rustdoc: change trait bound formatting

src/librustdoc/html/format.rs

@@ -353,7 +353,11 @@ pub(crate) fn print_where_clause<'a, 'tcx: 'a>(
         } else {
             let mut br_with_padding = String::with_capacity(6 * indent + 28);
             br_with_padding.push_str("<br>");
-            for _ in 0..indent + 4 {
+
+            let padding_amout =
+                if ending == Ending::Newline { indent + 4 } else { indent + "fn where ".len() };
+
+            for _ in 0..padding_amout {
                 br_with_padding.push_str(" ");
             }
             let where_preds = where_preds.to_string().replace("<br>", &br_with_padding);
@@ -367,8 +371,12 @@ pub(crate) fn print_where_clause<'a, 'tcx: 'a>(
                 if indent == 0 {
                     format!("<br><span class=\"where\">where{where_preds}</span>")
                 } else {
+                    // put the first one on the same line as the 'where' keyword
+                    let where_preds = where_preds.replacen(&br_with_padding, " ", 1);
+
                     let mut clause = br_with_padding;
-                    clause.truncate(clause.len() - 4);
+                    clause.truncate(clause.len() - "where ".len());
+
                     write!(clause, "<span class=\"where\">where{where_preds}</span>")?;
                     clause
                 }

src/librustdoc/html/render/print_item.rs

@@ -645,6 +645,10 @@ fn item_trait(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &clean:
             if count_consts != 0 && count_methods != 0 {
                 w.write_str("\n");
             }
+
+            if !required_methods.is_empty() {
+                write!(w, "    // Required method{}\n", pluralize(required_methods.len()));
+            }
             for (pos, m) in required_methods.iter().enumerate() {
                 render_assoc_item(
                     w,
@@ -663,6 +667,10 @@ fn item_trait(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &clean:
             if !required_methods.is_empty() && !provided_methods.is_empty() {
                 w.write_str("\n");
             }
+
+            if !provided_methods.is_empty() {
+                write!(w, "    // Provided method{}\n", pluralize(provided_methods.len()));
+            }
             for (pos, m) in provided_methods.iter().enumerate() {
                 render_assoc_item(
                     w,
@@ -672,16 +680,8 @@ fn item_trait(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &clean:
                     cx,
                     RenderMode::Normal,
                 );
-                match *m.kind {
-                    clean::MethodItem(ref inner, _)
-                        if !inner.generics.where_predicates.is_empty() =>
-                    {
-                        w.write_str(",\n    { ... }\n");
-                    }
-                    _ => {
-                        w.write_str(" { ... }\n");
-                    }
-                }
+
+                w.write_str(" { ... }\n");
 
                 if pos < provided_methods.len() - 1 {
                     w.write_str("<span class=\"item-spacer\"></span>");

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

@@ -1176,6 +1176,7 @@ a.test-arrow:hover {
 .item-spacer {
 	width: 100%;
 	height: 12px;
+	display: block;
 }
 
 .out-of-band > span.since {

tests/rustdoc/auxiliary/inline-default-methods.rs

@@ -4,3 +4,15 @@ pub trait Foo {
     fn bar(&self);
     fn foo(&mut self) {}
 }
+
+pub trait Bar {
+    fn bar(&self);
+    fn foo1(&mut self) {}
+    fn foo2(&mut self) {}
+}
+
+pub trait Baz {
+    fn bar1(&self);
+    fn bar2(&self);
+    fn foo(&mut self) {}
+}

tests/rustdoc/decl-trailing-whitespace.declaration.html

@@ -1,7 +1,9 @@
 <code>pub trait Write {
+    // Required methods
     fn <a href="#tymethod.poll_write" class="fn">poll_write</a>(<br />&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;self: <a class="enum" href="{{channel}}/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="struct" href="{{channel}}/alloc/string/struct.String.html" title="struct alloc::string::String">String</a>&gt;,<br />&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;cx: &amp;mut <a class="enum" href="{{channel}}/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="struct" href="{{channel}}/alloc/string/struct.String.html" title="struct alloc::string::String">String</a>&gt;,<br />&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;buf: &amp;mut [<a class="primitive" href="{{channel}}/std/primitive.usize.html">usize</a>]<br />&#160;&#160;&#160;&#160;) -&gt; <a class="enum" href="{{channel}}/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="enum" href="{{channel}}/core/result/enum.Result.html" title="enum core::result::Result">Result</a>&lt;<a class="primitive" href="{{channel}}/std/primitive.usize.html">usize</a>, <a class="struct" href="struct.Error.html" title="struct foo::Error">Error</a>&gt;&gt;;
 <span class="item-spacer" />    fn <a href="#tymethod.poll_flush" class="fn">poll_flush</a>(<br />&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;self: <a class="enum" href="{{channel}}/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="struct" href="{{channel}}/alloc/string/struct.String.html" title="struct alloc::string::String">String</a>&gt;,<br />&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;cx: &amp;mut <a class="enum" href="{{channel}}/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="struct" href="{{channel}}/alloc/string/struct.String.html" title="struct alloc::string::String">String</a>&gt;<br />&#160;&#160;&#160;&#160;) -&gt; <a class="enum" href="{{channel}}/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="enum" href="{{channel}}/core/result/enum.Result.html" title="enum core::result::Result">Result</a>&lt;<a class="primitive" href="{{channel}}/std/primitive.unit.html">()</a>, <a class="struct" href="struct.Error.html" title="struct foo::Error">Error</a>&gt;&gt;;
 <span class="item-spacer" />    fn <a href="#tymethod.poll_close" class="fn">poll_close</a>(<br />&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;self: <a class="enum" href="{{channel}}/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="struct" href="{{channel}}/alloc/string/struct.String.html" title="struct alloc::string::String">String</a>&gt;,<br />&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;cx: &amp;mut <a class="enum" href="{{channel}}/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="struct" href="{{channel}}/alloc/string/struct.String.html" title="struct alloc::string::String">String</a>&gt;<br />&#160;&#160;&#160;&#160;) -&gt; <a class="enum" href="{{channel}}/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="enum" href="{{channel}}/core/result/enum.Result.html" title="enum core::result::Result">Result</a>&lt;<a class="primitive" href="{{channel}}/std/primitive.unit.html">()</a>, <a class="struct" href="struct.Error.html" title="struct foo::Error">Error</a>&gt;&gt;;
 
+    // Provided method
     fn <a href="#method.poll_write_vectored" class="fn">poll_write_vectored</a>(<br />&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;self: <a class="enum" href="{{channel}}/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="struct" href="{{channel}}/alloc/string/struct.String.html" title="struct alloc::string::String">String</a>&gt;,<br />&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;cx: &amp;mut <a class="enum" href="{{channel}}/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="struct" href="{{channel}}/alloc/string/struct.String.html" title="struct alloc::string::String">String</a>&gt;,<br />&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;bufs: &amp;[<a class="primitive" href="{{channel}}/std/primitive.usize.html">usize</a>]<br />&#160;&#160;&#160;&#160;) -&gt; <a class="enum" href="{{channel}}/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="enum" href="{{channel}}/core/result/enum.Result.html" title="enum core::result::Result">Result</a>&lt;<a class="primitive" href="{{channel}}/std/primitive.usize.html">usize</a>, <a class="struct" href="struct.Error.html" title="struct foo::Error">Error</a>&gt;&gt; { ... }
-}</code>
+}</code>

tests/rustdoc/inline-default-methods.rs

@@ -4,6 +4,18 @@
 extern crate inline_default_methods;
 
 // @has inline_default_methods/trait.Foo.html
-// @has - '//pre[@class="rust item-decl"]' 'fn bar(&self);'
-// @has - '//pre[@class="rust item-decl"]' 'fn foo(&mut self) { ... }'
+// @has - '//pre[@class="rust item-decl"]' '// Required method fn bar(&self);'
+// @has - '//pre[@class="rust item-decl"]' '// Provided method fn foo(&mut self)'
 pub use inline_default_methods::Foo;
+
+// @has inline_default_methods/trait.Bar.html
+// @has - '//pre[@class="rust item-decl"]' '// Required method fn bar(&self);'
+// @has - '//pre[@class="rust item-decl"]' '// Provided methods fn foo1(&mut self)'
+// @has - '//pre[@class="rust item-decl"]' 'fn foo2(&mut self)'
+pub use inline_default_methods::Bar;
+
+// @has inline_default_methods/trait.Baz.html
+// @has - '//pre[@class="rust item-decl"]' '// Required methods fn bar1(&self);'
+// @has - '//pre[@class="rust item-decl"]' 'fn bar2(&self);'
+// @has - '//pre[@class="rust item-decl"]' '// Provided method fn foo(&mut self)'
+pub use inline_default_methods::Baz;

tests/rustdoc/issue-85454.rs

@@ -5,7 +5,7 @@
 extern crate issue_85454;
 
 // @has foo/trait.FromResidual.html
-// @has - '//pre[@class="rust item-decl"]' 'pub trait FromResidual<R = <Self as Try>::Residual> { fn from_residual(residual: R) -> Self; }'
+// @has - '//pre[@class="rust item-decl"]' 'pub trait FromResidual<R = <Self as Try>::Residual> { // Required method fn from_residual(residual: R) -> Self; }'
 pub trait FromResidual<R = <Self as Try>::Residual> {
     fn from_residual(residual: R) -> Self;
 }
@@ -24,6 +24,6 @@ pub enum ControlFlow<B, C = ()> {
 
 pub mod reexport {
     // @has foo/reexport/trait.FromResidual.html
-    // @has - '//pre[@class="rust item-decl"]' 'pub trait FromResidual<R = <Self as Try>::Residual> { fn from_residual(residual: R) -> Self; }'
+    // @has - '//pre[@class="rust item-decl"]' 'pub trait FromResidual<R = <Self as Try>::Residual> { // Required method fn from_residual(residual: R) -> Self; }'
     pub use issue_85454::*;
 }

tests/rustdoc/where.SWhere_TraitWhere_item-decl.html

@@ -1,8 +1,8 @@
 <pre class="rust item-decl"><code>pub trait TraitWhere {
-    type <a href="#associatedtype.Item" class="associatedtype">Item</a>&lt;'a&gt;<br />&#160;&#160;&#160;&#160;<span class="where">where<br />&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;Self: 'a</span>;
+    type <a href="#associatedtype.Item" class="associatedtype">Item</a>&lt;'a&gt;<br />&#160;&#160;&#160;&#160;&#160;&#160;&#160;<span class="where">where Self: 'a</span>;
 
-    fn <a href="#method.func" class="fn">func</a>(self)<br />&#160;&#160;&#160;&#160;<span class="where">where<br />&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;Self: <a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a></span>,
-    { ... }
-<span class="item-spacer" />    fn <a href="#method.lines" class="fn">lines</a>(self) -&gt; <a class="struct" href="{{channel}}/std/io/struct.Lines.html" title="struct std::io::Lines">Lines</a>&lt;Self&gt;<br />&#160;&#160;&#160;&#160;<span class="where">where<br />&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;Self: <a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a></span>,
-    { ... }
+    // Provided methods
+    fn <a href="#method.func" class="fn">func</a>(self)<br />&#160;&#160;&#160;&#160;&#160;&#160;&#160;<span class="where">where Self: <a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a></span> { ... }
+<span class="item-spacer" />    fn <a href="#method.lines" class="fn">lines</a>(self) -&gt; <a class="struct" href="{{channel}}/std/io/struct.Lines.html" title="struct std::io::Lines">Lines</a>&lt;Self&gt;<br />&#160;&#160;&#160;&#160;&#160;&#160;&#160;<span class="where">where Self: <a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a></span> { ... }
+<span class="item-spacer" />    fn <a href="#method.merge" class="fn">merge</a>&lt;T&gt;(self, a: T)<br />&#160;&#160;&#160;&#160;&#160;&#160;&#160;<span class="where">where Self: <a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a>,<br />&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;T: <a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a></span> { ... }
 }</code></pre>

tests/rustdoc/where.rs

@@ -41,6 +41,12 @@ pub trait TraitWhere {
     where
         Self: Sized,
     { todo!() }
+
+    fn merge<T>(self, a: T)
+    where
+        Self: Sized,
+        T: Sized,
+    { todo!() }
 }
 
 // @has foo/struct.Echo.html '//*[@class="impl"]//h3[@class="code-header"]' \

tests/rustdoc/whitespace-after-where-clause.trait.html

@@ -1,6 +1,7 @@
 <pre class="rust item-decl"><code>pub trait ToOwned&lt;T&gt;<span class="where fmt-newline">where<br />&#160;&#160;&#160;&#160;T: <a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>,</span>{
     type <a href="#associatedtype.Owned" class="associatedtype">Owned</a>;
 
+    // Required methods
     fn <a href="#tymethod.to_owned" class="fn">to_owned</a>(&amp;self) -&gt; Self::<a class="associatedtype" href="trait.ToOwned.html#associatedtype.Owned" title="type foo::ToOwned::Owned">Owned</a>;
 <span class="item-spacer" />    fn <a href="#tymethod.whatever" class="fn">whatever</a>(&amp;self) -&gt; T;
 }</code></pre>

tests/rustdoc/whitespace-after-where-clause.trait2.html

@@ -1,6 +1,7 @@
 <pre class="rust item-decl"><code>pub trait ToOwned2&lt;T:&#160;<a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>&gt; {
     type <a href="#associatedtype.Owned" class="associatedtype">Owned</a>;
 
+    // Required methods
     fn <a href="#tymethod.to_owned" class="fn">to_owned</a>(&amp;self) -&gt; Self::<a class="associatedtype" href="trait.ToOwned2.html#associatedtype.Owned" title="type foo::ToOwned2::Owned">Owned</a>;
 <span class="item-spacer" />    fn <a href="#tymethod.whatever" class="fn">whatever</a>(&amp;self) -&gt; T;
 }</code></pre>