query RPITIT in a trait or impl

Author: bvanjoi

compiler/rustc_hir_analysis/src/check/compare_impl_item.rs

@@ -15,6 +15,7 @@ use rustc_middle::ty::error::{ExpectedFound, TypeError};
 use rustc_middle::ty::{
     self, BottomUpFolder, GenericArgs, GenericParamDefKind, Ty, TyCtxt, TypeFoldable, TypeFolder,
     TypeSuperFoldable, TypeVisitable, TypeVisitableExt, TypeVisitor, TypingMode, Upcast,
+    associated_types_for_impl_traits_in_associated_fn,
 };
 use rustc_middle::{bug, span_bug};
 use rustc_span::{DUMMY_SP, Span};
@@ -757,7 +758,7 @@ pub(super) fn collect_return_position_impl_trait_in_trait_tys<'tcx>(
     // returning `-> Missing<impl Sized>`, that gets converted to `-> {type error}`,
     // and when walking through the signature we end up never collecting the def id
     // of the `impl Sized`. Insert that here, so we don't ICE later.
-    for assoc_item in tcx.associated_types_for_impl_traits_in_associated_fn(trait_m.def_id) {
+    for assoc_item in associated_types_for_impl_traits_in_associated_fn(tcx, trait_m.def_id) {
         if !remapped_types.contains_key(assoc_item) {
             remapped_types.insert(
                 *assoc_item,
@@ -2448,8 +2449,7 @@ fn param_env_with_gat_bounds<'tcx>(
                     ty::ImplTraitInTraitData::Impl { fn_def_id }
                     | ty::ImplTraitInTraitData::Trait { fn_def_id, .. },
                 ),
-        } => tcx
-            .associated_types_for_impl_traits_in_associated_fn(fn_def_id)
+        } => associated_types_for_impl_traits_in_associated_fn(tcx, fn_def_id)
             .iter()
             .map(|def_id| tcx.associated_item(*def_id))
             .collect(),

compiler/rustc_hir_analysis/src/check/wfcheck.rs

@@ -20,7 +20,7 @@ use rustc_middle::ty::trait_def::TraitSpecializationKind;
 use rustc_middle::ty::{
     self, AdtKind, GenericArgKind, GenericArgs, GenericParamDefKind, Ty, TyCtxt, TypeFlags,
     TypeFoldable, TypeSuperVisitable, TypeVisitable, TypeVisitableExt, TypeVisitor, TypingMode,
-    Upcast,
+    Upcast, associated_types_for_impl_traits_in_associated_fn,
 };
 use rustc_middle::{bug, span_bug};
 use rustc_session::parse::feature_err;
@@ -326,7 +326,9 @@ pub(crate) fn check_trait_item<'tcx>(
     let mut res = Ok(());
 
     if matches!(tcx.def_kind(def_id), DefKind::AssocFn) {
-        for &assoc_ty_def_id in tcx.associated_types_for_impl_traits_in_associated_fn(def_id) {
+        for &assoc_ty_def_id in
+            associated_types_for_impl_traits_in_associated_fn(tcx, def_id.to_def_id())
+        {
             res = res.and(check_associated_item(tcx, assoc_ty_def_id.expect_local()));
         }
     }

compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs

@@ -40,7 +40,7 @@ use rustc_middle::mir::interpret::LitToConstInput;
 use rustc_middle::ty::print::PrintPolyTraitRefExt as _;
 use rustc_middle::ty::{
     self, Const, GenericArgKind, GenericArgsRef, GenericParamDefKind, Ty, TyCtxt, TypeVisitableExt,
-    TypingMode, Upcast, fold_regions,
+    TypingMode, Upcast, associated_types_for_impl_traits_in_associated_fn, fold_regions,
 };
 use rustc_middle::{bug, span_bug};
 use rustc_session::lint::builtin::AMBIGUOUS_ASSOCIATED_ITEMS;
@@ -2602,7 +2602,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
         // do a linear search to map this to the synthetic associated type that
         // it will be lowered to.
         let def_id = if let Some(parent_def_id) = in_trait {
-            *tcx.associated_types_for_impl_traits_in_associated_fn(parent_def_id)
+            *associated_types_for_impl_traits_in_associated_fn(tcx, parent_def_id.to_def_id())
                 .iter()
                 .find(|rpitit| match tcx.opt_rpitit_info(**rpitit) {
                     Some(ty::ImplTraitInTraitData::Trait { opaque_def_id, .. }) => {

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

@@ -326,7 +326,7 @@ provide! { tcx, def_id, other, cdata,
             .process_decoded(tcx, || panic!("{def_id:?} does not have trait_impl_trait_tys")))
     }
 
-    associated_types_for_impl_traits_in_associated_fn => { table_defaulted_array }
+    associated_types_for_impl_traits_in_trait_or_impl => { table }
 
     visibility => { cdata.get_visibility(def_id.index) }
     adt_def => { cdata.get_adt_def(def_id.index, tcx) }

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -1382,17 +1382,6 @@ fn should_encode_const(def_kind: DefKind) -> bool {
     }
 }
 
-fn should_encode_fn_impl_trait_in_trait<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> bool {
-    if let Some(assoc_item) = tcx.opt_associated_item(def_id)
-        && assoc_item.container == ty::AssocItemContainer::Trait
-        && assoc_item.is_fn()
-    {
-        true
-    } else {
-        false
-    }
-}
-
 impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
     fn encode_attrs(&mut self, def_id: LocalDefId) {
         let tcx = self.tcx;
@@ -1617,9 +1606,9 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             {
                 record!(self.tables.trait_impl_trait_tys[def_id] <- table);
             }
-            if should_encode_fn_impl_trait_in_trait(tcx, def_id) {
-                let table = tcx.associated_types_for_impl_traits_in_associated_fn(def_id);
-                record_defaulted_array!(self.tables.associated_types_for_impl_traits_in_associated_fn[def_id] <- table);
+            if let DefKind::Impl { .. } | DefKind::Trait = def_kind {
+                let table = tcx.associated_types_for_impl_traits_in_trait_or_impl(def_id);
+                record!(self.tables.associated_types_for_impl_traits_in_trait_or_impl[def_id] <- table);
             }
         }
 

compiler/rustc_metadata/src/rmeta/mod.rs

@@ -403,7 +403,6 @@ define_tables! {
     explicit_implied_predicates_of: Table<DefIndex, LazyArray<(ty::Clause<'static>, Span)>>,
     explicit_implied_const_bounds: Table<DefIndex, LazyArray<(ty::PolyTraitRef<'static>, Span)>>,
     inherent_impls: Table<DefIndex, LazyArray<DefIndex>>,
-    associated_types_for_impl_traits_in_associated_fn: Table<DefIndex, LazyArray<DefId>>,
     opt_rpitit_info: Table<DefIndex, Option<LazyValue<ty::ImplTraitInTraitData>>>,
     // Reexported names are not associated with individual `DefId`s,
     // e.g. a glob import can introduce a lot of names, all with the same `DefId`.
@@ -482,6 +481,7 @@ define_tables! {
     assumed_wf_types_for_rpitit: Table<DefIndex, LazyArray<(Ty<'static>, Span)>>,
     opaque_ty_origin: Table<DefIndex, LazyValue<hir::OpaqueTyOrigin<DefId>>>,
     anon_const_kind: Table<DefIndex, LazyValue<ty::AnonConstKind>>,
+    associated_types_for_impl_traits_in_trait_or_impl: Table<DefIndex, LazyValue<ty::AssocTyForImplTraitInTraitOrImpl>>,
 }
 
 #[derive(TyEncodable, TyDecodable)]

compiler/rustc_middle/src/query/mod.rs

@@ -1079,21 +1079,9 @@ rustc_queries! {
         desc { |tcx| "comparing impl items against trait for `{}`", tcx.def_path_str(impl_id) }
     }
 
-    /// Given `fn_def_id` of a trait or of an impl that implements a given trait:
-    /// if `fn_def_id` is the def id of a function defined inside a trait, then it creates and returns
-    /// the associated items that correspond to each impl trait in return position for that trait.
-    /// if `fn_def_id` is the def id of a function defined inside an impl that implements a trait, then it
-    /// creates and returns the associated items that correspond to each impl trait in return position
-    /// of the implemented trait.
-    query associated_types_for_impl_traits_in_associated_fn(fn_def_id: DefId) -> &'tcx [DefId] {
-        desc { |tcx| "creating associated items for opaque types returned by `{}`", tcx.def_path_str(fn_def_id) }
-        cache_on_disk_if { fn_def_id.is_local() }
-        separate_provide_extern
-    }
-
-    query associated_types_for_impl_traits_in_trait(trait_id: DefId) -> &'tcx DefIdMap<&'tcx [DefId]> {
+    query associated_types_for_impl_traits_in_trait_or_impl(did: DefId) -> &'tcx ty::AssocTyForImplTraitInTraitOrImpl {
         arena_cache
-        desc { |tcx| "creating associated items for trait `{}`", tcx.def_path_str(trait_id) }
+        desc { |tcx| "creating rpitit for `{}`", tcx.def_path_str(did) }
         separate_provide_extern
     }
 

compiler/rustc_middle/src/ty/assoc.rs

@@ -1,4 +1,5 @@
 use rustc_attr_data_structures::{AttributeKind, find_attr};
+use rustc_data_structures::fx::FxIndexMap;
 use rustc_data_structures::sorted_map::SortedIndexMultiMap;
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Namespace};
@@ -285,3 +286,23 @@ impl AssocItems {
             .find(|item| tcx.hygienic_eq(ident, item.ident(tcx), parent_def_id))
     }
 }
+
+#[derive(Debug, Clone, PartialEq, Encodable, Decodable, HashStable)]
+pub struct AssocTyForImplTraitInTraitOrImpl(pub FxIndexMap<DefId, Vec<DefId>>);
+
+/// Given an `fn_def_id` of a trait or a trait implementation:
+///
+/// if `fn_def_id` is a function defined inside a trait, then it synthesizes
+/// a new def id corresponding to a new associated type for each return-
+/// position `impl Trait` in the signature.
+///
+/// if `fn_def_id` is a function inside of an impl, then for each synthetic
+/// associated type generated for the corresponding trait function described
+/// above, synthesize a corresponding associated type in the impl.
+pub fn associated_types_for_impl_traits_in_associated_fn(
+    tcx: TyCtxt<'_>,
+    fn_def_id: DefId,
+) -> &'_ [DefId] {
+    let parent_def_id = tcx.parent(fn_def_id);
+    &tcx.associated_types_for_impl_traits_in_trait_or_impl(parent_def_id).0[&fn_def_id]
+}

compiler/rustc_middle/src/ty/mod.rs

@@ -2194,8 +2194,7 @@ impl<'tcx> TyCtxt<'tcx> {
             return false;
         };
 
-        return !self
-            .associated_types_for_impl_traits_in_associated_fn(trait_item_def_id)
+        return !associated_types_for_impl_traits_in_associated_fn(self, trait_item_def_id)
             .is_empty();
     }
 }

compiler/rustc_middle/src/ty/parameterized.rs

@@ -67,6 +67,7 @@ trivially_parameterized_over_tcx! {
     crate::mir::ConstQualifs,
     ty::AsyncDestructor,
     ty::AssocItemContainer,
+    ty::AssocTyForImplTraitInTraitOrImpl,
     ty::Asyncness,
     ty::AnonConstKind,
     ty::DeducedParamAttrs,