Rollup merge of #98939 - GuillaumeGomez:rustdoc-disamb-impls, r=notriddle

rustdoc: Add more semantic information to impl IDs

Take over of #92745.

I fixed the last remaining issue for the links in the sidebar (mentioned by `@jsha)` and fixed the few links broken in the std/core docs.

cc `@camelid`
r? `@notriddle`

29 files changed, 102 insertions, 113 deletions

diff --git a/library/core/src/char/convert.rs b/library/core/src/char/convert.rs
index 778f06aeb63..7c5f82f5ea4 100644
--- a/library/core/src/char/convert.rs
+++ b/library/core/src/char/convert.rs
@@ -93,7 +93,7 @@ impl const From<char> for u128 {
 /// Map `char` with code point in U+0000..=U+00FF to byte in 0x00..=0xFF with same value, failing
 /// if the code point is greater than U+00FF.
 ///
-/// See [`impl From<u8> for char`](char#impl-From<u8>) for details on the encoding.
+/// See [`impl From<u8> for char`](char#impl-From<u8>-for-char) for details on the encoding.
 #[stable(feature = "u8_from_char", since = "1.59.0")]
 impl TryFrom<char> for u8 {
     type Error = TryFromCharError;
@@ -229,7 +229,7 @@ impl TryFrom<u32> for char {
 
 /// The error type returned when a conversion from [`prim@u32`] to [`prim@char`] fails.
 ///
-/// This `struct` is created by the [`char::try_from<u32>`](char#impl-TryFrom<u32>) method.
+/// This `struct` is created by the [`char::try_from<u32>`](char#impl-TryFrom<u32>-for-char) method.
 /// See its documentation for more.
 #[stable(feature = "try_from", since = "1.34.0")]
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
diff --git a/library/core/src/hash/mod.rs b/library/core/src/hash/mod.rs
index 1e4c22aea10..cf428e0b1cf 100644
--- a/library/core/src/hash/mod.rs
+++ b/library/core/src/hash/mod.rs
@@ -180,7 +180,7 @@ mod sip;
 /// [`HashMap`]: ../../std/collections/struct.HashMap.html
 /// [`HashSet`]: ../../std/collections/struct.HashSet.html
 /// [`hash`]: Hash::hash
-/// [impl]: ../../std/primitive.str.html#impl-Hash
+/// [impl]: ../../std/primitive.str.html#impl-Hash-for-str
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_diagnostic_item = "Hash"]
 pub trait Hash {
diff --git a/library/core/src/option.rs b/library/core/src/option.rs
index 28ea45ed235..bca73cb770f 100644
--- a/library/core/src/option.rs
+++ b/library/core/src/option.rs
@@ -389,7 +389,7 @@
 //! [`Option`] of a collection of each contained value of the original
 //! [`Option`] values, or [`None`] if any of the elements was [`None`].
 //!
-//! [impl-FromIterator]: Option#impl-FromIterator%3COption%3CA%3E%3E
+//! [impl-FromIterator]: Option#impl-FromIterator%3COption%3CA%3E%3E-for-Option%3CV%3E
 //!
 //! ```
 //! let v = [Some(2), Some(4), None, Some(8)];
@@ -405,8 +405,8 @@
 //! to provide the [`product`][Iterator::product] and
 //! [`sum`][Iterator::sum] methods.
 //!
-//! [impl-Product]: Option#impl-Product%3COption%3CU%3E%3E
-//! [impl-Sum]: Option#impl-Sum%3COption%3CU%3E%3E
+//! [impl-Product]: Option#impl-Product%3COption%3CU%3E%3E-for-Option%3CT%3E
+//! [impl-Sum]: Option#impl-Sum%3COption%3CU%3E%3E-for-Option%3CT%3E
 //!
 //! ```
 //! let v = [None, Some(1), Some(2), Some(3)];
diff --git a/library/core/src/result.rs b/library/core/src/result.rs
index c4dc34fff97..8a68cdf7d65 100644
--- a/library/core/src/result.rs
+++ b/library/core/src/result.rs
@@ -459,7 +459,7 @@
 //! [`Result`] of a collection of each contained value of the original
 //! [`Result`] values, or [`Err`] if any of the elements was [`Err`].
 //!
-//! [impl-FromIterator]: Result#impl-FromIterator%3CResult%3CA%2C%20E%3E%3E
+//! [impl-FromIterator]: Result#impl-FromIterator%3CResult%3CA%2C%20E%3E%3E-for-Result%3CV%2C%20E%3E
 //!
 //! ```
 //! let v = [Ok(2), Ok(4), Err("err!"), Ok(8)];
@@ -475,8 +475,8 @@
 //! to provide the [`product`][Iterator::product] and
 //! [`sum`][Iterator::sum] methods.
 //!
-//! [impl-Product]: Result#impl-Product%3CResult%3CU%2C%20E%3E%3E
-//! [impl-Sum]: Result#impl-Sum%3CResult%3CU%2C%20E%3E%3E
+//! [impl-Product]: Result#impl-Product%3CResult%3CU%2C%20E%3E%3E-for-Result%3CT%2C%20E%3E
+//! [impl-Sum]: Result#impl-Sum%3CResult%3CU%2C%20E%3E%3E-for-Result%3CT%2C%20E%3E
 //!
 //! ```
 //! let v = [Err("error!"), Ok(1), Ok(2), Ok(3), Err("foo")];
diff --git a/src/librustdoc/html/render/mod.rs b/src/librustdoc/html/render/mod.rs
index 548f6c3a987..e62a8bcfba6 100644
--- a/src/librustdoc/html/render/mod.rs
+++ b/src/librustdoc/html/render/mod.rs
@@ -634,7 +634,6 @@ fn render_impls(
                 &[],
                 ImplRenderingParameters {
                     show_def_docs: true,
-                    is_on_foreign_type: false,
                     show_default_items: true,
                     show_non_assoc_items: true,
                     toggle_open_by_default,
@@ -1071,7 +1070,6 @@ fn render_assoc_items_inner(
                 &[],
                 ImplRenderingParameters {
                     show_def_docs: true,
-                    is_on_foreign_type: false,
                     show_default_items: true,
                     show_non_assoc_items: true,
                     toggle_open_by_default: true,
@@ -1287,7 +1285,6 @@ fn notable_traits_decl(decl: &clean::FnDecl, cx: &Context<'_>) -> String {
 #[derive(Clone, Copy, Debug)]
 struct ImplRenderingParameters {
     show_def_docs: bool,
-    is_on_foreign_type: bool,
     show_default_items: bool,
     /// Whether or not to show methods.
     show_non_assoc_items: bool,
@@ -1603,7 +1600,6 @@ fn render_impl(
             parent,
             rendering_params.show_def_docs,
             use_absolute,
-            rendering_params.is_on_foreign_type,
             aliases,
         );
         if toggled {
@@ -1688,21 +1684,12 @@ pub(crate) fn render_impl_summary(
     containing_item: &clean::Item,
     show_def_docs: bool,
     use_absolute: Option<bool>,
-    is_on_foreign_type: bool,
     // This argument is used to reference same type with different paths to avoid duplication
     // in documentation pages for trait with automatic implementations like "Send" and "Sync".
     aliases: &[String],
 ) {
-    let id = cx.derive_id(match i.inner_impl().trait_ {
-        Some(ref t) => {
-            if is_on_foreign_type {
-                get_id_for_impl_on_foreign_type(&i.inner_impl().for_, t, cx)
-            } else {
-                format!("impl-{}", small_url_encode(format!("{:#}", t.print(cx))))
-            }
-        }
-        None => "impl".to_string(),
-    });
+    let id =
+        cx.derive_id(get_id_for_impl(&i.inner_impl().for_, i.inner_impl().trait_.as_ref(), cx));
     let aliases = if aliases.is_empty() {
         String::new()
     } else {
@@ -1986,21 +1973,18 @@ fn sidebar_assoc_items(cx: &Context<'_>, out: &mut Buffer, it: &clean::Item) {
                 let mut ret = impls
                     .iter()
                     .filter_map(|it| {
-                        if let Some(ref i) = it.inner_impl().trait_ {
-                            let i_display = format!("{:#}", i.print(cx));
-                            let out = Escape(&i_display);
-                            let encoded =
-                                id_map.derive(small_url_encode(format!("impl-{:#}", i.print(cx))));
-                            let prefix = match it.inner_impl().polarity {
-                                ty::ImplPolarity::Positive | ty::ImplPolarity::Reservation => "",
-                                ty::ImplPolarity::Negative => "!",
-                            };
-                            let generated =
-                                format!("<a href=\"#{}\">{}{}</a>", encoded, prefix, out);
-                            if links.insert(generated.clone()) { Some(generated) } else { None }
-                        } else {
-                            None
-                        }
+                        let trait_ = it.inner_impl().trait_.as_ref()?;
+                        let encoded =
+                            id_map.derive(get_id_for_impl(&it.inner_impl().for_, Some(trait_), cx));
+
+                        let i_display = format!("{:#}", trait_.print(cx));
+                        let out = Escape(&i_display);
+                        let prefix = match it.inner_impl().polarity {
+                            ty::ImplPolarity::Positive | ty::ImplPolarity::Reservation => "",
+                            ty::ImplPolarity::Negative => "!",
+                        };
+                        let generated = format!("<a href=\"#{}\">{}{}</a>", encoded, prefix, out);
+                        if links.insert(generated.clone()) { Some(generated) } else { None }
                     })
                     .collect::<Vec<String>>();
                 ret.sort();
@@ -2147,12 +2131,11 @@ fn sidebar_struct(cx: &Context<'_>, buf: &mut Buffer, it: &clean::Item, s: &clea
     }
 }
 
-fn get_id_for_impl_on_foreign_type(
-    for_: &clean::Type,
-    trait_: &clean::Path,
-    cx: &Context<'_>,
-) -> String {
-    small_url_encode(format!("impl-{:#}-for-{:#}", trait_.print(cx), for_.print(cx)))
+fn get_id_for_impl(for_: &clean::Type, trait_: Option<&clean::Path>, cx: &Context<'_>) -> String {
+    match trait_ {
+        Some(t) => small_url_encode(format!("impl-{:#}-for-{:#}", t.print(cx), for_.print(cx))),
+        None => small_url_encode(format!("impl-{:#}", for_.print(cx))),
+    }
 }
 
 fn extract_for_impl_name(item: &clean::Item, cx: &Context<'_>) -> Option<(String, String)> {
@@ -2161,10 +2144,7 @@ fn extract_for_impl_name(item: &clean::Item, cx: &Context<'_>) -> Option<(String
             i.trait_.as_ref().map(|trait_| {
                 // Alternative format produces no URLs,
                 // so this parameter does nothing.
-                (
-                    format!("{:#}", i.for_.print(cx)),
-                    get_id_for_impl_on_foreign_type(&i.for_, trait_, cx),
-                )
+                (format!("{:#}", i.for_.print(cx)), get_id_for_impl(&i.for_, Some(trait_), cx))
             })
         }
         _ => None,
diff --git a/src/librustdoc/html/render/print_item.rs b/src/librustdoc/html/render/print_item.rs
index 3525007baf3..86ee8e7acf6 100644
--- a/src/librustdoc/html/render/print_item.rs
+++ b/src/librustdoc/html/render/print_item.rs
@@ -864,7 +864,6 @@ fn item_trait(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &clean:
                     &[],
                     ImplRenderingParameters {
                         show_def_docs: false,
-                        is_on_foreign_type: true,
                         show_default_items: false,
                         show_non_assoc_items: true,
                         toggle_open_by_default: false,
@@ -1642,7 +1641,6 @@ fn render_implementor(
         aliases,
         ImplRenderingParameters {
             show_def_docs: false,
-            is_on_foreign_type: false,
             show_default_items: false,
             show_non_assoc_items: false,
             toggle_open_by_default: false,
diff --git a/src/test/rustdoc-gui/anchors.goml b/src/test/rustdoc-gui/anchors.goml
index ddfb23a4f86..84b8bbd1b32 100644
--- a/src/test/rustdoc-gui/anchors.goml
+++ b/src/test/rustdoc-gui/anchors.goml
@@ -28,7 +28,7 @@ move-cursor-to: "h2#implementations"
 assert-css: ("h2#implementations a.anchor", {"color": "rgb(0, 0, 0)"})
 
 // Same thing with the impl block title.
-move-cursor-to: "#impl"
-assert-css: ("#impl a.anchor", {"color": "rgb(0, 0, 0)"})
+move-cursor-to: "#impl-HeavilyDocumentedStruct"
+assert-css: ("#impl-HeavilyDocumentedStruct a.anchor", {"color": "rgb(0, 0, 0)"})
 
 assert-css: ("#title-for-struct-impl-item-doc", {"margin-left": "0px"})
diff --git a/src/test/rustdoc-gui/headers-color.goml b/src/test/rustdoc-gui/headers-color.goml
index cf9caa2d586..a47a9c8a14c 100644
--- a/src/test/rustdoc-gui/headers-color.goml
+++ b/src/test/rustdoc-gui/headers-color.goml
@@ -23,9 +23,9 @@ assert-css: (
     ALL,
 )
 
-goto: file://|DOC_PATH|/test_docs/struct.Foo.html#impl
+goto: file://|DOC_PATH|/test_docs/struct.Foo.html#impl-Foo
 assert-css: (
-    "#impl",
+    "#impl-Foo",
     {"color": "rgb(197, 197, 197)", "background-color": "rgba(255, 236, 164, 0.06)"},
 )
 
@@ -62,9 +62,9 @@ assert-css: (
     ALL,
 )
 
-goto: file://|DOC_PATH|/test_docs/struct.Foo.html#impl
+goto: file://|DOC_PATH|/test_docs/struct.Foo.html#impl-Foo
 assert-css: (
-    "#impl",
+    "#impl-Foo",
     {"color": "rgb(221, 221, 221)", "background-color": "rgb(73, 74, 61)"},
 )
 
@@ -99,8 +99,8 @@ assert-css: (
     ALL,
 )
 
-goto: file://|DOC_PATH|/test_docs/struct.Foo.html#impl
-assert-css: ("#impl", {"color": "rgb(0, 0, 0)", "background-color": "rgb(253, 255, 211)"})
+goto: file://|DOC_PATH|/test_docs/struct.Foo.html#impl-Foo
+assert-css: ("#impl-Foo", {"color": "rgb(0, 0, 0)", "background-color": "rgb(253, 255, 211)"})
 
 goto: file://|DOC_PATH|/test_docs/struct.Foo.html#method.must_use
 assert-css: (
diff --git a/src/test/rustdoc-gui/headings.goml b/src/test/rustdoc-gui/headings.goml
index 67e97eb686e..cc3dd61e99a 100644
--- a/src/test/rustdoc-gui/headings.goml
+++ b/src/test/rustdoc-gui/headings.goml
@@ -32,8 +32,8 @@ assert-css: ("h4#sub-heading-for-field", {"border-bottom-width": "0px"})
 assert-css: ("h2#implementations", {"font-size": "22px"})
 assert-css: ("h2#implementations", {"border-bottom-width": "1px"})
 
-assert-css: ("#impl > h3.code-header", {"font-size": "18px"})
-assert-css: ("#impl > h3.code-header", {"border-bottom-width": "0px"})
+assert-css: ("#impl-HeavilyDocumentedStruct > h3.code-header", {"font-size": "18px"})
+assert-css: ("#impl-HeavilyDocumentedStruct > h3.code-header", {"border-bottom-width": "0px"})
 assert-css: ("#method\.do_nothing > h4.code-header", {"font-size": "16px"})
 assert-css: ("#method\.do_nothing > h4.code-header", {"border-bottom-width": "0px"})
 
@@ -87,8 +87,8 @@ assert-css: ("h6#structy-prose-sub-heading", {"border-bottom-width": "0px"})
 assert-css: ("h2#implementations", {"font-size": "22px"})
 assert-css: ("h2#implementations", {"border-bottom-width": "1px"})
 
-assert-css: ("#impl > h3.code-header", {"font-size": "18px"})
-assert-css: ("#impl > h3.code-header", {"border-bottom-width": "0px"})
+assert-css: ("#impl-HeavilyDocumentedEnum > h3.code-header", {"font-size": "18px"})
+assert-css: ("#impl-HeavilyDocumentedEnum > h3.code-header", {"border-bottom-width": "0px"})
 assert-css: ("#method\.do_nothing > h4.code-header", {"font-size": "16px"})
 assert-css: ("#method\.do_nothing > h4.code-header", {"border-bottom-width": "0px"})
 
@@ -129,8 +129,8 @@ assert-css: ("h4#sub-heading-for-union-variant", {"border-bottom-width": "0px"})
 assert-css: ("h2#implementations", {"font-size": "22px"})
 assert-css: ("h2#implementations", {"border-bottom-width": "1px"})
 
-assert-css: ("#impl > h3.code-header", {"font-size": "18px"})
-assert-css: ("#impl > h3.code-header", {"border-bottom-width": "0px"})
+assert-css: ("#impl-HeavilyDocumentedUnion > h3.code-header", {"font-size": "18px"})
+assert-css: ("#impl-HeavilyDocumentedUnion > h3.code-header", {"border-bottom-width": "0px"})
 assert-css: ("h4#title-for-union-impl-doc", {"font-size": "16px"})
 assert-css: ("h4#title-for-union-impl-doc", {"border-bottom-width": "0px"})
 assert-css: ("h5#sub-heading-for-union-impl-doc", {"font-size": "16px"})
diff --git a/src/test/rustdoc-gui/implementors.goml b/src/test/rustdoc-gui/implementors.goml
index f29613f78b1..666a6e1253d 100644
--- a/src/test/rustdoc-gui/implementors.goml
+++ b/src/test/rustdoc-gui/implementors.goml
@@ -6,8 +6,8 @@ assert: "#implementors-list"
 assert-count: ("#implementors-list .impl", 2)
 // Now we check that both implementors have an anchor, an ID and a similar DOM.
 assert: ("#implementors-list .impl:nth-child(1) > a.anchor")
-assert-attribute: ("#implementors-list .impl:nth-child(1)", {"id": "impl-Whatever"})
-assert-attribute: ("#implementors-list .impl:nth-child(1) > a.anchor", {"href": "#impl-Whatever"})
+assert-attribute: ("#implementors-list .impl:nth-child(1)", {"id": "impl-Whatever-for-Struct"})
+assert-attribute: ("#implementors-list .impl:nth-child(1) > a.anchor", {"href": "#impl-Whatever-for-Struct"})
 assert: "#implementors-list .impl:nth-child(1) > .code-header.in-band"
 
 assert: ("#implementors-list .impl:nth-child(2) > a.anchor")
@@ -16,8 +16,16 @@ assert-attribute: ("#implementors-list .impl:nth-child(2) > a.anchor", {"href":
 assert: "#implementors-list .impl:nth-child(2) > .code-header.in-band"
 
 goto: file://|DOC_PATH|/test_docs/struct.HasEmptyTraits.html
-compare-elements-position-near-false: ("#impl-EmptyTrait1", "#impl-EmptyTrait2", {"y": 30})
-compare-elements-position-near: ("#impl-EmptyTrait3 h3", "#impl-EmptyTrait3 .item-info", {"y": 30})
+compare-elements-position-near-false: (
+    "#impl-EmptyTrait1-for-HasEmptyTraits",
+    "#impl-EmptyTrait2-for-HasEmptyTraits",
+    {"y": 30},
+)
+compare-elements-position-near: (
+    "#impl-EmptyTrait3-for-HasEmptyTraits h3",
+    "#impl-EmptyTrait3-for-HasEmptyTraits .item-info",
+    {"y": 30},
+)
 
 // Now check that re-exports work correctly.
 // There should be exactly one impl shown on both of these pages.
diff --git a/src/test/rustdoc-gui/item-info-overflow.goml b/src/test/rustdoc-gui/item-info-overflow.goml
index d6385e2acb8..b7095a3c532 100644
--- a/src/test/rustdoc-gui/item-info-overflow.goml
+++ b/src/test/rustdoc-gui/item-info-overflow.goml
@@ -15,14 +15,17 @@ assert-text: (
 // Checking the "item-info" on an impl block as well:
 goto: file://|DOC_PATH|/lib2/struct.LongItemInfo2.html
 compare-elements-property: (
-    "#impl-SimpleTrait .item-info",
-    "#impl-SimpleTrait + .docblock",
+    "#impl-SimpleTrait-for-LongItemInfo2 .item-info",
+    "#impl-SimpleTrait-for-LongItemInfo2 + .docblock",
     ["scrollWidth"],
 )
-assert-property: ("#impl-SimpleTrait .item-info", {"scrollWidth": "866"})
+assert-property: (
+    "#impl-SimpleTrait-for-LongItemInfo2 .item-info",
+    {"scrollWidth": "866"},
+)
 // Just to be sure we're comparing the correct "item-info":
 assert-text: (
-    "#impl-SimpleTrait .item-info",
+    "#impl-SimpleTrait-for-LongItemInfo2 .item-info",
     "Available on Android or Linux or Emscripten or DragonFly BSD",
     STARTS_WITH,
 )
diff --git a/src/test/rustdoc-gui/toggle-click-deadspace.goml b/src/test/rustdoc-gui/toggle-click-deadspace.goml
index 7bc3c563157..4a328c9f9e0 100644
--- a/src/test/rustdoc-gui/toggle-click-deadspace.goml
+++ b/src/test/rustdoc-gui/toggle-click-deadspace.goml
@@ -8,5 +8,5 @@ click: ".impl-items .rustdoc-toggle summary::before" // This is the position of
 assert-attribute-false: (".impl-items .rustdoc-toggle", {"open": ""})
 
 // Click the "Trait" part of "impl Trait" and verify it navigates.
-click: "#impl-Trait h3 a:first-of-type"
+click: "#impl-Trait-for-Foo h3 a:first-of-type"
 assert-text: (".fqn .in-band", "Trait lib2::Trait")
diff --git a/src/test/rustdoc/auto-trait-not-send.rs b/src/test/rustdoc/auto-trait-not-send.rs
index 7bd4f6dbd8c..661d905ab63 100644
--- a/src/test/rustdoc/auto-trait-not-send.rs
+++ b/src/test/rustdoc/auto-trait-not-send.rs
@@ -1,8 +1,8 @@
 #![crate_name = "foo"]
 
 // @has 'foo/struct.Foo.html'
-// @has - '//*[@id="impl-Send"]' 'impl !Send for Foo'
-// @has - '//*[@id="impl-Sync"]' 'impl !Sync for Foo'
+// @has - '//*[@id="impl-Send-for-Foo"]' 'impl !Send for Foo'
+// @has - '//*[@id="impl-Sync-for-Foo"]' 'impl !Sync for Foo'
 pub struct Foo(*const i8);
 pub trait Whatever: Send {}
 impl<T: Send + ?Sized> Whatever for T {}
diff --git a/src/test/rustdoc/blanket-reexport-item.rs b/src/test/rustdoc/blanket-reexport-item.rs
index 4c686730b11..676d656dabf 100644
--- a/src/test/rustdoc/blanket-reexport-item.rs
+++ b/src/test/rustdoc/blanket-reexport-item.rs
@@ -1,6 +1,6 @@
 #![crate_name = "foo"]
 
-// @has foo/struct.S.html '//*[@id="impl-Into%3CU%3E"]//h3[@class="code-header in-band"]' 'impl<T, U> Into<U> for T'
+// @has foo/struct.S.html '//*[@id="impl-Into%3CU%3E-for-S"]//h3[@class="code-header in-band"]' 'impl<T, U> Into<U> for T'
 pub struct S2 {}
 mod m {
     pub struct S {}
diff --git a/src/test/rustdoc/const-generics/const-generics-docs.rs b/src/test/rustdoc/const-generics/const-generics-docs.rs
index fc3a2731089..61af7de4794 100644
--- a/src/test/rustdoc/const-generics/const-generics-docs.rs
+++ b/src/test/rustdoc/const-generics/const-generics-docs.rs
@@ -36,7 +36,7 @@ pub struct Foo<const N: usize> where u8: Trait<N>;
 // @has foo/struct.Bar.html '//pre[@class="rust struct"]' 'pub struct Bar<T, const N: usize>(_)'
 pub struct Bar<T, const N: usize>([T; N]);
 
-// @has foo/struct.Foo.html '//*[@id="impl"]/h3[@class="code-header in-band"]' 'impl<const M: usize> Foo<M> where u8: Trait<M>'
+// @has foo/struct.Foo.html '//*[@id="impl-Foo%3CM%3E"]/h3[@class="code-header in-band"]' 'impl<const M: usize> Foo<M> where u8: Trait<M>'
 impl<const M: usize> Foo<M> where u8: Trait<M> {
     // @has - '//*[@id="associatedconstant.FOO_ASSOC"]' 'pub const FOO_ASSOC: usize'
     pub const FOO_ASSOC: usize = M + 13;
@@ -47,7 +47,7 @@ impl<const M: usize> Foo<M> where u8: Trait<M> {
     }
 }
 
-// @has foo/struct.Bar.html '//*[@id="impl"]/h3[@class="code-header in-band"]' 'impl<const M: usize> Bar<u8, M>'
+// @has foo/struct.Bar.html '//*[@id="impl-Bar%3Cu8%2C%20M%3E"]/h3[@class="code-header in-band"]' 'impl<const M: usize> Bar<u8, M>'
 impl<const M: usize> Bar<u8, M> {
     // @has - '//*[@id="method.hey"]' \
     //      'pub fn hey<const N: usize>(&self) -> Foo<N> where u8: Trait<N>'
diff --git a/src/test/rustdoc/const-generics/const-impl.rs b/src/test/rustdoc/const-generics/const-impl.rs
index a3ef084165a..f1181d54ac8 100644
--- a/src/test/rustdoc/const-generics/const-impl.rs
+++ b/src/test/rustdoc/const-generics/const-impl.rs
@@ -9,20 +9,20 @@ pub enum Order {
 }
 
 // @has foo/struct.VSet.html '//pre[@class="rust struct"]' 'pub struct VSet<T, const ORDER: Order>'
-// @has foo/struct.VSet.html '//*[@id="impl-Send"]/h3[@class="code-header in-band"]' 'impl<T, const ORDER: Order> Send for VSet<T, ORDER>'
-// @has foo/struct.VSet.html '//*[@id="impl-Sync"]/h3[@class="code-header in-band"]' 'impl<T, const ORDER: Order> Sync for VSet<T, ORDER>'
+// @has foo/struct.VSet.html '//*[@id="impl-Send-for-VSet%3CT%2C%20ORDER%3E"]/h3[@class="code-header in-band"]' 'impl<T, const ORDER: Order> Send for VSet<T, ORDER>'
+// @has foo/struct.VSet.html '//*[@id="impl-Sync-for-VSet%3CT%2C%20ORDER%3E"]/h3[@class="code-header in-band"]' 'impl<T, const ORDER: Order> Sync for VSet<T, ORDER>'
 pub struct VSet<T, const ORDER: Order> {
     inner: Vec<T>,
 }
 
-// @has foo/struct.VSet.html '//*[@id="impl"]/h3[@class="code-header in-band"]' 'impl<T> VSet<T, { Order::Sorted }>'
+// @has foo/struct.VSet.html '//*[@id="impl-VSet%3CT%2C%20{%20Order%3A%3ASorted%20}%3E"]/h3[@class="code-header in-band"]' 'impl<T> VSet<T, { Order::Sorted }>'
 impl<T> VSet<T, { Order::Sorted }> {
     pub fn new() -> Self {
         Self { inner: Vec::new() }
     }
 }
 
-// @has foo/struct.VSet.html '//*[@id="impl-1"]/h3[@class="code-header in-band"]' 'impl<T> VSet<T, { Order::Unsorted }>'
+// @has foo/struct.VSet.html '//*[@id="impl-VSet%3CT%2C%20{%20Order%3A%3AUnsorted%20}%3E"]/h3[@class="code-header in-band"]' 'impl<T> VSet<T, { Order::Unsorted }>'
 impl<T> VSet<T, { Order::Unsorted }> {
     pub fn new() -> Self {
         Self { inner: Vec::new() }
@@ -31,7 +31,7 @@ impl<T> VSet<T, { Order::Unsorted }> {
 
 pub struct Escape<const S: &'static str>;
 
-// @has foo/struct.Escape.html '//*[@id="impl"]/h3[@class="code-header in-band"]' 'impl Escape<r#"<script>alert("Escape");</script>"#>'
+// @has foo/struct.Escape.html '//*[@id="impl-Escape%3Cr#%22%3Cscript%3Ealert(%22Escape%22)%3B%3C/script%3E%22#%3E"]/h3[@class="code-header in-band"]' 'impl Escape<r#"<script>alert("Escape");</script>"#>'
 impl Escape<r#"<script>alert("Escape");</script>"#> {
     pub fn f() {}
 }
diff --git a/src/test/rustdoc/double-quote-escape.rs b/src/test/rustdoc/double-quote-escape.rs
index b7bbf140cfd..350c897417d 100644
--- a/src/test/rustdoc/double-quote-escape.rs
+++ b/src/test/rustdoc/double-quote-escape.rs
@@ -1,6 +1,5 @@
 #![crate_name = "foo"]
 
-
 pub trait Foo<T> {
     fn foo() {}
 }
@@ -8,5 +7,5 @@ pub trait Foo<T> {
 pub struct Bar;
 
 // @has foo/struct.Bar.html
-// @has - '//*[@class="sidebar-elems"]//section//a[@href="#impl-Foo%3Cunsafe%20extern%20%22C%22%20fn()%3E"]' 'Foo<unsafe extern "C" fn()>'
+// @has - '//*[@class="sidebar-elems"]//section//a[@href="#impl-Foo%3Cunsafe%20extern%20%22C%22%20fn()%3E-for-Bar"]' 'Foo<unsafe extern "C" fn()>'
 impl Foo<unsafe extern "C" fn()> for Bar {}
diff --git a/src/test/rustdoc/empty-impls.rs b/src/test/rustdoc/empty-impls.rs
index d18f404212f..83902d6f7ab 100644
--- a/src/test/rustdoc/empty-impls.rs
+++ b/src/test/rustdoc/empty-impls.rs
@@ -1,19 +1,19 @@
 #![crate_name = "foo"]
 
 // @has foo/struct.Foo.html
-// @has - '//div[@id="synthetic-implementations-list"]/*[@id="impl-Send"]' 'impl Send for Foo'
+// @has - '//div[@id="synthetic-implementations-list"]/*[@id="impl-Send-for-Foo"]' 'impl Send for Foo'
 pub struct Foo;
 
 pub trait EmptyTrait {}
 
-// @has - '//div[@id="trait-implementations-list"]/*[@id="impl-EmptyTrait"]' 'impl EmptyTrait for Foo'
+// @has - '//div[@id="trait-implementations-list"]/*[@id="impl-EmptyTrait-for-Foo"]' 'impl EmptyTrait for Foo'
 impl EmptyTrait for Foo {}
 
 pub trait NotEmpty {
     fn foo(&self);
 }
 
-// @has - '//div[@id="trait-implementations-list"]/details/summary/*[@id="impl-NotEmpty"]' 'impl NotEmpty for Foo'
+// @has - '//div[@id="trait-implementations-list"]/details/summary/*[@id="impl-NotEmpty-for-Foo"]' 'impl NotEmpty for Foo'
 impl NotEmpty for Foo {
     fn foo(&self) {}
 }
diff --git a/src/test/rustdoc/generic-impl.rs b/src/test/rustdoc/generic-impl.rs
index 1268c9587f8..c6beed70abe 100644
--- a/src/test/rustdoc/generic-impl.rs
+++ b/src/test/rustdoc/generic-impl.rs
@@ -2,12 +2,12 @@
 
 use std::fmt;
 
-// @!has foo/struct.Bar.html '//*[@id="impl-ToString"]//h3[@class="code-header in-band"]' 'impl<T> ToString for T'
+// @!has foo/struct.Bar.html '//*[@id="impl-ToString-for-Bar"]' ''
 pub struct Bar;
 
-// @has foo/struct.Foo.html '//*[@id="impl-ToString"]//h3[@class="code-header in-band"]' 'impl<T> ToString for T'
+// @has foo/struct.Foo.html '//*[@id="impl-ToString-for-Foo"]//h3[@class="code-header in-band"]' 'impl<T> ToString for T'
 pub struct Foo;
-// @has foo/struct.Foo.html '//*[@class="sidebar-elems"]//section//a[@href="#impl-ToString"]' 'ToString'
+// @has foo/struct.Foo.html '//*[@class="sidebar-elems"]//section//a[@href="#impl-ToString-for-Foo"]' 'ToString'
 
 impl fmt::Display for Foo {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
diff --git a/src/test/rustdoc/hidden-trait-struct-impls.rs b/src/test/rustdoc/hidden-trait-struct-impls.rs
index 1be956ef393..cc3f6337719 100644
--- a/src/test/rustdoc/hidden-trait-struct-impls.rs
+++ b/src/test/rustdoc/hidden-trait-struct-impls.rs
@@ -11,11 +11,11 @@ pub struct Bar;
 
 struct Hidden;
 
-// @!has foo/struct.Bar.html '//*[@id="impl-Foo"]' 'impl Foo for Bar'
+// @!has foo/struct.Bar.html '//*[@id="impl-Foo-for-Bar"]' 'impl Foo for Bar'
 impl Foo for Bar {}
-// @!has foo/struct.Bar.html '//*[@id="impl-Dark"]' 'impl Dark for Bar'
+// @!has foo/struct.Bar.html '//*[@id="impl-Dark-for-Bar"]' 'impl Dark for Bar'
 impl Dark for Bar {}
-// @has foo/struct.Bar.html '//*[@id="impl-Bam"]' 'impl Bam for Bar'
+// @has foo/struct.Bar.html '//*[@id="impl-Bam-for-Bar"]' 'impl Bam for Bar'
 // @has foo/trait.Bam.html '//*[@id="implementors-list"]' 'impl Bam for Bar'
 impl Bam for Bar {}
 // @!has foo/trait.Bam.html '//*[@id="implementors-list"]' 'impl Bam for Hidden'
diff --git a/src/test/rustdoc/impl-box.rs b/src/test/rustdoc/impl-box.rs
index a371db135cf..592b6c98587 100644
--- a/src/test/rustdoc/impl-box.rs
+++ b/src/test/rustdoc/impl-box.rs
@@ -5,7 +5,7 @@
 pub struct MyType;
 
 // @has 'impl_box/struct.MyType.html'
-// @has '-' '//*[@id="impl-Iterator"]' 'impl Iterator for Box<MyType>'
+// @has '-' '//*[@id="impl-Iterator-for-Box%3CMyType%3E"]' 'impl Iterator for Box<MyType>'
 
 impl Iterator for Box<MyType> {
     type Item = ();
diff --git a/src/test/rustdoc/issue-29503.rs b/src/test/rustdoc/issue-29503.rs
index 490d7e51e32..635c3175f81 100644
--- a/src/test/rustdoc/issue-29503.rs
+++ b/src/test/rustdoc/issue-29503.rs
@@ -5,7 +5,7 @@ pub trait MyTrait {
     fn my_string(&self) -> String;
 }
 
-// @has - "//div[@id='implementors-list']//*[@id='impl-MyTrait']//h3[@class='code-header in-band']" "impl<T> MyTrait for T where T: Debug"
+// @has - "//div[@id='implementors-list']//*[@id='impl-MyTrait-for-T']//h3[@class='code-header in-band']" "impl<T> MyTrait for T where T: Debug"
 impl<T> MyTrait for T
 where
     T: fmt::Debug,
diff --git a/src/test/rustdoc/issue-75588.rs b/src/test/rustdoc/issue-75588.rs
index a8cb16ec34c..ac97b94fb35 100644
--- a/src/test/rustdoc/issue-75588.rs
+++ b/src/test/rustdoc/issue-75588.rs
@@ -13,5 +13,5 @@ extern crate real_gimli;
 // @!has foo/trait.Deref.html '//*[@id="impl-Deref-for-EndianSlice"]//h3[@class="code-header in-band"]' 'impl Deref for EndianSlice'
 pub use realcore::Deref;
 
-// @has foo/trait.Join.html '//*[@id="impl-Join"]//h3[@class="code-header in-band"]' 'impl Join for Foo'
+// @has foo/trait.Join.html '//*[@id="impl-Join-for-Foo"]//h3[@class="code-header in-band"]' 'impl Join for Foo'
 pub use realcore::Join;
diff --git a/src/test/rustdoc/issue-78701.rs b/src/test/rustdoc/issue-78701.rs
index 796d553fac4..e3e46468f38 100644
--- a/src/test/rustdoc/issue-78701.rs
+++ b/src/test/rustdoc/issue-78701.rs
@@ -5,8 +5,8 @@
 // the ID is correctly derived.
 
 // @has 'foo/struct.AnotherStruct.html'
-// @count - '//*[@class="sidebar"]//a[@href="#impl-AnAmazingTrait"]' 1
-// @count - '//*[@class="sidebar"]//a[@href="#impl-AnAmazingTrait-1"]' 1
+// @count - '//*[@class="sidebar"]//a[@href="#impl-AnAmazingTrait-for-AnotherStruct%3C()%3E"]' 1
+// @count - '//*[@class="sidebar"]//a[@href="#impl-AnAmazingTrait-for-AnotherStruct%3CT%3E"]' 1
 
 pub trait Something {}
 
diff --git a/src/test/rustdoc/primitive/primitive-generic-impl.rs b/src/test/rustdoc/primitive/primitive-generic-impl.rs
index 28adff84c70..eebb2cf5a35 100644
--- a/src/test/rustdoc/primitive/primitive-generic-impl.rs
+++ b/src/test/rustdoc/primitive/primitive-generic-impl.rs
@@ -1,7 +1,7 @@
 #![feature(rustdoc_internals)]
 #![crate_name = "foo"]
 
-// @has foo/primitive.i32.html '//*[@id="impl-ToString"]//h3[@class="code-header in-band"]' 'impl<T> ToString for T'
+// @has foo/primitive.i32.html '//*[@id="impl-ToString-for-i32"]//h3[@class="code-header in-band"]' 'impl<T> ToString for T'
 
 #[doc(primitive = "i32")]
 /// Some useless docs, wouhou!
diff --git a/src/test/rustdoc/rfc-2632-const-trait-impl.rs b/src/test/rustdoc/rfc-2632-const-trait-impl.rs
index ec70a69ff10..f3e211e3017 100644
--- a/src/test/rustdoc/rfc-2632-const-trait-impl.rs
+++ b/src/test/rustdoc/rfc-2632-const-trait-impl.rs
@@ -29,10 +29,11 @@ pub trait Tr<T> {
     }
 }
 
-// @!has - '//section[@id="impl-Tr%3CT%3E"]/h3[@class="code-header in-band"]' '~const'
-// @has - '//section[@id="impl-Tr%3CT%3E"]/h3[@class="code-header in-band"]/a[@class="trait"]' 'Clone'
-// @!has - '//section[@id="impl-Tr%3CT%3E"]/h3[@class="code-header in-band"]/span[@class="where"]' '~const'
-// @has - '//section[@id="impl-Tr%3CT%3E"]/h3[@class="code-header in-band"]/span[@class="where fmt-newline"]' ': Clone'
+// @has - '//section[@id="impl-Tr%3CT%3E-for-T"]' ''
+// @!has - '//section[@id="impl-Tr%3CT%3E-for-T"]/h3[@class="code-header in-band"]' '~const'
+// @has - '//section[@id="impl-Tr%3CT%3E-for-T"]/h3[@class="code-header in-band"]/a[@class="trait"]' 'Clone'
+// @!has - '//section[@id="impl-Tr%3CT%3E-for-T"]/h3[@class="code-header in-band"]/span[@class="where"]' '~const'
+// @has - '//section[@id="impl-Tr%3CT%3E-for-T"]/h3[@class="code-header in-band"]/span[@class="where fmt-newline"]' ': Clone'
 impl<T: ~const Clone + ~const Destruct> const Tr<T> for T
 where
     Option<T>: ~const Clone + ~const Destruct,
diff --git a/src/test/rustdoc/sized_trait.rs b/src/test/rustdoc/sized_trait.rs
index 252a8126036..9d2c1967757 100644
--- a/src/test/rustdoc/sized_trait.rs
+++ b/src/test/rustdoc/sized_trait.rs
@@ -11,7 +11,7 @@ pub struct Bar {
 pub struct Foo<T: ?Sized>(T);
 
 // @has foo/struct.Unsized.html
-// @has - '//*[@id="impl-Sized"]//h3[@class="code-header in-band"]' 'impl !Sized for Unsized'
+// @has - '//*[@id="impl-Sized-for-Unsized"]//h3[@class="code-header in-band"]' 'impl !Sized for Unsized'
 pub struct Unsized {
     data: [u8],
 }
diff --git a/src/test/rustdoc/src-links-auto-impls.rs b/src/test/rustdoc/src-links-auto-impls.rs
index 0f461a1185b..69be9aa8d5f 100644
--- a/src/test/rustdoc/src-links-auto-impls.rs
+++ b/src/test/rustdoc/src-links-auto-impls.rs
@@ -1,12 +1,12 @@
 #![crate_name = "foo"]
 
 // @has foo/struct.Unsized.html
-// @has - '//*[@id="impl-Sized"]/h3[@class="code-header in-band"]' 'impl !Sized for Unsized'
-// @!has - '//*[@id="impl-Sized"]//a[@class="srclink"]' 'source'
-// @has - '//*[@id="impl-Sync"]/h3[@class="code-header in-band"]' 'impl Sync for Unsized'
-// @!has - '//*[@id="impl-Sync"]//a[@class="srclink"]' 'source'
-// @has - '//*[@id="impl-Any"]/h3[@class="code-header in-band"]' 'impl<T> Any for T'
-// @has - '//*[@id="impl-Any"]//a[@class="srclink"]' 'source'
+// @has - '//*[@id="impl-Sized-for-Unsized"]/h3[@class="code-header in-band"]' 'impl !Sized for Unsized'
+// @!has - '//*[@id="impl-Sized-for-Unsized"]//a[@class="srclink"]' 'source'
+// @has - '//*[@id="impl-Sync-for-Unsized"]/h3[@class="code-header in-band"]' 'impl Sync for Unsized'
+// @!has - '//*[@id="impl-Sync-for-Unsized"]//a[@class="srclink"]' 'source'
+// @has - '//*[@id="impl-Any-for-Unsized"]/h3[@class="code-header in-band"]' 'impl<T> Any for T'
+// @has - '//*[@id="impl-Any-for-Unsized"]//a[@class="srclink"]' 'source'
 pub struct Unsized {
     data: [u8],
 }
diff --git a/src/test/rustdoc/trait-impl.rs b/src/test/rustdoc/trait-impl.rs
index 05ccc074bf1..4f7e2dfe3b9 100644
--- a/src/test/rustdoc/trait-impl.rs
+++ b/src/test/rustdoc/trait-impl.rs
@@ -43,5 +43,5 @@ impl Trait for Struct {
     // @!has - '//*[@id="method.d"]/../../div[@class="docblock"]/p/em'
     fn d() {}
 
-    // @has - '//*[@id="impl-Trait"]/h3//a/@href' 'trait.Trait.html'
+    // @has - '//*[@id="impl-Trait-for-Struct"]/h3//a/@href' 'trait.Trait.html'
 }