Do not assume child bound assumptions for rigid alias

Author: compiler-errors

compiler/rustc_middle/src/ty/context.rs

@@ -345,6 +345,20 @@ impl<'tcx> Interner for TyCtxt<'tcx> {
         self.item_bounds(def_id).map_bound(IntoIterator::into_iter)
     }
 
+    fn item_self_bounds(
+        self,
+        def_id: DefId,
+    ) -> ty::EarlyBinder<'tcx, impl IntoIterator<Item = ty::Clause<'tcx>>> {
+        self.item_super_predicates(def_id).map_bound(IntoIterator::into_iter)
+    }
+
+    fn item_non_self_bounds(
+        self,
+        def_id: DefId,
+    ) -> ty::EarlyBinder<'tcx, impl IntoIterator<Item = ty::Clause<'tcx>>> {
+        self.item_non_self_assumptions(def_id).map_bound(IntoIterator::into_iter)
+    }
+
     fn predicates_of(
         self,
         def_id: DefId,

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

@@ -510,7 +510,12 @@ where
         candidates: &mut Vec<Candidate<I>>,
     ) {
         let () = self.probe(|_| ProbeKind::NormalizedSelfTyAssembly).enter(|ecx| {
-            ecx.assemble_alias_bound_candidates_recur(goal.predicate.self_ty(), goal, candidates);
+            ecx.assemble_alias_bound_candidates_recur(
+                goal.predicate.self_ty(),
+                goal,
+                candidates,
+                true,
+            );
         });
     }
 
@@ -528,6 +533,7 @@ where
         self_ty: I::Ty,
         goal: Goal<I, G>,
         candidates: &mut Vec<Candidate<I>>,
+        is_self: bool,
     ) {
         let (kind, alias_ty) = match self_ty.kind() {
             ty::Bool
@@ -580,16 +586,34 @@ where
             }
         };
 
-        for assumption in
-            self.cx().item_bounds(alias_ty.def_id).iter_instantiated(self.cx(), alias_ty.args)
-        {
-            candidates.extend(G::probe_and_consider_implied_clause(
-                self,
-                CandidateSource::AliasBound,
-                goal,
-                assumption,
-                [],
-            ));
+        if is_self {
+            for assumption in self
+                .cx()
+                .item_self_bounds(alias_ty.def_id)
+                .iter_instantiated(self.cx(), alias_ty.args)
+            {
+                candidates.extend(G::probe_and_consider_implied_clause(
+                    self,
+                    CandidateSource::AliasBound,
+                    goal,
+                    assumption,
+                    [],
+                ));
+            }
+        } else {
+            for assumption in self
+                .cx()
+                .item_non_self_bounds(alias_ty.def_id)
+                .iter_instantiated(self.cx(), alias_ty.args)
+            {
+                candidates.extend(G::probe_and_consider_implied_clause(
+                    self,
+                    CandidateSource::AliasBound,
+                    goal,
+                    assumption,
+                    [],
+                ));
+            }
         }
 
         candidates.extend(G::consider_additional_alias_assumptions(self, goal, alias_ty));
@@ -601,7 +625,7 @@ where
         // Recurse on the self type of the projection.
         match self.structurally_normalize_ty(goal.param_env, alias_ty.self_ty()) {
             Ok(next_self_ty) => {
-                self.assemble_alias_bound_candidates_recur(next_self_ty, goal, candidates)
+                self.assemble_alias_bound_candidates_recur(next_self_ty, goal, candidates, false)
             }
             Err(NoSolution) => {}
         }

compiler/rustc_type_ir/src/interner.rs

@@ -203,6 +203,16 @@ pub trait Interner:
         def_id: Self::DefId,
     ) -> ty::EarlyBinder<Self, impl IntoIterator<Item = Self::Clause>>;
 
+    fn item_self_bounds(
+        self,
+        def_id: Self::DefId,
+    ) -> ty::EarlyBinder<Self, impl IntoIterator<Item = Self::Clause>>;
+
+    fn item_non_self_bounds(
+        self,
+        def_id: Self::DefId,
+    ) -> ty::EarlyBinder<Self, impl IntoIterator<Item = Self::Clause>>;
+
     fn predicates_of(
         self,
         def_id: Self::DefId,

tests/ui/associated-type-bounds/cant-see-copy-bound-from-child-rigid.stderr renamed to tests/ui/associated-type-bounds/cant-see-copy-bound-from-child-rigid.current.stderr

@@ -1,5 +1,5 @@
 error[E0382]: use of moved value: `x`
-  --> $DIR/cant-see-copy-bound-from-child-rigid.rs:14:9
+  --> $DIR/cant-see-copy-bound-from-child-rigid.rs:18:9
    |
 LL | fn foo<T: Trait>(x: T::Assoc) -> (T::Assoc, T::Assoc)
    |                  - move occurs because `x` has type `<T as Trait>::Assoc`, which does not implement the `Copy` trait

tests/ui/associated-type-bounds/cant-see-copy-bound-from-child-rigid.next.stderr

@@ -0,0 +1,14 @@
+error[E0382]: use of moved value: `x`
+  --> $DIR/cant-see-copy-bound-from-child-rigid.rs:18:9
+   |
+LL | fn foo<T: Trait>(x: T::Assoc) -> (T::Assoc, T::Assoc)
+   |                  - move occurs because `x` has type `<T as Trait>::Assoc`, which does not implement the `Copy` trait
+...
+LL |     (x, x)
+   |      -  ^ value used here after move
+   |      |
+   |      value moved here
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0382`.

tests/ui/associated-type-bounds/cant-see-copy-bound-from-child-rigid.rs

@@ -1,3 +1,7 @@
+//@ revisions: current next
+//@ ignore-compare-mode-next-solver (explicit revisions)
+//@[next] compile-flags: -Znext-solver
+
 trait Id {
     type This: ?Sized;
 }

tests/ui/traits/const-traits/const-impl-trait.stderr

@@ -99,6 +99,16 @@ note: `PartialEq` can't be used with `~const` because it isn't annotated with `#
   --> $SRC_DIR/core/src/cmp.rs:LL:COL
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
+error: `~const` can only be applied to `#[const_trait]` traits
+  --> $DIR/const-impl-trait.rs:27:22
+   |
+LL |     fn huh() -> impl ~const PartialEq + ~const Destruct + Copy {
+   |                      ^^^^^^ can't be applied to `PartialEq`
+   |
+note: `PartialEq` can't be used with `~const` because it isn't annotated with `#[const_trait]`
+  --> $SRC_DIR/core/src/cmp.rs:LL:COL
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
 error: `~const` can only be applied to `#[const_trait]` traits
   --> $DIR/const-impl-trait.rs:23:22
    |
@@ -120,9 +130,9 @@ note: `PartialEq` can't be used with `~const` because it isn't annotated with `#
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error: `~const` can only be applied to `#[const_trait]` traits
-  --> $DIR/const-impl-trait.rs:27:22
+  --> $DIR/const-impl-trait.rs:23:22
    |
-LL |     fn huh() -> impl ~const PartialEq + ~const Destruct + Copy {
+LL |     fn huh() -> impl ~const PartialEq + ~const Destruct + Copy;
    |                      ^^^^^^ can't be applied to `PartialEq`
    |
 note: `PartialEq` can't be used with `~const` because it isn't annotated with `#[const_trait]`
@@ -181,7 +191,7 @@ LL |     a == a
    |
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
 
-error: aborting due to 20 previous errors
+error: aborting due to 21 previous errors
 
 Some errors have detailed explanations: E0015, E0635.
 For more information about an error, try `rustc --explain E0015`.