Add check for an unstable attribute on the re-export, and update the test

Author: semicoleon

compiler/rustc_middle/src/middle/stability.rs

@@ -307,17 +307,11 @@ fn suggestion_for_allocator_api(
 }
 
 /// An override option for eval_stability.
-pub enum EvalOverride {
+pub enum AllowUnstable {
     /// Don't emit an unstable error for the item
-    AllowUnstable,
+    Yes,
     /// Handle the item normally
-    None,
-}
-
-impl Default for EvalOverride {
-    fn default() -> Self {
-        Self::None
-    }
+    No,
 }
 
 impl<'tcx> TyCtxt<'tcx> {
@@ -337,7 +331,7 @@ impl<'tcx> TyCtxt<'tcx> {
         span: Span,
         method_span: Option<Span>,
     ) -> EvalResult {
-        self.eval_stability_override(def_id, id, span, method_span, Default::default())
+        self.eval_stability_override(def_id, id, span, method_span, AllowUnstable::No)
     }
 
     /// Evaluates the stability of an item.
@@ -357,7 +351,7 @@ impl<'tcx> TyCtxt<'tcx> {
         id: Option<HirId>,
         span: Span,
         method_span: Option<Span>,
-        eval_override: EvalOverride,
+        eval_override: AllowUnstable,
     ) -> EvalResult {
         // Deprecated attributes apply in-crate and cross-crate.
         if let Some(id) = id {
@@ -455,7 +449,7 @@ impl<'tcx> TyCtxt<'tcx> {
                     }
                 }
 
-                if matches!(eval_override, EvalOverride::AllowUnstable) {
+                if matches!(eval_override, AllowUnstable::Yes) {
                     return EvalResult::Allow;
                 }
 
@@ -485,7 +479,7 @@ impl<'tcx> TyCtxt<'tcx> {
         span: Span,
         method_span: Option<Span>,
     ) {
-        self.check_stability_override(def_id, id, span, method_span, Default::default())
+        self.check_stability_override(def_id, id, span, method_span, AllowUnstable::No)
     }
 
     /// Checks if an item is stable or error out.
@@ -503,7 +497,7 @@ impl<'tcx> TyCtxt<'tcx> {
         id: Option<HirId>,
         span: Span,
         method_span: Option<Span>,
-        eval_override: EvalOverride,
+        eval_override: AllowUnstable,
     ) {
         self.check_optional_stability(
             def_id,
@@ -529,7 +523,7 @@ impl<'tcx> TyCtxt<'tcx> {
         id: Option<HirId>,
         span: Span,
         method_span: Option<Span>,
-        eval_override: EvalOverride,
+        eval_override: AllowUnstable,
         unmarked: impl FnOnce(Span, DefId),
     ) {
         let soft_handler = |lint, span, msg: &_| {

compiler/rustc_passes/src/stability.rs

@@ -13,7 +13,7 @@ use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::{FieldDef, Generics, HirId, Item, TraitRef, Ty, TyKind, Variant};
 use rustc_middle::hir::nested_filter;
 use rustc_middle::middle::privacy::AccessLevels;
-use rustc_middle::middle::stability::{DeprecationEntry, EvalOverride, Index};
+use rustc_middle::middle::stability::{AllowUnstable, DeprecationEntry, Index};
 use rustc_middle::ty::{self, query::Providers, TyCtxt};
 use rustc_session::lint;
 use rustc_session::lint::builtin::{INEFFECTIVE_UNSTABLE_TRAIT_IMPL, USELESS_DEPRECATED};
@@ -813,28 +813,29 @@ impl<'tcx> Visitor<'tcx> for Checker<'tcx> {
                 Some(id),
                 path.span,
                 method_span,
-                if is_path_reexport(self.tcx, id) {
-                    EvalOverride::AllowUnstable
-                } else {
-                    EvalOverride::None
-                },
+                if is_unstable_reexport(self.tcx, id) { AllowUnstable::Yes } else { AllowUnstable::No },
             )
         }
         intravisit::walk_path(self, path)
     }
 }
 
-/// Check whether a path is a `use` item
-fn is_path_reexport<'tcx>(tcx: TyCtxt<'tcx>, id: hir::HirId) -> bool {
+/// Check whether a path is a `use` item that has been marked as unstable.
+fn is_unstable_reexport<'tcx>(tcx: TyCtxt<'tcx>, id: hir::HirId) -> bool {
     // Get the LocalDefId so we can lookup the item to check the kind.
     let Some(def_id) = tcx.hir().opt_local_def_id(id) else { return false};
 
-    // If this is a path that isn't a use, we don't need to do anything special
-    if !matches!(tcx.hir().item(hir::ItemId { def_id }).kind, ItemKind::Use(..)) {
+    let Some(stab) = tcx.stability().local_stability(def_id) else {
+        return false;
+    };
+
+    if stab.level.is_stable() {
+        // The re-export is not marked as unstable, don't override
         return false;
     }
 
-    if tcx.visibility(def_id) != ty::Visibility::Public {
+    // If this is a path that isn't a use, we don't need to do anything special
+    if !matches!(tcx.hir().item(hir::ItemId { def_id }).kind, ItemKind::Use(..)) {
         return false;
     }
 

compiler/rustc_typeck/src/astconv/mod.rs

@@ -24,6 +24,7 @@ use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::intravisit::{walk_generics, Visitor as _};
 use rustc_hir::lang_items::LangItem;
 use rustc_hir::{GenericArg, GenericArgs};
+use rustc_middle::middle::stability::AllowUnstable;
 use rustc_middle::ty::subst::{self, GenericArgKind, InternalSubsts, Subst, SubstsRef};
 use rustc_middle::ty::GenericParamDefKind;
 use rustc_middle::ty::{self, Const, DefIdTree, EarlyBinder, Ty, TyCtxt, TypeFoldable};
@@ -426,7 +427,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                             Some(arg.id()),
                             arg.span(),
                             None,
-                            Default::default(),
+                            AllowUnstable::No,
                             |_, _| {
                                 // Default generic parameters may not be marked
                                 // with stability attributes, i.e. when the

src/test/ui/stability-attribute/allow-unstable-reexport.rs

@@ -8,12 +8,18 @@
 extern crate lint_stability;
 extern crate lint_stability_reexport;
 
-#[stable(feature = "lint_stability", since = "1.0.0")]
+#[unstable(feature = "unstable_test_feature", issue = "none")]
 pub use lint_stability::unstable;
+
 // We want to confirm that using a re-export through another crate behaves
 // the same way as using an item directly
+#[unstable(feature = "unstable_test_feature", issue = "none")]
+pub use lint_stability_reexport::unstable_text; 
+
+// Ensure items which aren't marked as unstable can't re-export unstable items
 #[stable(feature = "lint_stability", since = "1.0.0")]
-pub use lint_stability_reexport::unstable_text;
+pub use lint_stability::unstable as unstable2;
+//~^ ERROR use of unstable library feature 'unstable_test_feature'
 
 fn main() {
     // Since we didn't enable the feature in this crate, we still can't

src/test/ui/stability-attribute/allow-unstable-reexport.stderr

@@ -1,19 +1,27 @@
 error[E0658]: use of unstable library feature 'unstable_test_feature'
-  --> $DIR/allow-unstable-reexport.rs:21:5
+  --> $DIR/allow-unstable-reexport.rs:20:9
+   |
+LL | pub use lint_stability::unstable as unstable2;
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add `#![feature(unstable_test_feature)]` to the crate attributes to enable
+
+error[E0658]: use of unstable library feature 'unstable_test_feature'
+  --> $DIR/allow-unstable-reexport.rs:26:5
    |
 LL |     unstable();
    |     ^^^^^^^^
    |
    = help: add `#![feature(unstable_test_feature)]` to the crate attributes to enable
 
 error[E0658]: use of unstable library feature 'unstable_test_feature': text
-  --> $DIR/allow-unstable-reexport.rs:22:5
+  --> $DIR/allow-unstable-reexport.rs:27:5
    |
 LL |     unstable_text();
    |     ^^^^^^^^^^^^^
    |
    = help: add `#![feature(unstable_test_feature)]` to the crate attributes to enable
 
-error: aborting due to 2 previous errors
+error: aborting due to 3 previous errors
 
 For more information about this error, try `rustc --explain E0658`.