Make queries more explicit

compiler/rustc_hir_analysis/src/collect.rs

@@ -70,10 +70,10 @@ pub fn provide(providers: &mut Providers) {
         predicates_of: predicates_of::predicates_of,
         predicates_defined_on,
         explicit_predicates_of: predicates_of::explicit_predicates_of,
-        super_predicates_of: predicates_of::super_predicates_of,
-        implied_predicates_of: predicates_of::implied_predicates_of,
-        super_predicates_that_define_assoc_item:
-            predicates_of::super_predicates_that_define_assoc_item,
+        explicit_super_predicates_of: predicates_of::explicit_super_predicates_of,
+        explicit_implied_predicates_of: predicates_of::explicit_implied_predicates_of,
+        explicit_supertraits_containing_assoc_item:
+            predicates_of::explicit_supertraits_containing_assoc_item,
         trait_explicit_predicates_and_bounds: predicates_of::trait_explicit_predicates_and_bounds,
         type_param_predicates: predicates_of::type_param_predicates,
         trait_def,
@@ -691,14 +691,14 @@ fn lower_item(tcx: TyCtxt<'_>, item_id: hir::ItemId) {
         hir::ItemKind::Trait(..) => {
             tcx.ensure().generics_of(def_id);
             tcx.ensure().trait_def(def_id);
-            tcx.at(it.span).super_predicates_of(def_id);
+            tcx.at(it.span).explicit_super_predicates_of(def_id);
             tcx.ensure().predicates_of(def_id);
             tcx.ensure().associated_items(def_id);
         }
         hir::ItemKind::TraitAlias(..) => {
             tcx.ensure().generics_of(def_id);
-            tcx.at(it.span).implied_predicates_of(def_id);
-            tcx.at(it.span).super_predicates_of(def_id);
+            tcx.at(it.span).explicit_implied_predicates_of(def_id);
+            tcx.at(it.span).explicit_super_predicates_of(def_id);
             tcx.ensure().predicates_of(def_id);
         }
         hir::ItemKind::Struct(struct_def, _) | hir::ItemKind::Union(struct_def, _) => {

compiler/rustc_hir_analysis/src/collect/predicates_of.rs

@@ -519,21 +519,21 @@ pub(super) fn explicit_predicates_of<'tcx>(
 /// Ensures that the super-predicates of the trait with a `DefId`
 /// of `trait_def_id` are lowered and stored. This also ensures that
 /// the transitive super-predicates are lowered.
-pub(super) fn super_predicates_of(
+pub(super) fn explicit_super_predicates_of(
     tcx: TyCtxt<'_>,
     trait_def_id: LocalDefId,
 ) -> ty::GenericPredicates<'_> {
     implied_predicates_with_filter(tcx, trait_def_id.to_def_id(), PredicateFilter::SelfOnly)
 }
 
-pub(super) fn super_predicates_that_define_assoc_item(
+pub(super) fn explicit_supertraits_containing_assoc_item(
     tcx: TyCtxt<'_>,
     (trait_def_id, assoc_name): (DefId, Ident),
 ) -> ty::GenericPredicates<'_> {
     implied_predicates_with_filter(tcx, trait_def_id, PredicateFilter::SelfThatDefines(assoc_name))
 }
 
-pub(super) fn implied_predicates_of(
+pub(super) fn explicit_implied_predicates_of(
     tcx: TyCtxt<'_>,
     trait_def_id: LocalDefId,
 ) -> ty::GenericPredicates<'_> {
@@ -560,7 +560,7 @@ pub(super) fn implied_predicates_with_filter(
         // if `assoc_name` is None, then the query should've been redirected to an
         // external provider
         assert!(matches!(filter, PredicateFilter::SelfThatDefines(_)));
-        return tcx.super_predicates_of(trait_def_id);
+        return tcx.explicit_super_predicates_of(trait_def_id);
     };
 
     let Node::Item(item) = tcx.hir_node_by_def_id(trait_def_id) else {
@@ -601,7 +601,7 @@ pub(super) fn implied_predicates_with_filter(
                 if let ty::ClauseKind::Trait(bound) = pred.kind().skip_binder()
                     && bound.polarity == ty::PredicatePolarity::Positive
                 {
-                    tcx.at(span).super_predicates_of(bound.def_id());
+                    tcx.at(span).explicit_super_predicates_of(bound.def_id());
                 }
             }
         }
@@ -611,7 +611,7 @@ pub(super) fn implied_predicates_with_filter(
                 if let ty::ClauseKind::Trait(bound) = pred.kind().skip_binder()
                     && bound.polarity == ty::PredicatePolarity::Positive
                 {
-                    tcx.at(span).implied_predicates_of(bound.def_id());
+                    tcx.at(span).explicit_implied_predicates_of(bound.def_id());
                 }
             }
         }

compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs

@@ -1760,7 +1760,7 @@ fn supertrait_hrtb_vars(
             if let Some(assoc_item) = trait_defines_associated_item_named(def_id) {
                 break Some((bound_vars.into_iter().collect(), assoc_item));
             }
-            let predicates = tcx.super_predicates_that_define_assoc_item((def_id, assoc_name));
+            let predicates = tcx.explicit_supertraits_containing_assoc_item((def_id, assoc_name));
             let obligations = predicates.predicates.iter().filter_map(|&(pred, _)| {
                 let bound_predicate = pred.kind();
                 match bound_predicate.skip_binder() {

compiler/rustc_infer/src/traits/util.rs

@@ -275,10 +275,10 @@ fn elaborate(&mut self, elaboratable: &O) {
                 }
                 // Get predicates implied by the trait, or only super predicates if we only care about self predicates.
                 let predicates = match self.mode {
-                    Filter::All => tcx.implied_predicates_of(data.def_id()),
-                    Filter::OnlySelf => tcx.super_predicates_of(data.def_id()),
+                    Filter::All => tcx.explicit_implied_predicates_of(data.def_id()),
+                    Filter::OnlySelf => tcx.explicit_super_predicates_of(data.def_id()),
                     Filter::OnlySelfThatDefines(ident) => {
-                        tcx.super_predicates_that_define_assoc_item((data.def_id(), ident))
+                        tcx.explicit_supertraits_containing_assoc_item((data.def_id(), ident))
                     }
                 };
 
@@ -420,7 +420,7 @@ pub fn transitive_bounds<'tcx>(
 
 /// A specialized variant of `elaborate` that only elaborates trait references that may
 /// define the given associated item with the name `assoc_name`. It uses the
-/// `super_predicates_that_define_assoc_item` query to avoid enumerating super-predicates that
+/// `explicit_supertraits_containing_assoc_item` query to avoid enumerating super-predicates that
 /// aren't related to `assoc_item`. This is used when resolving types like `Self::Item` or
 /// `T::Item` and helps to avoid cycle errors (see e.g. #35237).
 pub fn transitive_bounds_that_define_assoc_item<'tcx>(

compiler/rustc_lint/src/multiple_supertrait_upcastable.rs

@@ -45,7 +45,7 @@ fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx hir::Item<'tcx>) {
         {
             let direct_super_traits_iter = cx
                 .tcx
-                .super_predicates_of(def_id)
+                .explicit_super_predicates_of(def_id)
                 .predicates
                 .into_iter()
                 .filter_map(|(pred, _)| pred.as_trait_clause());

compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs

@@ -211,8 +211,8 @@ fn into_args(self) -> (DefId, SimplifiedType) {
     explicit_predicates_of => { table }
     generics_of => { table }
     inferred_outlives_of => { table_defaulted_array }
-    super_predicates_of => { table }
-    implied_predicates_of => { table }
+    explicit_super_predicates_of => { table }
+    explicit_implied_predicates_of => { table }
     type_of => { table }
     type_alias_is_lazy => { cdata.root.tables.type_alias_is_lazy.get(cdata, def_id.index) }
     variances_of => { table }

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -1431,8 +1431,8 @@ fn encode_def_ids(&mut self) {
             }
             if let DefKind::Trait = def_kind {
                 record!(self.tables.trait_def[def_id] <- self.tcx.trait_def(def_id));
-                record!(self.tables.super_predicates_of[def_id] <- self.tcx.super_predicates_of(def_id));
-                record!(self.tables.implied_predicates_of[def_id] <- self.tcx.implied_predicates_of(def_id));
+                record!(self.tables.explicit_super_predicates_of[def_id] <- self.tcx.explicit_super_predicates_of(def_id));
+                record!(self.tables.explicit_implied_predicates_of[def_id] <- self.tcx.explicit_implied_predicates_of(def_id));
 
                 let module_children = self.tcx.module_children_local(local_id);
                 record_array!(self.tables.module_children_non_reexports[def_id] <-
@@ -1440,8 +1440,8 @@ fn encode_def_ids(&mut self) {
             }
             if let DefKind::TraitAlias = def_kind {
                 record!(self.tables.trait_def[def_id] <- self.tcx.trait_def(def_id));
-                record!(self.tables.super_predicates_of[def_id] <- self.tcx.super_predicates_of(def_id));
-                record!(self.tables.implied_predicates_of[def_id] <- self.tcx.implied_predicates_of(def_id));
+                record!(self.tables.explicit_super_predicates_of[def_id] <- self.tcx.explicit_super_predicates_of(def_id));
+                record!(self.tables.explicit_implied_predicates_of[def_id] <- self.tcx.explicit_implied_predicates_of(def_id));
             }
             if let DefKind::Trait | DefKind::Impl { .. } = def_kind {
                 let associated_item_def_ids = self.tcx.associated_item_def_ids(def_id);

compiler/rustc_metadata/src/rmeta/mod.rs

@@ -416,10 +416,10 @@ fn encode(&self, buf: &mut FileEncoder) -> LazyTables {
     lookup_deprecation_entry: Table<DefIndex, LazyValue<attr::Deprecation>>,
     explicit_predicates_of: Table<DefIndex, LazyValue<ty::GenericPredicates<'static>>>,
     generics_of: Table<DefIndex, LazyValue<ty::Generics>>,
-    super_predicates_of: Table<DefIndex, LazyValue<ty::GenericPredicates<'static>>>,
+    explicit_super_predicates_of: Table<DefIndex, LazyValue<ty::GenericPredicates<'static>>>,
     // As an optimization, we only store this for trait aliases,
-    // since it's identical to super_predicates_of for traits.
-    implied_predicates_of: Table<DefIndex, LazyValue<ty::GenericPredicates<'static>>>,
+    // since it's identical to explicit_super_predicates_of for traits.
+    explicit_implied_predicates_of: Table<DefIndex, LazyValue<ty::GenericPredicates<'static>>>,
     type_of: Table<DefIndex, LazyValue<ty::EarlyBinder<'static, Ty<'static>>>>,
     variances_of: Table<DefIndex, LazyArray<ty::Variance>>,
     fn_sig: Table<DefIndex, LazyValue<ty::EarlyBinder<'static, ty::PolyFnSig<'static>>>>,

compiler/rustc_middle/src/query/mod.rs

@@ -646,6 +646,9 @@
     }
 
     /// Returns the predicates written explicitly by the user.
+    ///
+    /// You should probably use `predicates_of` unless you're looking for
+    /// predicates with explicit spans for diagnostics purposes.
     query explicit_predicates_of(key: DefId) -> ty::GenericPredicates<'tcx> {
         desc { |tcx| "computing explicit predicates of `{}`", tcx.def_path_str(key) }
         cache_on_disk_if { key.is_local() }
@@ -662,29 +665,32 @@
         feedable
     }
 
-    /// Maps from the `DefId` of a trait to the list of
-    /// super-predicates. This is a subset of the full list of
-    /// predicates. We store these in a separate map because we must
-    /// evaluate them even during type conversion, often before the
-    /// full predicates are available (note that supertraits have
-    /// additional acyclicity requirements).
-    query super_predicates_of(key: DefId) -> ty::GenericPredicates<'tcx> {
+    /// Maps from the `DefId` of a trait to the list of super-predicates of the trait,
+    /// *before* elaboration (so it doesn't contain transitive super-predicates). This
+    /// is a subset of the full list of predicates. We store these in a separate map
+    /// because we must evaluate them even during type conversion, often before the full
+    /// predicates are available (note that super-predicates must not be cyclic).
+    query explicit_super_predicates_of(key: DefId) -> ty::GenericPredicates<'tcx> {
         desc { |tcx| "computing the super predicates of `{}`", tcx.def_path_str(key) }
         cache_on_disk_if { key.is_local() }
         separate_provide_extern
     }
 
-    query implied_predicates_of(key: DefId) -> ty::GenericPredicates<'tcx> {
+    /// The predicates of the trait that are implied during elaboration. This is a
+    /// superset of the super-predicates of the trait, but a subset of the predicates
+    /// of the trait. For regular traits, this includes all super-predicates and their
+    /// associated type bounds. For trait aliases, currently, this includes all of the
+    /// predicates of the trait alias.
+    query explicit_implied_predicates_of(key: DefId) -> ty::GenericPredicates<'tcx> {
         desc { |tcx| "computing the implied predicates of `{}`", tcx.def_path_str(key) }
         cache_on_disk_if { key.is_local() }
         separate_provide_extern
     }
 
-    /// The `Option<Ident>` is the name of an associated type. If it is `None`, then this query
-    /// returns the full set of predicates. If `Some<Ident>`, then the query returns only the
-    /// subset of super-predicates that reference traits that define the given associated type.
-    /// This is used to avoid cycles in resolving types like `T::Item`.
-    query super_predicates_that_define_assoc_item(key: (DefId, rustc_span::symbol::Ident)) -> ty::GenericPredicates<'tcx> {
+    /// The Ident is the name of an associated type.The query returns only the subset
+    /// of supertraits that define the given associated type. This is used to avoid
+    /// cycles in resolving type-dependent associated item paths like `T::Item`.
+    query explicit_supertraits_containing_assoc_item(key: (DefId, rustc_span::symbol::Ident)) -> ty::GenericPredicates<'tcx> {
         desc { |tcx| "computing the super traits of `{}` with associated type name `{}`",
             tcx.def_path_str(key.0),
             key.1

compiler/rustc_middle/src/traits/util.rs

@@ -35,7 +35,7 @@ struct Elaborator<'tcx> {
 impl<'tcx> Elaborator<'tcx> {
     fn elaborate(&mut self, trait_ref: PolyTraitRef<'tcx>) {
         let super_predicates =
-            self.tcx.super_predicates_of(trait_ref.def_id()).predicates.iter().filter_map(
+            self.tcx.explicit_super_predicates_of(trait_ref.def_id()).predicates.iter().filter_map(
                 |&(pred, _)| {
                     let clause = pred.instantiate_supertrait(self.tcx, trait_ref);
                     self.visited.insert(clause).then_some(clause)

compiler/rustc_middle/src/ty/context.rs

@@ -342,12 +342,15 @@ fn own_predicates_of(
         )
     }
 
-    fn super_predicates_of(
+    fn explicit_super_predicates_of(
         self,
         def_id: DefId,
     ) -> ty::EarlyBinder<'tcx, impl IntoIterator<Item = ty::Clause<'tcx>>> {
         ty::EarlyBinder::bind(
-            self.super_predicates_of(def_id).instantiate_identity(self).predicates.into_iter(),
+            self.explicit_super_predicates_of(def_id)
+                .instantiate_identity(self)
+                .predicates
+                .into_iter(),
         )
     }
 
@@ -2473,7 +2476,7 @@ fn super_traits_of(self, trait_def_id: DefId) -> impl Iterator<Item = DefId> + '
 
         iter::from_fn(move || -> Option<DefId> {
             let trait_did = stack.pop()?;
-            let generic_predicates = self.super_predicates_of(trait_did);
+            let generic_predicates = self.explicit_super_predicates_of(trait_did);
 
             for (predicate, _) in generic_predicates.predicates {
                 if let ty::ClauseKind::Trait(data) = predicate.kind().skip_binder() {

compiler/rustc_middle/src/ty/vtable.rs

@@ -67,7 +67,7 @@ impl Iterator for SupertraitDefIds<'_> {
 
     fn next(&mut self) -> Option<DefId> {
         let def_id = self.stack.pop()?;
-        let predicates = self.tcx.super_predicates_of(def_id);
+        let predicates = self.tcx.explicit_super_predicates_of(def_id);
         let visited = &mut self.visited;
         self.stack.extend(
             predicates

compiler/rustc_next_trait_solver/src/solve/assembly/structural_traits.rs

@@ -668,8 +668,9 @@ pub(in crate::solve) fn predicates_for_object_candidate<D, I>(
 {
     let cx = ecx.cx();
     let mut requirements = vec![];
-    requirements
-        .extend(cx.super_predicates_of(trait_ref.def_id).iter_instantiated(cx, trait_ref.args));
+    requirements.extend(
+        cx.explicit_super_predicates_of(trait_ref.def_id).iter_instantiated(cx, trait_ref.args),
+    );
 
     // FIXME(associated_const_equality): Also add associated consts to
     // the requirements here.

compiler/rustc_trait_selection/src/traits/object_safety.rs

@@ -187,7 +187,7 @@ fn predicates_reference_self(
 ) -> SmallVec<[Span; 1]> {
     let trait_ref = ty::Binder::dummy(ty::TraitRef::identity(tcx, trait_def_id));
     let predicates = if supertraits_only {
-        tcx.super_predicates_of(trait_def_id)
+        tcx.explicit_super_predicates_of(trait_def_id)
     } else {
         tcx.predicates_of(trait_def_id)
     };
@@ -256,7 +256,7 @@ fn super_predicates_have_non_lifetime_binders(
     if !tcx.features().non_lifetime_binders {
         return SmallVec::new();
     }
-    tcx.super_predicates_of(trait_def_id)
+    tcx.explicit_super_predicates_of(trait_def_id)
         .predicates
         .iter()
         .filter_map(|(pred, span)| pred.has_non_region_bound_vars().then_some(*span))

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

@@ -574,7 +574,7 @@ fn confirm_object_candidate(
         // Check supertraits hold. This is so that their associated type bounds
         // will be checked in the code below.
         for super_trait in tcx
-            .super_predicates_of(trait_predicate.def_id())
+            .explicit_super_predicates_of(trait_predicate.def_id())
             .instantiate(tcx, trait_predicate.trait_ref.args)
             .predicates
             .into_iter()

compiler/rustc_trait_selection/src/traits/util.rs

@@ -128,7 +128,7 @@ fn expand(&mut self, item: &TraitAliasExpansionInfo<'tcx>) -> bool {
         }
 
         // Get components of trait alias.
-        let predicates = tcx.super_predicates_of(trait_ref.def_id());
+        let predicates = tcx.explicit_super_predicates_of(trait_ref.def_id());
         debug!(?predicates);
 
         let items = predicates.predicates.iter().rev().filter_map(|(pred, span)| {

compiler/rustc_trait_selection/src/traits/vtable.rs

@@ -117,7 +117,7 @@ fn prepare_vtable_segments_inner<'tcx, T>(
             let &(inner_most_trait_ref, _, _) = stack.last().unwrap();
 
             let mut direct_super_traits_iter = tcx
-                .super_predicates_of(inner_most_trait_ref.def_id())
+                .explicit_super_predicates_of(inner_most_trait_ref.def_id())
                 .predicates
                 .into_iter()
                 .filter_map(move |(pred, _)| {

compiler/rustc_type_ir/src/interner.rs

@@ -209,8 +209,7 @@ fn own_predicates_of(
         def_id: Self::DefId,
     ) -> ty::EarlyBinder<Self, impl IntoIterator<Item = Self::Clause>>;
 
-    // FIXME: Rename this so it's obvious it's only *immediate* super predicates.
-    fn super_predicates_of(
+    fn explicit_super_predicates_of(
         self,
         def_id: Self::DefId,
     ) -> ty::EarlyBinder<Self, impl IntoIterator<Item = Self::Clause>>;

src/librustdoc/clean/simplify.rs

@@ -113,7 +113,7 @@ fn trait_is_same_or_supertrait(cx: &DocContext<'_>, child: DefId, trait_: DefId)
     if child == trait_ {
         return true;
     }
-    let predicates = cx.tcx.super_predicates_of(child);
+    let predicates = cx.tcx.explicit_super_predicates_of(child);
     debug_assert!(cx.tcx.generics_of(child).has_self);
     let self_ty = cx.tcx.types.self_param;
     predicates

src/tools/clippy/clippy_lints/src/implied_bounds_in_impls.rs

@@ -246,7 +246,7 @@ fn collect_supertrait_bounds<'tcx>(cx: &LateContext<'tcx>, bounds: GenericBounds
                 && let [.., path] = poly_trait.trait_ref.path.segments
                 && poly_trait.bound_generic_params.is_empty()
                 && let Some(trait_def_id) = path.res.opt_def_id()
-                && let predicates = cx.tcx.super_predicates_of(trait_def_id).predicates
+                && let predicates = cx.tcx.explicit_super_predicates_of(trait_def_id).predicates
                 // If the trait has no supertrait, there is no need to collect anything from that bound
                 && !predicates.is_empty()
             {

src/tools/clippy/clippy_lints/src/methods/type_id_on_box.rs

@@ -24,7 +24,7 @@ fn is_subtrait_of_any(cx: &LateContext<'_>, ty: Ty<'_>) -> bool {
                 cx.tcx.is_diagnostic_item(sym::Any, tr.def_id)
                     || cx
                         .tcx
-                        .super_predicates_of(tr.def_id)
+                        .explicit_super_predicates_of(tr.def_id)
                         .predicates
                         .iter()
                         .any(|(clause, _)| {

src/tools/clippy/clippy_lints/src/needless_maybe_sized.rs

@@ -91,7 +91,7 @@ fn search(cx: &LateContext<'_>, path: &mut Vec<DefId>) -> bool {
             return true;
         }
 
-        for &(predicate, _) in cx.tcx.super_predicates_of(trait_def_id).predicates {
+        for &(predicate, _) in cx.tcx.explicit_super_predicates_of(trait_def_id).predicates {
             if let ClauseKind::Trait(trait_predicate) = predicate.kind().skip_binder()
                 && trait_predicate.polarity == PredicatePolarity::Positive
                 && !path.contains(&trait_predicate.def_id())