privacy: Report priv-in-pub as errors in associated type *bounds*

Author: petrochenkov

compiler/rustc_privacy/src/lib.rs

@@ -33,8 +33,8 @@ use rustc_middle::middle::privacy::{EffectiveVisibilities, EffectiveVisibility,
 use rustc_middle::query::Providers;
 use rustc_middle::ty::print::PrintTraitRefExt as _;
 use rustc_middle::ty::{
-    self, Const, GenericParamDefKind, TraitRef, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable,
-    TypeVisitor,
+    self, AssocContainer, Const, GenericParamDefKind, TraitRef, Ty, TyCtxt, TypeSuperVisitable,
+    TypeVisitable, TypeVisitor,
 };
 use rustc_middle::{bug, span_bug};
 use rustc_session::lint;
@@ -1601,6 +1601,9 @@ impl<'tcx> PrivateItemsInPublicInterfacesChecker<'_, 'tcx> {
         if check_ty {
             check.ty();
         }
+        if is_assoc_ty && item.container == AssocContainer::Trait {
+            check.bounds();
+        }
     }
 
     fn get(&self, def_id: LocalDefId) -> Option<EffectiveVisibility> {
@@ -1633,15 +1636,6 @@ impl<'tcx> PrivateItemsInPublicInterfacesChecker<'_, 'tcx> {
 
                 for assoc_item in tcx.associated_items(id.owner_id).in_definition_order() {
                     self.check_assoc_item(assoc_item, item_visibility, effective_vis);
-
-                    if assoc_item.is_type() {
-                        self.check(
-                            assoc_item.def_id.expect_local(),
-                            item_visibility,
-                            effective_vis,
-                        )
-                        .bounds();
-                    }
                 }
             }
             DefKind::TraitAlias => {

tests/ui/privacy/private-in-public-assoc-ty.rs

@@ -22,11 +22,11 @@ mod m {
     // applies only to the aliased types, not bounds.
     pub trait PubTr {
         type Alias1: PrivTr;
-        //~^ WARN trait `PrivTr` is more private than the item `PubTr::Alias1`
+        //~^ ERROR private trait `PrivTr` in public interface
         type Alias2: PubTrAux1<Priv> = u8;
-        //~^ WARN type `Priv` is more private than the item `PubTr::Alias2`
+        //~^ ERROR private type `Priv` in public interface
         type Alias3: PubTrAux2<A = Priv> = u8;
-        //~^ WARN type `Priv` is more private than the item `PubTr::Alias3`
+        //~^ ERROR private type `Priv` in public interface
 
         type Alias4 = Priv;
         //~^ ERROR private type `Priv` in public interface

tests/ui/privacy/private-in-public-assoc-ty.stderr

@@ -7,42 +7,32 @@ LL |     struct Priv;
 LL |         type A = Priv;
    |         ^^^^^^ can't leak private type
 
-warning: trait `PrivTr` is more private than the item `PubTr::Alias1`
+error[E0446]: private trait `PrivTr` in public interface
   --> $DIR/private-in-public-assoc-ty.rs:24:9
    |
-LL |         type Alias1: PrivTr;
-   |         ^^^^^^^^^^^^^^^^^^^ associated type `PubTr::Alias1` is reachable at visibility `pub(crate)`
-   |
-note: but trait `PrivTr` is only usable at visibility `pub(self)`
-  --> $DIR/private-in-public-assoc-ty.rs:9:5
-   |
 LL |     trait PrivTr {}
-   |     ^^^^^^^^^^^^
-   = note: `#[warn(private_bounds)]` on by default
+   |     ------------ `PrivTr` declared as private
+...
+LL |         type Alias1: PrivTr;
+   |         ^^^^^^^^^^^^^^^^^^^ can't leak private trait
 
-warning: type `Priv` is more private than the item `PubTr::Alias2`
+error[E0446]: private type `Priv` in public interface
   --> $DIR/private-in-public-assoc-ty.rs:26:9
    |
-LL |         type Alias2: PubTrAux1<Priv> = u8;
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ associated type `PubTr::Alias2` is reachable at visibility `pub(crate)`
-   |
-note: but type `Priv` is only usable at visibility `pub(self)`
-  --> $DIR/private-in-public-assoc-ty.rs:8:5
-   |
 LL |     struct Priv;
-   |     ^^^^^^^^^^^
+   |     ----------- `Priv` declared as private
+...
+LL |         type Alias2: PubTrAux1<Priv> = u8;
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ can't leak private type
 
-warning: type `Priv` is more private than the item `PubTr::Alias3`
+error[E0446]: private type `Priv` in public interface
   --> $DIR/private-in-public-assoc-ty.rs:28:9
    |
-LL |         type Alias3: PubTrAux2<A = Priv> = u8;
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ associated type `PubTr::Alias3` is reachable at visibility `pub(crate)`
-   |
-note: but type `Priv` is only usable at visibility `pub(self)`
-  --> $DIR/private-in-public-assoc-ty.rs:8:5
-   |
 LL |     struct Priv;
-   |     ^^^^^^^^^^^
+   |     ----------- `Priv` declared as private
+...
+LL |         type Alias3: PubTrAux2<A = Priv> = u8;
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ can't leak private type
 
 error[E0446]: private type `Priv` in public interface
   --> $DIR/private-in-public-assoc-ty.rs:31:9
@@ -71,6 +61,6 @@ LL |     trait PrivTr {}
 LL |         type Exist = impl PrivTr;
    |         ^^^^^^^^^^ can't leak private trait
 
-error: aborting due to 4 previous errors; 3 warnings emitted
+error: aborting due to 7 previous errors
 
 For more information about this error, try `rustc --explain E0446`.

tests/ui/privacy/private-in-public-warn.rs

@@ -45,7 +45,7 @@ mod traits {
     pub trait Tr2<T: PrivTr> {} //~ ERROR trait `traits::PrivTr` is more private than the item `traits::Tr2`
     pub trait Tr3 {
         type Alias: PrivTr;
-        //~^ ERROR trait `traits::PrivTr` is more private than the item `traits::Tr3::Alias`
+        //~^ ERROR private trait `traits::PrivTr` in public interface
         fn f<T: PrivTr>(arg: T) {}
         //~^ ERROR trait `traits::PrivTr` is more private than the item `traits::Tr3::f`
         fn g() -> impl PrivTr;

tests/ui/privacy/private-in-public-warn.stderr

@@ -170,17 +170,14 @@ note: but trait `traits::PrivTr` is only usable at visibility `pub(self)`
 LL |     trait PrivTr {}
    |     ^^^^^^^^^^^^
 
-error: trait `traits::PrivTr` is more private than the item `traits::Tr3::Alias`
+error[E0446]: private trait `traits::PrivTr` in public interface
   --> $DIR/private-in-public-warn.rs:47:9
    |
-LL |         type Alias: PrivTr;
-   |         ^^^^^^^^^^^^^^^^^^ associated type `traits::Tr3::Alias` is reachable at visibility `pub(crate)`
-   |
-note: but trait `traits::PrivTr` is only usable at visibility `pub(self)`
-  --> $DIR/private-in-public-warn.rs:37:5
-   |
 LL |     trait PrivTr {}
-   |     ^^^^^^^^^^^^
+   |     ------------ `traits::PrivTr` declared as private
+...
+LL |         type Alias: PrivTr;
+   |         ^^^^^^^^^^^^^^^^^^ can't leak private trait
 
 error: trait `traits::PrivTr` is more private than the item `traits::Tr3::f`
   --> $DIR/private-in-public-warn.rs:49:9