Add #[doc(search_hidden)] attribute

compiler/rustc_ast_passes/src/feature_gate.rs

@@ -261,6 +261,7 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
                     masked => doc_masked
                     spotlight => doc_spotlight
                     keyword => doc_keyword
+                    search_hidden => doc_search_hidden
                 );
             }
         }

compiler/rustc_feature/src/active.rs

@@ -610,6 +610,9 @@ declare_features! (
     /// Allows unsized fn parameters.
     (active, unsized_fn_params, "1.49.0", Some(48055), None),
 
+    /// Allows `#[doc(search_hidden)]`.
+    (active, doc_search_hidden, "1.49.0", Some(67368), None),
+
     // -------------------------------------------------------------------------
     // feature-group-end: actual feature gates
     // -------------------------------------------------------------------------

compiler/rustc_span/src/symbol.rs

@@ -447,6 +447,7 @@ symbols! {
         doc_cfg,
         doc_keyword,
         doc_masked,
+        doc_search_hidden,
         doc_spotlight,
         doctest,
         document_private_items,
@@ -964,6 +965,7 @@ symbols! {
         sanitizer_runtime,
         saturating_add,
         saturating_sub,
+        search_hidden,
         self_in_typedefs,
         self_struct_ctor,
         semitransparent,

src/doc/rustdoc/src/unstable-features.md

@@ -422,3 +422,19 @@ Calculating code examples follows these rules:
   * static
   * typedef
 2. If one of the previously listed items has a code example, then it'll be counted.
+
+### Hide an item from the doc search
+
+If you want an item to be visible from the documentation but to not show up when using
+the documentation search, you can use the `#[doc(search_hidden)]` attribute. For
+example:
+
+```rust
+#![feature(doc_search_hidden)]
+
+#[doc(search_hidden)]
+pub struct Bar;
+```
+
+If you look for "Bar" in the search, it won't appear. However, the type will appear in
+the documentation like it normally should.

src/librustdoc/clean/types.rs

@@ -718,6 +718,10 @@ impl Attributes {
             .filter(|v| !v.is_empty())
             .collect::<FxHashSet<_>>()
     }
+
+    pub fn is_search_hidden(&self) -> bool {
+        self.has_doc_flag(sym::search_hidden)
+    }
 }
 
 impl PartialEq for Attributes {

src/librustdoc/formats/cache.rs

@@ -308,7 +308,7 @@ impl DocFolder for Cache {
                     // A crate has a module at its root, containing all items,
                     // which should not be indexed. The crate-item itself is
                     // inserted later on when serializing the search-index.
-                    if item.def_id.index != CRATE_DEF_INDEX {
+                    if item.def_id.index != CRATE_DEF_INDEX && !item.attrs.is_search_hidden() {
                         self.search_index.push(IndexItem {
                             ty: item.type_(),
                             name: s.to_string(),

src/librustdoc/html/render/cache.rs

@@ -73,6 +73,9 @@ pub fn build_index(krate: &clean::Crate, cache: &mut Cache) -> String {
     // Attach all orphan items to the type's definition if the type
     // has since been learned.
     for &(did, ref item) in orphan_impl_items {
+        if item.attrs.is_search_hidden() {
+            continue;
+        }
         if let Some(&(ref fqp, _)) = paths.get(&did) {
             search_index.push(IndexItem {
                 ty: item.type_(),

src/test/rustdoc-js/search_hidden.js

@@ -0,0 +1,9 @@
+// exact-check
+
+const QUERY = 'Bar';
+
+const EXPECTED = {
+    'others': [
+        { 'path': 'search_hidden', 'name': 'Bar2' },
+    ],
+};

src/test/rustdoc-js/search_hidden.rs

@@ -0,0 +1,8 @@
+#![feature(doc_search_hidden)]
+
+#[doc(search_hidden)]
+/// Foo
+pub struct Bar;
+
+/// Bar
+pub struct Bar2;

src/test/ui/feature-gates/feature-gate-doc_search_hidden.rs

@@ -0,0 +1,4 @@
+#[doc(search_hidden)] //~ ERROR: `#[doc(search_hidden)]` is experimental
+pub struct Bar;
+
+fn main() {}

src/test/ui/feature-gates/feature-gate-doc_search_hidden.stderr

@@ -0,0 +1,12 @@
+error[E0658]: `#[doc(search_hidden)]` is experimental
+  --> $DIR/feature-gate-doc_search_hidden.rs:1:1
+   |
+LL | #[doc(search_hidden)]
+   | ^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #67368 <https://github.com/rust-lang/rust/issues/67368> for more information
+   = help: add `#![feature(doc_search_hidden)]` to the crate attributes to enable
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0658`.