Remove normalization from opaque_types_defined_by

compiler/rustc_ty_utils/src/opaque_types.rs

@@ -2,16 +2,12 @@ use rustc_data_structures::fx::FxHashSet;
 use rustc_hir::intravisit::Visitor;
 use rustc_hir::{def::DefKind, def_id::LocalDefId};
 use rustc_hir::{intravisit, CRATE_HIR_ID};
-use rustc_infer::infer::TyCtxtInferExt;
 use rustc_middle::query::Providers;
-use rustc_middle::traits::ObligationCause;
 use rustc_middle::ty::util::{CheckRegions, NotUniqueParam};
-use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitableExt};
+use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_middle::ty::{TypeSuperVisitable, TypeVisitable, TypeVisitor};
-use rustc_span::def_id::CRATE_DEF_ID;
 use rustc_span::Span;
 use rustc_trait_selection::traits::check_substs_compatible;
-use rustc_trait_selection::traits::ObligationCtxt;
 use std::ops::ControlFlow;
 
 use crate::errors::{DuplicateArg, NotParam};
@@ -139,20 +135,7 @@ impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for OpaqueTypeCollector<'tcx> {
                     rustc_hir::OpaqueTyOrigin::FnReturn(_)
                     | rustc_hir::OpaqueTyOrigin::AsyncFn(_) => {}
                     rustc_hir::OpaqueTyOrigin::TyAlias { in_assoc_ty } => {
-                        if in_assoc_ty {
+                        if !in_assoc_ty {
-                            // Only associated items can be defining for opaque types in associated types.
-                            if let Some(parent) = self.parent() {
-                                let mut current = alias_ty.def_id.expect_local();
-                                while current != parent && current != CRATE_DEF_ID {
-                                    current = self.tcx.local_parent(current);
-                                }
-                                if current != parent {
-                                    return ControlFlow::Continue(());
-                                }
-                            } else {
-                                return ControlFlow::Continue(());
-                            }
-                        } else {
                             if !self.check_tait_defining_scope(alias_ty.def_id.expect_local()) {
                                 return ControlFlow::Continue(());
                             }
@@ -246,28 +229,6 @@ impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for OpaqueTypeCollector<'tcx> {
                         }
                     }
                 }
-
-                // Normalize trivial projections.
-                let mut infcx = self.tcx.infer_ctxt();
-                let infcx = infcx.build();
-                let t = if t.has_escaping_bound_vars() {
-                    let (t, _mapped_regions, _mapped_types, _mapped_consts) =
-                        rustc_trait_selection::traits::project::BoundVarReplacer::replace_bound_vars(
-                            &infcx,
-                            &mut self.universes,
-                            t,
-                        );
-                    t
-                } else {
-                    t
-                };
-                let ocx = ObligationCtxt::new(&infcx);
-                let cause = ObligationCause::dummy_with_span(self.span());
-                let normalized = ocx.normalize(&cause, self.tcx.param_env(self.item), t);
-                trace!(?normalized);
-                if normalized != t {
-                    normalized.visit_with(self)?;
-                }
             }
             ty::Adt(def, _) if def.did().is_local() => {
                 if !self.seen.insert(def.did().expect_local()) {

tests/ui/lint/issue-99387.rs

@@ -1,4 +1,5 @@
-// check-pass
+//! Test that we don't follow through projections to find
+//! opaque types.
 
 #![feature(type_alias_impl_trait)]
 #![allow(private_in_public)]
@@ -18,6 +19,7 @@ impl<'a> Tr for &'a () {
 }
 
 pub fn ohno<'a>() -> <&'a () as Tr>::Item {
+    //~^ ERROR item constrains opaque type that is not in its signature
     None.into_iter()
 }
 

tests/ui/lint/issue-99387.stderr

@@ -0,0 +1,15 @@
+error: item constrains opaque type that is not in its signature
+  --> $DIR/issue-99387.rs:21:22
+   |
+LL | pub fn ohno<'a>() -> <&'a () as Tr>::Item {
+   |                      ^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: this item must mention the opaque type in its signature in order to be able to register hidden types
+note: this item must mention the opaque type in its signature in order to be able to register hidden types
+  --> $DIR/issue-99387.rs:21:8
+   |
+LL | pub fn ohno<'a>() -> <&'a () as Tr>::Item {
+   |        ^^^^
+
+error: aborting due to previous error
+

tests/ui/type-alias-impl-trait/higher_kinded_params2.rs

@@ -3,8 +3,6 @@
 
 // edition: 2021
 
-// check-pass
-
 #![feature(type_alias_impl_trait)]
 
 trait B {
@@ -26,6 +24,7 @@ type Successors<'a> = impl std::fmt::Debug + 'a;
 impl Terminator {
     fn successors(&self, mut f: for<'x> fn(&'x ()) -> <&'x A as B>::C) -> Successors<'_> {
         f = g;
+        //~^ ERROR item constrains opaque type that is not in its signature
     }
 }
 

tests/ui/type-alias-impl-trait/higher_kinded_params2.stderr

@@ -0,0 +1,15 @@
+error: item constrains opaque type that is not in its signature
+  --> $DIR/higher_kinded_params2.rs:26:13
+   |
+LL |         f = g;
+   |             ^
+   |
+   = note: this item must mention the opaque type in its signature in order to be able to register hidden types
+note: this item must mention the opaque type in its signature in order to be able to register hidden types
+  --> $DIR/higher_kinded_params2.rs:25:8
+   |
+LL |     fn successors(&self, mut f: for<'x> fn(&'x ()) -> <&'x A as B>::C) -> Successors<'_> {
+   |        ^^^^^^^^^^
+
+error: aborting due to previous error
+

tests/ui/type-alias-impl-trait/higher_kinded_params3.rs

@@ -23,9 +23,9 @@ type Successors<'a> = impl std::fmt::Debug + 'a;
 
 impl Terminator {
     fn successors(&self, mut f: for<'x> fn(&'x ()) -> <&'x A as B>::C) -> Successors<'_> {
-        //~^ ERROR non-defining opaque type use in defining scope
         f = g;
         //~^ ERROR mismatched types
+        //~| ERROR item constrains opaque type that is not in its signature
     }
 }
 

tests/ui/type-alias-impl-trait/higher_kinded_params3.stderr

@@ -1,17 +1,18 @@
-error[E0792]: non-defining opaque type use in defining scope
+error: item constrains opaque type that is not in its signature
-  --> $DIR/higher_kinded_params3.rs:25:33
+  --> $DIR/higher_kinded_params3.rs:26:13
+   |
+LL |         f = g;
+   |             ^
+   |
+   = note: this item must mention the opaque type in its signature in order to be able to register hidden types
+note: this item must mention the opaque type in its signature in order to be able to register hidden types
+  --> $DIR/higher_kinded_params3.rs:25:8
    |
 LL |     fn successors(&self, mut f: for<'x> fn(&'x ()) -> <&'x A as B>::C) -> Successors<'_> {
-   |                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ argument `'x` is not a generic parameter
+   |        ^^^^^^^^^^
-   |
-note: for this opaque type
-  --> $DIR/higher_kinded_params3.rs:18:17
-   |
-LL | type Tait<'a> = impl std::fmt::Debug + 'a;
-   |                 ^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0308]: mismatched types
-  --> $DIR/higher_kinded_params3.rs:27:9
+  --> $DIR/higher_kinded_params3.rs:26:9
    |
 LL | type Tait<'a> = impl std::fmt::Debug + 'a;
    |                 ------------------------- the expected opaque type
@@ -24,5 +25,4 @@ LL |         f = g;
 
 error: aborting due to 2 previous errors
 
-Some errors have detailed explanations: E0308, E0792.
+For more information about this error, try `rustc --explain E0308`.
-For more information about an error, try `rustc --explain E0308`.

tests/ui/type-alias-impl-trait/issue-70121.rs

@@ -1,5 +1,3 @@
-// check-pass
-
 #![feature(type_alias_impl_trait)]
 
 pub type Successors<'a> = impl Iterator<Item = &'a ()>;
@@ -17,6 +15,7 @@ impl<'a> Tr for &'a () {
 }
 
 pub fn kazusa<'a>() -> <&'a () as Tr>::Item {
+    //~^ ERROR item constrains opaque type that is not in its signature
     None.into_iter()
 }
 

tests/ui/type-alias-impl-trait/issue-70121.stderr

@@ -0,0 +1,15 @@
+error: item constrains opaque type that is not in its signature
+  --> $DIR/issue-70121.rs:17:24
+   |
+LL | pub fn kazusa<'a>() -> <&'a () as Tr>::Item {
+   |                        ^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: this item must mention the opaque type in its signature in order to be able to register hidden types
+note: this item must mention the opaque type in its signature in order to be able to register hidden types
+  --> $DIR/issue-70121.rs:17:8
+   |
+LL | pub fn kazusa<'a>() -> <&'a () as Tr>::Item {
+   |        ^^^^^^
+
+error: aborting due to previous error
+