Rollup merge of rust-lang#56874 - JohnHeitmann:docs-spacing, r=Guilla…

…umeGomez

Simplify foreign type rendering.

Simplified foreign type rendering by switching from tables to flexbox. Also, removed some seemingly extraneous elements like “ghost” spans.

Reduces element count on the `std::iter::Iterator` page by 30%. On my laptop it drops Iterator page load time from ~15s to ~10s. Frame times during scrolling are a hair lower too.

Known visual changes (happy to tweak based on feedback):
* The main `impl ...` headers are now getting the default, larger, h3 font size. This was an accident, but I liked how it turned out so I didn't fix it.
* There's a hair less vertical spacing between the end of a where block and the start of the next fn. Now, all spacing is consistent. I think this looks a bit worse. I may tweak vertical spacing more here or in a follow-up that cleans up vertical spacing more broadly.
* "[src]" links are all sized at 17px. A few were 19px in the original.

I haven't yet done heavy cross-browser or cross-crate testing. I was hoping to get a quick thumbs up or thumbs down here at this first draft, then if this is on the right track I'll spend some time on that testing.

TODO:

- [x] Test on Chrome
- [x] Test on Firefox
- [ ] ~~Test on UC Android~~
- [x] Test on Edge
- [x] Test on iOS safari
- [x] Test on desktop safari
- [x] Update automated tests
- [x] Increase vertical margin
- [x] Fix "Important traits for" hover overlap
- [x] Wait for rust-lang#55798 to land & merge it

src/librustdoc/html/render.rs

@@ -3059,7 +3059,7 @@ fn item_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, "{extra}<h3 id='{id}' class='method'><code id='{ns_id}'>",
+        write!(w, "<h3 id='{id}' class='method'>{extra}<code id='{ns_id}'>",
                extra = render_spotlight_traits(m)?,
                id = id,
                ns_id = ns_id)?;
@@ -3444,7 +3444,7 @@ fn item_union(w: &mut fmt::Formatter, cx: &Context, it: &clean::Item,
             let id = format!("{}.{}", ItemType::StructField, name);
             write!(w, "<span id=\"{id}\" class=\"{shortty} small-section-header\">\
                            <a href=\"#{id}\" class=\"anchor field\"></a>\
-                           <span class='invisible'><code>{name}: {ty}</code></span>\
+                           <code>{name}: {ty}</code>\
                        </span>",
                    id = id,
                    name = name,
@@ -3999,8 +3999,7 @@ fn render_impl(w: &mut fmt::Formatter, cx: &Context, i: &Impl, link: AssocItemLi
             None => "impl".to_string(),
         });
         if let Some(use_absolute) = use_absolute {
-            write!(w, "<h3 id='{}' class='impl'><span class='in-band'><table class='table-display'>\
-                       <tbody><tr><td><code>", id)?;
+            write!(w, "<h3 id='{}' class='impl'><code class='in-band'>", id)?;
             fmt_impl_for_trait_page(&i.inner_impl(), w, use_absolute)?;
             if show_def_docs {
                 for it in &i.inner_impl().items {
@@ -4014,22 +4013,18 @@ fn render_impl(w: &mut fmt::Formatter, cx: &Context, i: &Impl, link: AssocItemLi
             }
             write!(w, "</code>")?;
         } else {
-            write!(w, "<h3 id='{}' class='impl'><span class='in-band'><table class='table-display'>\
-                       <tbody><tr><td><code>{}</code>",
-                   id, i.inner_impl())?;
+            write!(w, "<h3 id='{}' class='impl'><code class='in-band'>{}</code>",
+                id, i.inner_impl()
+            )?;
         }
         write!(w, "<a href='#{}' class='anchor'></a>", id)?;
-        write!(w, "</td><td><span class='out-of-band'>")?;
         let since = i.impl_item.stability.as_ref().map(|s| &s.since[..]);
+        render_stability_since_raw(w, since, outer_version)?;
         if let Some(l) = (Item { item: &i.impl_item, cx: cx }).src_href() {
-            write!(w, "<div class='ghost'></div>")?;
-            render_stability_since_raw(w, since, outer_version)?;
             write!(w, "<a class='srclink' href='{}' title='{}'>[src]</a>",
                    l, "goto source code")?;
-        } else {
-            render_stability_since_raw(w, since, outer_version)?;
         }
-        write!(w, "</span></td></tr></tbody></table></span></h3>")?;
+        write!(w, "</h3>")?;
         if let Some(ref dox) = cx.shared.maybe_collapsed_doc_value(&i.impl_item) {
             let mut ids = cx.id_map.borrow_mut();
             write!(w, "<div class='docblock'>{}</div>",
@@ -4065,20 +4060,15 @@ fn render_impl(w: &mut fmt::Formatter, cx: &Context, i: &Impl, link: AssocItemLi
                     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, "<table id='{}' class='table-display'><tbody><tr><td><code>", ns_id)?;
+                    write!(w, "<code id='{}'>", ns_id)?;
                     render_assoc_item(w, item, link.anchor(&id), ItemType::Impl)?;
                     write!(w, "</code>")?;
+                    render_stability_since_raw(w, item.stable_since(), outer_version)?;
                     if let Some(l) = (Item { cx, item }).src_href() {
-                        write!(w, "</td><td><span class='out-of-band'>")?;
-                        write!(w, "<div class='ghost'></div>")?;
-                        render_stability_since_raw(w, item.stable_since(), outer_version)?;
-                        write!(w, "<a class='srclink' href='{}' title='{}'>[src]</a></span>",
+                        write!(w, "<a class='srclink' href='{}' title='{}'>[src]</a>",
                                l, "goto source code")?;
-                    } else {
-                        write!(w, "</td><td>")?;
-                        render_stability_since_raw(w, item.stable_since(), outer_version)?;
                     }
-                    write!(w, "</td></tr></tbody></table></h4>")?;
+                    write!(w, "</h4>")?;
                 }
             }
             clean::TypedefItem(ref tydef, _) => {
@@ -4090,40 +4080,18 @@ fn render_impl(w: &mut fmt::Formatter, cx: &Context, i: &Impl, link: AssocItemLi
                 write!(w, "</code></h4>")?;
             }
             clean::AssociatedConstItem(ref ty, ref default) => {
-                let mut version = String::new();
-
-                render_stability_since_raw(&mut version, item.stable_since(), outer_version)?;
-
                 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)?;
-                if !version.is_empty() {
-                    write!(w, "<table id='{}' class='table-display'><tbody><tr><td><code>", ns_id)?;
-                } else {
-                    write!(w, "<code id='{}'>", ns_id)?;
-                }
+                write!(w, "<code id='{}'>", ns_id)?;
                 assoc_const(w, item, ty, default.as_ref(), link.anchor(&id))?;
-                if !version.is_empty() {
-                    write!(w, "</code>")?;
-                }
-                let src = if let Some(l) = (Item { cx, item }).src_href() {
-                    if !version.is_empty() {
-                        write!(w, "</td><td><span class='out-of-band'>")?;
-                        write!(w, "<div class='ghost'></div>{}", version)?;
-                    }
-                    format!("<a class='srclink' href='{}' title='{}'>[src]</a>",
-                            l, "goto source code")
-                } else {
-                    if !version.is_empty() {
-                        write!(w, "</td><td>{}", version)?;
-                    }
-                    String::new()
-                };
-                if version.is_empty() {
-                    write!(w, "</code>{}</h4>", src)?;
-                } else {
-                    write!(w, "{}</span></td></tr></tbody></table></h4>", src)?;
+                write!(w, "</code>")?;
+                render_stability_since_raw(w, item.stable_since(), outer_version)?;
+                if let Some(l) = (Item { cx, item }).src_href() {
+                    write!(w, "<a class='srclink' href='{}' title='{}'>[src]</a>",
+                            l, "goto source code")?;
                 }
+                write!(w, "</h4>")?;
             }
             clean::AssociatedTypeItem(ref bounds, ref default) => {
                 let id = cx.derive_id(format!("{}.{}", item_type, name));

src/librustdoc/html/static/main.js

@@ -2409,8 +2409,17 @@ if (!DOMTokenList.prototype.remove) {
             e.remove();
         });
         onEachLazy(main.childNodes, function(e) {
+            // Unhide the actual content once loading is complete. Headers get
+            // flex treatment for their horizontal layout, divs get block treatment
+            // for vertical layout (column-oriented flex layout for divs caused
+            // errors in mobile browsers).
             if (e.tagName === "H2" || e.tagName === "H3") {
-                e.nextElementSibling.style.display = "block";
+                let nextTagName = e.nextElementSibling.tagName;
+                if (nextTagName == "H2" || nextTagName == "H3") {
+                    e.nextElementSibling.style.display = "flex";
+                } else {
+                    e.nextElementSibling.style.display = "block";
+                }
             }
         });
     }

src/librustdoc/html/static/rustdoc.css

@@ -89,8 +89,9 @@ h2, h3:not(.impl):not(.method):not(.type):not(.tymethod), h4:not(.method):not(.t
 	border-bottom: 1px solid;
 }
 h3.impl, h3.method, h4.method, h3.type, h4.type, h4.associatedconstant {
+	flex-basis: 100%;
 	font-weight: 600;
-	margin-top: 10px;
+	margin-top: 16px;
 	margin-bottom: 10px;
 	position: relative;
 }
@@ -356,7 +357,8 @@ nav.sub {
 #main > .docblock h3, #main > .docblock h4, #main > .docblock h5 { font-size: 1em; }
 
 #main > h2 + div, #main > h2 + h3, #main > h3 + div {
-	display: none;
+	display: none; /* Changed to flex or block via js once the page is loaded */
+	flex-wrap: wrap;
 }
 
 .docblock h1 { font-size: 1em; }
@@ -390,7 +392,7 @@ h4 > code, h3 > code, .invisible > code {
 }
 
 .in-band, code {
-	z-index: 5;
+	z-index: -5;
 }
 
 .invisible {
@@ -534,6 +536,10 @@ h4 > code, h3 > code, .invisible > code {
 	margin-top: -8px;
 }
 
+.impl-items {
+	flex-basis: 100%;
+}
+
 #main > .stability {
 	margin-top: 0;
 }
@@ -784,6 +790,33 @@ body.blur > :not(#help) {
 	top: 0;
 }
 
+.impl-items .since, .impl .since {
+	flex-grow: 0;
+	padding-left: 12px;
+	padding-right: 2px;
+	position: initial;
+}
+
+.impl-items .srclink, .impl .srclink {
+	flex-grow: 0;
+	/* Override header settings otherwise it's too bold */
+	font-size: 17px;
+	font-weight: normal;
+}
+
+.impl-items code, .impl code {
+	flex-grow: 1;
+}
+
+.impl-items h4, h4.impl, h3.impl {
+	display: flex;
+	flex-basis: 100%;
+	font-size: 16px;
+	margin-bottom: 12px;
+	/* Push the src link out to the right edge consistently */
+	justify-content: space-between;
+}
+
 .variants_table {
 	width: 100%;
 }
@@ -871,15 +904,6 @@ h3 > .collapse-toggle, h4 > .collapse-toggle {
 	margin-left: 20px;
 }
 
-.ghost {
-	display: none;
-}
-
-.ghost + .since {
-	position: initial;
-	display: table-cell;
-}
-
 .since + .srclink {
 	display: table-cell;
 	padding-left: 10px;
@@ -1119,7 +1143,7 @@ span.since {
 	margin-left: 5px;
 	top: -5px;
 	left: 105%;
-	z-index: 1;
+	z-index: 10;
 }
 
 .tooltip:hover .tooltiptext {
@@ -1361,8 +1385,9 @@ h3.important {
 	margin-top: 16px;
 }
 
-.content > .methods > div.important-traits {
+.content > .methods > .method > div.important-traits {
 	position: absolute;
+	font-weight: 400;
 	left: -42px;
 	margin-top: 2px;
 }

src/test/rustdoc/assoc-consts-version.rs

@@ -10,7 +10,7 @@
 pub struct SomeStruct;
 
 impl SomeStruct {
-    // @has 'foo/struct.SomeStruct.html' '//*[@id="SOME_CONST.v"]//div[@class="since"]' '1.1.2'
+    // @has 'foo/struct.SomeStruct.html' '//*[@id="associatedconstant.SOME_CONST"]//div[@class="since"]' '1.1.2'
     #[stable(since="1.1.2", feature="rust2")]
     pub const SOME_CONST: usize = 0;
 }

src/test/rustdoc/const.rs

@@ -3,7 +3,7 @@
 pub struct Foo;
 
 impl Foo {
-    // @has const/struct.Foo.html '//*[@id="new.v"]//code' 'const unsafe fn new'
+    // @has const/struct.Foo.html '//code[@id="new.v"]' 'const unsafe fn new'
     pub const unsafe fn new() -> Foo {
         Foo
     }

src/test/rustdoc/issue-25001.rs

@@ -9,17 +9,17 @@ pub trait Bar {
 
 impl Foo<u8> {
     // @has - '//*[@id="method.pass"]//code' 'fn pass()'
-    // @has - '//*[@id="pass.v"]//code' 'fn pass()'
+    // @has - '//code[@id="pass.v"]' 'fn pass()'
     pub fn pass() {}
 }
 impl Foo<u16> {
     // @has - '//*[@id="method.pass-1"]//code' 'fn pass() -> usize'
-    // @has - '//*[@id="pass.v-1"]//code' 'fn pass() -> usize'
+    // @has - '//code[@id="pass.v-1"]' 'fn pass() -> usize'
     pub fn pass() -> usize { 42 }
 }
 impl Foo<u32> {
     // @has - '//*[@id="method.pass-2"]//code' 'fn pass() -> isize'
-    // @has - '//*[@id="pass.v-2"]//code' 'fn pass() -> isize'
+    // @has - '//code[@id="pass.v-2"]' 'fn pass() -> isize'
     pub fn pass() -> isize { 42 }
 }
 

src/test/rustdoc/issue-51236.rs

@@ -7,7 +7,7 @@ pub mod traits {
 }
 
 // @has issue_51236/struct.Owned.html
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//*/code' "impl<T> Send for \
+// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' "impl<T> Send for \
 // Owned<T> where <T as Owned<'static>>::Reader: Send"
 pub struct Owned<T> where T: for<'a> ::traits::Owned<'a> {
     marker: PhantomData<<T as ::traits::Owned<'static>>::Reader>,

src/test/rustdoc/issue-54705.rs

@@ -3,10 +3,10 @@ pub trait ScopeHandle<'scope> {}
 
 
 // @has issue_54705/struct.ScopeFutureContents.html
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//*/code' "impl<'scope, S> \
+// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' "impl<'scope, S> \
 // Send for ScopeFutureContents<'scope, S> where S: Sync"
 //
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//*/code' "impl<'scope, S> \
+// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' "impl<'scope, S> \
 // Sync for ScopeFutureContents<'scope, S> where S: Sync"
 pub struct ScopeFutureContents<'scope, S>
     where S: ScopeHandle<'scope>,

src/test/rustdoc/issue-55321.rs

@@ -1,16 +1,16 @@
 #![feature(optin_builtin_traits)]
 
 // @has issue_55321/struct.A.html
-// @has - '//*[@id="implementations-list"]/*[@class="impl"]//*/code' "impl !Send for A"
-// @has - '//*[@id="implementations-list"]/*[@class="impl"]//*/code' "impl !Sync for A"
+// @has - '//*[@id="implementations-list"]/*[@class="impl"]//code' "impl !Send for A"
+// @has - '//*[@id="implementations-list"]/*[@class="impl"]//code' "impl !Sync for A"
 pub struct A();
 
 impl !Send for A {}
 impl !Sync for A {}
 
 // @has issue_55321/struct.B.html
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//*/code' "impl<T> !Send for \
+// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' "impl<T> !Send for \
 // B<T>"
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//*/code' "impl<T> !Sync for \
+// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' "impl<T> !Sync for \
 // B<T>"
 pub struct B<T: ?Sized>(A, Box<T>);

src/test/rustdoc/issue-56822.rs

@@ -17,7 +17,7 @@ impl<'a, T> MyTrait for Inner<'a, T> {
 }
 
 // @has issue_56822/struct.Parser.html
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//*/code' "impl<'a> Send for \
+// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' "impl<'a> Send for \
 // Parser<'a>"
 pub struct Parser<'a> {
     field: <Wrapper<Inner<'a, u8>> as MyTrait>::Output

src/test/rustdoc/synthetic_auto/complex.rs

@@ -20,7 +20,7 @@ mod foo {
 }
 
 // @has complex/struct.NotOuter.html
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//*/code' "impl<'a, T, K: \
+// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' "impl<'a, T, K: \
 // ?Sized> Send for NotOuter<'a, T, K> where K: for<'b> Fn((&'b bool, &'a u8)) \
 // -> &'b i8, T: MyTrait<'a>, <T as MyTrait<'a>>::MyItem: Copy, 'a: 'static"
 

src/test/rustdoc/synthetic_auto/lifetimes.rs

@@ -9,10 +9,10 @@ where
 {}
 
 // @has lifetimes/struct.Foo.html
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//*/code' "impl<'c, K> Send \
+// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' "impl<'c, K> Send \
 // for Foo<'c, K> where K: for<'b> Fn(&'b bool) -> &'c u8, 'c: 'static"
 //
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//*/code' "impl<'c, K> Sync \
+// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' "impl<'c, K> Sync \
 // for Foo<'c, K> where K: Sync"
 pub struct Foo<'c, K: 'c> {
     inner_field: Inner<'c, K>,

src/test/rustdoc/synthetic_auto/manual.rs

@@ -1,8 +1,8 @@
 // @has manual/struct.Foo.html
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//*/code' 'impl<T> Sync for \
+// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' 'impl<T> Sync for \
 // Foo<T> where T: Sync'
 //
-// @has - '//*[@id="implementations-list"]/*[@class="impl"]//*/code' \
+// @has - '//*[@id="implementations-list"]/*[@class="impl"]//code' \
 // 'impl<T> Send for Foo<T>'
 //
 // @count - '//*[@id="implementations-list"]/*[@class="impl"]' 1

src/test/rustdoc/synthetic_auto/negative.rs

@@ -3,10 +3,10 @@ pub struct Inner<T: Copy> {
 }
 
 // @has negative/struct.Outer.html
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//*/code' "impl<T> !Send for \
+// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' "impl<T> !Send for \
 // Outer<T>"
 //
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//*/code' "impl<T> \
+// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' "impl<T> \
 // !Sync for Outer<T>"
 pub struct Outer<T: Copy> {
     inner_field: Inner<T>,