Auto merge of #49757 - GuillaumeGomez:never-search, r=QuietMisdreavus

Add specific never search

Fixes #49529.

r? @QuietMisdreavus

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

@@ -373,3 +373,19 @@ This is an internal flag intended for the standard library and compiler that app
 `#[unstable]` attribute to any dependent crate that doesn't have another stability attribute. This
 allows `rustdoc` to be able to generate documentation for the compiler crates and the standard
 library, as an equivalent command-line argument is provided to `rustc` when building those crates.
+
+### `doc_alias` feature
+
+This feature allows you to add alias(es) to an item when using the `rustdoc` search through the
+`doc(alias)` attribute. Example:
+
+```rust,no_run
+#![feature(doc_alias)]
+
+#[doc(alias = "x")]
+#[doc(alias = "big")]
+pub struct BigX;
+```
+
+Then, when looking for it through the `rustdoc` search, if you enter "x" or
+"big", search will show the `BigX` struct first.

src/doc/unstable-book/src/language-features/doc-alias.md

@@ -0,0 +1,23 @@
+# `doc_alias`
+
+The tracking issue for this feature is: [#50146]
+
+[#50146]: https://github.com/rust-lang/rust/issues/50146
+
+------------------------
+
+You can add alias(es) to an item when using the `rustdoc` search through the
+`doc(alias)` attribute. Example:
+
+```rust,no_run
+#![feature(doc_alias)]
+
+#[doc(alias = "x")]
+#[doc(alias = "big")]
+pub struct BigX;
+```
+
+Then, when looking for it through the `rustdoc` search, if you enter "x" or
+"big", search will show the `BigX` struct first.
+
+Note that this feature is currently hidden behind the `feature(doc_alias)` gate.

src/libcore/lib.rs

@@ -102,6 +102,7 @@
 #![feature(unboxed_closures)]
 #![feature(untagged_unions)]
 #![feature(unwind_attributes)]
+#![feature(doc_alias)]
 
 #![cfg_attr(not(stage0), feature(mmx_target_feature))]
 #![cfg_attr(not(stage0), feature(tbm_target_feature))]

src/libcore/macros.rs

@@ -295,6 +295,7 @@ macro_rules! debug_assert_ne {
 /// ```
 #[macro_export]
 #[stable(feature = "rust1", since = "1.0.0")]
+#[doc(alias = "?")]
 macro_rules! try {
     ($expr:expr) => (match $expr {
         $crate::result::Result::Ok(val) => val,

src/libcore/ops/arith.rs

@@ -87,6 +87,7 @@
     message="cannot add `{RHS}` to `{Self}`",
     label="no implementation for `{Self} + {RHS}`",
 )]
+#[doc(alias = "+")]
 pub trait Add<RHS=Self> {
     /// The resulting type after applying the `+` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -183,6 +184,7 @@ add_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 }
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_on_unimplemented(message="cannot subtract `{RHS}` from `{Self}`",
                          label="no implementation for `{Self} - {RHS}`")]
+#[doc(alias = "-")]
 pub trait Sub<RHS=Self> {
     /// The resulting type after applying the `-` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -301,6 +303,7 @@ sub_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 }
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_on_unimplemented(message="cannot multiply `{RHS}` to `{Self}`",
                          label="no implementation for `{Self} * {RHS}`")]
+#[doc(alias = "*")]
 pub trait Mul<RHS=Self> {
     /// The resulting type after applying the `*` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -423,6 +426,7 @@ mul_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 }
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_on_unimplemented(message="cannot divide `{Self}` by `{RHS}`",
                          label="no implementation for `{Self} / {RHS}`")]
+#[doc(alias = "/")]
 pub trait Div<RHS=Self> {
     /// The resulting type after applying the `/` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -506,6 +510,7 @@ div_impl_float! { f32 f64 }
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_on_unimplemented(message="cannot mod `{Self}` by `{RHS}`",
                          label="no implementation for `{Self} % {RHS}`")]
+#[doc(alias = "%")]
 pub trait Rem<RHS=Self> {
     /// The resulting type after applying the `%` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -589,6 +594,7 @@ rem_impl_float! { f32 f64 }
 /// ```
 #[lang = "neg"]
 #[stable(feature = "rust1", since = "1.0.0")]
+#[doc(alias = "-")]
 pub trait Neg {
     /// The resulting type after applying the `-` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -664,6 +670,8 @@ neg_impl_numeric! { isize i8 i16 i32 i64 i128 f32 f64 }
 #[stable(feature = "op_assign_traits", since = "1.8.0")]
 #[rustc_on_unimplemented(message="cannot add-assign `{Rhs}` to `{Self}`",
                          label="no implementation for `{Self} += {Rhs}`")]
+#[doc(alias = "+")]
+#[doc(alias = "+=")]
 pub trait AddAssign<Rhs=Self> {
     /// Performs the `+=` operation.
     #[stable(feature = "op_assign_traits", since = "1.8.0")]
@@ -718,6 +726,8 @@ add_assign_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 }
 #[stable(feature = "op_assign_traits", since = "1.8.0")]
 #[rustc_on_unimplemented(message="cannot subtract-assign `{Rhs}` from `{Self}`",
                          label="no implementation for `{Self} -= {Rhs}`")]
+#[doc(alias = "-")]
+#[doc(alias = "-=")]
 pub trait SubAssign<Rhs=Self> {
     /// Performs the `-=` operation.
     #[stable(feature = "op_assign_traits", since = "1.8.0")]
@@ -763,6 +773,8 @@ sub_assign_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 }
 #[stable(feature = "op_assign_traits", since = "1.8.0")]
 #[rustc_on_unimplemented(message="cannot multiply-assign `{Rhs}` to `{Self}`",
                          label="no implementation for `{Self} *= {Rhs}`")]
+#[doc(alias = "*")]
+#[doc(alias = "*=")]
 pub trait MulAssign<Rhs=Self> {
     /// Performs the `*=` operation.
     #[stable(feature = "op_assign_traits", since = "1.8.0")]
@@ -808,6 +820,8 @@ mul_assign_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 }
 #[stable(feature = "op_assign_traits", since = "1.8.0")]
 #[rustc_on_unimplemented(message="cannot divide-assign `{Self}` by `{Rhs}`",
                          label="no implementation for `{Self} /= {Rhs}`")]
+#[doc(alias = "/")]
+#[doc(alias = "/=")]
 pub trait DivAssign<Rhs=Self> {
     /// Performs the `/=` operation.
     #[stable(feature = "op_assign_traits", since = "1.8.0")]
@@ -856,6 +870,8 @@ div_assign_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 }
 #[stable(feature = "op_assign_traits", since = "1.8.0")]
 #[rustc_on_unimplemented(message="cannot mod-assign `{Self}` by `{Rhs}``",
                          label="no implementation for `{Self} %= {Rhs}`")]
+#[doc(alias = "%")]
+#[doc(alias = "%=")]
 pub trait RemAssign<Rhs=Self> {
     /// Performs the `%=` operation.
     #[stable(feature = "op_assign_traits", since = "1.8.0")]

src/libcore/ops/index.rs

@@ -62,6 +62,9 @@
 #[lang = "index"]
 #[rustc_on_unimplemented = "the type `{Self}` cannot be indexed by `{Idx}`"]
 #[stable(feature = "rust1", since = "1.0.0")]
+#[doc(alias = "]")]
+#[doc(alias = "[")]
+#[doc(alias = "[]")]
 pub trait Index<Idx: ?Sized> {
     /// The returned type after indexing.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -146,6 +149,9 @@ pub trait Index<Idx: ?Sized> {
 #[lang = "index_mut"]
 #[rustc_on_unimplemented = "the type `{Self}` cannot be mutably indexed by `{Idx}`"]
 #[stable(feature = "rust1", since = "1.0.0")]
+#[doc(alias = "[")]
+#[doc(alias = "]")]
+#[doc(alias = "[]")]
 pub trait IndexMut<Idx: ?Sized>: Index<Idx> {
     /// Performs the mutable indexing (`container[index]`) operation.
     #[stable(feature = "rust1", since = "1.0.0")]

src/libcore/ops/try.rs

@@ -28,6 +28,7 @@
                that implement `{Try}`",
       label="the `?` operator cannot be applied to type `{Self}`")
 )]
+#[doc(alias = "?")]
 pub trait Try {
     /// The type of this value when viewed as successful.
     #[unstable(feature = "try_trait", issue = "42327")]

src/librustdoc/html/item_type.rs

@@ -19,7 +19,7 @@ use clean;
 /// discriminants. JavaScript then is used to decode them into the original value.
 /// Consequently, every change to this type should be synchronized to
 /// the `itemTypes` mapping table in `static/main.js`.
-#[derive(Copy, PartialEq, Clone)]
+#[derive(Copy, PartialEq, Clone, Debug)]
 pub enum ItemType {
     Module          = 0,
     ExternCrate     = 1,

src/librustdoc/html/layout.rs

@@ -145,6 +145,7 @@ pub fn render<T: fmt::Display, S: fmt::Display>(
     </script>\
     <script src=\"{root_path}main{suffix}.js\"></script>\
     <script defer src=\"{root_path}search-index.js\"></script>\
+    <script defer src=\"{root_path}aliases.js\"></script>\
 </body>\
 </html>",
     css_extension = if css_file_extension {

src/librustdoc/html/render.rs

@@ -329,6 +329,10 @@ pub struct Cache {
     // yet when its implementation methods are being indexed. Caches such methods
     // and their parent id here and indexes them at the end of crate parsing.
     orphan_impl_items: Vec<(DefId, clean::Item)>,
+
+    /// Aliases added through `#[doc(alias = "...")]`. Since a few items can have the same alias,
+    /// we need the alias element to have an array of items.
+    aliases: FxHashMap<String, Vec<IndexItem>>,
 }
 
 /// Temporary storage for data obtained during `RustdocVisitor::clean()`.
@@ -369,6 +373,7 @@ struct Sidebar<'a> { cx: &'a Context, item: &'a clean::Item, }
 
 /// Struct representing one entry in the JS search index. These are all emitted
 /// by hand to a large JS file at the end of cache-creation.
+#[derive(Debug)]
 struct IndexItem {
     ty: ItemType,
     name: String,
@@ -396,6 +401,7 @@ impl ToJson for IndexItem {
 }
 
 /// A type used for the search index.
+#[derive(Debug)]
 struct Type {
     name: Option<String>,
     generics: Option<Vec<String>>,
@@ -418,9 +424,10 @@ impl ToJson for Type {
 }
 
 /// Full type of functions/methods in the search index.
+#[derive(Debug)]
 struct IndexItemFunctionType {
     inputs: Vec<Type>,
-    output: Option<Type>
+    output: Option<Type>,
 }
 
 impl ToJson for IndexItemFunctionType {
@@ -609,6 +616,7 @@ pub fn run(mut krate: clean::Crate,
         owned_box_did,
         masked_crates: mem::replace(&mut krate.masked_crates, FxHashSet()),
         typarams: external_typarams,
+        aliases: FxHashMap(),
     };
 
     // Cache where all our extern crates are located
@@ -847,8 +855,7 @@ themePicker.onclick = function() {{
     write(cx.dst.join("COPYRIGHT.txt"),
           include_bytes!("static/COPYRIGHT.txt"))?;
 
-    fn collect(path: &Path, krate: &str,
-               key: &str) -> io::Result<Vec<String>> {
+    fn collect(path: &Path, krate: &str, key: &str) -> io::Result<Vec<String>> {
         let mut ret = Vec::new();
         if path.exists() {
             for line in BufReader::new(File::open(path)?).lines() {
@@ -865,6 +872,40 @@ themePicker.onclick = function() {{
         Ok(ret)
     }
 
+    fn show_item(item: &IndexItem, krate: &str) -> String {
+        format!("{{'crate':'{}','ty':{},'name':'{}','path':'{}'{}}}",
+                krate, item.ty as usize, item.name, item.path,
+                if let Some(p) = item.parent_idx {
+                    format!(",'parent':{}", p)
+                } else {
+                    String::new()
+                })
+    }
+
+    let dst = cx.dst.join("aliases.js");
+    {
+        let mut all_aliases = try_err!(collect(&dst, &krate.name, "ALIASES"), &dst);
+        let mut w = try_err!(File::create(&dst), &dst);
+        let mut output = String::with_capacity(100);
+        for (alias, items) in &cache.aliases {
+            if items.is_empty() {
+                continue
+            }
+            output.push_str(&format!("\"{}\":[{}],",
+                                     alias,
+                                     items.iter()
+                                          .map(|v| show_item(v, &krate.name))
+                                          .collect::<Vec<_>>()
+                                          .join(",")));
+        }
+        all_aliases.push(format!("ALIASES['{}'] = {{{}}};", krate.name, output));
+        all_aliases.sort();
+        try_err!(writeln!(&mut w, "var ALIASES = {{}};"), &dst);
+        for aliases in &all_aliases {
+            try_err!(writeln!(&mut w, "{}", aliases), &dst);
+        }
+    }
+
     // Update the search index
     let dst = cx.dst.join("search-index.js");
     let mut all_indexes = try_err!(collect(&dst, &krate.name, "searchIndex"), &dst);
@@ -1251,13 +1292,13 @@ impl DocFolder for Cache {
                 // `public_items` map, so we can skip inserting into the
                 // paths map if there was already an entry present and we're
                 // not a public item.
-                if
-                    !self.paths.contains_key(&item.def_id) ||
-                    self.access_levels.is_public(item.def_id)
+                if !self.paths.contains_key(&item.def_id) ||
+                   self.access_levels.is_public(item.def_id)
                 {
                     self.paths.insert(item.def_id,
                                       (self.stack.clone(), item.type_()));
                 }
+                self.add_aliases(&item);
             }
             // Link variants to their parent enum because pages aren't emitted
             // for each variant.
@@ -1268,6 +1309,7 @@ impl DocFolder for Cache {
             }
 
             clean::PrimitiveItem(..) if item.visibility.is_some() => {
+                self.add_aliases(&item);
                 self.paths.insert(item.def_id, (self.stack.clone(),
                                                 item.type_()));
             }
@@ -1372,6 +1414,36 @@ impl<'a> Cache {
             }
         }
     }
+
+    fn add_aliases(&mut self, item: &clean::Item) {
+        if item.def_id.index == CRATE_DEF_INDEX {
+            return
+        }
+        if let Some(ref item_name) = item.name {
+            let path = self.paths.get(&item.def_id)
+                                 .map(|p| p.0.join("::").to_string())
+                                 .unwrap_or("std".to_owned());
+            for alias in item.attrs.lists("doc")
+                                   .filter(|a| a.check_name("alias"))
+                                   .filter_map(|a| a.value_str()
+                                                    .map(|s| s.to_string().replace("\"", "")))
+                                   .filter(|v| !v.is_empty())
+                                   .collect::<FxHashSet<_>>()
+                                   .into_iter() {
+                self.aliases.entry(alias)
+                            .or_insert(Vec::with_capacity(1))
+                            .push(IndexItem {
+                                ty: item.type_(),
+                                name: item_name.to_string(),
+                                path: path.clone(),
+                                desc: String::new(),
+                                parent: None,
+                                parent_idx: None,
+                                search_type: get_index_search_type(&item),
+                            });
+            }
+        }
+    }
 }
 
 #[derive(Debug, Eq, PartialEq, Hash)]