[rustdoc] Sort impl associated items by kinds and then by appearance

src/librustdoc/html/render/mod.rs

@@ -1794,13 +1794,64 @@ fn render_impl(
     let mut default_impl_items = Buffer::empty_from(w);
     let impl_ = i.inner_impl();
 
+    // Impl items are grouped by kinds:
+    //
+    // 1. Constants
+    // 2. Types
+    // 3. Functions
+    //
+    // This order is because you can have associated constants used in associated types (like array
+    // length), and both in associcated functions. So with this order, when reading from top to
+    // bottom, you should see items definitions before they're actually used most of the time.
+    let mut assoc_types = Vec::new();
+    let mut methods = Vec::new();
+
     if !impl_.is_negative_trait_impl() {
         for trait_item in &impl_.items {
+            match *trait_item.kind {
+                clean::MethodItem(..) | clean::TyMethodItem(_) => methods.push(trait_item),
+                clean::TyAssocTypeItem(..) | clean::AssocTypeItem(..) => {
+                    assoc_types.push(trait_item)
+                }
+                clean::TyAssocConstItem(..) | clean::AssocConstItem(_) => {
+                    // We render it directly since they're supposed to come first.
+                    doc_impl_item(
+                        &mut default_impl_items,
+                        &mut impl_items,
+                        cx,
+                        trait_item,
+                        if trait_.is_some() { &i.impl_item } else { parent },
+                        link,
+                        render_mode,
+                        false,
+                        trait_,
+                        rendering_params,
+                    );
+                }
+                _ => {}
+            }
+        }
+
+        for assoc_type in assoc_types {
             doc_impl_item(
                 &mut default_impl_items,
                 &mut impl_items,
                 cx,
-                trait_item,
+                assoc_type,
+                if trait_.is_some() { &i.impl_item } else { parent },
+                link,
+                render_mode,
+                false,
+                trait_,
+                rendering_params,
+            );
+        }
+        for method in methods {
+            doc_impl_item(
+                &mut default_impl_items,
+                &mut impl_items,
+                cx,
+                method,
                 if trait_.is_some() { &i.impl_item } else { parent },
                 link,
                 render_mode,

src/librustdoc/html/render/print_item.rs

@@ -843,55 +843,55 @@ fn item_trait(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &clean:
         }
     }
 
-    if !required_types.is_empty() {
+    if !required_consts.is_empty() {
         write_section_heading(
             w,
-            "Required Associated Types",
-            "required-associated-types",
+            "Required Associated Constants",
+            "required-associated-consts",
             None,
             "<div class=\"methods\">",
         );
-        for t in required_types {
+        for t in required_consts {
             trait_item(w, cx, t, it);
         }
         w.write_str("</div>");
     }
-    if !provided_types.is_empty() {
+    if !provided_consts.is_empty() {
         write_section_heading(
             w,
-            "Provided Associated Types",
-            "provided-associated-types",
+            "Provided Associated Constants",
+            "provided-associated-consts",
             None,
             "<div class=\"methods\">",
         );
-        for t in provided_types {
+        for t in provided_consts {
             trait_item(w, cx, t, it);
         }
         w.write_str("</div>");
     }
 
-    if !required_consts.is_empty() {
+    if !required_types.is_empty() {
         write_section_heading(
             w,
-            "Required Associated Constants",
-            "required-associated-consts",
+            "Required Associated Types",
+            "required-associated-types",
             None,
             "<div class=\"methods\">",
         );
-        for t in required_consts {
+        for t in required_types {
             trait_item(w, cx, t, it);
         }
         w.write_str("</div>");
     }
-    if !provided_consts.is_empty() {
+    if !provided_types.is_empty() {
         write_section_heading(
             w,
-            "Provided Associated Constants",
-            "provided-associated-consts",
+            "Provided Associated Types",
+            "provided-associated-types",
             None,
             "<div class=\"methods\">",
         );
-        for t in provided_consts {
+        for t in provided_types {
             trait_item(w, cx, t, it);
         }
         w.write_str("</div>");

src/librustdoc/html/render/sidebar.rs

@@ -302,10 +302,10 @@ fn sidebar_trait<'a>(
 
     blocks.extend(
         [
-            ("required-associated-types", "Required Associated Types", req_assoc),
-            ("provided-associated-types", "Provided Associated Types", prov_assoc),
             ("required-associated-consts", "Required Associated Constants", req_assoc_const),
             ("provided-associated-consts", "Provided Associated Constants", prov_assoc_const),
+            ("required-associated-types", "Required Associated Types", req_assoc),
+            ("provided-associated-types", "Provided Associated Types", prov_assoc),
             ("required-methods", "Required Methods", req_method),
             ("provided-methods", "Provided Methods", prov_method),
             ("foreign-impls", "Implementations on Foreign Types", foreign_impls),
@@ -394,29 +394,22 @@ fn sidebar_assoc_items<'a>(
     let cache = cx.cache();
 
     let mut assoc_consts = Vec::new();
+    let mut assoc_types = Vec::new();
     let mut methods = Vec::new();
     if let Some(v) = cache.impls.get(&did) {
         let mut used_links = FxHashSet::default();
         let mut id_map = IdMap::new();
 
         {
             let used_links_bor = &mut used_links;
-            assoc_consts.extend(
-                v.iter()
-                    .filter(|i| i.inner_impl().trait_.is_none())
-                    .flat_map(|i| get_associated_constants(i.inner_impl(), used_links_bor)),
-            );
+            for impl_ in v.iter().map(|i| i.inner_impl()).filter(|i| i.trait_.is_none()) {
+                assoc_consts.extend(get_associated_constants(impl_, used_links_bor));
+                assoc_types.extend(get_associated_types(impl_, used_links_bor));
+                methods.extend(get_methods(impl_, false, used_links_bor, false, cx.tcx()));
+            }
             // We want links' order to be reproducible so we don't use unstable sort.
             assoc_consts.sort();
-
-            #[rustfmt::skip] // rustfmt makes the pipeline less readable
-            methods.extend(
-                v.iter()
-                    .filter(|i| i.inner_impl().trait_.is_none())
-                    .flat_map(|i| get_methods(i.inner_impl(), false, used_links_bor, false, cx.tcx())),
-            );
-
-            // We want links' order to be reproducible so we don't use unstable sort.
+            assoc_types.sort();
             methods.sort();
         }
 
@@ -426,6 +419,11 @@ fn sidebar_assoc_items<'a>(
                 "associatedconstant",
                 assoc_consts,
             ),
+            LinkBlock::new(
+                Link::new("implementations", "Associated Types"),
+                "associatedtype",
+                assoc_types,
+            ),
             LinkBlock::new(Link::new("implementations", "Methods"), "method", methods),
         ];
 
@@ -452,6 +450,7 @@ fn sidebar_assoc_items<'a>(
                 &mut blocks,
             );
         }
+
         links.append(&mut blocks);
     }
 }
@@ -715,3 +714,19 @@ fn get_associated_constants<'a>(
         })
         .collect::<Vec<_>>()
 }
+
+fn get_associated_types<'a>(
+    i: &'a clean::Impl,
+    used_links: &mut FxHashSet<String>,
+) -> Vec<Link<'a>> {
+    i.items
+        .iter()
+        .filter_map(|item| match item.name {
+            Some(ref name) if !name.is_empty() && item.is_associated_type() => Some(Link::new(
+                get_next_url(used_links, format!("{typ}.{name}", typ = ItemType::AssocType)),
+                name.as_str(),
+            )),
+            _ => None,
+        })
+        .collect::<Vec<_>>()
+}

tests/rustdoc/impl-associated-items-order.rs

@@ -0,0 +1,42 @@
+// This test ensures that impl associated items always follow this order:
+//
+// 1. Consts
+// 2. Types
+// 3. Functions
+
+#![feature(inherent_associated_types)]
+#![allow(incomplete_features)]
+#![crate_name = "foo"]
+
+//@ has 'foo/struct.Bar.html'
+pub struct Bar;
+
+impl Bar {
+    //@ has - '//*[@id="implementations-list"]//*[@class="impl-items"]/section[3]/h4' \
+    // 'pub fn foo()'
+    pub fn foo() {}
+    //@ has - '//*[@id="implementations-list"]//*[@class="impl-items"]/section[1]/h4' \
+    // 'pub const X: u8 = 12u8'
+    pub const X: u8 = 12;
+    //@ has - '//*[@id="implementations-list"]//*[@class="impl-items"]/section[2]/h4' \
+    // 'pub type Y = u8'
+    pub type Y = u8;
+}
+
+pub trait Foo {
+    const W: u32;
+    fn yeay();
+    type Z;
+}
+
+impl Foo for Bar {
+    //@ has - '//*[@id="trait-implementations-list"]//*[@class="impl-items"]/section[2]/h4' \
+    // 'type Z = u8'
+    type Z = u8;
+    //@ has - '//*[@id="trait-implementations-list"]//*[@class="impl-items"]/section[1]/h4' \
+    // 'const W: u32 = 12u32'
+    const W: u32 = 12;
+    //@ has - '//*[@id="trait-implementations-list"]//*[@class="impl-items"]/section[3]/h4' \
+    // 'fn yeay()'
+    fn yeay() {}
+}

tests/rustdoc/impl-associated-items-sidebar.rs

@@ -0,0 +1,42 @@
+// This test ensures that impl/trait associated items are listed in the sidebar.
+
+// ignore-tidy-linelength
+
+#![feature(inherent_associated_types)]
+#![feature(associated_type_defaults)]
+#![allow(incomplete_features)]
+#![crate_name = "foo"]
+
+//@ has 'foo/struct.Bar.html'
+pub struct Bar;
+
+impl Bar {
+    //@ has - '//*[@class="sidebar-elems"]//h3[1]' 'Associated Constants'
+    //@ has - '//*[@class="sidebar-elems"]//ul[@class="block associatedconstant"]/li/a[@href="#associatedconstant.X"]' 'X'
+    pub const X: u8 = 12;
+    //@ has - '//*[@class="sidebar-elems"]//h3[2]' 'Associated Types'
+    //@ has - '//*[@class="sidebar-elems"]//ul[@class="block associatedtype"]/li/a[@href="#associatedtype.Y"]' 'Y'
+    pub type Y = u8;
+}
+
+//@ has 'foo/trait.Foo.html'
+pub trait Foo {
+    //@ has - '//*[@class="sidebar-elems"]//h3[5]' 'Required Methods'
+    //@ has - '//*[@class="sidebar-elems"]//ul[@class="block"][5]/li/a[@href="#tymethod.yeay"]' 'yeay'
+    fn yeay();
+    //@ has - '//*[@class="sidebar-elems"]//h3[6]' 'Provided Methods'
+    //@ has - '//*[@class="sidebar-elems"]//ul[@class="block"][6]/li/a[@href="#method.boo"]' 'boo'
+    fn boo() {}
+    //@ has - '//*[@class="sidebar-elems"]//h3[1]' 'Required Associated Constants'
+    //@ has - '//*[@class="sidebar-elems"]//ul[@class="block"][1]/li/a[@href="#associatedconstant.W"]' 'W'
+    const W: u32;
+    //@ has - '//*[@class="sidebar-elems"]//h3[2]' 'Provided Associated Constants'
+    //@ has - '//*[@class="sidebar-elems"]//ul[@class="block"][2]/li/a[@href="#associatedconstant.U"]' 'U'
+    const U: u32 = 0;
+    //@ has - '//*[@class="sidebar-elems"]//h3[3]' 'Required Associated Types'
+    //@ has - '//*[@class="sidebar-elems"]//ul[@class="block"][3]/li/a[@href="#associatedtype.Z"]' 'Z'
+    type Z;
+    //@ has - '//*[@class="sidebar-elems"]//h3[4]' 'Provided Associated Types'
+    //@ has - '//*[@class="sidebar-elems"]//ul[@class="block"][4]/li/a[@href="#associatedtype.T"]' 'T'
+    type T = u32;
+}