Add color on item name in item declaration

[GuillaumeGomez]

Fixes #117555.

I'm really not convinced this is a good idea. It does put more colors, but I'm not sure it's adding any value. We have two different color systems: one for source codes and one for documentation. Item declaration is actually using the same system as "documentation", so only highlighting links.

So in this draft, I generated an empty link on the item name to add some color, but again, really not convinced by this approach...

You can test it here.

Some screenshots:

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[rust-log-analyzer]

The job x86_64-gnu-llvm-15 failed! Check out the build log: (web) (plain)

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##[group]Testing stage2 compiletest suite=rustdoc mode=rustdoc (x86_64-unknown-linux-gnu)
warning: `tidy` is not installed; diffs will not be generated

running 671 tests
iF..................F...............................F......F..........F.F...............  88/671
.........i................................................................F............F 176/671
......................................F.........F..........F.FF.........F............... 264/671
........................................................................................ 440/671
........................................................................................ 440/671
......F.i............................................F.................................. 528/671
........................i.F.......F..........F.......................................... 616/671
........................F........................F...F.
failures:

---- [rustdoc] tests/rustdoc/array-links.rs stdout ----


error: htmldocck failed!
status: exit status: 1
command: "/usr/bin/python3" "/checkout/src/etc/htmldocck.py" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc/array-links" "/checkout/tests/rustdoc/array-links.rs"
--- expected ---


<code>pub fn alpha() -&gt; &amp;'static [<a class="primitive" href="https://doc.rust-lang.org/nightly/core/primitive.u32.html">u32</a>; <a class="primitive" href="https://doc.rust-lang.org/nightly/core/primitive.array.html">1</a>]</code>


--- actual ---


<code>pub fn <a class="fn" href="#">alpha</a>() -&gt; &amp;'static [<a class="primitive" href="https://doc.rust-lang.org/nightly/core/primitive.u32.html">u32</a>; <a class="primitive" href="https://doc.rust-lang.org/nightly/core/primitive.array.html">1</a>]</code>
--- expected ---


<code>pub fn beta&lt;T&gt;() -&gt; &amp;'static <a class="primitive" href="https://doc.rust-lang.org/nightly/core/primitive.array.html">[T; 1]</a></code>

--- actual ---


<code>pub fn <a class="fn" href="#">beta</a>&lt;T&gt;() -&gt; &amp;'static <a class="primitive" href="https://doc.rust-lang.org/nightly/core/primitive.array.html">[T; 1]</a></code>
--- expected ---


<code>pub fn gamma() -&gt; <a class="struct" href="struct.MyBox.html" title="struct foo::MyBox">MyBox</a>&lt;[<a class="primitive" href="https://doc.rust-lang.org/nightly/core/primitive.u32.html">u32</a>; <a class="primitive" href="https://doc.rust-lang.org/nightly/core/primitive.array.html">1</a>]&gt;</code>

--- actual ---


<code>pub fn <a class="fn" href="#">gamma</a>() -&gt; <a class="struct" href="struct.MyBox.html" title="struct foo::MyBox">MyBox</a>&lt;[<a class="primitive" href="https://doc.rust-lang.org/nightly/core/primitive.u32.html">u32</a>; <a class="primitive" href="https://doc.rust-lang.org/nightly/core/primitive.array.html">1</a>]&gt;</code>
--- expected ---


<code>pub fn delta&lt;T&gt;() -&gt; <a class="struct" href="struct.MyBox.html" title="struct foo::MyBox">MyBox</a>&lt;<a class="primitive" href="https://doc.rust-lang.org/nightly/core/primitive.array.html">[T; 1]</a>&gt;</code>

--- actual ---


<code>pub fn <a class="fn" href="#">delta</a>&lt;T&gt;() -&gt; <a class="struct" href="struct.MyBox.html" title="struct foo::MyBox">MyBox</a>&lt;<a class="primitive" href="https://doc.rust-lang.org/nightly/core/primitive.array.html">[T; 1]</a>&gt;</code>
--- stderr -------------------------------
--- stderr -------------------------------
text: 'pub fn ' != "pub fn alpha() -> &'static ["
children 1 do not match: code
7: @snapshot check failed
 Actual snapshot value is different than expected
 // @snapshot link_slice_u32 - '//pre[@class="rust item-decl"]/code'
text: 'pub fn ' != "pub fn beta<T>() -> &'static "
children 1 do not match: code
13: @snapshot check failed
 Actual snapshot value is different than expected
 // @snapshot link_slice_generic - '//pre[@class="rust item-decl"]/code'
text: 'pub fn ' != 'pub fn gamma() -> '
children 1 do not match: code
19: @snapshot check failed
 Actual snapshot value is different than expected
 // @snapshot link_box_u32 - '//pre[@class="rust item-decl"]/code'
text: 'pub fn ' != 'pub fn delta<T>() -> '
children 1 do not match: code
25: @snapshot check failed
 Actual snapshot value is different than expected
 // @snapshot link_box_generic - '//pre[@class="rust item-decl"]/code'
Encountered 4 errors
------------------------------------------



---- [rustdoc] tests/rustdoc/async-fn.rs stdout ----

error: htmldocck failed!
status: exit status: 1
command: "/usr/bin/python3" "/checkout/src/etc/htmldocck.py" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc/async-fn" "/checkout/tests/rustdoc/async-fn.rs"
--- stderr -------------------------------
53: @has check failed
53: @has check failed
 `XPATH PATTERN` did not match
 // @has - '//pre[@class="rust item-decl"]' 'pub async fn const_generics<const N: usize>(_: impl Trait<N>)'
70: @has check failed
 `XPATH PATTERN` did not match
 // @has - '//pre[@class="rust item-decl"]' "pub async fn lifetime_for_trait(foo: &str) -> Box<dyn Bar + '_>"
73: @has check failed
 `XPATH PATTERN` did not match
 // @has - '//pre[@class="rust item-decl"]' "pub async fn elided_in_input_trait(t: impl Pattern<'_>)"
94: @has check failed
 `XPATH PATTERN` did not match
 // @has - '//pre[@class="rust item-decl"]' "pub async fn named_trait<'a, 'b>(foo: impl Pattern<'a>) -> impl Pattern<'b>"
Encountered 4 errors
------------------------------------------



---- [rustdoc] tests/rustdoc/const-intrinsic.rs stdout ----

error: htmldocck failed!
status: exit status: 1
command: "/usr/bin/python3" "/checkout/src/etc/htmldocck.py" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc/const-intrinsic" "/checkout/tests/rustdoc/const-intrinsic.rs"
--- stderr -------------------------------
9: @has check failed
9: @has check failed
 `XPATH PATTERN` did not match
     // @has - '//pre[@class="rust item-decl"]' 'pub const unsafe extern "rust-intrinsic" fn transmute<T, U>(_: T) -> U'
15: @has check failed
 `XPATH PATTERN` did not match
     // @has - '//pre[@class="rust item-decl"]' 'pub unsafe extern "rust-intrinsic" fn unreachable() -> !'
Encountered 2 errors
------------------------------------------



---- [rustdoc] tests/rustdoc/const-generics/const-generics-docs.rs stdout ----

error: htmldocck failed!
status: exit status: 1
command: "/usr/bin/python3" "/checkout/src/etc/htmldocck.py" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc/const-generics/const-generics-docs" "/checkout/tests/rustdoc/const-generics/const-generics-docs.rs"
--- stderr -------------------------------
6: @has check failed
6: @has check failed
 `XPATH PATTERN` did not match
 // @has foo/fn.extern_fn.html '//pre[@class="rust item-decl"]' 'pub fn extern_fn<const N: usize>() -> impl Iterator<Item = [u8; N]>'
65: @has check failed
 `XPATH PATTERN` did not match
 // @has foo/fn.a_sink.html '//pre[@class="rust item-decl"]' 'pub async fn a_sink<const N: usize>(v: [u8; N]) -> impl Trait<N>'
Encountered 2 errors
------------------------------------------



---- [rustdoc] tests/rustdoc/decl-trailing-whitespace.rs stdout ----

error: htmldocck failed!
status: exit status: 1
command: "/usr/bin/python3" "/checkout/src/etc/htmldocck.py" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc/decl-trailing-whitespace" "/checkout/tests/rustdoc/decl-trailing-whitespace.rs"
--- expected ---


<code>pub trait Write {
    // Required methods
    fn <a href="#tymethod.poll_write" class="fn">poll_write</a>(
        self,
        cx: &amp;mut <a class="enum" href="https://doc.rust-lang.org/nightly/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="struct" href="https://doc.rust-lang.org/nightly/alloc/string/struct.String.html" title="struct alloc::string::String">String</a>&gt;,
        buf: &amp;mut [<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.usize.html">usize</a>]
    ) -&gt; <a class="enum" href="https://doc.rust-lang.org/nightly/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a>&lt;<a class="primitive" href="https://doc.rust-lang.org/nightly/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>(self, cx: &amp;mut <a class="enum" href="https://doc.rust-lang.org/nightly/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="struct" href="https://doc.rust-lang.org/nightly/alloc/string/struct.String.html" title="struct alloc::string::String">String</a>&gt;) -&gt; <a class="enum" href="https://doc.rust-lang.org/nightly/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a>&lt;<a class="primitive" href="https://doc.rust-lang.org/nightly/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>(self, cx: &amp;mut <a class="enum" href="https://doc.rust-lang.org/nightly/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="struct" href="https://doc.rust-lang.org/nightly/alloc/string/struct.String.html" title="struct alloc::string::String">String</a>&gt;) -&gt; <a class="enum" href="https://doc.rust-lang.org/nightly/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a>&lt;<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.unit.html">()</a>, <a class="struct" href="struct.Error.html" title="struct foo::Error">Error</a>&gt;&gt;;
    // Provided method
    // Provided method
    fn <a href="#method.poll_write_vectored" class="fn">poll_write_vectored</a>(
        self,
        cx: &amp;mut <a class="enum" href="https://doc.rust-lang.org/nightly/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="struct" href="https://doc.rust-lang.org/nightly/alloc/string/struct.String.html" title="struct alloc::string::String">String</a>&gt;,
        bufs: &amp;[<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.usize.html">usize</a>]
    ) -&gt; <a class="enum" href="https://doc.rust-lang.org/nightly/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a>&lt;<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.usize.html">usize</a>, <a class="struct" href="struct.Error.html" title="struct foo::Error">Error</a>&gt;&gt; { ... }
}</code>

--- actual ---


<code>pub trait <a class="trait" href="#">Write</a> {
    // Required methods
    fn <a href="#tymethod.poll_write" class="fn">poll_write</a>(
        self,
        cx: &amp;mut <a class="enum" href="https://doc.rust-lang.org/nightly/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="struct" href="https://doc.rust-lang.org/nightly/alloc/string/struct.String.html" title="struct alloc::string::String">String</a>&gt;,
        buf: &amp;mut [<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.usize.html">usize</a>]
    ) -&gt; <a class="enum" href="https://doc.rust-lang.org/nightly/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a>&lt;<a class="primitive" href="https://doc.rust-lang.org/nightly/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>(self, cx: &amp;mut <a class="enum" href="https://doc.rust-lang.org/nightly/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="struct" href="https://doc.rust-lang.org/nightly/alloc/string/struct.String.html" title="struct alloc::string::String">String</a>&gt;) -&gt; <a class="enum" href="https://doc.rust-lang.org/nightly/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a>&lt;<a class="primitive" href="https://doc.rust-lang.org/nightly/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>(self, cx: &amp;mut <a class="enum" href="https://doc.rust-lang.org/nightly/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="struct" href="https://doc.rust-lang.org/nightly/alloc/string/struct.String.html" title="struct alloc::string::String">String</a>&gt;) -&gt; <a class="enum" href="https://doc.rust-lang.org/nightly/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a>&lt;<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.unit.html">()</a>, <a class="struct" href="struct.Error.html" title="struct foo::Error">Error</a>&gt;&gt;;
    // Provided method
    // Provided method
    fn <a href="#method.poll_write_vectored" class="fn">poll_write_vectored</a>(
        self,
        cx: &amp;mut <a class="enum" href="https://doc.rust-lang.org/nightly/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="struct" href="https://doc.rust-lang.org/nightly/alloc/string/struct.String.html" title="struct alloc::string::String">String</a>&gt;,
        bufs: &amp;[<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.usize.html">usize</a>]
    ) -&gt; <a class="enum" href="https://doc.rust-lang.org/nightly/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a>&lt;<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.usize.html">usize</a>, <a class="struct" href="struct.Error.html" title="struct foo::Error">Error</a>&gt;&gt; { ... }
}</code>
--- stderr -------------------------------
--- stderr -------------------------------
text: 'pub trait ' != 'pub trait Write {\n    // Required methods\n    fn '
children 1 do not match: code
10: @snapshot check failed
 Actual snapshot value is different than expected
     // @snapshot 'declaration' - '//*[@class="rust item-decl"]//code'
Encountered 1 errors
------------------------------------------



---- [rustdoc] tests/rustdoc/decl-line-wrapping-empty-arg-list.rs stdout ----

error: htmldocck failed!
status: exit status: 1
command: "/usr/bin/python3" "/checkout/src/etc/htmldocck.py" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc/decl-line-wrapping-empty-arg-list" "/checkout/tests/rustdoc/decl-line-wrapping-empty-arg-list.rs"
--- expected ---


<pre class="rust item-decl"><code>pub fn create(
) -&gt; <a class="struct" href="struct.Padding00000000000000000000000000000000000000000000000000000000000000000000000000000000.html" title="struct decl_line_wrapping_empty_arg_list::Padding00000000000000000000000000000000000000000000000000000000000000000000000000000000">Padding00000000000000000000000000000000000000000000000000000000000000000000000000000000</a></code></pre>

--- actual ---


<pre class="rust item-decl"><code>pub fn <a class="fn" href="#">create</a>(
) -&gt; <a class="struct" href="struct.Padding00000000000000000000000000000000000000000000000000000000000000000000000000000000.html" title="struct decl_line_wrapping_empty_arg_list::Padding00000000000000000000000000000000000000000000000000000000000000000000000000000000">Padding00000000000000000000000000000000000000000000000000000000000000000000000000000000</a></code></pre>
--- stderr -------------------------------
--- stderr -------------------------------
text: 'pub fn ' != 'pub fn create(\n) -> '
children 1 do not match: code
children 1 do not match: pre
9: @snapshot check failed
 Actual snapshot value is different than expected
 // @snapshot decl - '//pre[@class="rust item-decl"]'
Encountered 1 errors
------------------------------------------



---- [rustdoc] tests/rustdoc/ffi.rs stdout ----

error: htmldocck failed!
status: exit status: 1
command: "/usr/bin/python3" "/checkout/src/etc/htmldocck.py" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc/ffi" "/checkout/tests/rustdoc/ffi.rs"
--- stderr -------------------------------
6: @has check failed
6: @has check failed
 `XPATH PATTERN` did not match
 // @has ffi/fn.foreigner.html //pre 'pub unsafe extern "C" fn foreigner(cold_as_ice: u32)'
10: @has check failed
 `XPATH PATTERN` did not match
     // @has ffi/fn.another.html //pre 'pub unsafe extern "C" fn another(cold_as_ice: u32)'
Encountered 2 errors
------------------------------------------



---- [rustdoc] tests/rustdoc/generic-associated-types/issue-94683.rs stdout ----

error: htmldocck failed!
status: exit status: 1
command: "/usr/bin/python3" "/checkout/src/etc/htmldocck.py" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc/generic-associated-types/issue-94683" "/checkout/tests/rustdoc/generic-associated-types/issue-94683.rs"
--- stderr -------------------------------
--- stderr -------------------------------
10: @hasraw check failed
 `PATTERN` did not match
 // @hasraw - "pub type T = "
Encountered 1 errors
------------------------------------------



---- [rustdoc] tests/rustdoc/inherent-projections.rs stdout ----

error: htmldocck failed!
status: exit status: 1
command: "/usr/bin/python3" "/checkout/src/etc/htmldocck.py" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc/inherent-projections" "/checkout/tests/rustdoc/inherent-projections.rs"
--- stderr -------------------------------
16: @has check failed
16: @has check failed
 `XPATH PATTERN` did not match
 // @has 'inherent_projections/fn.user.html' '//pre[@class="rust item-decl"]' "user(_: for<'a> fn(_: Carrier<'a>::Focus))"
Encountered 1 errors
------------------------------------------



---- [rustdoc] tests/rustdoc/inline_cross/attributes.rs stdout ----

error: htmldocck failed!
status: exit status: 1
command: "/usr/bin/python3" "/checkout/src/etc/htmldocck.py" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc/inline_cross/attributes" "/checkout/tests/rustdoc/inline_cross/attributes.rs"
--- stderr -------------------------------
6: @has check failed
6: @has check failed
 `XPATH PATTERN` did not match
 // @has - '//*[@class="rust item-decl"]//*[@class="code-attribute"]' '#[non_exhaustive]'
Encountered 1 errors
------------------------------------------



---- [rustdoc] tests/rustdoc/inline_cross/dyn_trait.rs stdout ----

error: htmldocck failed!
status: exit status: 1
command: "/usr/bin/python3" "/checkout/src/etc/htmldocck.py" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc/inline_cross/dyn_trait" "/checkout/tests/rustdoc/inline_cross/dyn_trait.rs"
--- stderr -------------------------------
139: @has check failed
139: @has check failed
 `XPATH PATTERN` did not match
 // @has - '//pre[@class="rust item-decl"]' "apit_rpit(o: impl Outer<dyn Inner>) -> impl Outer<dyn Inner>"
Encountered 1 errors
------------------------------------------



---- [rustdoc] tests/rustdoc/inline_cross/impl_trait.rs stdout ----

error: htmldocck failed!
status: exit status: 1
command: "/usr/bin/python3" "/checkout/src/etc/htmldocck.py" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc/inline_cross/impl_trait" "/checkout/tests/rustdoc/inline_cross/impl_trait.rs"
--- stderr -------------------------------
20: @has check failed
20: @has check failed
 `XPATH PATTERN` did not match
 // @has - '//pre[@class="rust item-decl"]' "_x: impl Iterator<Item = impl Iterator<Item = u8>> + Clone)"
Encountered 1 errors
------------------------------------------



---- [rustdoc] tests/rustdoc/inline_cross/impl-sized.rs stdout ----

error: htmldocck failed!
status: exit status: 1
command: "/usr/bin/python3" "/checkout/src/etc/htmldocck.py" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc/inline_cross/impl-sized" "/checkout/tests/rustdoc/inline_cross/impl-sized.rs"
--- stderr -------------------------------
11: @has check failed
11: @has check failed
 `XPATH PATTERN` did not match
 // @has - '//pre[@class="rust item-decl"]' "sized_outlives<'a>(x: impl Sized + 'a) -> impl Sized + 'a"
20: @has check failed
 `XPATH PATTERN` did not match
 // @has - '//pre[@class="rust item-decl"]' "debug_maybe_sized(x: &(impl Debug + ?Sized)) -> &(impl Debug + ?Sized)"
25: @has check failed
 `XPATH PATTERN` did not match
 // @has - '//pre[@class="rust item-decl"]' "maybe_sized_outlives<'t>(x: &(impl ?Sized + 't)) -> &(impl ?Sized + 't)"
Encountered 3 errors
------------------------------------------



---- [rustdoc] tests/rustdoc/inline_cross/repr.rs stdout ----

error: htmldocck failed!
status: exit status: 1
command: "/usr/bin/python3" "/checkout/src/etc/htmldocck.py" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc/inline_cross/repr" "/checkout/tests/rustdoc/inline_cross/repr.rs"
--- stderr -------------------------------
11: @has check failed
11: @has check failed
 `XPATH PATTERN` did not match
 // @has - '//*[@class="rust item-decl"]//*[@class="code-attribute"]' '#[repr(C, align(8))]'
14: @has check failed
 `XPATH PATTERN` did not match
 // @has - '//*[@class="rust item-decl"]//*[@class="code-attribute"]' '#[repr(simd, packed(2))]'
17: @has check failed
 `XPATH PATTERN` did not match
 // @has - '//*[@class="rust item-decl"]//*[@class="code-attribute"]' '#[repr(transparent)]'
20: @has check failed
 `XPATH PATTERN` did not match
 // @has - '//*[@class="rust item-decl"]//*[@class="code-attribute"]' '#[repr(isize)]'
23: @has check failed
 `XPATH PATTERN` did not match
 // @has - '//*[@class="rust item-decl"]//*[@class="code-attribute"]' '#[repr(u8)]'
35: @has check failed
 `XPATH PATTERN` did not match
 // @has - '//*[@class="rust item-decl"]//*[@class="code-attribute"]' '#[repr(transparent)]'
Encountered 6 errors
------------------------------------------



---- [rustdoc] tests/rustdoc/legacy-const-generic.rs stdout ----

error: htmldocck failed!
status: exit status: 1
command: "/usr/bin/python3" "/checkout/src/etc/htmldocck.py" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc/legacy-const-generic" "/checkout/tests/rustdoc/legacy-const-generic.rs"
--- stderr -------------------------------
5: @has check failed
5: @has check failed
 `XPATH PATTERN` did not match
 // @has - '//pre[@class="rust item-decl"]' 'fn foo(x: usize, const Y: usize, z: usize) -> [usize; 3]'
12: @has check failed
 `XPATH PATTERN` did not match
 // @has - '//pre[@class="rust item-decl"]' 'fn bar(x: usize, const Y: usize, const Z: usize) -> [usize; 3]'
Encountered 2 errors
------------------------------------------



---- [rustdoc] tests/rustdoc/nested-modules.rs stdout ----

error: htmldocck failed!
status: exit status: 1
command: "/usr/bin/python3" "/checkout/src/etc/htmldocck.py" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc/nested-modules" "/checkout/tests/rustdoc/nested-modules.rs"
--- stderr -------------------------------
--- stderr -------------------------------
10: @hasraw check failed
 `PATTERN` did not match
         // @hasraw aCrate/a_nested_module/fn.a_nested_public_function.html 'pub fn a_nested_public_function()'
14: @hasraw check failed
 `PATTERN` did not match
         // @hasraw aCrate/a_nested_module/fn.another_nested_public_function.html 'pub fn another_nested_public_function()'
Encountered 2 errors
------------------------------------------



---- [rustdoc] tests/rustdoc/safe-intrinsic.rs stdout ----

error: htmldocck failed!
status: exit status: 1
command: "/usr/bin/python3" "/checkout/src/etc/htmldocck.py" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc/safe-intrinsic" "/checkout/tests/rustdoc/safe-intrinsic.rs"
--- stderr -------------------------------
14: @has check failed
14: @has check failed
 `XPATH PATTERN` did not match
     // @has - '//pre[@class="rust item-decl"]' 'pub unsafe extern "rust-intrinsic" fn unreachable() -> !'
Encountered 1 errors
------------------------------------------



---- [rustdoc] tests/rustdoc/repr.rs stdout ----

error: htmldocck failed!
status: exit status: 1
command: "/usr/bin/python3" "/checkout/src/etc/htmldocck.py" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc/repr" "/checkout/tests/rustdoc/repr.rs"
--- stderr -------------------------------
13: @has check failed
13: @has check failed
 `XPATH PATTERN` did not match
 // @has - '//*[@class="rust item-decl"]//*[@class="code-attribute"]' '#[repr(transparent)]'
22: @has check failed
 `XPATH PATTERN` did not match
 // @has - '//*[@class="rust item-decl"]//*[@class="code-attribute"]' '#[repr(transparent)]'
Encountered 2 errors
------------------------------------------



---- [rustdoc] tests/rustdoc/slice-links.rs stdout ----

error: htmldocck failed!
status: exit status: 1
command: "/usr/bin/python3" "/checkout/src/etc/htmldocck.py" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc/slice-links" "/checkout/tests/rustdoc/slice-links.rs"
--- expected ---


<code>pub fn alpha() -&gt; &amp;'static [<a class="primitive" href="https://doc.rust-lang.org/nightly/core/primitive.u32.html">u32</a>]</code>

--- actual ---


<code>pub fn <a class="fn" href="#">alpha</a>() -&gt; &amp;'static [<a class="primitive" href="https://doc.rust-lang.org/nightly/core/primitive.u32.html">u32</a>]</code>
--- expected ---


<code>pub fn beta&lt;T&gt;() -&gt; &amp;'static <a class="primitive" href="https://doc.rust-lang.org/nightly/core/primitive.slice.html">[T]</a></code>

--- actual ---


<code>pub fn <a class="fn" href="#">beta</a>&lt;T&gt;() -&gt; &amp;'static <a class="primitive" href="https://doc.rust-lang.org/nightly/core/primitive.slice.html">[T]</a></code>
--- expected ---


<code>pub fn gamma() -&gt; <a class="struct" href="struct.MyBox.html" title="struct foo::MyBox">MyBox</a>&lt;[<a class="primitive" href="https://doc.rust-lang.org/nightly/core/primitive.u32.html">u32</a>]&gt;</code>

--- actual ---


<code>pub fn <a class="fn" href="#">gamma</a>() -&gt; <a class="struct" href="struct.MyBox.html" title="struct foo::MyBox">MyBox</a>&lt;[<a class="primitive" href="https://doc.rust-lang.org/nightly/core/primitive.u32.html">u32</a>]&gt;</code>
--- expected ---


<code>pub fn delta&lt;T&gt;() -&gt; <a class="struct" href="struct.MyBox.html" title="struct foo::MyBox">MyBox</a>&lt;<a class="primitive" href="https://doc.rust-lang.org/nightly/core/primitive.slice.html">[T]</a>&gt;</code>

--- actual ---


<code>pub fn <a class="fn" href="#">delta</a>&lt;T&gt;() -&gt; <a class="struct" href="struct.MyBox.html" title="struct foo::MyBox">MyBox</a>&lt;<a class="primitive" href="https://doc.rust-lang.org/nightly/core/primitive.slice.html">[T]</a>&gt;</code>
--- stderr -------------------------------
--- stderr -------------------------------
text: 'pub fn ' != "pub fn alpha() -> &'static ["
children 1 do not match: code
7: @snapshot check failed
 Actual snapshot value is different than expected
 // @snapshot link_slice_u32 - '//pre[@class="rust item-decl"]/code'
text: 'pub fn ' != "pub fn beta<T>() -> &'static "
children 1 do not match: code
13: @snapshot check failed
 Actual snapshot value is different than expected
 // @snapshot link_slice_generic - '//pre[@class="rust item-decl"]/code'
text: 'pub fn ' != 'pub fn gamma() -> '
children 1 do not match: code
19: @snapshot check failed

[Wilfred]

Stupid question: why do we have two different colour systems? What's stopping us rendering all the 'documentation' system the same way as source code?

(Full disclosure: I've been helping maintain the VS Code syntax highlighter for Rust recently, so I might be extra sensitive to highlighting inconsistencies.)

[PatchMixolydic]

This doesn't seem to be working for macros.

std::pin::pin!:

std::println!:

[GuillaumeGomez]

The macros are the exceptions: they use code highlighting and not doc highlighting.

Stupid question: why do we have two different colour systems? What's stopping us rendering all the 'documentation' system the same way as source code?

(Full disclosure: I've been helping maintain the VS Code syntax highlighter for Rust recently, so I might be extra sensitive to highlighting inconsistencies.)

In documentation, we want to put more importance not on keywords but on items name (which you can click most of the time). You don't read documentation the same you read source code, hence why we have two different colour systems.

[Wilfred]

we want to put more importance not on keywords but on items name (which you can click most of the time)

Gotcha, that makes sense. So the goal is to distinguish examples (full highlighting) with prose that has clickable links?

I see new, Vec and Global are links here. I agree that highlighting pub const would be distracting.

That makes total sense: in the header here you absolutely want to be able click Global and Allocator. The surprising thing is the background colour on the item declaration, despite using the more minimal documentation highlighter.

I guess options might be:

(1) Add comment highlighting to the documentation highlighter. I think this would help users read the declaration, because it makes the rest of the declaration more prominent.

(2) Add a third highlighter, 'full highlighting but with links'. We could use it for declarations, and maybe even code snippets and highlighted source code like https://doc.rust-lang.org/src/alloc/vec/mod.rs.html too. Racket does this, and it makes the docs super easy to navigate: https://docs.racket-lang.org/guide/Lists__Iteration__and_Recursion.html#%28part._.Predefined_.List_.Loops%29

If these seem reasonable, I'm also willing to help if you have code pointers :)

[GuillaumeGomez]

This is a very nice write-up. Adding comment highlighting seems like the best choice (ie, dimming it out a bit to give it less importance?)

(2) Add a third highlighter, 'full highlighting but with links'. We could use it for declarations, and maybe even code snippets and highlighted source code like https://doc.rust-lang.org/src/alloc/vec/mod.rs.html too. Racket does this, and it makes the docs super easy to navigate: https://docs.racket-lang.org/guide/Lists__Iteration__and_Recursion.html#%28part._.Predefined_.List_.Loops%29

I'm not sure to fully understand what you're suggesting here. By code snippets you mean code in paragraph like this one? If so, we definitely don't want to add highlighting for that because we can't ever be sure what language this is and if the snippet is actually complete.

The code examples and source code pages are already highlighted, so not sure what you mean there either.

In any case, having highlighting for comments in item declarations is easy to do: wrap the text inside <span class="comment">text</span> and it's done, CSS is already done. Which gives:

The "tricky" part is to find where the comments are generated (a grep will find that easily) and to not forget any kind comments in the types declaration. It's the same files that are updated in this PR. Want to send a PR for that? :)

Closing this PR in any case.