[rustdoc] Fix doc_cfg feature on reexports

src/librustdoc/passes/propagate_doc_cfg.rs

@@ -78,19 +78,21 @@ impl CfgPropagator<'_, '_> {
         // We need to merge an item attributes with its parent's in case it's an impl as an
         // impl might not be defined in the same module as the item it implements.
         //
+        // Same if it's an inlined item: we need to get the full original `cfg`.
+        //
         // Otherwise, `cfg_info` already tracks everything we need so nothing else to do!
-        if matches!(item.kind, ItemKind::ImplItem(_))
-            && let Some(mut next_def_id) = item.item_id.as_local_def_id()
-        {
-            while let Some(parent_def_id) = self.cx.tcx.opt_local_parent(next_def_id) {
-                let x = load_attrs(self.cx.tcx, parent_def_id.to_def_id());
-                add_only_cfg_attributes(&mut attrs, x);
-                next_def_id = parent_def_id;
+        if matches!(item.kind, ItemKind::ImplItem(_)) || item.inline_stmt_id.is_some() {
+            if let Some(mut next_def_id) = item.item_id.as_local_def_id() {
+                while let Some(parent_def_id) = self.cx.tcx.opt_local_parent(next_def_id) {
+                    let x = load_attrs(self.cx.tcx, parent_def_id.to_def_id());
+                    add_only_cfg_attributes(&mut attrs, x);
+                    next_def_id = parent_def_id;
+                }
             }
         }
         // We also need to merge an item attributes with its parent's in case it's a macro with
         // the `#[macro_export]` attribute, because it might not be defined at crate root.
-        if matches!(item.kind, ItemKind::MacroItem(_))
+        else if matches!(item.kind, ItemKind::MacroItem(_))
             && item.inner.attrs.other_attrs.iter().any(|attr| {
                 matches!(
                     attr,

src/librustdoc/visit_ast.rs

@@ -244,6 +244,7 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
         res: Res,
         renamed: Option<Symbol>,
         please_inline: bool,
+        import_id: Option<LocalDefId>,
     ) -> bool {
         debug!("maybe_inline_local (renamed: {renamed:?}) res: {res:?}");
 
@@ -338,20 +339,20 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
                 let prev = mem::replace(&mut self.inlining, true);
                 for &i in m.item_ids {
                     let i = tcx.hir_item(i);
-                    self.visit_item_inner(i, None, Some(def_id));
+                    self.visit_item_inner(i, None, Some(import_id.unwrap_or(def_id)));
                 }
                 self.inlining = prev;
                 true
             }
             Node::Item(it) if !is_glob => {
                 let prev = mem::replace(&mut self.inlining, true);
-                self.visit_item_inner(it, renamed, Some(def_id));
+                self.visit_item_inner(it, renamed, Some(import_id.unwrap_or(def_id)));
                 self.inlining = prev;
                 true
             }
             Node::ForeignItem(it) if !is_glob => {
                 let prev = mem::replace(&mut self.inlining, true);
-                self.visit_foreign_item_inner(it, renamed, Some(def_id));
+                self.visit_foreign_item_inner(it, renamed, Some(import_id.unwrap_or(def_id)));
                 self.inlining = prev;
                 true
             }
@@ -519,8 +520,13 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
                             hir::UseKind::Glob => None,
                             hir::UseKind::ListStem => unreachable!(),
                         };
-                        if self.maybe_inline_local(item.owner_id.def_id, res, ident, please_inline)
-                        {
+                        if self.maybe_inline_local(
+                            item.owner_id.def_id,
+                            res,
+                            ident,
+                            please_inline,
+                            import_id,
+                        ) {
                             debug!("Inlining {:?}", item.owner_id.def_id);
                             continue;
                         }

tests/rustdoc-html/doc-cfg/reexports.rs

@@ -0,0 +1,34 @@
+// This test ensures that reexports cfgs are correctly computed.
+// Regression test for <https://github.com/rust-lang/rust/issues/150268>.
+
+// ignore-tidy-linelength
+
+#![feature(doc_cfg)]
+#![crate_name = "foo"]
+
+//@has 'foo/struct.FlatBanana.html'
+//@has - '//*[@class="item-info"]/*[@class="stab portability"]' 'Available on non-crate feature banana and non-crate feature yoyo only.'
+
+//@has 'foo/struct.SubBanana.html'
+//@has - '//*[@class="item-info"]/*[@class="stab portability"]' 'Available on non-crate feature ananas and non-crate feature banana and non-crate feature yoyo only.'
+
+#[cfg(not(feature = "yoyo"))]
+pub use self::banana::*;
+
+//@has 'foo/struct.Yolo.html'
+//@has - '//*[@class="item-info"]/*[@class="stab portability"]' 'Available on non-crate feature ananas and non-crate feature banana only.'
+pub use self::banana::SubBanana as Yolo;
+
+#[cfg(not(feature = "banana"))]
+mod banana {
+    /// Depends on `banana` feature.
+    pub struct FlatBanana {}
+
+    #[cfg(not(feature = "ananas"))]
+    mod sub_banana {
+        /// Also depends on `banana` feature.
+        pub struct SubBanana {}
+    }
+
+    pub use self::sub_banana::*;
+}