De-emphasize unstable items in rustdoc item table

Author: dtolnay

src/librustdoc/html/render/print_item.rs

@@ -147,6 +147,7 @@ macro_rules! item_template_methods {
 const ITEM_TABLE_OPEN: &str = "<ul class=\"item-table\">";
 const ITEM_TABLE_CLOSE: &str = "</ul>";
 const ITEM_TABLE_ROW_OPEN: &str = "<li>";
+const ITEM_TABLE_ROW_OPEN_UNSTABLE: &str = "<li class=\"unstable\">";
 const ITEM_TABLE_ROW_CLOSE: &str = "</li>";
 
 // A component in a `use` path, like `string` in std::string::ToString
@@ -527,7 +528,12 @@ fn item_module(w: &mut Buffer, cx: &mut Context<'_>, item: &clean::Item, items:
                     _ => "",
                 };
 
-                w.write_str(ITEM_TABLE_ROW_OPEN);
+                w.write_str(if is_unstable(myitem, tcx) {
+                    ITEM_TABLE_ROW_OPEN_UNSTABLE
+                } else {
+                    ITEM_TABLE_ROW_OPEN
+                });
+
                 let docs =
                     MarkdownSummaryLine(&myitem.doc_value(), &myitem.links(cx)).into_string();
                 let (docs_before, docs_after) = if docs.is_empty() {
@@ -594,11 +600,7 @@ fn extra_info_tags<'a, 'tcx: 'a>(
             write!(f, "{}", tag_html("deprecated", "", message))?;
         }
 
-        // The "rustc_private" crates are permanently unstable so it makes no sense
-        // to render "unstable" everywhere.
-        if item.stability(tcx).as_ref().map(|s| s.is_unstable() && s.feature != sym::rustc_private)
-            == Some(true)
-        {
+        if is_unstable(item, tcx) {
             write!(f, "{}", tag_html("unstable", "", "Experimental"))?;
         }
 
@@ -625,6 +627,13 @@ fn extra_info_tags<'a, 'tcx: 'a>(
     })
 }
 
+fn is_unstable<'a, 'tcx: 'a>(item: &'a clean::Item, tcx: TyCtxt<'tcx>) -> bool {
+    // The "rustc_private" crates are permanently unstable so it makes no sense
+    // to render "unstable" everywhere.
+    item.stability(tcx).as_ref().map(|s| s.is_unstable() && s.feature != sym::rustc_private)
+        == Some(true)
+}
+
 fn item_function(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, f: &clean::Function) {
     let tcx = cx.tcx();
     let header = it.fn_header(tcx).expect("printing a function which isn't a function");

src/librustdoc/html/static/css/rustdoc.css

@@ -819,6 +819,9 @@ table,
 .item-table > li > .item-name {
 	padding-right: 1.25rem;
 }
+.item-table > li.unstable > .item-name > a {
+	opacity: 0.70;
+}
 
 .search-results-title {
 	margin-top: 0;

tests/rustdoc/stability.rs

@@ -2,6 +2,8 @@
 
 #![unstable(feature = "test", issue = "none")]
 
+// @has stability/index.html '//ul[@class="item-table"]/li[@class="unstable"]//a' Unstable
+
 pub struct Unstable {
     // @has stability/struct.Unstable.html \
     //      '//span[@class="item-info"]//div[@class="stab unstable"]' \