rustdoc: Correctly handle reexports when --document-private-items is used

src/librustdoc/passes/strip_priv_imports.rs

@@ -12,6 +12,11 @@ pub(super) fn strip_priv_imports(krate: clean::Crate, cx: &mut DocContext<'_>) -
     }
 
     let is_json_output = cx.is_json_output();
-    ImportStripper { tcx: cx.tcx, is_json_output, document_hidden: cx.document_hidden() }
-        .fold_crate(krate)
+    ImportStripper {
+        tcx: cx.tcx,
+        is_json_output,
+        document_hidden: cx.document_hidden(),
+        document_private: cx.document_private(),
+    }
+    .fold_crate(krate)
 }

src/librustdoc/passes/strip_private.rs

@@ -25,9 +25,13 @@ pub(super) fn strip_private(mut krate: clean::Crate, cx: &mut DocContext<'_>) ->
             is_json_output,
             tcx: cx.tcx,
         };
-        krate =
-            ImportStripper { tcx: cx.tcx, is_json_output, document_hidden: cx.document_hidden() }
-                .fold_crate(stripper.fold_crate(krate));
+        krate = ImportStripper {
+            tcx: cx.tcx,
+            is_json_output,
+            document_hidden: cx.document_hidden(),
+            document_private: cx.document_private(),
+        }
+        .fold_crate(stripper.fold_crate(krate));
     }
 
     // strip all impls referencing private items

src/librustdoc/passes/stripper.rs

@@ -268,6 +268,7 @@ pub(crate) struct ImportStripper<'tcx> {
     pub(crate) tcx: TyCtxt<'tcx>,
     pub(crate) is_json_output: bool,
     pub(crate) document_hidden: bool,
+    pub(crate) document_private: bool,
 }
 
 impl ImportStripper<'_> {
@@ -290,6 +291,7 @@ impl DocFolder for ImportStripper<'_> {
                 debug!("ImportStripper: stripping {:?}", i.name);
                 None
             }
+            clean::ImportItem(imp) if self.document_private => Some(self.fold_item_recur(i)),
             // clean::ImportItem(_) if !self.document_hidden && i.is_doc_hidden() => None,
             clean::ExternCrateItem { .. } | clean::ImportItem(..)
                 if i.visibility(self.tcx) != Some(Visibility::Public) =>

src/librustdoc/visit_ast.rs

@@ -490,7 +490,15 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
         let tcx = self.cx.tcx;
 
         let def_id = item.owner_id.to_def_id();
-        let is_pub = tcx.visibility(def_id).is_public();
+        // Explanations: if the item is public, nothing more to check. If not, then we check if
+        // we're documenting private item. If we are, then we want all items, except if it's a
+        // `use`. In this case, we want to check if it's a reexport.
+        let is_pub = tcx.visibility(def_id).is_public()
+            || (self.cx.document_private()
+                && (!matches!(item.kind, hir::ItemKind::Use(..))
+                    || def_id.as_local().is_some_and(|def_id| {
+                        tcx.visibility(def_id).is_accessible_from(CRATE_DEF_ID, tcx)
+                    })));
 
         if is_pub {
             self.store_path(item.owner_id.to_def_id());
@@ -592,7 +600,7 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
 
             // If there was a private module in the current path then don't bother inlining
             // anything as it will probably be stripped anyway.
-            if is_pub && self.inside_public_path {
+            if is_pub && (self.inside_public_path || self.cx.document_private()) {
                 let please_inline = if let Some(res_did) = res.opt_def_id()
                     && matches!(tcx.def_kind(res_did), DefKind::Macro(MacroKinds::BANG))
                 {

tests/rustdoc-html/inline_local/document-private-reexports.rs

@@ -0,0 +1,52 @@
+// Test ensures that when we use the `--document-private-items` option, reexports
+// work the same as for "public" items.
+// Regression test for <https://github.com/rust-lang/rust/issues/159109>.
+
+//@ compile-flags: --document-private-items
+
+#![crate_name = "foo"]
+
+//@ has 'foo/index.html'
+// The four reexports, the `not_hidden` and `foofoo` (private) modules.
+//@ count - '//*[@class="item-table"]/dt' 6
+//@ has - '//*[@class="item-table"]/dt/a[@href="not_hidden/index.html"]' 'not_hidden'
+//@ has - '//*[@class="item-table"]/dt/a[@href="struct.Top.html"]' 'Top'
+//@ has - '//*[@class="item-table"]/dt/a[@href="struct.NotHidden.html"]' 'NotHidden'
+//@ has - '//*[@class="item-table"]/dt/a[@href="struct.Hidden2.html"]' 'Hidden2'
+//@ has - '//*[@class="item-table"]/dt/a[@href="struct.X.html"]' 'X'
+//@ has - '//*[@class="item-table"]/dt/a[@href="foofoo/index.html"]' 'foofoo'
+
+#[doc(hidden)]
+pub(crate) struct TopHidden;
+
+#[doc(inline)]
+pub(crate) use TopHidden as Top;
+
+#[doc(hidden)]
+mod hidden {
+    pub(crate) struct NotHidden;
+}
+
+pub(crate) use self::hidden::NotHidden;
+// Even though there is no `pub` of any kind, we display it because we're at the
+// crate root.
+use self::hidden::NotHidden as X;
+
+mod not_hidden {
+    #[doc(hidden)]
+    pub(crate) struct Hidden;
+}
+
+#[doc(inline)]
+pub(crate) use self::not_hidden::Hidden as Hidden2;
+
+//@ has 'foo/foofoo/index.html'
+//@ count - '//*[@class="item-table"]/dt' 1
+//@ has - '//*[@class="item-table"]/dt/a[@href="struct.Something.html"]' 'Something'
+mod foofoo {
+    // Since there is no `pub` of any kind, we don't display it, even if there is `doc(inline)`.
+    #[doc(inline)]
+    use crate::not_hidden::Hidden;
+    #[doc(inline)]
+    pub(crate) use crate::not_hidden::Hidden as Something;
+}

tests/rustdoc-html/inline_local/glob-private-document-private-items.rs

@@ -17,32 +17,32 @@ pub use mod1::*;
 //@ has foo/index.html
 //@ hasraw - "mod1"
 //@ hasraw - "Mod1Public"
-//@ !hasraw - "Mod1Private"
-//@ !hasraw - "mod2"
+//@ hasraw - "Mod1Private"
+//@ hasraw - "mod2"
 //@ hasraw - "Mod2Public"
-//@ !hasraw - "Mod2Private"
+//@ hasraw - "Mod2Private"
 //@ has foo/struct.Mod1Public.html
-//@ !has foo/struct.Mod1Private.html
+//@ has foo/struct.Mod1Private.html
 //@ has foo/struct.Mod2Public.html
-//@ !has foo/struct.Mod2Private.html
+//@ has foo/struct.Mod2Private.html
 
 //@ has foo/mod1/index.html
 //@ hasraw - "mod2"
 //@ hasraw - "Mod1Public"
 //@ hasraw - "Mod1Private"
-//@ !hasraw - "Mod2Public"
-//@ !hasraw - "Mod2Private"
+//@ hasraw - "Mod2Public"
+//@ hasraw - "Mod2Private"
 //@ has foo/mod1/struct.Mod1Public.html
 //@ has foo/mod1/struct.Mod1Private.html
-//@ !has foo/mod1/struct.Mod2Public.html
-//@ !has foo/mod1/struct.Mod2Private.html
+//@ has foo/mod1/struct.Mod2Public.html
+//@ has foo/mod1/struct.Mod2Private.html
 
 //@ has foo/mod1/mod2/index.html
 //@ hasraw - "Mod2Public"
 //@ hasraw - "Mod2Private"
 //@ has foo/mod1/mod2/struct.Mod2Public.html
 //@ has foo/mod1/mod2/struct.Mod2Private.html
 
-//@ !has foo/mod2/index.html
-//@ !has foo/mod2/struct.Mod2Public.html
-//@ !has foo/mod2/struct.Mod2Private.html
+//@ has foo/mod2/index.html
+//@ has foo/mod2/struct.Mod2Public.html
+//@ has foo/mod2/struct.Mod2Private.html