Encode cross-crate opaque type origin

compiler/rustc_ast_lowering/src/lib.rs

@@ -272,7 +272,7 @@ enum ImplTraitContext {
     /// Example: `fn foo() -> impl Debug`, where `impl Debug` is conceptually
     /// equivalent to a new opaque type like `type T = impl Debug; fn foo() -> T`.
     ///
-    OpaqueTy { origin: hir::OpaqueTyOrigin },
+    OpaqueTy { origin: hir::OpaqueTyOrigin<LocalDefId> },
     /// `impl Trait` is unstably accepted in this position.
     FeatureGated(ImplTraitPosition, Symbol),
     /// `impl Trait` is not accepted in this position.
@@ -1416,7 +1416,7 @@ fn lower_ty_direct(&mut self, t: &Ty, itctx: ImplTraitContext) -> hir::Ty<'hir>
     fn lower_opaque_impl_trait(
         &mut self,
         span: Span,
-        origin: hir::OpaqueTyOrigin,
+        origin: hir::OpaqueTyOrigin<LocalDefId>,
         opaque_ty_node_id: NodeId,
         bounds: &GenericBounds,
         itctx: ImplTraitContext,
@@ -1458,7 +1458,7 @@ fn lower_opaque_impl_trait(
     fn lower_opaque_inner(
         &mut self,
         opaque_ty_node_id: NodeId,
-        origin: hir::OpaqueTyOrigin,
+        origin: hir::OpaqueTyOrigin<LocalDefId>,
         opaque_ty_span: Span,
         lower_item_bounds: impl FnOnce(&mut Self) -> &'hir [hir::GenericBound<'hir>],
     ) -> hir::TyKind<'hir> {

compiler/rustc_borrowck/src/region_infer/opaque_types.rs

@@ -502,7 +502,7 @@ fn get_canonical_args(&self) -> ty::GenericArgsRef<'tcx> {
         }
 
         let &Self { tcx, def_id, .. } = self;
-        let origin = tcx.opaque_type_origin(def_id);
+        let origin = tcx.local_opaque_ty_origin(def_id);
         let parent = match origin {
             hir::OpaqueTyOrigin::FnReturn { parent, .. }
             | hir::OpaqueTyOrigin::AsyncFn { parent, .. }

compiler/rustc_hir/src/hir.rs

@@ -2746,7 +2746,7 @@ pub struct OpaqueTy<'hir> {
     pub hir_id: HirId,
     pub def_id: LocalDefId,
     pub bounds: GenericBounds<'hir>,
-    pub origin: OpaqueTyOrigin,
+    pub origin: OpaqueTyOrigin<LocalDefId>,
     pub span: Span,
 }
 
@@ -2784,33 +2784,35 @@ pub struct PreciseCapturingNonLifetimeArg {
     pub res: Res,
 }
 
-#[derive(Copy, Clone, PartialEq, Eq, Debug, HashStable_Generic)]
+#[derive(Copy, Clone, PartialEq, Eq, Debug)]
+#[derive(HashStable_Generic, Encodable, Decodable)]
 pub enum RpitContext {
     Trait,
     TraitImpl,
 }
 
 /// From whence the opaque type came.
-#[derive(Copy, Clone, PartialEq, Eq, Debug, HashStable_Generic)]
-pub enum OpaqueTyOrigin {
+#[derive(Copy, Clone, PartialEq, Eq, Debug)]
+#[derive(HashStable_Generic, Encodable, Decodable)]
+pub enum OpaqueTyOrigin<D> {
     /// `-> impl Trait`
     FnReturn {
         /// The defining function.
-        parent: LocalDefId,
+        parent: D,
         // Whether this is an RPITIT (return position impl trait in trait)
         in_trait_or_impl: Option<RpitContext>,
     },
     /// `async fn`
     AsyncFn {
         /// The defining function.
-        parent: LocalDefId,
+        parent: D,
         // Whether this is an AFIT (async fn in trait)
         in_trait_or_impl: Option<RpitContext>,
     },
     /// type aliases: `type Foo = impl Trait;`
     TyAlias {
         /// The type alias or associated type parent of the TAIT/ATPIT
-        parent: LocalDefId,
+        parent: D,
         /// associated types in impl blocks for traits.
         in_assoc_ty: bool,
     },

compiler/rustc_hir_analysis/src/check/check.rs

@@ -268,7 +268,7 @@ fn check_opaque_meets_bounds<'tcx>(
     tcx: TyCtxt<'tcx>,
     def_id: LocalDefId,
     span: Span,
-    origin: &hir::OpaqueTyOrigin,
+    origin: &hir::OpaqueTyOrigin<LocalDefId>,
 ) -> Result<(), ErrorGuaranteed> {
     let defining_use_anchor = match *origin {
         hir::OpaqueTyOrigin::FnReturn { parent, .. }
@@ -677,7 +677,7 @@ pub(crate) fn check_item_type(tcx: TyCtxt<'_>, def_id: LocalDefId) {
         DefKind::OpaqueTy => {
             check_opaque_precise_captures(tcx, def_id);
 
-            let origin = tcx.opaque_type_origin(def_id);
+            let origin = tcx.local_opaque_ty_origin(def_id);
             if let hir::OpaqueTyOrigin::FnReturn { parent: fn_def_id, .. }
             | hir::OpaqueTyOrigin::AsyncFn { parent: fn_def_id, .. } = origin
                 && let hir::Node::TraitItem(trait_item) = tcx.hir_node_by_def_id(fn_def_id)

compiler/rustc_hir_analysis/src/collect.rs

@@ -86,7 +86,7 @@ pub fn provide(providers: &mut Providers) {
         impl_trait_header,
         coroutine_kind,
         coroutine_for_closure,
-        is_type_alias_impl_trait,
+        opaque_ty_origin,
         rendered_precise_capturing_args,
         ..*providers
     };
@@ -1759,9 +1759,18 @@ fn coroutine_for_closure(tcx: TyCtxt<'_>, def_id: LocalDefId) -> DefId {
     def_id.to_def_id()
 }
 
-fn is_type_alias_impl_trait<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> bool {
-    let opaque = tcx.hir().expect_opaque_ty(def_id);
-    matches!(opaque.origin, hir::OpaqueTyOrigin::TyAlias { .. })
+fn opaque_ty_origin<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> hir::OpaqueTyOrigin<DefId> {
+    match tcx.hir_node_by_def_id(def_id).expect_opaque_ty().origin {
+        hir::OpaqueTyOrigin::FnReturn { parent, in_trait_or_impl } => {
+            hir::OpaqueTyOrigin::FnReturn { parent: parent.to_def_id(), in_trait_or_impl }
+        }
+        hir::OpaqueTyOrigin::AsyncFn { parent, in_trait_or_impl } => {
+            hir::OpaqueTyOrigin::AsyncFn { parent: parent.to_def_id(), in_trait_or_impl }
+        }
+        hir::OpaqueTyOrigin::TyAlias { parent, in_assoc_ty } => {
+            hir::OpaqueTyOrigin::TyAlias { parent: parent.to_def_id(), in_assoc_ty }
+        }
+    }
 }
 
 fn rendered_precise_capturing_args<'tcx>(

compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs

@@ -20,6 +20,7 @@
 pub mod generics;
 mod lint;
 
+use std::assert_matches::assert_matches;
 use std::slice;
 
 use rustc_ast::TraitObjectSyntax;
@@ -1811,7 +1812,7 @@ pub fn lower_path(
         match path.res {
             Res::Def(DefKind::OpaqueTy, did) => {
                 // Check for desugared `impl Trait`.
-                assert!(tcx.is_type_alias_impl_trait(did));
+                assert_matches!(tcx.opaque_ty_origin(did), hir::OpaqueTyOrigin::TyAlias { .. });
                 let item_segment = path.segments.split_last().unwrap();
                 let _ = self
                     .prohibit_generic_args(item_segment.1.iter(), GenericsArgsErrExtend::OpaqueTy);

compiler/rustc_hir_typeck/src/_match.rs

@@ -601,7 +601,7 @@ pub(crate) fn return_position_impl_trait_from_match_expectation(
             _ => return None,
         };
         let hir::OpaqueTyOrigin::FnReturn { parent: parent_def_id, .. } =
-            self.tcx.opaque_type_origin(def_id)
+            self.tcx.local_opaque_ty_origin(def_id)
         else {
             return None;
         };

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

@@ -155,7 +155,10 @@ pub fn handle_opaque_type(
                     // however in `fn fut() -> impl Future<Output = i32> { async { 42 } }`, where
                     // it is of no concern, so we only check for TAITs.
                     if self.can_define_opaque_ty(b_def_id)
-                        && self.tcx.is_type_alias_impl_trait(b_def_id)
+                        && matches!(
+                            self.tcx.opaque_ty_origin(b_def_id),
+                            hir::OpaqueTyOrigin::TyAlias { .. }
+                        )
                     {
                         self.dcx().emit_err(OpaqueHiddenTypeDiag {
                             span,

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

@@ -316,10 +316,7 @@ fn into_args(self) -> (DefId, SimplifiedType) {
             })
             .unwrap_or_default()
     }
-    is_type_alias_impl_trait => {
-        debug_assert_eq!(tcx.def_kind(def_id), DefKind::OpaqueTy);
-        cdata.root.tables.is_type_alias_impl_trait.get(cdata, def_id.index)
-    }
+    opaque_ty_origin => { table }
     assumed_wf_types_for_rpitit => { table }
     collect_return_position_impl_trait_in_trait_tys => {
         Ok(cdata

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -1188,7 +1188,7 @@ fn should_encode_type(tcx: TyCtxt<'_>, def_id: LocalDefId, def_kind: DefKind) ->
         | DefKind::SyntheticCoroutineBody => true,
 
         DefKind::OpaqueTy => {
-            let origin = tcx.opaque_type_origin(def_id);
+            let origin = tcx.local_opaque_ty_origin(def_id);
             if let hir::OpaqueTyOrigin::FnReturn { parent, .. }
             | hir::OpaqueTyOrigin::AsyncFn { parent, .. } = origin
                 && let hir::Node::TraitItem(trait_item) = tcx.hir_node_by_def_id(parent)
@@ -1530,9 +1530,7 @@ fn encode_def_ids(&mut self) {
             if let DefKind::OpaqueTy = def_kind {
                 self.encode_explicit_item_bounds(def_id);
                 self.encode_explicit_item_super_predicates(def_id);
-                self.tables
-                    .is_type_alias_impl_trait
-                    .set(def_id.index, self.tcx.is_type_alias_impl_trait(def_id));
+                record!(self.tables.opaque_ty_origin[def_id] <- self.tcx.opaque_ty_origin(def_id));
                 self.encode_precise_capturing_args(def_id);
             }
             if tcx.impl_method_has_trait_impl_trait_tys(def_id)

compiler/rustc_metadata/src/rmeta/mod.rs

@@ -378,7 +378,6 @@ fn encode(&self, buf: &mut FileEncoder) -> LazyTables {
 - defaulted:
     intrinsic: Table<DefIndex, Option<LazyValue<ty::IntrinsicDef>>>,
     is_macro_rules: Table<DefIndex, bool>,
-    is_type_alias_impl_trait: Table<DefIndex, bool>,
     type_alias_is_lazy: Table<DefIndex, bool>,
     attr_flags: Table<DefIndex, AttrFlags>,
     // The u64 is the crate-local part of the DefPathHash. All hashes in this crate have the same
@@ -469,6 +468,7 @@ fn encode(&self, buf: &mut FileEncoder) -> LazyTables {
     doc_link_resolutions: Table<DefIndex, LazyValue<DocLinkResMap>>,
     doc_link_traits_in_scope: Table<DefIndex, LazyArray<DefId>>,
     assumed_wf_types_for_rpitit: Table<DefIndex, LazyArray<(Ty<'static>, Span)>>,
+    opaque_ty_origin: Table<DefIndex, LazyValue<hir::OpaqueTyOrigin<DefId>>>,
 }
 
 #[derive(TyEncodable, TyDecodable)]

compiler/rustc_middle/src/query/erase.rs

@@ -280,6 +280,7 @@ impl EraseType for $ty {
     rustc_hir::IsAsync,
     rustc_hir::ItemLocalId,
     rustc_hir::LangItem,
+    rustc_hir::OpaqueTyOrigin<rustc_hir::def_id::DefId>,
     rustc_hir::OwnerId,
     rustc_hir::Upvar,
     rustc_index::bit_set::FiniteBitSet<u32>,

compiler/rustc_middle/src/query/mod.rs

@@ -260,11 +260,10 @@
         separate_provide_extern
     }
 
-    query is_type_alias_impl_trait(key: DefId) -> bool
+    query opaque_ty_origin(key: DefId) -> hir::OpaqueTyOrigin<DefId>
     {
-        desc { "determine whether the opaque is a type-alias impl trait" }
+        desc { "determine where the opaque originates from" }
         separate_provide_extern
-        feedable
     }
 
     query unsizing_params_for_adt(key: DefId) -> &'tcx rustc_index::bit_set::BitSet<u32>

compiler/rustc_middle/src/ty/context.rs

@@ -2103,11 +2103,9 @@ pub fn local_visibility(self, def_id: LocalDefId) -> Visibility {
     }
 
     /// Returns the origin of the opaque type `def_id`.
-    #[track_caller]
-    pub fn opaque_type_origin(self, def_id: LocalDefId) -> hir::OpaqueTyOrigin {
-        let origin = self.hir().expect_opaque_ty(def_id).origin;
-        trace!("opaque_type_origin({def_id:?}) => {origin:?}");
-        origin
+    #[instrument(skip(self), level = "trace", ret)]
+    pub fn local_opaque_ty_origin(self, def_id: LocalDefId) -> hir::OpaqueTyOrigin<LocalDefId> {
+        self.hir().expect_opaque_ty(def_id).origin
     }
 }
 

compiler/rustc_middle/src/ty/parameterized.rs

@@ -94,6 +94,7 @@ impl $crate::ty::ParameterizedOverTcx for $ty {
     rustc_hir::def_id::DefId,
     rustc_hir::def_id::DefIndex,
     rustc_hir::definitions::DefKey,
+    rustc_hir::OpaqueTyOrigin<rustc_hir::def_id::DefId>,
     rustc_index::bit_set::BitSet<u32>,
     rustc_index::bit_set::FiniteBitSet<u32>,
     rustc_session::cstore::ForeignModule,

compiler/rustc_trait_selection/src/error_reporting/infer/note_and_explain.rs

@@ -384,7 +384,10 @@ fn foo(&self, x: T) -> T { x }
                                     | DefKind::AssocFn
                                     | DefKind::AssocConst
                             )
-                            && tcx.is_type_alias_impl_trait(opaque_ty.def_id)
+                            && matches!(
+                                tcx.opaque_ty_origin(opaque_ty.def_id),
+                                hir::OpaqueTyOrigin::TyAlias { .. }
+                            )
                             && !tcx
                                 .opaque_types_defined_by(body_owner_def_id.expect_local())
                                 .contains(&opaque_ty.def_id.expect_local())

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

@@ -2648,7 +2648,7 @@ fn report_opaque_type_auto_trait_leakage(
         obligation: &PredicateObligation<'tcx>,
         def_id: DefId,
     ) -> ErrorGuaranteed {
-        let name = match self.tcx.opaque_type_origin(def_id.expect_local()) {
+        let name = match self.tcx.local_opaque_ty_origin(def_id.expect_local()) {
             hir::OpaqueTyOrigin::FnReturn { .. } | hir::OpaqueTyOrigin::AsyncFn { .. } => {
                 "opaque type".to_string()
             }

compiler/rustc_ty_utils/src/assoc.rs

@@ -246,7 +246,7 @@ fn associated_type_for_impl_trait_in_trait(
 ) -> LocalDefId {
     let (hir::OpaqueTyOrigin::FnReturn { parent: fn_def_id, .. }
     | hir::OpaqueTyOrigin::AsyncFn { parent: fn_def_id, .. }) =
-        tcx.opaque_type_origin(opaque_ty_def_id)
+        tcx.local_opaque_ty_origin(opaque_ty_def_id)
     else {
         bug!("expected opaque for {opaque_ty_def_id:?}");
     };
@@ -284,8 +284,6 @@ fn associated_type_for_impl_trait_in_trait(
     // Copy defaultness of the containing function.
     trait_assoc_ty.defaultness(tcx.defaultness(fn_def_id));
 
-    trait_assoc_ty.is_type_alias_impl_trait(false);
-
     // There are no inferred outlives for the synthesized associated type.
     trait_assoc_ty.inferred_outlives_of(&[]);
 

compiler/rustc_ty_utils/src/opaque_types.rs

@@ -139,7 +139,7 @@ fn visit_opaque_ty(&mut self, alias_ty: ty::AliasTy<'tcx>) {
         }
 
         // TAITs outside their defining scopes are ignored.
-        let origin = self.tcx.opaque_type_origin(alias_ty.def_id.expect_local());
+        let origin = self.tcx.local_opaque_ty_origin(alias_ty.def_id.expect_local());
         trace!(?origin);
         match origin {
             rustc_hir::OpaqueTyOrigin::FnReturn { .. }