Auto merge of rust-lang#95024 - koehlma:rustdoc-private-items, r=GuillaumeGomez,camelid,jsha

rustdoc: add 🔒 to items with restricted visibility

This change marks items with restricted visibility with 🔒 when building with `--document-private-items`:

<img width="278" alt="Screen Shot 2022-03-20 at 23 50 24" src="https://user-images.githubusercontent.com/509209/159189513-9e4b09bb-6785-41a5-bfe2-df02f83f8641.png">

There also appears a “Restricted Visibility” tooltip when hovering over the emoji.

---

The original PR for reference:

This change makes private items slightly transparent (similar to `unstable` items in rustc):

<img width="272" alt="Screen Shot 2022-03-16 at 22 17 43" src="https://user-images.githubusercontent.com/509209/158692627-a1f6f5ec-e043-4aa2-9352-8d2b15c31c08.png">

I found myself using `--document-private-items` a lot recently because I find the documentation of private internals quite helpful when working on a larger project. However, not being able to distinguish private from public items (see rust-lang#87785) when looking at the documentation makes this somewhat cumbersome.

This PR addresses the third suggestion of issue rust-lang#87785 by marking private items typographically. It seems to me that the other suggestions are more involved but this is at least a first step.

A private item is also made slightly transparent in the path displayed in the header of a page:

<img width="467" alt="Screen Shot 2022-03-16 at 22 19 51" src="https://user-images.githubusercontent.com/509209/158692885-0bbd3417-3c0b-486f-b8ab-99c05c6fa7ca.png">

I am looking forward to feedback and suggestions.

Author: bors

Diff for: src/librustdoc/html/render/print_item.rs

@@ -376,17 +376,26 @@ fn item_module(w: &mut Buffer, cx: &Context<'_>, item: &clean::Item, items: &[cl
                 let stab = myitem.stability_class(cx.tcx());
                 let add = if stab.is_some() { " " } else { "" };
 
+                let visibility_emoji = match myitem.visibility {
+                    clean::Visibility::Restricted(_) => {
+                        "<span title=\"Restricted Visibility\">&nbsp;🔒</span> "
+                    }
+                    _ => "",
+                };
+
                 let doc_value = myitem.doc_value().unwrap_or_default();
                 w.write_str(ITEM_TABLE_ROW_OPEN);
                 write!(
                     w,
                     "<div class=\"item-left {stab}{add}module-item\">\
-                         <a class=\"{class}\" href=\"{href}\" title=\"{title}\">{name}</a>\
-                             {unsafety_flag}\
-                             {stab_tags}\
+                            <a class=\"{class}\" href=\"{href}\" title=\"{title}\">{name}</a>\
+                            {visibility_emoji}\
+                            {unsafety_flag}\
+                            {stab_tags}\
                      </div>\
                      <div class=\"item-right docblock-short\">{docs}</div>",
                     name = myitem.name.unwrap(),
+                    visibility_emoji = visibility_emoji,
                     stab_tags = extra_info_tags(myitem, item, cx.tcx()),
                     docs = MarkdownSummaryLine(&doc_value, &myitem.links(cx)).into_string(),
                     class = myitem.type_(),

Diff for: src/test/rustdoc/visibility.rs

@@ -4,42 +4,68 @@
 
 #![crate_name = "foo"]
 
+// @!has 'foo/index.html' '//a[@href="struct.FooPublic.html"]/..' 'FooPublic 🔒'
 // @has 'foo/struct.FooPublic.html' '//pre' 'pub struct FooPublic'
 pub struct FooPublic;
+// @has 'foo/index.html' '//a[@href="struct.FooJustCrate.html"]/..' 'FooJustCrate 🔒'
 // @has 'foo/struct.FooJustCrate.html' '//pre' 'pub(crate) struct FooJustCrate'
 crate struct FooJustCrate;
+// @has 'foo/index.html' '//a[@href="struct.FooPubCrate.html"]/..' 'FooPubCrate 🔒'
 // @has 'foo/struct.FooPubCrate.html' '//pre' 'pub(crate) struct FooPubCrate'
 pub(crate) struct FooPubCrate;
+// @has 'foo/index.html' '//a[@href="struct.FooSelf.html"]/..' 'FooSelf 🔒'
 // @has 'foo/struct.FooSelf.html' '//pre' 'pub(crate) struct FooSelf'
 pub(self) struct FooSelf;
+// @has 'foo/index.html' '//a[@href="struct.FooInSelf.html"]/..' 'FooInSelf 🔒'
 // @has 'foo/struct.FooInSelf.html' '//pre' 'pub(crate) struct FooInSelf'
 pub(in self) struct FooInSelf;
+// @has 'foo/index.html' '//a[@href="struct.FooPriv.html"]/..' 'FooPriv 🔒'
 // @has 'foo/struct.FooPriv.html' '//pre' 'pub(crate) struct FooPriv'
 struct FooPriv;
 
+// @!has 'foo/index.html' '//a[@href="pub_mod/index.html"]/..' 'pub_mod 🔒'
+pub mod pub_mod {}
+
+// @has 'foo/index.html' '//a[@href="pub_crate_mod/index.html"]/..' 'pub_crate_mod 🔒'
+pub(crate) mod pub_crate_mod {}
+
+// @has 'foo/index.html' '//a[@href="a/index.html"]/..' 'a 🔒'
 mod a {
+    // @has 'foo/a/index.html' '//a[@href="struct.FooASuper.html"]/..' 'FooASuper 🔒'
     // @has 'foo/a/struct.FooASuper.html' '//pre' 'pub(crate) struct FooASuper'
     pub(super) struct FooASuper;
+    // @has 'foo/a/index.html' '//a[@href="struct.FooAInSuper.html"]/..' 'FooAInSuper 🔒'
     // @has 'foo/a/struct.FooAInSuper.html' '//pre' 'pub(crate) struct FooAInSuper'
     pub(in super) struct FooAInSuper;
+    // @has 'foo/a/index.html' '//a[@href="struct.FooAInA.html"]/..' 'FooAInA 🔒'
     // @has 'foo/a/struct.FooAInA.html' '//pre' 'struct FooAInA'
     // @!has 'foo/a/struct.FooAInA.html' '//pre' 'pub'
     pub(in a) struct FooAInA;
+    // @has 'foo/a/index.html' '//a[@href="struct.FooAPriv.html"]/..' 'FooAPriv 🔒'
     // @has 'foo/a/struct.FooAPriv.html' '//pre' 'struct FooAPriv'
     // @!has 'foo/a/struct.FooAPriv.html' '//pre' 'pub'
     struct FooAPriv;
 
+    // @has 'foo/a/index.html' '//a[@href="b/index.html"]/..' 'b 🔒'
     mod b {
+        // @has 'foo/a/b/index.html' '//a[@href="struct.FooBSuper.html"]/..' 'FooBSuper 🔒'
         // @has 'foo/a/b/struct.FooBSuper.html' '//pre' 'pub(super) struct FooBSuper'
         pub(super) struct FooBSuper;
+        // @has 'foo/a/b/index.html' '//a[@href="struct.FooBInSuperSuper.html"]/..' 'FooBInSuperSuper 🔒'
         // @has 'foo/a/b/struct.FooBInSuperSuper.html' '//pre' 'pub(crate) struct FooBInSuperSuper'
         pub(in super::super) struct FooBInSuperSuper;
+        // @has 'foo/a/b/index.html' '//a[@href="struct.FooBInAB.html"]/..' 'FooBInAB 🔒'
         // @has 'foo/a/b/struct.FooBInAB.html' '//pre' 'struct FooBInAB'
         // @!has 'foo/a/b/struct.FooBInAB.html' '//pre' 'pub'
         pub(in a::b) struct FooBInAB;
+        // @has 'foo/a/b/index.html' '//a[@href="struct.FooBPriv.html"]/..' 'FooBPriv 🔒'
         // @has 'foo/a/b/struct.FooBPriv.html' '//pre' 'struct FooBPriv'
         // @!has 'foo/a/b/struct.FooBPriv.html' '//pre' 'pub'
         struct FooBPriv;
+
+        // @!has 'foo/a/b/index.html' '//a[@href="struct.FooBPub.html"]/..' 'FooBPub 🔒'
+        // @has 'foo/a/b/struct.FooBPub.html' '//pre' 'pub struct FooBPub'
+        pub struct FooBPub;
     }
 }
 
@@ -53,13 +79,18 @@ mod a {
 //
 // @has 'foo/trait.PubTrait.html' '//pre' 'fn function();'
 // @!has 'foo/trait.PubTrait.html' '//pre' 'pub fn function();'
+//
+// @!has 'foo/index.html' '//a[@href="trait.PubTrait.html"]/..' 'PubTrait 🔒'
 
 pub trait PubTrait {
     type Type;
     const CONST: usize;
     fn function();
 }
 
+// @has 'foo/index.html' '//a[@href="trait.PrivTrait.html"]/..' 'PrivTrait 🔒'
+trait PrivTrait {}
+
 // @has 'foo/struct.FooPublic.html' '//h4[@class="code-header"]' 'type Type'
 // @!has 'foo/struct.FooPublic.html' '//h4[@class="code-header"]' 'pub type Type'
 //