Fix display for "const" deref methods in rustdoc

src/librustdoc/html/render/mod.rs

@@ -861,6 +861,7 @@ fn render_assoc_item(
     link: AssocItemLink<'_>,
     parent: ItemType,
     cx: &Context<'_>,
+    render_mode: RenderMode,
 ) {
     fn method(
         w: &mut Buffer,
@@ -871,6 +872,7 @@ fn render_assoc_item(
         link: AssocItemLink<'_>,
         parent: ItemType,
         cx: &Context<'_>,
+        render_mode: RenderMode,
     ) {
         let name = meth.name.as_ref().unwrap();
         let href = match link {
@@ -893,8 +895,14 @@ fn render_assoc_item(
             }
         };
         let vis = meth.visibility.print_with_space(meth.def_id, cx).to_string();
-        let constness =
+        // FIXME: Once https://github.com/rust-lang/rust/issues/67792 is implemented, we can remove
-            print_constness_with_space(&header.constness, meth.const_stability(cx.tcx()));
+        // this condition.
+        let constness = match render_mode {
+            RenderMode::Normal => {
+                print_constness_with_space(&header.constness, meth.const_stability(cx.tcx()))
+            }
+            RenderMode::ForDeref { .. } => "",
+        };
         let asyncness = header.asyncness.print_with_space();
         let unsafety = header.unsafety.print_with_space();
         let defaultness = print_default_space(meth.is_default());
@@ -945,10 +953,10 @@ fn render_assoc_item(
     match *item.kind {
         clean::StrippedItem(..) => {}
         clean::TyMethodItem(ref m) => {
-            method(w, item, m.header, &m.generics, &m.decl, link, parent, cx)
+            method(w, item, m.header, &m.generics, &m.decl, link, parent, cx, render_mode)
         }
         clean::MethodItem(ref m, _) => {
-            method(w, item, m.header, &m.generics, &m.decl, link, parent, cx)
+            method(w, item, m.header, &m.generics, &m.decl, link, parent, cx, render_mode)
         }
         clean::AssocConstItem(ref ty, ref default) => assoc_const(
             w,
@@ -1415,7 +1423,7 @@ fn render_impl(
                         "<div id=\"{}\" class=\"{}{} has-srclink\">",
                         id, item_type, in_trait_class,
                     );
-                    render_rightside(w, cx, item, containing_item);
+                    render_rightside(w, cx, item, containing_item, render_mode);
                     write!(w, "<a href=\"#{}\" class=\"anchor\"></a>", id);
                     w.write_str("<h4 class=\"code-header\">");
                     render_assoc_item(
@@ -1424,6 +1432,7 @@ fn render_impl(
                         link.anchor(source_id.as_ref().unwrap_or(&id)),
                         ItemType::Impl,
                         cx,
+                        render_mode,
                     );
                     w.write_str("</h4>");
                     w.write_str("</div>");
@@ -1459,7 +1468,7 @@ fn render_impl(
                     "<div id=\"{}\" class=\"{}{} has-srclink\">",
                     id, item_type, in_trait_class
                 );
-                render_rightside(w, cx, item, containing_item);
+                render_rightside(w, cx, item, containing_item, render_mode);
                 write!(w, "<a href=\"#{}\" class=\"anchor\"></a>", id);
                 w.write_str("<h4 class=\"code-header\">");
                 assoc_const(
@@ -1638,16 +1647,28 @@ fn render_rightside(
     cx: &Context<'_>,
     item: &clean::Item,
     containing_item: &clean::Item,
+    render_mode: RenderMode,
 ) {
     let tcx = cx.tcx();
 
+    let const_stable_since;
+    // FIXME: Once https://github.com/rust-lang/rust/issues/67792 is implemented, we can remove
+    // this condition.
+    let (const_stability, const_stable_since) = match render_mode {
+        RenderMode::Normal => {
+            const_stable_since = containing_item.const_stable_since(tcx);
+            (item.const_stability(tcx), const_stable_since.as_deref())
+        }
+        RenderMode::ForDeref { .. } => (None, None),
+    };
+
     write!(w, "<div class=\"rightside\">");
     render_stability_since_raw(
         w,
         item.stable_since(tcx).as_deref(),
-        item.const_stability(tcx),
+        const_stability,
         containing_item.stable_since(tcx).as_deref(),
-        containing_item.const_stable_since(tcx).as_deref(),
+        const_stable_since,
     );
 
     write_srclink(cx, item, w);
@@ -1683,7 +1704,7 @@ pub(crate) fn render_impl_summary(
         format!(" data-aliases=\"{}\"", aliases.join(","))
     };
     write!(w, "<div id=\"{}\" class=\"impl has-srclink\"{}>", id, aliases);
-    render_rightside(w, cx, &i.impl_item, containing_item);
+    render_rightside(w, cx, &i.impl_item, containing_item, RenderMode::Normal);
     write!(w, "<a href=\"#{}\" class=\"anchor\"></a>", id);
     write!(w, "<h3 class=\"code-header in-band\">");
 

src/librustdoc/html/render/print_item.rs

@@ -556,7 +556,14 @@ fn item_trait(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::Tra
                     );
                 }
                 for t in &types {
-                    render_assoc_item(w, t, AssocItemLink::Anchor(None), ItemType::Trait, cx);
+                    render_assoc_item(
+                        w,
+                        t,
+                        AssocItemLink::Anchor(None),
+                        ItemType::Trait,
+                        cx,
+                        RenderMode::Normal,
+                    );
                     w.write_str(";\n");
                 }
                 // If there are too many associated constants, hide everything after them
@@ -580,7 +587,14 @@ fn item_trait(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::Tra
                     w.write_str("\n");
                 }
                 for t in &consts {
-                    render_assoc_item(w, t, AssocItemLink::Anchor(None), ItemType::Trait, cx);
+                    render_assoc_item(
+                        w,
+                        t,
+                        AssocItemLink::Anchor(None),
+                        ItemType::Trait,
+                        cx,
+                        RenderMode::Normal,
+                    );
                     w.write_str(";\n");
                 }
                 if !toggle && should_hide_fields(count_methods) {
@@ -591,7 +605,14 @@ fn item_trait(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::Tra
                     w.write_str("\n");
                 }
                 for (pos, m) in required.iter().enumerate() {
-                    render_assoc_item(w, m, AssocItemLink::Anchor(None), ItemType::Trait, cx);
+                    render_assoc_item(
+                        w,
+                        m,
+                        AssocItemLink::Anchor(None),
+                        ItemType::Trait,
+                        cx,
+                        RenderMode::Normal,
+                    );
                     w.write_str(";\n");
 
                     if pos < required.len() - 1 {
@@ -602,7 +623,14 @@ fn item_trait(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::Tra
                     w.write_str("\n");
                 }
                 for (pos, m) in provided.iter().enumerate() {
-                    render_assoc_item(w, m, AssocItemLink::Anchor(None), ItemType::Trait, cx);
+                    render_assoc_item(
+                        w,
+                        m,
+                        AssocItemLink::Anchor(None),
+                        ItemType::Trait,
+                        cx,
+                        RenderMode::Normal,
+                    );
                     match *m.kind {
                         clean::MethodItem(ref inner, _)
                             if !inner.generics.where_predicates.is_empty() =>
@@ -655,7 +683,14 @@ fn item_trait(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::Tra
         write_srclink(cx, m, w);
         write!(w, "</div>");
         write!(w, "<h4 class=\"code-header\">");
-        render_assoc_item(w, m, AssocItemLink::Anchor(Some(&id)), ItemType::Impl, cx);
+        render_assoc_item(
+            w,
+            m,
+            AssocItemLink::Anchor(Some(&id)),
+            ItemType::Impl,
+            cx,
+            RenderMode::Normal,
+        );
         w.write_str("</h4>");
         w.write_str("</div>");
         if toggled {