Fix handling of items inside a doc(hidden) block

src/librustdoc/clean/mod.rs

@@ -2225,21 +2225,17 @@ fn clean_maybe_renamed_item<'tcx>(
             get_all_import_attributes(use_node, cx.tcx, item.owner_id.def_id, &mut extra_attrs);
         }
 
-        if !extra_attrs.is_empty() {
+        let mut item = if !extra_attrs.is_empty() {
             extra_attrs.extend_from_slice(inline::load_attrs(cx, def_id));
             let attrs = Attributes::from_ast(&extra_attrs);
             let cfg = extra_attrs.cfg(cx.tcx, &cx.cache.hidden_cfg);
 
-            vec![Item::from_def_id_and_attrs_and_parts(
-                def_id,
-                Some(name),
-                kind,
-                Box::new(attrs),
-                cfg,
-            )]
+            Item::from_def_id_and_attrs_and_parts(def_id, Some(name), kind, Box::new(attrs), cfg)
         } else {
-            vec![Item::from_def_id_and_parts(def_id, Some(name), kind, cx)]
-        }
+            Item::from_def_id_and_parts(def_id, Some(name), kind, cx)
+        };
+        item.inline_stmt_id = import_id.map(|def_id| def_id.to_def_id());
+        vec![item]
     })
 }
 

src/librustdoc/html/render/write_shared.rs

@@ -138,7 +138,7 @@ pub(super) fn write_shared(
         Ok((ret, krates))
     }
 
-    /// Read a file and return all lines that match the <code>"{crate}":{data},\</code> format,
+    /// Read a file and return all lines that match the <code>"{crate}":{data},\ </code> format,
     /// and return a tuple `(Vec<DataString>, Vec<CrateNameString>)`.
     ///
     /// This forms the payload of files that look like this:

src/librustdoc/passes/strip_hidden.rs

@@ -1,4 +1,6 @@
 //! Strip all doc(hidden) items from the output.
+
+use rustc_middle::ty::TyCtxt;
 use rustc_span::symbol::sym;
 use std::mem;
 
@@ -7,6 +9,7 @@ use crate::clean::{Item, ItemIdSet, NestedAttributesExt};
 use crate::core::DocContext;
 use crate::fold::{strip_item, DocFolder};
 use crate::passes::{ImplStripper, Pass};
+use crate::visit_ast::inherits_doc_hidden;
 
 pub(crate) const STRIP_HIDDEN: Pass = Pass {
     name: "strip-hidden",
@@ -21,7 +24,12 @@ pub(crate) fn strip_hidden(krate: clean::Crate, cx: &mut DocContext<'_>) -> clea
 
     // strip all #[doc(hidden)] items
     let krate = {
-        let mut stripper = Stripper { retained: &mut retained, update_retained: true };
+        let mut stripper = Stripper {
+            retained: &mut retained,
+            update_retained: true,
+            tcx: cx.tcx,
+            is_in_hidden_item: false,
+        };
         stripper.fold_crate(krate)
     };
 
@@ -36,40 +44,89 @@ pub(crate) fn strip_hidden(krate: clean::Crate, cx: &mut DocContext<'_>) -> clea
     stripper.fold_crate(krate)
 }
 
-struct Stripper<'a> {
+struct Stripper<'a, 'tcx> {
     retained: &'a mut ItemIdSet,
     update_retained: bool,
+    tcx: TyCtxt<'tcx>,
+    is_in_hidden_item: bool,
+}
+
+impl<'a, 'tcx> Stripper<'a, 'tcx> {
+    fn set_is_in_hidden_item_and_fold(&mut self, is_in_hidden_item: bool, i: Item) -> Item {
+        let prev = self.is_in_hidden_item;
+        self.is_in_hidden_item |= is_in_hidden_item;
+        let ret = self.fold_item_recur(i);
+        self.is_in_hidden_item = prev;
+        ret
+    }
+
+    /// In case `i` is a non-hidden impl block, then we special-case it by changing the value
+    /// of `is_in_hidden_item` to `true` because the impl children inherit its visibility.
+    fn recurse_in_impl(&mut self, i: Item) -> Item {
+        let prev = mem::replace(&mut self.is_in_hidden_item, false);
+        let ret = self.fold_item_recur(i);
+        self.is_in_hidden_item = prev;
+        ret
+    }
 }
 
-impl<'a> DocFolder for Stripper<'a> {
+impl<'a, 'tcx> DocFolder for Stripper<'a, 'tcx> {
     fn fold_item(&mut self, i: Item) -> Option<Item> {
-        if i.attrs.lists(sym::doc).has_word(sym::hidden) {
-            debug!("strip_hidden: stripping {:?} {:?}", i.type_(), i.name);
-            // Use a dedicated hidden item for fields, variants, and modules.
-            // We need to keep private fields and variants, so that the docs
-            // can show a placeholder "// some variants omitted". We need to keep
-            // private modules, because they can contain impl blocks, and impl
-            // block privacy is inherited from the type and trait, not from the
-            // module it's defined in. Both of these are marked "stripped," and
-            // not included in the final docs, but since they still have an effect
-            // on the final doc, cannot be completely removed from the Clean IR.
-            match *i.kind {
-                clean::StructFieldItem(..) | clean::ModuleItem(..) | clean::VariantItem(..) => {
-                    // We need to recurse into stripped modules to
-                    // strip things like impl methods but when doing so
-                    // we must not add any items to the `retained` set.
-                    let old = mem::replace(&mut self.update_retained, false);
-                    let ret = strip_item(self.fold_item_recur(i));
-                    self.update_retained = old;
-                    return Some(ret);
-                }
-                _ => return None,
+        let has_doc_hidden = i.attrs.lists(sym::doc).has_word(sym::hidden);
+        let is_impl = matches!(*i.kind, clean::ImplItem(..));
+        let mut is_hidden = has_doc_hidden;
+        if !is_impl {
+            is_hidden = self.is_in_hidden_item || has_doc_hidden;
+            if !is_hidden && i.inline_stmt_id.is_none() {
+                // We don't need to check if it's coming from a reexport since the reexport itself was
+                // already checked.
+                is_hidden = i
+                    .item_id
+                    .as_def_id()
+                    .and_then(|def_id| def_id.as_local())
+                    .map(|def_id| inherits_doc_hidden(self.tcx, def_id))
+                    .unwrap_or(false);
             }
-        } else {
+        }
+        if !is_hidden {
             if self.update_retained {
                 self.retained.insert(i.item_id);
             }
+            return Some(if is_impl {
+                self.recurse_in_impl(i)
+            } else {
+                self.set_is_in_hidden_item_and_fold(false, i)
+            });
+        }
+        debug!("strip_hidden: stripping {:?} {:?}", i.type_(), i.name);
+        // Use a dedicated hidden item for fields, variants, and modules.
+        // We need to keep private fields and variants, so that the docs
+        // can show a placeholder "// some variants omitted". We need to keep
+        // private modules, because they can contain impl blocks, and impl
+        // block privacy is inherited from the type and trait, not from the
+        // module it's defined in. Both of these are marked "stripped," and
+        // not included in the final docs, but since they still have an effect
+        // on the final doc, cannot be completely removed from the Clean IR.
+        match *i.kind {
+            clean::StructFieldItem(..) | clean::ModuleItem(..) | clean::VariantItem(..) => {
+                // We need to recurse into stripped modules to
+                // strip things like impl methods but when doing so
+                // we must not add any items to the `retained` set.
+                let old = mem::replace(&mut self.update_retained, false);
+                let ret = strip_item(self.set_is_in_hidden_item_and_fold(true, i));
+                self.update_retained = old;
+                Some(ret)
+            }
+            _ => {
+                let ret = self.set_is_in_hidden_item_and_fold(true, i);
+                if has_doc_hidden {
+                    // If the item itself has `#[doc(hidden)]`, then we simply remove it.
+                    None
+                } else {
+                    // However if it's a "descendant" of a `#[doc(hidden)]` item, then we strip it.
+                    Some(strip_item(ret))
+                }
+            }
         }
-        Some(self.fold_item_recur(i))
     }
 }