Rollup merge of rust-lang#69514 - GuillaumeGomez:remove-spotlight, r=…

…kinnison

Remove spotlight

I had a few comments saying that this feature was at best misunderstood or not even used so I decided to organize a poll about on [twitter](https://twitter.com/imperioworld_/status/1232769353503956994). After 87 votes, the result is very clear: it's not useful. Considering the amount of code we have just to run it, I think it's definitely worth it to remove it.

r? @kinnison

cc @ollie27

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

@@ -138,27 +138,6 @@ Book][unstable-doc-cfg] and [its tracking issue][issue-doc-cfg].
 [unstable-doc-cfg]: ../unstable-book/language-features/doc-cfg.html
 [issue-doc-cfg]: https://github.com/rust-lang/rust/issues/43781
 
-### Adding your trait to the "Important Traits" dialog
-
-Rustdoc keeps a list of a few traits that are believed to be "fundamental" to a given type when
-implemented on it. These traits are intended to be the primary interface for their types, and are
-often the only thing available to be documented on their types. For this reason, Rustdoc will track
-when a given type implements one of these traits and call special attention to it when a function
-returns one of these types. This is the "Important Traits" dialog, visible as a circle-i button next
-to the function, which, when clicked, shows the dialog.
-
-In the standard library, the traits that qualify for inclusion are `Iterator`, `io::Read`, and
-`io::Write`. However, rather than being implemented as a hard-coded list, these traits have a
-special marker attribute on them: `#[doc(spotlight)]`. This means that you could apply this
-attribute to your own trait to include it in the "Important Traits" dialog in documentation.
-
-The `#[doc(spotlight)]` attribute currently requires the `#![feature(doc_spotlight)]` feature gate.
-For more information, see [its chapter in the Unstable Book][unstable-spotlight] and [its tracking
-issue][issue-spotlight].
-
-[unstable-spotlight]: ../unstable-book/language-features/doc-spotlight.html
-[issue-spotlight]: https://github.com/rust-lang/rust/issues/45040
-
 ### Exclude certain dependencies from documentation
 
 The standard library uses several dependencies which, in turn, use several types and traits from the

src/libcore/future/future.rs

@@ -24,7 +24,6 @@ use crate::task::{Context, Poll};
 /// `.await` the value.
 ///
 /// [`Waker`]: ../task/struct.Waker.html
-#[doc(spotlight)]
 #[must_use = "futures do nothing unless you `.await` or poll them"]
 #[stable(feature = "futures_api", since = "1.36.0")]
 #[lang = "future_trait"]

src/libcore/iter/traits/iterator.rs

@@ -92,7 +92,6 @@ fn _assert_is_object_safe(_: &dyn Iterator<Item = ()>) {}
     label = "`{Self}` is not an iterator",
     message = "`{Self}` is not an iterator"
 )]
-#[doc(spotlight)]
 #[must_use = "iterators are lazy and do nothing unless consumed"]
 pub trait Iterator {
     /// The type of the elements being iterated over.

src/libcore/lib.rs

@@ -90,7 +90,6 @@
 #![feature(custom_inner_attributes)]
 #![feature(decl_macro)]
 #![feature(doc_cfg)]
-#![feature(doc_spotlight)]
 #![feature(extern_types)]
 #![feature(fundamental)]
 #![feature(intrinsics)]

src/librustc_ast_passes/feature_gate.rs

@@ -245,7 +245,6 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
                     include => external_doc
                     cfg => doc_cfg
                     masked => doc_masked
-                    spotlight => doc_spotlight
                     alias => doc_alias
                     keyword => doc_keyword
                 );

src/librustc_feature/active.rs

@@ -360,9 +360,6 @@ declare_features! (
     /// Allows `#[doc(masked)]`.
     (active, doc_masked, "1.21.0", Some(44027), None),
 
-    /// Allows `#[doc(spotlight)]`.
-    (active, doc_spotlight, "1.22.0", Some(45040), None),
-
     /// Allows `#[doc(include = "some-file")]`.
     (active, external_doc, "1.22.0", Some(44732), None),
 

src/librustc_span/symbol.rs

@@ -270,7 +270,6 @@ symbols! {
         doc_cfg,
         doc_keyword,
         doc_masked,
-        doc_spotlight,
         doctest,
         document_private_items,
         dotdoteq_in_patterns,
@@ -689,7 +688,6 @@ symbols! {
         Some,
         specialization,
         speed,
-        spotlight,
         sse4a_target_feature,
         stable,
         staged_api,

src/librustdoc/clean/inline.rs

@@ -198,15 +198,13 @@ pub fn build_external_trait(cx: &DocContext<'_>, did: DefId) -> clean::Trait {
     let generics = (cx.tcx.generics_of(did), predicates).clean(cx);
     let generics = filter_non_trait_generics(did, generics);
     let (generics, supertrait_bounds) = separate_supertrait_bounds(generics);
-    let is_spotlight = load_attrs(cx, did).clean(cx).has_doc_flag(sym::spotlight);
     let is_auto = cx.tcx.trait_is_auto(did);
     clean::Trait {
         auto: auto_trait,
         unsafety: cx.tcx.trait_def(did).unsafety,
         generics,
         items: trait_items,
         bounds: supertrait_bounds,
-        is_spotlight,
         is_auto,
     }
 }

src/librustdoc/clean/mod.rs

@@ -1013,7 +1013,6 @@ impl Clean<FnRetTy> for hir::FnRetTy<'_> {
 impl Clean<Item> for doctree::Trait<'_> {
     fn clean(&self, cx: &DocContext<'_>) -> Item {
         let attrs = self.attrs.clean(cx);
-        let is_spotlight = attrs.has_doc_flag(sym::spotlight);
         Item {
             name: Some(self.name.clean(cx)),
             attrs,
@@ -1028,7 +1027,6 @@ impl Clean<Item> for doctree::Trait<'_> {
                 items: self.items.iter().map(|ti| ti.clean(cx)).collect(),
                 generics: self.generics.clean(cx),
                 bounds: self.bounds.clean(cx),
-                is_spotlight,
                 is_auto: self.is_auto.clean(cx),
             }),
         }

src/librustdoc/clean/types.rs

@@ -951,7 +951,6 @@ pub struct Trait {
     pub items: Vec<Item>,
     pub generics: Generics,
     pub bounds: Vec<GenericBound>,
-    pub is_spotlight: bool,
     pub is_auto: bool,
 }
 

src/librustdoc/html/format.rs

@@ -63,22 +63,10 @@ impl Buffer {
         Buffer { for_html: false, buffer: String::new() }
     }
 
-    crate fn is_empty(&self) -> bool {
-        self.buffer.is_empty()
-    }
-
     crate fn into_inner(self) -> String {
         self.buffer
     }
 
-    crate fn insert_str(&mut self, idx: usize, s: &str) {
-        self.buffer.insert_str(idx, s);
-    }
-
-    crate fn push_str(&mut self, s: &str) {
-        self.buffer.push_str(s);
-    }
-
     // Intended for consumption by write! and writeln! (std::fmt) but without
     // the fmt::Result return type imposed by fmt::Write (and avoiding the trait
     // import).

src/librustdoc/html/render.rs

@@ -2325,7 +2325,7 @@ fn item_function(w: &mut Buffer, cx: &Context, it: &clean::Item, f: &clean::Func
         f.generics.print()
     )
     .len();
-    write!(w, "{}<pre class='rust fn'>", render_spotlight_traits(it));
+    write!(w, "<pre class='rust fn'>");
     render_attributes(w, it, false);
     write!(
         w,
@@ -2528,13 +2528,7 @@ fn item_trait(w: &mut Buffer, cx: &Context, it: &clean::Item, t: &clean::Trait)
         let item_type = m.type_();
         let id = cx.derive_id(format!("{}.{}", item_type, name));
         let ns_id = cx.derive_id(format!("{}.{}", name, item_type.name_space()));
-        write!(
-            w,
-            "<h3 id='{id}' class='method'>{extra}<code id='{ns_id}'>",
-            extra = render_spotlight_traits(m),
-            id = id,
-            ns_id = ns_id
-        );
+        write!(w, "<h3 id='{id}' class='method'><code id='{ns_id}'>", id = id, ns_id = ns_id);
         render_assoc_item(w, m, AssocItemLink::Anchor(Some(&id)), ItemType::Impl);
         write!(w, "</code>");
         render_stability_since(w, m, t);
@@ -3520,76 +3514,6 @@ fn should_render_item(item: &clean::Item, deref_mut_: bool) -> bool {
     }
 }
 
-fn render_spotlight_traits(item: &clean::Item) -> String {
-    match item.inner {
-        clean::FunctionItem(clean::Function { ref decl, .. })
-        | clean::TyMethodItem(clean::TyMethod { ref decl, .. })
-        | clean::MethodItem(clean::Method { ref decl, .. })
-        | clean::ForeignFunctionItem(clean::Function { ref decl, .. }) => spotlight_decl(decl),
-        _ => String::new(),
-    }
-}
-
-fn spotlight_decl(decl: &clean::FnDecl) -> String {
-    let mut out = Buffer::html();
-    let mut trait_ = String::new();
-
-    if let Some(did) = decl.output.def_id() {
-        let c = cache();
-        if let Some(impls) = c.impls.get(&did) {
-            for i in impls {
-                let impl_ = i.inner_impl();
-                if impl_.trait_.def_id().map_or(false, |d| c.traits[&d].is_spotlight) {
-                    if out.is_empty() {
-                        out.push_str(&format!(
-                            "<h3 class=\"important\">Important traits for {}</h3>\
-                                      <code class=\"content\">",
-                            impl_.for_.print()
-                        ));
-                        trait_.push_str(&impl_.for_.print().to_string());
-                    }
-
-                    //use the "where" class here to make it small
-                    out.push_str(&format!(
-                        "<span class=\"where fmt-newline\">{}</span>",
-                        impl_.print()
-                    ));
-                    let t_did = impl_.trait_.def_id().unwrap();
-                    for it in &impl_.items {
-                        if let clean::TypedefItem(ref tydef, _) = it.inner {
-                            out.push_str("<span class=\"where fmt-newline\">    ");
-                            assoc_type(
-                                &mut out,
-                                it,
-                                &[],
-                                Some(&tydef.type_),
-                                AssocItemLink::GotoSource(t_did, &FxHashSet::default()),
-                                "",
-                            );
-                            out.push_str(";</span>");
-                        }
-                    }
-                }
-            }
-        }
-    }
-
-    if !out.is_empty() {
-        out.insert_str(
-            0,
-            &format!(
-                "<div class=\"important-traits\"><div class='tooltip'>ⓘ\
-                                    <span class='tooltiptext'>Important traits for {}</span></div>\
-                                    <div class=\"content hidden\">",
-                trait_
-            ),
-        );
-        out.push_str("</code></div></div>");
-    }
-
-    out.into_inner()
-}
-
 fn render_impl(
     w: &mut Buffer,
     cx: &Context,
@@ -3696,14 +3620,13 @@ fn render_impl(
                 (true, " hidden")
             };
         match item.inner {
-            clean::MethodItem(clean::Method { ref decl, .. })
-            | clean::TyMethodItem(clean::TyMethod { ref decl, .. }) => {
+            clean::MethodItem(clean::Method { .. })
+            | clean::TyMethodItem(clean::TyMethod { .. }) => {
                 // Only render when the method is not static or we allow static methods
                 if render_method_item {
                     let id = cx.derive_id(format!("{}.{}", item_type, name));
                     let ns_id = cx.derive_id(format!("{}.{}", name, item_type.name_space()));
                     write!(w, "<h4 id='{}' class=\"{}{}\">", id, item_type, extra_class);
-                    write!(w, "{}", spotlight_decl(decl));
                     write!(w, "<code id='{}'>", ns_id);
                     render_assoc_item(w, item, link.anchor(&id), ItemType::Impl);
                     write!(w, "</code>");

src/librustdoc/html/static/main.js

@@ -341,7 +341,6 @@ function getSearchElement() {
     function handleEscape(ev) {
         var help = getHelpElement();
         var search = getSearchElement();
-        hideModal();
         if (hasClass(help, "hidden") === false) {
             displayHelp(false, ev, help);
         } else if (hasClass(search, "hidden") === false) {
@@ -373,7 +372,6 @@ function getSearchElement() {
             case "s":
             case "S":
                 displayHelp(false, ev);
-                hideModal();
                 ev.preventDefault();
                 focusSearchBar();
                 break;
@@ -386,7 +384,6 @@ function getSearchElement() {
 
             case "?":
                 if (ev.shiftKey) {
-                    hideModal();
                     displayHelp(true, ev);
                 }
                 break;
@@ -2504,31 +2501,6 @@ function getSearchElement() {
         lineNumbersFunc(e);
     });
 
-    function showModal(content) {
-        var modal = document.createElement("div");
-        modal.id = "important";
-        addClass(modal, "modal");
-        modal.innerHTML = "<div class=\"modal-content\"><div class=\"close\" id=\"modal-close\">✕" +
-                          "</div><div class=\"whiter\"></div><span class=\"docblock\">" + content +
-                          "</span></div>";
-        document.getElementsByTagName("body")[0].appendChild(modal);
-        document.getElementById("modal-close").onclick = hideModal;
-        modal.onclick = hideModal;
-    }
-
-    function hideModal() {
-        var modal = document.getElementById("important");
-        if (modal) {
-            modal.parentNode.removeChild(modal);
-        }
-    }
-
-    onEachLazy(document.getElementsByClassName("important-traits"), function(e) {
-        e.onclick = function() {
-            showModal(e.lastElementChild.innerHTML);
-        };
-    });
-
     // In the search display, allows to switch between tabs.
     function printTab(nb) {
         if (nb === 0 || nb === 1 || nb === 2) {