^ ast_bounds
-    /// //     param_ty
-    /// ```
-    ///
-    /// The `sized_by_default` parameter indicates if, in this context, the `param_ty` should be
-    /// considered `Sized` unless there is an explicit `?Sized` bound. This would be true in the
-    /// example above, but is not true in supertrait listings like `trait Foo: Bar + Baz`.
-    ///
-    /// `span` should be the declaration size of the parameter.
-    pub(crate) fn compute_bounds(
-        &self,
-        param_ty: Ty<'tcx>,
-        ast_bounds: &[hir::GenericBound<'_>],
-        only_self_bounds: OnlySelfBounds,
-    ) -> Bounds<'tcx> {
-        let mut bounds = Bounds::default();
-        self.add_bounds(
-            param_ty,
-            ast_bounds.iter(),
-            &mut bounds,
-            ty::List::empty(),
-            only_self_bounds,
-        );
-        debug!(?bounds);
-
-        bounds
-    }
-
-    /// Convert the bounds in `ast_bounds` that refer to traits which define an associated type
-    /// named `assoc_name` into ty::Bounds. Ignore the rest.
-    pub(crate) fn compute_bounds_that_match_assoc_item(
-        &self,
-        param_ty: Ty<'tcx>,
-        ast_bounds: &[hir::GenericBound<'_>],
-        assoc_name: Ident,
-    ) -> Bounds<'tcx> {
-        let mut result = Vec::new();
-
-        for ast_bound in ast_bounds {
-            if let Some(trait_ref) = ast_bound.trait_ref()
-                && let Some(trait_did) = trait_ref.trait_def_id()
-                && self.tcx().trait_may_define_assoc_item(trait_did, assoc_name)
-            {
-                result.push(ast_bound.clone());
-            }
-        }
-
-        let mut bounds = Bounds::default();
-        self.add_bounds(
-            param_ty,
-            result.iter(),
-            &mut bounds,
-            ty::List::empty(),
-            OnlySelfBounds(true),
-        );
-        debug!(?bounds);
-
-        bounds
-    }
-
-    /// Given an HIR binding like `Item = Foo` or `Item: Foo`, pushes the corresponding predicates
-    /// onto `bounds`.
-    ///
-    /// **A note on binders:** given something like `T: for<'a> Iterator<Item = &'a u32>`, the
-    /// `trait_ref` here will be `for<'a> T: Iterator`. The `binding` data however is from *inside*
-    /// the binder (e.g., `&'a u32`) and hence may reference bound regions.
-    #[instrument(level = "debug", skip(self, bounds, speculative, dup_bindings, path_span))]
-    fn add_predicates_for_ast_type_binding(
-        &self,
-        hir_ref_id: hir::HirId,
-        trait_ref: ty::PolyTraitRef<'tcx>,
-        binding: &ConvertedBinding<'_, 'tcx>,
-        bounds: &mut Bounds<'tcx>,
-        speculative: bool,
-        dup_bindings: &mut FxHashMap<DefId, Span>,
-        path_span: Span,
-        constness: ty::BoundConstness,
-        only_self_bounds: OnlySelfBounds,
-        polarity: ty::ImplPolarity,
-    ) -> Result<(), ErrorGuaranteed> {
-        // Given something like `U: SomeTrait<T = X>`, we want to produce a
-        // predicate like `<U as SomeTrait>::T = X`. This is somewhat
-        // subtle in the event that `T` is defined in a supertrait of
-        // `SomeTrait`, because in that case we need to upcast.
-        //
-        // That is, consider this case:
-        //
-        // ```
-        // trait SubTrait: SuperTrait<i32> { }
-        // trait SuperTrait<A> { type T; }
-        //
-        // ... B: SubTrait<T = foo> ...
-        // ```
-        //
-        // We want to produce `<B as SuperTrait<i32>>::T == foo`.
-
-        let tcx = self.tcx();
-
-        let return_type_notation =
-            binding.gen_args.parenthesized == hir::GenericArgsParentheses::ReturnTypeNotation;
-
-        let candidate = if return_type_notation {
-            if self.trait_defines_associated_item_named(
-                trait_ref.def_id(),
-                ty::AssocKind::Fn,
-                binding.item_name,
-            ) {
-                trait_ref
-            } else {
-                self.one_bound_for_assoc_method(
-                    traits::supertraits(tcx, trait_ref),
-                    trait_ref.print_only_trait_path(),
-                    binding.item_name,
-                    path_span,
-                )?
-            }
-        } else if self.trait_defines_associated_item_named(
-            trait_ref.def_id(),
-            ty::AssocKind::Type,
-            binding.item_name,
-        ) {
-            // Simple case: X is defined in the current trait.
-            trait_ref
-        } else {
-            // Otherwise, we have to walk through the supertraits to find
-            // those that do.
-            self.one_bound_for_assoc_type(
-                || traits::supertraits(tcx, trait_ref),
-                trait_ref.skip_binder().print_only_trait_name(),
-                binding.item_name,
-                path_span,
-                match binding.kind {
-                    ConvertedBindingKind::Equality(term) => Some(term),
-                    _ => None,
-                },
-            )?
-        };
-
-        let (assoc_ident, def_scope) =
-            tcx.adjust_ident_and_get_scope(binding.item_name, candidate.def_id(), hir_ref_id);
-
-        // We have already adjusted the item name above, so compare with `ident.normalize_to_macros_2_0()` instead
-        // of calling `filter_by_name_and_kind`.
-        let find_item_of_kind = |kind| {
-            tcx.associated_items(candidate.def_id())
-                .filter_by_name_unhygienic(assoc_ident.name)
-                .find(|i| i.kind == kind && i.ident(tcx).normalize_to_macros_2_0() == assoc_ident)
-        };
-        let assoc_item = if return_type_notation {
-            find_item_of_kind(ty::AssocKind::Fn)
-        } else {
-            find_item_of_kind(ty::AssocKind::Type)
-                .or_else(|| find_item_of_kind(ty::AssocKind::Const))
-        }
-        .expect("missing associated type");
-
-        if !assoc_item.visibility(tcx).is_accessible_from(def_scope, tcx) {
-            tcx.sess
-                .struct_span_err(
-                    binding.span,
-                    format!("{} `{}` is private", assoc_item.kind, binding.item_name),
-                )
-                .span_label(binding.span, format!("private {}", assoc_item.kind))
-                .emit();
-        }
-        tcx.check_stability(assoc_item.def_id, Some(hir_ref_id), binding.span, None);
-
-        if !speculative {
-            dup_bindings
-                .entry(assoc_item.def_id)
-                .and_modify(|prev_span| {
-                    tcx.sess.emit_err(ValueOfAssociatedStructAlreadySpecified {
-                        span: binding.span,
-                        prev_span: *prev_span,
-                        item_name: binding.item_name,
-                        def_path: tcx.def_path_str(assoc_item.container_id(tcx)),
-                    });
-                })
-                .or_insert(binding.span);
-        }
-
-        let projection_ty = if return_type_notation {
-            let mut emitted_bad_param_err = false;
-            // If we have an method return type bound, then we need to substitute
-            // the method's early bound params with suitable late-bound params.
-            let mut num_bound_vars = candidate.bound_vars().len();
-            let substs =
-                candidate.skip_binder().substs.extend_to(tcx, assoc_item.def_id, |param, _| {
-                    let subst = match param.kind {
-                        GenericParamDefKind::Lifetime => ty::Region::new_late_bound(
-                            tcx,
-                            ty::INNERMOST,
-                            ty::BoundRegion {
-                                var: ty::BoundVar::from_usize(num_bound_vars),
-                                kind: ty::BoundRegionKind::BrNamed(param.def_id, param.name),
-                            },
-                        )
-                        .into(),
-                        GenericParamDefKind::Type { .. } => {
-                            if !emitted_bad_param_err {
-                                tcx.sess.emit_err(
-                                    crate::errors::ReturnTypeNotationIllegalParam::Type {
-                                        span: path_span,
-                                        param_span: tcx.def_span(param.def_id),
-                                    },
-                                );
-                                emitted_bad_param_err = true;
-                            }
-                            tcx.mk_bound(
-                                ty::INNERMOST,
-                                ty::BoundTy {
-                                    var: ty::BoundVar::from_usize(num_bound_vars),
-                                    kind: ty::BoundTyKind::Param(param.def_id, param.name),
-                                },
-                            )
-                            .into()
-                        }
-                        GenericParamDefKind::Const { .. } => {
-                            if !emitted_bad_param_err {
-                                tcx.sess.emit_err(
-                                    crate::errors::ReturnTypeNotationIllegalParam::Const {
-                                        span: path_span,
-                                        param_span: tcx.def_span(param.def_id),
-                                    },
-                                );
-                                emitted_bad_param_err = true;
-                            }
-                            let ty = tcx
-                                .type_of(param.def_id)
-                                .no_bound_vars()
-                                .expect("ct params cannot have early bound vars");
-                            tcx.mk_const(
-                                ty::ConstKind::Bound(
-                                    ty::INNERMOST,
-                                    ty::BoundVar::from_usize(num_bound_vars),
-                                ),
-                                ty,
-                            )
-                            .into()
-                        }
-                    };
-                    num_bound_vars += 1;
-                    subst
-                });
-
-            // Next, we need to check that the return-type notation is being used on
-            // an RPITIT (return-position impl trait in trait) or AFIT (async fn in trait).
-            let output = tcx.fn_sig(assoc_item.def_id).skip_binder().output();
-            let output = if let ty::Alias(ty::Projection, alias_ty) = *output.skip_binder().kind()
-                && tcx.def_kind(alias_ty.def_id) == DefKind::ImplTraitPlaceholder
-            {
-                alias_ty
-            } else {
-                return Err(self.tcx().sess.emit_err(
-                    crate::errors::ReturnTypeNotationOnNonRpitit {
-                        span: binding.span,
-                        ty: tcx.liberate_late_bound_regions(assoc_item.def_id, output),
-                        fn_span: tcx.hir().span_if_local(assoc_item.def_id),
-                        note: (),
-                    },
-                ));
-            };
-
-            // Finally, move the fn return type's bound vars over to account for the early bound
-            // params (and trait ref's late bound params). This logic is very similar to
-            // `Predicate::subst_supertrait`, and it's no coincidence why.
-            let shifted_output = tcx.shift_bound_var_indices(num_bound_vars, output);
-            let subst_output = ty::EarlyBinder::bind(shifted_output).subst(tcx, substs);
-
-            let bound_vars = tcx.late_bound_vars(binding.hir_id);
-            ty::Binder::bind_with_vars(subst_output, bound_vars)
-        } else {
-            // Include substitutions for generic parameters of associated types
-            candidate.map_bound(|trait_ref| {
-                let ident = Ident::new(assoc_item.name, binding.item_name.span);
-                let item_segment = hir::PathSegment {
-                    ident,
-                    hir_id: binding.hir_id,
-                    res: Res::Err,
-                    args: Some(binding.gen_args),
-                    infer_args: false,
-                };
-
-                let substs_trait_ref_and_assoc_item = self.create_substs_for_associated_item(
-                    path_span,
-                    assoc_item.def_id,
-                    &item_segment,
-                    trait_ref.substs,
-                );
-
-                debug!(?substs_trait_ref_and_assoc_item);
-
-                tcx.mk_alias_ty(assoc_item.def_id, substs_trait_ref_and_assoc_item)
-            })
-        };
-
-        if !speculative {
-            // Find any late-bound regions declared in `ty` that are not
-            // declared in the trait-ref or assoc_item. These are not well-formed.
-            //
-            // Example:
-            //
-            //     for<'a> <T as Iterator>::Item = &'a str // <-- 'a is bad
-            //     for<'a> <T as FnMut<(&'a u32,)>>::Output = &'a str // <-- 'a is ok
-            if let ConvertedBindingKind::Equality(ty) = binding.kind {
-                let late_bound_in_trait_ref =
-                    tcx.collect_constrained_late_bound_regions(&projection_ty);
-                let late_bound_in_ty =
-                    tcx.collect_referenced_late_bound_regions(&trait_ref.rebind(ty));
-                debug!(?late_bound_in_trait_ref);
-                debug!(?late_bound_in_ty);
-
-                // FIXME: point at the type params that don't have appropriate lifetimes:
-                // struct S1<F: for<'a> Fn(&i32, &i32) -> &'a i32>(F);
-                //                         ----  ----     ^^^^^^^
-                self.validate_late_bound_regions(
-                    late_bound_in_trait_ref,
-                    late_bound_in_ty,
-                    |br_name| {
-                        struct_span_err!(
-                            tcx.sess,
-                            binding.span,
-                            E0582,
-                            "binding for associated type `{}` references {}, \
-                             which does not appear in the trait input types",
-                            binding.item_name,
-                            br_name
-                        )
-                    },
-                );
-            }
-        }
-
-        match binding.kind {
-            ConvertedBindingKind::Equality(..) if return_type_notation => {
-                return Err(self.tcx().sess.emit_err(
-                    crate::errors::ReturnTypeNotationEqualityBound { span: binding.span },
-                ));
-            }
-            ConvertedBindingKind::Equality(mut term) => {
-                // "Desugar" a constraint like `T: Iterator<Item = u32>` this to
-                // the "projection predicate" for:
-                //
-                // `<T as Iterator>::Item = u32`
-                let assoc_item_def_id = projection_ty.skip_binder().def_id;
-                let def_kind = tcx.def_kind(assoc_item_def_id);
-                match (def_kind, term.unpack()) {
-                    (hir::def::DefKind::AssocTy, ty::TermKind::Ty(_))
-                    | (hir::def::DefKind::AssocConst, ty::TermKind::Const(_)) => (),
-                    (_, _) => {
-                        let got = if let Some(_) = term.ty() { "type" } else { "constant" };
-                        let expected = tcx.def_descr(assoc_item_def_id);
-                        let mut err = tcx.sess.struct_span_err(
-                            binding.span,
-                            format!("expected {expected} bound, found {got}"),
-                        );
-                        err.span_note(
-                            tcx.def_span(assoc_item_def_id),
-                            format!("{expected} defined here"),
-                        );
-
-                        if let hir::def::DefKind::AssocConst = def_kind
-                          && let Some(t) = term.ty() && (t.is_enum() || t.references_error())
-                          && tcx.features().associated_const_equality {
-                            err.span_suggestion(
-                                binding.span,
-                                "if equating a const, try wrapping with braces",
-                                format!("{} = {{ const }}", binding.item_name),
-                                Applicability::HasPlaceholders,
-                            );
-                        }
-                        let reported = err.emit();
-                        term = match def_kind {
-                            hir::def::DefKind::AssocTy => tcx.ty_error(reported).into(),
-                            hir::def::DefKind::AssocConst => tcx
-                                .const_error(
-                                    tcx.type_of(assoc_item_def_id)
-                                        .subst(tcx, projection_ty.skip_binder().substs),
-                                    reported,
-                                )
-                                .into(),
-                            _ => unreachable!(),
-                        };
-                    }
-                }
-                bounds.push_projection_bound(
-                    tcx,
-                    projection_ty
-                        .map_bound(|projection_ty| ty::ProjectionPredicate { projection_ty, term }),
-                    binding.span,
-                );
-            }
-            ConvertedBindingKind::Constraint(ast_bounds) => {
-                // "Desugar" a constraint like `T: Iterator<Item: Debug>` to
-                //
-                // `<T as Iterator>::Item: Debug`
-                //
-                // Calling `skip_binder` is okay, because `add_bounds` expects the `param_ty`
-                // parameter to have a skipped binder.
-                //
-                // NOTE: If `only_self_bounds` is true, do NOT expand this associated
-                // type bound into a trait predicate, since we only want to add predicates
-                // for the `Self` type.
-                if !only_self_bounds.0 {
-                    let param_ty = tcx.mk_alias(ty::Projection, projection_ty.skip_binder());
-                    self.add_bounds(
-                        param_ty,
-                        ast_bounds.iter(),
-                        bounds,
-                        projection_ty.bound_vars(),
-                        only_self_bounds,
-                    );
-                }
-            }
-        }
-        Ok(())
-    }
-
     fn ast_path_to_ty(
         &self,
         span: Span,
@@ -1527,15 +962,16 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                     ty::Clause::TypeOutlives(_) => {
                         // Do nothing, we deal with regions separately
                     }
-                    ty::Clause::RegionOutlives(_) | ty::Clause::ConstArgHasType(..) => bug!(),
+                    ty::Clause::RegionOutlives(_)
+                    | ty::Clause::ConstArgHasType(..)
+                    | ty::Clause::WellFormed(_)
+                    | ty::Clause::ConstEvaluatable(_) => bug!(),
                 },
-                ty::PredicateKind::WellFormed(_)
+                ty::PredicateKind::AliasRelate(..)
-                | ty::PredicateKind::AliasRelate(..)
                 | ty::PredicateKind::ObjectSafe(_)
                 | ty::PredicateKind::ClosureKind(_, _, _)
                 | ty::PredicateKind::Subtype(_)
                 | ty::PredicateKind::Coerce(_)
-                | ty::PredicateKind::ConstEvaluatable(_)
                 | ty::PredicateKind::ConstEquate(_, _)
                 | ty::PredicateKind::TypeWellFormedFromEnv(_)
                 | ty::PredicateKind::Ambiguous => bug!(),

compiler/rustc_hir_analysis/src/check/check.rs

@@ -439,7 +439,8 @@ fn check_opaque_meets_bounds<'tcx>(
     // Additionally require the hidden type to be well-formed with only the generics of the opaque type.
     // Defining use functions may have more bounds than the opaque type, which is ok, as long as the
     // hidden type is well formed even without those bounds.
-    let predicate = ty::Binder::dummy(ty::PredicateKind::WellFormed(hidden_ty.into()));
+    let predicate =
+        ty::Binder::dummy(ty::PredicateKind::Clause(ty::Clause::WellFormed(hidden_ty.into())));
     ocx.register_obligation(Obligation::new(tcx, misc_cause, param_env, predicate));
 
     // Check that all obligations are satisfied by the implementation's

compiler/rustc_hir_analysis/src/check/compare_impl_item.rs

@@ -321,7 +321,9 @@ fn compare_method_predicate_entailment<'tcx>(
             infcx.tcx,
             ObligationCause::dummy(),
             param_env,
-            ty::Binder::dummy(ty::PredicateKind::WellFormed(unnormalized_impl_fty.into())),
+            ty::Binder::dummy(ty::PredicateKind::Clause(ty::Clause::WellFormed(
+                unnormalized_impl_fty.into(),
+            ))),
         ));
     }
 

compiler/rustc_hir_analysis/src/check/wfcheck.rs

@@ -81,7 +81,7 @@ impl<'tcx> WfCheckingCtxt<'_, 'tcx> {
             self.tcx(),
             cause,
             param_env,
-            ty::Binder::dummy(ty::PredicateKind::WellFormed(arg)),
+            ty::Binder::dummy(ty::PredicateKind::Clause(ty::Clause::WellFormed(arg))),
         ));
     }
 }
@@ -1032,9 +1032,9 @@ fn check_type_defn<'tcx>(tcx: TyCtxt<'tcx>, item: &hir::Item<'tcx>, all_sized: b
                     tcx,
                     cause,
                     wfcx.param_env,
-                    ty::Binder::dummy(ty::PredicateKind::ConstEvaluatable(
+                    ty::Binder::dummy(ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(
                         ty::Const::from_anon_const(tcx, discr_def_id.expect_local()),
-                    )),
+                    ))),
                 ));
             }
         }
@@ -1876,7 +1876,8 @@ impl<'tcx> WfCheckingCtxt<'_, 'tcx> {
             // We lower empty bounds like `Vec<dyn Copy>:` as
             // `WellFormed(Vec<dyn Copy>)`, which will later get checked by
             // regular WF checking
-            if let ty::PredicateKind::WellFormed(..) = pred.kind().skip_binder() {
+            if let ty::PredicateKind::Clause(ty::Clause::WellFormed(..)) = pred.kind().skip_binder()
+            {
                 continue;
             }
             // Match the existing behavior.

compiler/rustc_hir_analysis/src/collect/predicates_of.rs

@@ -219,7 +219,7 @@ fn gather_explicit_predicates_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Gen
                     } else {
                         let span = bound_pred.bounded_ty.span;
                         let predicate = ty::Binder::bind_with_vars(
-                            ty::PredicateKind::WellFormed(ty.into()),
+                            ty::PredicateKind::Clause(ty::Clause::WellFormed(ty.into())),
                             bound_vars,
                         );
                         predicates.insert((predicate.to_predicate(tcx), span));
@@ -353,7 +353,7 @@ fn const_evaluatable_predicates_of(
             if let ty::ConstKind::Unevaluated(_) = ct.kind() {
                 let span = self.tcx.def_span(c.def_id);
                 self.preds.insert((
-                    ty::Binder::dummy(ty::PredicateKind::ConstEvaluatable(ct))
+                    ty::Binder::dummy(ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(ct)))
                         .to_predicate(self.tcx),
                     span,
                 ));

compiler/rustc_hir_analysis/src/hir_wf_check.rs

@@ -79,7 +79,7 @@ fn diagnostic_hir_wf_check<'tcx>(
                 self.tcx,
                 cause,
                 self.param_env,
-                ty::PredicateKind::WellFormed(tcx_ty.into()),
+                ty::PredicateKind::Clause(ty::Clause::WellFormed(tcx_ty.into())),
             ));
 
             for error in ocx.select_all_or_error() {

compiler/rustc_hir_analysis/src/impl_wf_check/min_specialization.rs

@@ -542,12 +542,12 @@ fn trait_predicate_kind<'tcx>(
         | ty::PredicateKind::Clause(ty::Clause::Projection(_))
         | ty::PredicateKind::Clause(ty::Clause::ConstArgHasType(..))
         | ty::PredicateKind::AliasRelate(..)
-        | ty::PredicateKind::WellFormed(_)
+        | ty::PredicateKind::Clause(ty::Clause::WellFormed(_))
         | ty::PredicateKind::Subtype(_)
         | ty::PredicateKind::Coerce(_)
         | ty::PredicateKind::ObjectSafe(_)
         | ty::PredicateKind::ClosureKind(..)
-        | ty::PredicateKind::ConstEvaluatable(..)
+        | ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(..))
         | ty::PredicateKind::ConstEquate(..)
         | ty::PredicateKind::Ambiguous
         | ty::PredicateKind::TypeWellFormedFromEnv(..) => None,

compiler/rustc_hir_analysis/src/outlives/explicit.rs

@@ -55,13 +55,13 @@ impl<'tcx> ExplicitPredicatesMap<'tcx> {
                     ty::PredicateKind::Clause(ty::Clause::Trait(..))
                     | ty::PredicateKind::Clause(ty::Clause::Projection(..))
                     | ty::PredicateKind::Clause(ty::Clause::ConstArgHasType(..))
-                    | ty::PredicateKind::WellFormed(..)
+                    | ty::PredicateKind::Clause(ty::Clause::WellFormed(..))
                     | ty::PredicateKind::AliasRelate(..)
                     | ty::PredicateKind::ObjectSafe(..)
                     | ty::PredicateKind::ClosureKind(..)
                     | ty::PredicateKind::Subtype(..)
                     | ty::PredicateKind::Coerce(..)
-                    | ty::PredicateKind::ConstEvaluatable(..)
+                    | ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(..))
                     | ty::PredicateKind::ConstEquate(..)
                     | ty::PredicateKind::Ambiguous
                     | ty::PredicateKind::TypeWellFormedFromEnv(..) => (),

compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs

@@ -483,7 +483,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             self.tcx,
             cause,
             self.param_env,
-            ty::Binder::dummy(ty::PredicateKind::WellFormed(arg)),
+            ty::Binder::dummy(ty::PredicateKind::Clause(ty::Clause::WellFormed(arg))),
         ));
     }
 
@@ -668,10 +668,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 | ty::PredicateKind::Coerce(..)
                 | ty::PredicateKind::Clause(ty::Clause::RegionOutlives(..))
                 | ty::PredicateKind::Clause(ty::Clause::TypeOutlives(..))
-                | ty::PredicateKind::WellFormed(..)
+                | ty::PredicateKind::Clause(ty::Clause::WellFormed(..))
                 | ty::PredicateKind::ObjectSafe(..)
                 | ty::PredicateKind::AliasRelate(..)
-                | ty::PredicateKind::ConstEvaluatable(..)
+                | ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(..))
                 | ty::PredicateKind::ConstEquate(..)
                 // N.B., this predicate is created by breaking down a
                 // `ClosureType: FnFoo()` predicate, where

compiler/rustc_hir_typeck/src/fn_ctxt/adjust_fulfillment_errors.rs

@@ -32,7 +32,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             ty::PredicateKind::Clause(ty::Clause::ConstArgHasType(arg, ty)) => {
                 vec![ty.into(), arg.into()]
             }
-            ty::PredicateKind::ConstEvaluatable(e) => vec![e.into()],
+            ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(e)) => vec![e.into()],
             _ => return false,
         };
 

compiler/rustc_hir_typeck/src/method/mod.rs

@@ -452,7 +452,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             tcx,
             obligation.cause,
             self.param_env,
-            ty::Binder::dummy(ty::PredicateKind::WellFormed(method_ty.into())),
+            ty::Binder::dummy(ty::PredicateKind::Clause(ty::Clause::WellFormed(method_ty.into()))),
         ));
 
         let callee = MethodCallee { def_id, substs, sig: fn_sig };

compiler/rustc_hir_typeck/src/method/probe.rs

@@ -838,11 +838,11 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
                 | ty::PredicateKind::Coerce(..)
                 | ty::PredicateKind::Clause(ty::Clause::Projection(..))
                 | ty::PredicateKind::Clause(ty::Clause::RegionOutlives(..))
-                | ty::PredicateKind::WellFormed(..)
+                | ty::PredicateKind::Clause(ty::Clause::WellFormed(..))
                 | ty::PredicateKind::ObjectSafe(..)
                 | ty::PredicateKind::ClosureKind(..)
                 | ty::PredicateKind::Clause(ty::Clause::TypeOutlives(..))
-                | ty::PredicateKind::ConstEvaluatable(..)
+                | ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(..))
                 | ty::PredicateKind::ConstEquate(..)
                 | ty::PredicateKind::Ambiguous
                 | ty::PredicateKind::AliasRelate(..)

compiler/rustc_hir_typeck/src/method/suggest.rs

@@ -696,7 +696,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 };
 
                 // Don't point out the span of `WellFormed` predicates.
-                if !matches!(p.kind().skip_binder(), ty::PredicateKind::Clause(_)) {
+                if !matches!(
+                    p.kind().skip_binder(),
+                    ty::PredicateKind::Clause(ty::Clause::Projection(..) | ty::Clause::Trait(..))
+                ) {
                     continue;
                 };
 

compiler/rustc_infer/src/infer/combine.rs

@@ -417,7 +417,7 @@ impl<'infcx, 'tcx> CombineFields<'infcx, 'tcx> {
                 self.tcx(),
                 self.trace.cause.clone(),
                 self.param_env,
-                ty::Binder::dummy(ty::PredicateKind::WellFormed(b_ty.into())),
+                ty::Binder::dummy(ty::PredicateKind::Clause(ty::Clause::WellFormed(b_ty.into()))),
             ));
         }
 

compiler/rustc_infer/src/infer/outlives/mod.rs

@@ -29,11 +29,11 @@ pub fn explicit_outlives_bounds<'tcx>(
             | ty::PredicateKind::AliasRelate(..)
             | ty::PredicateKind::Coerce(..)
             | ty::PredicateKind::Subtype(..)
-            | ty::PredicateKind::WellFormed(..)
+            | ty::PredicateKind::Clause(ty::Clause::WellFormed(..))
             | ty::PredicateKind::ObjectSafe(..)
             | ty::PredicateKind::ClosureKind(..)
             | ty::PredicateKind::Clause(ty::Clause::TypeOutlives(..))
-            | ty::PredicateKind::ConstEvaluatable(..)
+            | ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(..))
             | ty::PredicateKind::ConstEquate(..)
             | ty::PredicateKind::Ambiguous
             | ty::PredicateKind::TypeWellFormedFromEnv(..) => None,

compiler/rustc_infer/src/traits/util.rs

@@ -227,7 +227,7 @@ impl<'tcx, O: Elaboratable<'tcx>> Elaborator<'tcx, O> {
                 debug!(?data, ?obligations, "super_predicates");
                 self.extend_deduped(obligations);
             }
-            ty::PredicateKind::WellFormed(..) => {
+            ty::PredicateKind::Clause(ty::Clause::WellFormed(..)) => {
                 // Currently, we do not elaborate WF predicates,
                 // although we easily could.
             }
@@ -249,7 +249,7 @@ impl<'tcx, O: Elaboratable<'tcx>> Elaborator<'tcx, O> {
             ty::PredicateKind::ClosureKind(..) => {
                 // Nothing to elaborate when waiting for a closure's kind to be inferred.
             }
-            ty::PredicateKind::ConstEvaluatable(..) => {
+            ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(..)) => {
                 // Currently, we do not elaborate const-evaluatable
                 // predicates.
             }

compiler/rustc_lint/src/builtin.rs

@@ -1610,13 +1610,13 @@ impl<'tcx> LateLintPass<'tcx> for TrivialConstraints {
                     Clause(Clause::Projection(..)) |
                     AliasRelate(..) |
                     // Ignore bounds that a user can't type
-                    WellFormed(..) |
+                    Clause(Clause::WellFormed(..)) |
+                    // FIXME(generic_const_exprs): `ConstEvaluatable` can be written
+                    Clause(Clause::ConstEvaluatable(..)) |
                     ObjectSafe(..) |
                     ClosureKind(..) |
                     Subtype(..) |
                     Coerce(..) |
-                    // FIXME(generic_const_exprs): `ConstEvaluatable` can be written
-                    ConstEvaluatable(..) |
                     ConstEquate(..) |
                     Ambiguous |
                     TypeWellFormedFromEnv(..) => continue,

compiler/rustc_middle/src/ty/flags.rs

@@ -270,14 +270,14 @@ impl FlagComputation {
                 self.add_alias_ty(projection_ty);
                 self.add_term(term);
             }
-            ty::PredicateKind::WellFormed(arg) => {
+            ty::PredicateKind::Clause(ty::Clause::WellFormed(arg)) => {
                 self.add_substs(slice::from_ref(&arg));
             }
             ty::PredicateKind::ObjectSafe(_def_id) => {}
             ty::PredicateKind::ClosureKind(_def_id, substs, _kind) => {
                 self.add_substs(substs);
             }
-            ty::PredicateKind::ConstEvaluatable(uv) => {
+            ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(uv)) => {
                 self.add_const(uv);
             }
             ty::PredicateKind::ConstEquate(expected, found) => {

compiler/rustc_middle/src/ty/mod.rs

@@ -523,7 +523,7 @@ impl<'tcx> Predicate<'tcx> {
             ty::PredicateKind::Clause(ty::Clause::Trait(data)) => {
                 tcx.trait_is_coinductive(data.def_id())
             }
-            ty::PredicateKind::WellFormed(_) => true,
+            ty::PredicateKind::Clause(ty::Clause::WellFormed(_)) => true,
             _ => false,
         }
     }
@@ -536,7 +536,7 @@ impl<'tcx> Predicate<'tcx> {
     #[inline]
     pub fn allow_normalization(self) -> bool {
         match self.kind().skip_binder() {
-            PredicateKind::WellFormed(_) => false,
+            PredicateKind::Clause(Clause::WellFormed(_)) => false,
             PredicateKind::Clause(Clause::Trait(_))
             | PredicateKind::Clause(Clause::RegionOutlives(_))
             | PredicateKind::Clause(Clause::TypeOutlives(_))
@@ -547,7 +547,7 @@ impl<'tcx> Predicate<'tcx> {
             | PredicateKind::ClosureKind(_, _, _)
             | PredicateKind::Subtype(_)
             | PredicateKind::Coerce(_)
-            | PredicateKind::ConstEvaluatable(_)
+            | PredicateKind::Clause(Clause::ConstEvaluatable(_))
             | PredicateKind::ConstEquate(_, _)
             | PredicateKind::Ambiguous
             | PredicateKind::TypeWellFormedFromEnv(_) => true,
@@ -584,6 +584,12 @@ pub enum Clause<'tcx> {
     /// Ensures that a const generic argument to a parameter `const N: u8`
     /// is of type `u8`.
     ConstArgHasType(Const<'tcx>, Ty<'tcx>),
+
+    /// No syntax: `T` well-formed.
+    WellFormed(GenericArg<'tcx>),
+
+    /// Constant initializer must evaluate successfully.
+    ConstEvaluatable(ty::Const<'tcx>),
 }
 
 impl<'tcx> Binder<'tcx, Clause<'tcx>> {
@@ -610,9 +616,6 @@ pub enum PredicateKind<'tcx> {
     /// Prove a clause
     Clause(Clause<'tcx>),
 
-    /// No syntax: `T` well-formed.
-    WellFormed(GenericArg<'tcx>),
-
     /// Trait must be object-safe.
     ObjectSafe(DefId),
 
@@ -638,9 +641,6 @@ pub enum PredicateKind<'tcx> {
     /// logic.
     Coerce(CoercePredicate<'tcx>),
 
-    /// Constant initializer must evaluate successfully.
-    ConstEvaluatable(ty::Const<'tcx>),
-
     /// Constants must be equal. The first component is the const that is expected.
     ConstEquate(Const<'tcx>, Const<'tcx>),
 
@@ -1324,11 +1324,11 @@ impl<'tcx> Predicate<'tcx> {
             | PredicateKind::Subtype(..)
             | PredicateKind::Coerce(..)
             | PredicateKind::Clause(Clause::RegionOutlives(..))
-            | PredicateKind::WellFormed(..)
+            | PredicateKind::Clause(Clause::WellFormed(..))
             | PredicateKind::ObjectSafe(..)
             | PredicateKind::ClosureKind(..)
             | PredicateKind::Clause(Clause::TypeOutlives(..))
-            | PredicateKind::ConstEvaluatable(..)
+            | PredicateKind::Clause(Clause::ConstEvaluatable(..))
             | PredicateKind::ConstEquate(..)
             | PredicateKind::Ambiguous
             | PredicateKind::TypeWellFormedFromEnv(..) => None,
@@ -1345,11 +1345,11 @@ impl<'tcx> Predicate<'tcx> {
             | PredicateKind::Subtype(..)
             | PredicateKind::Coerce(..)
             | PredicateKind::Clause(Clause::RegionOutlives(..))
-            | PredicateKind::WellFormed(..)
+            | PredicateKind::Clause(Clause::WellFormed(..))
             | PredicateKind::ObjectSafe(..)
             | PredicateKind::ClosureKind(..)
             | PredicateKind::Clause(Clause::TypeOutlives(..))
-            | PredicateKind::ConstEvaluatable(..)
+            | PredicateKind::Clause(Clause::ConstEvaluatable(..))
             | PredicateKind::ConstEquate(..)
             | PredicateKind::Ambiguous
             | PredicateKind::TypeWellFormedFromEnv(..) => None,
@@ -1367,10 +1367,10 @@ impl<'tcx> Predicate<'tcx> {
             | PredicateKind::Subtype(..)
             | PredicateKind::Coerce(..)
             | PredicateKind::Clause(Clause::RegionOutlives(..))
-            | PredicateKind::WellFormed(..)
+            | PredicateKind::Clause(Clause::WellFormed(..))
             | PredicateKind::ObjectSafe(..)
             | PredicateKind::ClosureKind(..)
-            | PredicateKind::ConstEvaluatable(..)
+            | PredicateKind::Clause(Clause::ConstEvaluatable(..))
             | PredicateKind::ConstEquate(..)
             | PredicateKind::Ambiguous
             | PredicateKind::TypeWellFormedFromEnv(..) => None,
@@ -1384,10 +1384,8 @@ impl<'tcx> Predicate<'tcx> {
             PredicateKind::AliasRelate(..)
             | PredicateKind::Subtype(..)
             | PredicateKind::Coerce(..)
-            | PredicateKind::WellFormed(..)
             | PredicateKind::ObjectSafe(..)
             | PredicateKind::ClosureKind(..)
-            | PredicateKind::ConstEvaluatable(..)
             | PredicateKind::ConstEquate(..)
             | PredicateKind::Ambiguous
             | PredicateKind::TypeWellFormedFromEnv(..) => None,

compiler/rustc_middle/src/ty/print/pretty.rs

@@ -2877,7 +2877,7 @@ define_print_and_forward_display! {
             ty::PredicateKind::Clause(ty::Clause::ConstArgHasType(ct, ty)) => {
                 p!("the constant `", print(ct), "` has type `", print(ty), "`")
             },
-            ty::PredicateKind::WellFormed(arg) => p!(print(arg), " well-formed"),
+            ty::PredicateKind::Clause(ty::Clause::WellFormed(arg)) => p!(print(arg), " well-formed"),
             ty::PredicateKind::ObjectSafe(trait_def_id) => {
                 p!("the trait `", print_def_path(trait_def_id, &[]), "` is object-safe")
             }
@@ -2886,7 +2886,7 @@ define_print_and_forward_display! {
                 print_value_path(closure_def_id, &[]),
                 write("` implements the trait `{}`", kind)
             ),
-            ty::PredicateKind::ConstEvaluatable(ct) => {
+            ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(ct)) => {
                 p!("the constant `", print(ct), "` can be evaluated")
             }
             ty::PredicateKind::ConstEquate(c1, c2) => {

compiler/rustc_middle/src/ty/structural_impls.rs

@@ -179,6 +179,10 @@ impl<'tcx> fmt::Debug for ty::Clause<'tcx> {
             ty::Clause::RegionOutlives(ref pair) => pair.fmt(f),
             ty::Clause::TypeOutlives(ref pair) => pair.fmt(f),
             ty::Clause::Projection(ref pair) => pair.fmt(f),
+            ty::Clause::WellFormed(ref data) => write!(f, "WellFormed({:?})", data),
+            ty::Clause::ConstEvaluatable(ct) => {
+                write!(f, "ConstEvaluatable({ct:?})")
+            }
         }
     }
 }
@@ -189,16 +193,12 @@ impl<'tcx> fmt::Debug for ty::PredicateKind<'tcx> {
             ty::PredicateKind::Clause(ref a) => a.fmt(f),
             ty::PredicateKind::Subtype(ref pair) => pair.fmt(f),
             ty::PredicateKind::Coerce(ref pair) => pair.fmt(f),
-            ty::PredicateKind::WellFormed(data) => write!(f, "WellFormed({:?})", data),
             ty::PredicateKind::ObjectSafe(trait_def_id) => {
                 write!(f, "ObjectSafe({:?})", trait_def_id)
             }
             ty::PredicateKind::ClosureKind(closure_def_id, closure_substs, kind) => {
                 write!(f, "ClosureKind({:?}, {:?}, {:?})", closure_def_id, closure_substs, kind)
             }
-            ty::PredicateKind::ConstEvaluatable(ct) => {
-                write!(f, "ConstEvaluatable({ct:?})")
-            }
             ty::PredicateKind::ConstEquate(c1, c2) => write!(f, "ConstEquate({:?}, {:?})", c1, c2),
             ty::PredicateKind::TypeWellFormedFromEnv(ty) => {
                 write!(f, "TypeWellFormedFromEnv({:?})", ty)

compiler/rustc_privacy/src/lib.rs

@@ -182,8 +182,8 @@ where
                 ct.visit_with(self)?;
                 ty.visit_with(self)
             }
-            ty::PredicateKind::ConstEvaluatable(ct) => ct.visit_with(self),
+            ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(ct)) => ct.visit_with(self),
-            ty::PredicateKind::WellFormed(arg) => arg.visit_with(self),
+            ty::PredicateKind::Clause(ty::Clause::WellFormed(arg)) => arg.visit_with(self),
 
             ty::PredicateKind::ObjectSafe(_)
             | ty::PredicateKind::ClosureKind(_, _, _)

compiler/rustc_trait_selection/src/solve/eval_ctxt.rs

@@ -319,14 +319,14 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
                 ty::PredicateKind::ObjectSafe(trait_def_id) => {
                     self.compute_object_safe_goal(trait_def_id)
                 }
-                ty::PredicateKind::WellFormed(arg) => {
+                ty::PredicateKind::Clause(ty::Clause::WellFormed(arg)) => {
                     self.compute_well_formed_goal(Goal { param_env, predicate: arg })
                 }
                 ty::PredicateKind::Ambiguous => {
                     self.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS)
                 }
                 // FIXME: implement this predicate :)
-                ty::PredicateKind::ConstEvaluatable(_) => {
+                ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(_)) => {
                     self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
                 }
                 ty::PredicateKind::ConstEquate(_, _) => {

compiler/rustc_trait_selection/src/solve/fulfill.rs

@@ -119,10 +119,8 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentCtxt<'tcx> {
                                     )
                                 }
                                 ty::PredicateKind::Clause(_)
-                                | ty::PredicateKind::WellFormed(_)
                                 | ty::PredicateKind::ObjectSafe(_)
                                 | ty::PredicateKind::ClosureKind(_, _, _)
-                                | ty::PredicateKind::ConstEvaluatable(_)
                                 | ty::PredicateKind::Ambiguous => {
                                     FulfillmentErrorCode::CodeSelectionError(
                                         SelectionError::Unimplemented,

compiler/rustc_trait_selection/src/traits/auto_trait.rs

@@ -826,14 +826,14 @@ impl<'tcx> AutoTraitFinder<'tcx> {
                 // we start out with a `ParamEnv` with no inference variables,
                 // and these don't correspond to adding any new bounds to
                 // the `ParamEnv`.
-                ty::PredicateKind::WellFormed(..)
+                ty::PredicateKind::Clause(ty::Clause::WellFormed(..))
                 | ty::PredicateKind::Clause(ty::Clause::ConstArgHasType(..))
                 | ty::PredicateKind::AliasRelate(..)
                 | ty::PredicateKind::ObjectSafe(..)
                 | ty::PredicateKind::ClosureKind(..)
                 | ty::PredicateKind::Subtype(..)
                 // FIXME(generic_const_exprs): you can absolutely add this as a where clauses
-                | ty::PredicateKind::ConstEvaluatable(..)
+                | ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(..))
                 | ty::PredicateKind::Coerce(..) => {}
                 ty::PredicateKind::TypeWellFormedFromEnv(..) => {
                     bug!("predicate should only exist in the environment: {bound_predicate:?}")

compiler/rustc_trait_selection/src/traits/const_evaluatable.rs

@@ -207,7 +207,7 @@ fn satisfied_from_param_env<'tcx>(
 
     for pred in param_env.caller_bounds() {
         match pred.kind().skip_binder() {
-            ty::PredicateKind::ConstEvaluatable(ce) => {
+            ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(ce)) => {
                 let b_ct = tcx.expand_abstract_consts(ce);
                 let mut v = Visitor { ct, infcx, param_env, single_match };
                 let _ = b_ct.visit_with(&mut v);

compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs

@@ -1048,7 +1048,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                         self.report_closure_error(&obligation, closure_def_id, found_kind, kind)
                     }
 
-                    ty::PredicateKind::WellFormed(ty) => {
+                    ty::PredicateKind::Clause(ty::Clause::WellFormed(ty)) => {
                         match self.tcx.sess.opts.unstable_opts.trait_solver {
                             TraitSolver::Classic => {
                                 // WF predicates cannot themselves make
@@ -1069,7 +1069,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                         }
                     }
 
-                    ty::PredicateKind::ConstEvaluatable(..) => {
+                    ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(..)) => {
                         // Errors for `ConstEvaluatable` predicates show up as
                         // `SelectionError::ConstEvalFailure`,
                         // not `Unimplemented`.
@@ -2415,7 +2415,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                 err
             }
 
-            ty::PredicateKind::WellFormed(arg) => {
+            ty::PredicateKind::Clause(ty::Clause::WellFormed(arg)) => {
                 // Same hacky approach as above to avoid deluging user
                 // with error messages.
                 if arg.references_error()
@@ -2487,7 +2487,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                 }
             }
 
-            ty::PredicateKind::ConstEvaluatable(data) => {
+            ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(data)) => {
                 if predicate.references_error() || self.tainted_by_errors().is_some() {
                     return;
                 }
@@ -3325,7 +3325,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         }
 
         match obligation.predicate.kind().skip_binder() {
-            ty::PredicateKind::ConstEvaluatable(ct) => {
+            ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(ct)) => {
                 let ty::ConstKind::Unevaluated(uv) = ct.kind() else {
                     bug!("const evaluatable failed for non-unevaluated const `{ct:?}`");
                 };

compiler/rustc_trait_selection/src/traits/fulfill.rs

@@ -354,12 +354,12 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                 ty::PredicateKind::Clause(ty::Clause::RegionOutlives(_))
                 | ty::PredicateKind::Clause(ty::Clause::TypeOutlives(_))
                 | ty::PredicateKind::Clause(ty::Clause::ConstArgHasType(..))
-                | ty::PredicateKind::WellFormed(_)
+                | ty::PredicateKind::Clause(ty::Clause::WellFormed(_))
                 | ty::PredicateKind::ObjectSafe(_)
                 | ty::PredicateKind::ClosureKind(..)
                 | ty::PredicateKind::Subtype(_)
                 | ty::PredicateKind::Coerce(_)
-                | ty::PredicateKind::ConstEvaluatable(..)
+                | ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(..))
                 | ty::PredicateKind::ConstEquate(..) => {
                     let pred =
                         ty::Binder::dummy(infcx.instantiate_binder_with_placeholders(binder));
@@ -433,7 +433,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                     }
                 }
 
-                ty::PredicateKind::WellFormed(arg) => {
+                ty::PredicateKind::Clause(ty::Clause::WellFormed(arg)) => {
                     match wf::obligations(
                         self.selcx.infcx,
                         obligation.param_env,
@@ -498,7 +498,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                     }
                 }
 
-                ty::PredicateKind::ConstEvaluatable(uv) => {
+                ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(uv)) => {
                     match const_evaluatable::is_const_evaluatable(
                         self.selcx.infcx,
                         uv,

compiler/rustc_trait_selection/src/traits/object_safety.rs

@@ -310,7 +310,7 @@ fn predicate_references_self<'tcx>(
 
         ty::PredicateKind::AliasRelate(..) => bug!("`AliasRelate` not allowed as assumption"),
 
-        ty::PredicateKind::WellFormed(..)
+        ty::PredicateKind::Clause(ty::Clause::WellFormed(..))
         | ty::PredicateKind::ObjectSafe(..)
         | ty::PredicateKind::Clause(ty::Clause::TypeOutlives(..))
         | ty::PredicateKind::Clause(ty::Clause::RegionOutlives(..))
@@ -318,7 +318,7 @@ fn predicate_references_self<'tcx>(
         | ty::PredicateKind::Subtype(..)
         | ty::PredicateKind::Coerce(..)
         // FIXME(generic_const_exprs): this can mention `Self`
-        | ty::PredicateKind::ConstEvaluatable(..)
+        | ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(..))
         | ty::PredicateKind::ConstEquate(..)
         | ty::PredicateKind::Ambiguous
         | ty::PredicateKind::TypeWellFormedFromEnv(..) => None,
@@ -361,11 +361,11 @@ fn generics_require_sized_self(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
         | ty::PredicateKind::Subtype(..)
         | ty::PredicateKind::Coerce(..)
         | ty::PredicateKind::Clause(ty::Clause::RegionOutlives(..))
-        | ty::PredicateKind::WellFormed(..)
+        | ty::PredicateKind::Clause(ty::Clause::WellFormed(..))
         | ty::PredicateKind::ObjectSafe(..)
         | ty::PredicateKind::ClosureKind(..)
         | ty::PredicateKind::Clause(ty::Clause::TypeOutlives(..))
-        | ty::PredicateKind::ConstEvaluatable(..)
+        | ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(..))
         | ty::PredicateKind::ConstEquate(..)
         | ty::PredicateKind::AliasRelate(..)
         | ty::PredicateKind::Ambiguous

compiler/rustc_trait_selection/src/traits/query/type_op/ascribe_user_type.rs

@@ -67,7 +67,8 @@ fn relate_mir_and_user_ty<'tcx>(
     ocx.eq(&cause, param_env, mir_ty, user_ty)?;
 
     // FIXME(#104764): We should check well-formedness before normalization.
-    let predicate = ty::Binder::dummy(ty::PredicateKind::WellFormed(user_ty.into()));
+    let predicate =
+        ty::Binder::dummy(ty::PredicateKind::Clause(ty::Clause::WellFormed(user_ty.into())));
     ocx.register_obligation(Obligation::new(ocx.infcx.tcx, cause, param_env, predicate));
     Ok(())
 }
@@ -119,7 +120,9 @@ fn relate_mir_and_user_substs<'tcx>(
         let impl_self_ty = ocx.normalize(&cause, param_env, impl_self_ty);
 
         ocx.eq(&cause, param_env, self_ty, impl_self_ty)?;
-        let predicate = ty::Binder::dummy(ty::PredicateKind::WellFormed(impl_self_ty.into()));
+        let predicate = ty::Binder::dummy(ty::PredicateKind::Clause(ty::Clause::WellFormed(
+            impl_self_ty.into(),
+        )));
         ocx.register_obligation(Obligation::new(tcx, cause.clone(), param_env, predicate));
     }
 
@@ -134,7 +137,7 @@ fn relate_mir_and_user_substs<'tcx>(
     // them?  This would only be relevant if some input
     // type were ill-formed but did not appear in `ty`,
     // which...could happen with normalization...
-    let predicate = ty::Binder::dummy(ty::PredicateKind::WellFormed(ty.into()));
+    let predicate = ty::Binder::dummy(ty::PredicateKind::Clause(ty::Clause::WellFormed(ty.into())));
     ocx.register_obligation(Obligation::new(tcx, cause, param_env, predicate));
     Ok(())
 }

compiler/rustc_trait_selection/src/traits/query/type_op/implied_outlives_bounds.rs

@@ -130,14 +130,14 @@ pub fn compute_implied_outlives_bounds_inner<'tcx>(
                 | ty::PredicateKind::Clause(ty::Clause::Projection(..))
                 | ty::PredicateKind::ClosureKind(..)
                 | ty::PredicateKind::ObjectSafe(..)
-                | ty::PredicateKind::ConstEvaluatable(..)
+                | ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(..))
                 | ty::PredicateKind::ConstEquate(..)
                 | ty::PredicateKind::Ambiguous
                 | ty::PredicateKind::AliasRelate(..)
                 | ty::PredicateKind::TypeWellFormedFromEnv(..) => {}
 
                 // We need to search through *all* WellFormed predicates
-                ty::PredicateKind::WellFormed(arg) => {
+                ty::PredicateKind::Clause(ty::Clause::WellFormed(arg)) => {
                     wf_args.push(arg);
                 }
 

compiler/rustc_trait_selection/src/traits/select/mod.rs

@@ -674,7 +674,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                     }
                 }
 
-                ty::PredicateKind::WellFormed(arg) => {
+                ty::PredicateKind::Clause(ty::Clause::WellFormed(arg)) => {
                     // So, there is a bit going on here. First, `WellFormed` predicates
                     // are coinductive, like trait predicates with auto traits.
                     // This means that we need to detect if we have recursively
@@ -862,7 +862,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                     }
                 }
 
-                ty::PredicateKind::ConstEvaluatable(uv) => {
+                ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(uv)) => {
                     match const_evaluatable::is_const_evaluatable(
                         self.infcx,
                         uv,

compiler/rustc_trait_selection/src/traits/wf.rs

@@ -160,11 +160,11 @@ pub fn predicate_obligations<'tcx>(
             wf.compute(ct.into());
             wf.compute(ty.into());
         }
-        ty::PredicateKind::WellFormed(arg) => {
+        ty::PredicateKind::Clause(ty::Clause::WellFormed(arg)) => {
             wf.compute(arg);
         }
 
-        ty::PredicateKind::ConstEvaluatable(ct) => {
+        ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(ct)) => {
             wf.compute(ct.into());
         }
 
@@ -386,7 +386,7 @@ impl<'a, 'tcx> WfPredicates<'a, 'tcx> {
                         cause,
                         depth,
                         param_env,
-                        ty::Binder::dummy(ty::PredicateKind::WellFormed(arg)),
+                        ty::Binder::dummy(ty::PredicateKind::Clause(ty::Clause::WellFormed(arg))),
                     )
                 }),
         );
@@ -478,7 +478,7 @@ impl<'a, 'tcx> WfPredicates<'a, 'tcx> {
                         cause.clone(),
                         depth,
                         param_env,
-                        ty::Binder::dummy(ty::PredicateKind::WellFormed(arg)),
+                        ty::Binder::dummy(ty::PredicateKind::Clause(ty::Clause::WellFormed(arg))),
                     )
                 }),
         );
@@ -521,8 +521,9 @@ impl<'a, 'tcx> WfPredicates<'a, 'tcx> {
                                 let obligations = self.nominal_obligations(uv.def, uv.substs);
                                 self.out.extend(obligations);
 
-                                let predicate =
+                                let predicate = ty::Binder::dummy(ty::PredicateKind::Clause(
-                                    ty::Binder::dummy(ty::PredicateKind::ConstEvaluatable(ct));
+                                    ty::Clause::ConstEvaluatable(ct),
+                                ));
                                 let cause = self.cause(traits::WellFormed(None));
                                 self.out.push(traits::Obligation::with_depth(
                                     self.tcx(),
@@ -541,7 +542,9 @@ impl<'a, 'tcx> WfPredicates<'a, 'tcx> {
                                 cause,
                                 self.recursion_depth,
                                 self.param_env,
-                                ty::Binder::dummy(ty::PredicateKind::WellFormed(ct.into())),
+                                ty::Binder::dummy(ty::PredicateKind::Clause(
+                                    ty::Clause::WellFormed(ct.into()),
+                                )),
                             ));
                         }
                         ty::ConstKind::Expr(_) => {
@@ -552,8 +555,9 @@ impl<'a, 'tcx> WfPredicates<'a, 'tcx> {
                             // the future we may allow directly lowering to `ConstKind::Expr` in which case
                             // we would not be proving bounds we should.
 
-                            let predicate =
+                            let predicate = ty::Binder::dummy(ty::PredicateKind::Clause(
-                                ty::Binder::dummy(ty::PredicateKind::ConstEvaluatable(ct));
+                                ty::Clause::ConstEvaluatable(ct),
+                            ));
                             let cause = self.cause(traits::WellFormed(None));
                             self.out.push(traits::Obligation::with_depth(
                                 self.tcx(),
@@ -784,7 +788,9 @@ impl<'a, 'tcx> WfPredicates<'a, 'tcx> {
                         cause,
                         self.recursion_depth,
                         param_env,
-                        ty::Binder::dummy(ty::PredicateKind::WellFormed(ty.into())),
+                        ty::Binder::dummy(ty::PredicateKind::Clause(ty::Clause::WellFormed(
+                            ty.into(),
+                        ))),
                     ));
                 }
             }
@@ -969,11 +975,11 @@ pub(crate) fn required_region_bounds<'tcx>(
                 | ty::PredicateKind::Clause(ty::Clause::ConstArgHasType(..))
                 | ty::PredicateKind::Subtype(..)
                 | ty::PredicateKind::Coerce(..)
-                | ty::PredicateKind::WellFormed(..)
+                | ty::PredicateKind::Clause(ty::Clause::WellFormed(..))
                 | ty::PredicateKind::ObjectSafe(..)
                 | ty::PredicateKind::ClosureKind(..)
                 | ty::PredicateKind::Clause(ty::Clause::RegionOutlives(..))
-                | ty::PredicateKind::ConstEvaluatable(..)
+                | ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(..))
                 | ty::PredicateKind::ConstEquate(..)
                 | ty::PredicateKind::Ambiguous
                 | ty::PredicateKind::AliasRelate(..)

compiler/rustc_traits/src/chalk/lowering.rs

@@ -122,7 +122,7 @@ impl<'tcx> LowerInto<'tcx, chalk_ir::InEnvironment<chalk_ir::Goal<RustInterner<'
                         predicate.lower_into(interner),
                     ))
                 }
-                ty::PredicateKind::WellFormed(arg) => match arg.unpack() {
+                ty::PredicateKind::Clause(ty::Clause::WellFormed(arg)) => match arg.unpack() {
                     ty::GenericArgKind::Type(ty) => chalk_ir::DomainGoal::WellFormed(
                         chalk_ir::WellFormed::Ty(ty.lower_into(interner)),
                     ),
@@ -137,7 +137,7 @@ impl<'tcx> LowerInto<'tcx, chalk_ir::InEnvironment<chalk_ir::Goal<RustInterner<'
                 | ty::PredicateKind::ClosureKind(..)
                 | ty::PredicateKind::Subtype(..)
                 | ty::PredicateKind::Coerce(..)
-                | ty::PredicateKind::ConstEvaluatable(..)
+                | ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(..))
                 | ty::PredicateKind::Ambiguous
                 | ty::PredicateKind::ConstEquate(..) => bug!("unexpected predicate {}", predicate),
             };
@@ -192,7 +192,7 @@ impl<'tcx> LowerInto<'tcx, chalk_ir::GoalData<RustInterner<'tcx>>> for ty::Predi
                     chalk_ir::WhereClause::AliasEq(predicate.lower_into(interner)),
                 ))
             }
-            ty::PredicateKind::WellFormed(arg) => match arg.unpack() {
+            ty::PredicateKind::Clause(ty::Clause::WellFormed(arg)) => match arg.unpack() {
                 GenericArgKind::Type(ty) => match ty.kind() {
                     // FIXME(chalk): In Chalk, a placeholder is WellFormed if it
                     // `FromEnv`. However, when we "lower" Params, we don't update
@@ -231,7 +231,7 @@ impl<'tcx> LowerInto<'tcx, chalk_ir::GoalData<RustInterner<'tcx>>> for ty::Predi
             | ty::PredicateKind::Clause(ty::Clause::ConstArgHasType(..))
             | ty::PredicateKind::AliasRelate(..)
             | ty::PredicateKind::Coerce(..)
-            | ty::PredicateKind::ConstEvaluatable(..)
+            | ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(..))
             | ty::PredicateKind::Ambiguous
             | ty::PredicateKind::ConstEquate(..) => {
                 chalk_ir::GoalData::All(chalk_ir::Goals::empty(interner))
@@ -672,7 +672,7 @@ impl<'tcx> LowerInto<'tcx, Option<chalk_ir::QuantifiedWhereClause<RustInterner<'
             ty::PredicateKind::Clause(ty::Clause::Projection(predicate)) => {
                 Some(chalk_ir::WhereClause::AliasEq(predicate.lower_into(interner)))
             }
-            ty::PredicateKind::WellFormed(_ty) => None,
+            ty::PredicateKind::Clause(ty::Clause::WellFormed(_ty)) => None,
             ty::PredicateKind::Clause(ty::Clause::ConstArgHasType(..)) => None,
 
             ty::PredicateKind::ObjectSafe(..)
@@ -680,7 +680,7 @@ impl<'tcx> LowerInto<'tcx, Option<chalk_ir::QuantifiedWhereClause<RustInterner<'
             | ty::PredicateKind::ClosureKind(..)
             | ty::PredicateKind::Subtype(..)
             | ty::PredicateKind::Coerce(..)
-            | ty::PredicateKind::ConstEvaluatable(..)
+            | ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(..))
             | ty::PredicateKind::ConstEquate(..)
             | ty::PredicateKind::Ambiguous
             | ty::PredicateKind::TypeWellFormedFromEnv(..) => {
@@ -807,7 +807,7 @@ impl<'tcx> LowerInto<'tcx, Option<chalk_solve::rust_ir::QuantifiedInlineBound<Ru
                 ))
             }
             ty::PredicateKind::Clause(ty::Clause::TypeOutlives(_predicate)) => None,
-            ty::PredicateKind::WellFormed(_ty) => None,
+            ty::PredicateKind::Clause(ty::Clause::WellFormed(_ty)) => None,
             ty::PredicateKind::Clause(ty::Clause::ConstArgHasType(..)) => None,
 
             ty::PredicateKind::Clause(ty::Clause::RegionOutlives(..))
@@ -816,7 +816,7 @@ impl<'tcx> LowerInto<'tcx, Option<chalk_solve::rust_ir::QuantifiedInlineBound<Ru
             | ty::PredicateKind::ClosureKind(..)
             | ty::PredicateKind::Subtype(..)
             | ty::PredicateKind::Coerce(..)
-            | ty::PredicateKind::ConstEvaluatable(..)
+            | ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(..))
             | ty::PredicateKind::ConstEquate(..)
             | ty::PredicateKind::Ambiguous
             | ty::PredicateKind::TypeWellFormedFromEnv(..) => {

compiler/rustc_traits/src/normalize_erasing_regions.rs

@@ -62,12 +62,12 @@ fn not_outlives_predicate(p: ty::Predicate<'_>) -> bool {
         | ty::PredicateKind::Clause(ty::Clause::Projection(..))
         | ty::PredicateKind::Clause(ty::Clause::ConstArgHasType(..))
         | ty::PredicateKind::AliasRelate(..)
-        | ty::PredicateKind::WellFormed(..)
+        | ty::PredicateKind::Clause(ty::Clause::WellFormed(..))
         | ty::PredicateKind::ObjectSafe(..)
         | ty::PredicateKind::ClosureKind(..)
         | ty::PredicateKind::Subtype(..)
         | ty::PredicateKind::Coerce(..)
-        | ty::PredicateKind::ConstEvaluatable(..)
+        | ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(..))
         | ty::PredicateKind::ConstEquate(..)
         | ty::PredicateKind::Ambiguous
         | ty::PredicateKind::TypeWellFormedFromEnv(..) => true,

src/librustdoc/clean/mod.rs

@@ -344,8 +344,8 @@ pub(crate) fn clean_predicate<'tcx>(
             Some(clean_projection_predicate(bound_predicate.rebind(pred), cx))
         }
         // FIXME(generic_const_exprs): should this do something?
-        ty::PredicateKind::ConstEvaluatable(..) => None,
+        ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(..)) => None,
-        ty::PredicateKind::WellFormed(..) => None,
+        ty::PredicateKind::Clause(ty::Clause::WellFormed(..)) => None,
         ty::PredicateKind::Clause(ty::Clause::ConstArgHasType(..)) => None,
 
         ty::PredicateKind::Subtype(..)

src/tools/clippy/clippy_utils/src/qualify_min_const_fn.rs

@@ -33,8 +33,8 @@ pub fn is_min_const_fn<'tcx>(tcx: TyCtxt<'tcx>, body: &Body<'tcx>, msrv: &Msrv)
                     | ty::Clause::Trait(..)
                     | ty::Clause::ConstArgHasType(..),
                 )
-                | ty::PredicateKind::WellFormed(_)
+                | ty::PredicateKind::Clause(ty::Clause::WellFormed(_))
-                | ty::PredicateKind::ConstEvaluatable(..)
+                | ty::PredicateKind::Clause(ty::Clause::ConstEvaluatable(..))
                 | ty::PredicateKind::ConstEquate(..)
                 | ty::PredicateKind::TypeWellFormedFromEnv(..) => continue,
                 ty::PredicateKind::AliasRelate(..) => panic!("alias relate predicate on function: {predicate:#?}"),