Auto merge of #91291 - GuillaumeGomez:const-deref-method, r=camelid

Fix const deref methods display

Fixes https://github.com/rust-lang/rust/issues/90855 (more information in the issue).

r? `@camelid`

5 files changed, 122 insertions, 35 deletions

diff --git a/src/librustdoc/clean/types.rs b/src/librustdoc/clean/types.rs
index 11dd140504a..02a4fc5fb65 100644
--- a/src/librustdoc/clean/types.rs
+++ b/src/librustdoc/clean/types.rs
@@ -376,8 +376,8 @@ impl Item {
         self.def_id.as_def_id().and_then(|did| tcx.lookup_stability(did))
     }
 
-    crate fn const_stability<'tcx>(&self, tcx: TyCtxt<'tcx>) -> Option<&'tcx ConstStability> {
-        self.def_id.as_def_id().and_then(|did| tcx.lookup_const_stability(did))
+    crate fn const_stability<'tcx>(&self, tcx: TyCtxt<'tcx>) -> Option<ConstStability> {
+        self.def_id.as_def_id().and_then(|did| tcx.lookup_const_stability(did)).map(|cs| *cs)
     }
 
     crate fn deprecation(&self, tcx: TyCtxt<'_>) -> Option<Deprecation> {
@@ -602,16 +602,16 @@ impl Item {
         })
     }
 
-    crate fn stable_since(&self, tcx: TyCtxt<'_>) -> Option<SymbolStr> {
+    crate fn stable_since(&self, tcx: TyCtxt<'_>) -> Option<Symbol> {
         match self.stability(tcx)?.level {
-            StabilityLevel::Stable { since, .. } => Some(since.as_str()),
+            StabilityLevel::Stable { since, .. } => Some(since),
             StabilityLevel::Unstable { .. } => None,
         }
     }
 
-    crate fn const_stable_since(&self, tcx: TyCtxt<'_>) -> Option<SymbolStr> {
+    crate fn const_stable_since(&self, tcx: TyCtxt<'_>) -> Option<Symbol> {
         match self.const_stability(tcx)?.level {
-            StabilityLevel::Stable { since, .. } => Some(since.as_str()),
+            StabilityLevel::Stable { since, .. } => Some(since),
             StabilityLevel::Unstable { .. } => None,
         }
     }
diff --git a/src/librustdoc/html/format.rs b/src/librustdoc/html/format.rs
index 34742fac0e4..fdb52703edf 100644
--- a/src/librustdoc/html/format.rs
+++ b/src/librustdoc/html/format.rs
@@ -1349,10 +1349,7 @@ impl PrintWithSpace for hir::Mutability {
     }
 }
 
-crate fn print_constness_with_space(
-    c: &hir::Constness,
-    s: Option<&ConstStability>,
-) -> &'static str {
+crate fn print_constness_with_space(c: &hir::Constness, s: Option<ConstStability>) -> &'static str {
     match (c, s) {
         // const stable or when feature(staged_api) is not set
         (
diff --git a/src/librustdoc/html/render/mod.rs b/src/librustdoc/html/render/mod.rs
index 8bf7d0416dd..166e0840127 100644
--- a/src/librustdoc/html/render/mod.rs
+++ b/src/librustdoc/html/render/mod.rs
@@ -804,17 +804,17 @@ fn assoc_type(
 
 fn render_stability_since_raw(
     w: &mut Buffer,
-    ver: Option<&str>,
-    const_stability: Option<&ConstStability>,
-    containing_ver: Option<&str>,
-    containing_const_ver: Option<&str>,
+    ver: Option<Symbol>,
+    const_stability: Option<ConstStability>,
+    containing_ver: Option<Symbol>,
+    containing_const_ver: Option<Symbol>,
 ) {
     let ver = ver.filter(|inner| !inner.is_empty());
 
     match (ver, const_stability) {
         // stable and const stable
         (Some(v), Some(ConstStability { level: StabilityLevel::Stable { since }, .. }))
-            if Some(since.as_str()).as_deref() != containing_const_ver =>
+            if Some(since) != containing_const_ver =>
         {
             write!(
                 w,
@@ -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 =
-            print_constness_with_space(&header.constness, meth.const_stability(cx.tcx()));
+        // FIXME: Once https://github.com/rust-lang/rust/issues/67792 is implemented, we can remove
+        // 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,
@@ -1422,7 +1430,7 @@ 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(
@@ -1431,6 +1439,7 @@ 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>");
@@ -1466,7 +1475,7 @@ 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(
@@ -1645,16 +1654,24 @@ fn render_rightside(
     cx: &Context<'_>,
     item: &clean::Item,
     containing_item: &clean::Item,
+    render_mode: RenderMode,
 ) {
     let tcx = cx.tcx();
 
+    // 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 => (item.const_stability(tcx), containing_item.const_stable_since(tcx)),
+        RenderMode::ForDeref { .. } => (None, None),
+    };
+
     write!(w, "<div class=\"rightside\">");
     render_stability_since_raw(
         w,
-        item.stable_since(tcx).as_deref(),
-        item.const_stability(tcx),
-        containing_item.stable_since(tcx).as_deref(),
-        containing_item.const_stable_since(tcx).as_deref(),
+        item.stable_since(tcx),
+        const_stability,
+        containing_item.stable_since(tcx),
+        const_stable_since,
     );
 
     write_srclink(cx, item, w);
@@ -1690,7 +1707,7 @@ 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\">");
 
diff --git a/src/librustdoc/html/render/print_item.rs b/src/librustdoc/html/render/print_item.rs
index 62fdec15af4..e139ac8581e 100644
--- a/src/librustdoc/html/render/print_item.rs
+++ b/src/librustdoc/html/render/print_item.rs
@@ -101,7 +101,7 @@ pub(super) fn print_item(
     let mut stability_since_raw = Buffer::new();
     render_stability_since_raw(
         &mut stability_since_raw,
-        item.stable_since(cx.tcx()).as_deref(),
+        item.stable_since(cx.tcx()),
         item.const_stability(cx.tcx()),
         None,
         None,
@@ -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 {
@@ -1427,10 +1462,10 @@ fn render_stability_since(
 ) {
     render_stability_since_raw(
         w,
-        item.stable_since(tcx).as_deref(),
+        item.stable_since(tcx),
         item.const_stability(tcx),
-        containing_item.stable_since(tcx).as_deref(),
-        containing_item.const_stable_since(tcx).as_deref(),
+        containing_item.stable_since(tcx),
+        containing_item.const_stable_since(tcx),
     )
 }
 
diff --git a/src/test/rustdoc/deref-const-fn.rs b/src/test/rustdoc/deref-const-fn.rs
new file mode 100644
index 00000000000..ca51f3c7b5a
--- /dev/null
+++ b/src/test/rustdoc/deref-const-fn.rs
@@ -0,0 +1,38 @@
+// This test ensures that the const methods from Deref aren't shown as const.
+// For more information, see https://github.com/rust-lang/rust/issues/90855.
+
+#![crate_name = "foo"]
+
+#![feature(staged_api)]
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+// @has 'foo/struct.Bar.html'
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Bar;
+
+impl Bar {
+    // @has - '//*[@id="method.len"]' 'pub const fn len(&self) -> usize'
+    // @has - '//*[@id="method.len"]//span[@class="since"]' '1.0.0 (const: 1.0.0)'
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_const_stable(feature = "rust1", since = "1.0.0")]
+    pub const fn len(&self) -> usize { 0 }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Foo {
+    value: Bar,
+}
+
+// @has 'foo/struct.Foo.html'
+// @has - '//*[@id="method.len"]' 'pub fn len(&self) -> usize'
+// @!has - '//*[@id="method.len"]//span[@class="since"]' '1.0.0'
+// @!has - '//*[@id="method.len"]//span[@class="since"]' '(const: 1.0.0)'
+#[stable(feature = "rust1", since = "1.0.0")]
+impl std::ops::Deref for Foo {
+    type Target = Bar;
+
+    fn deref(&self) -> &Self::Target {
+        &self.value
+    }
+}