Rollup merge of #108723 - notriddle:notriddle/where-clause, r=GuillaumeGomez

rustdoc: function signature search with traits in `where` clause

## Before

![image](https://user-images.githubusercontent.com/1593513/222873534-a640a72a-c654-4702-9f3b-175129d9591d.png)

## After

![image](https://user-images.githubusercontent.com/1593513/222873544-fdfc431d-2b65-4b56-bede-0302ea9f153a.png)

4 files changed, 55 insertions, 21 deletions

diff --git a/src/librustdoc/html/render/search_index.rs b/src/librustdoc/html/render/search_index.rs
index 090ea2cb157..e22ac6ec19b 100644
--- a/src/librustdoc/html/render/search_index.rs
+++ b/src/librustdoc/html/render/search_index.rs
@@ -7,9 +7,7 @@ use rustc_span::symbol::Symbol;
 use serde::ser::{Serialize, SerializeStruct, Serializer};
 
 use crate::clean;
-use crate::clean::types::{
-    FnRetTy, Function, GenericBound, Generics, ItemId, Type, WherePredicate,
-};
+use crate::clean::types::{FnRetTy, Function, Generics, ItemId, Type, WherePredicate};
 use crate::formats::cache::{Cache, OrphanImplItem};
 use crate::formats::item_type::ItemType;
 use crate::html::format::join_with_double_colon;
@@ -482,29 +480,23 @@ fn add_generics_and_bounds_as_types<'tcx, 'a>(
     if let Type::Generic(arg_s) = *arg {
         // First we check if the bounds are in a `where` predicate...
         if let Some(where_pred) = generics.where_predicates.iter().find(|g| match g {
-            WherePredicate::BoundPredicate { ty, .. } => ty.def_id(cache) == arg.def_id(cache),
+            WherePredicate::BoundPredicate { ty: Type::Generic(ty_s), .. } => *ty_s == arg_s,
             _ => false,
         }) {
             let mut ty_generics = Vec::new();
             let bounds = where_pred.get_bounds().unwrap_or_else(|| &[]);
             for bound in bounds.iter() {
-                if let GenericBound::TraitBound(poly_trait, _) = bound {
-                    for param_def in poly_trait.generic_params.iter() {
-                        match &param_def.kind {
-                            clean::GenericParamDefKind::Type { default: Some(ty), .. } => {
-                                add_generics_and_bounds_as_types(
-                                    self_,
-                                    generics,
-                                    ty,
-                                    tcx,
-                                    recurse + 1,
-                                    &mut ty_generics,
-                                    cache,
-                                )
-                            }
-                            _ => {}
-                        }
-                    }
+                if let Some(path) = bound.get_trait_path() {
+                    let ty = Type::Path { path };
+                    add_generics_and_bounds_as_types(
+                        self_,
+                        generics,
+                        &ty,
+                        tcx,
+                        recurse + 1,
+                        &mut ty_generics,
+                        cache,
+                    );
                 }
             }
             insert_ty(res, arg.clone(), ty_generics);
diff --git a/tests/rustdoc-js-std/option-type-signatures.js b/tests/rustdoc-js-std/option-type-signatures.js
new file mode 100644
index 00000000000..dee4819e81a
--- /dev/null
+++ b/tests/rustdoc-js-std/option-type-signatures.js
@@ -0,0 +1,7 @@
+const QUERY = 'option, fnonce -> option';
+
+const EXPECTED = {
+    'others': [
+        { 'path': 'std::option::Option', 'name': 'map' },
+    ],
+};
diff --git a/tests/rustdoc-js/where-clause.js b/tests/rustdoc-js/where-clause.js
new file mode 100644
index 00000000000..6cb42a455a3
--- /dev/null
+++ b/tests/rustdoc-js/where-clause.js
@@ -0,0 +1,19 @@
+const QUERY = ['trait<nested>', '-> trait<nested>', 't1, t2'];
+
+const EXPECTED = [
+    {
+        'in_args': [
+           { 'path': 'where_clause', 'name': 'abracadabra' },
+        ],
+    },
+    {
+        'others': [
+            { 'path': 'where_clause', 'name': 'alacazam' },
+        ],
+    },
+    {
+        'others': [
+            { 'path': 'where_clause', 'name': 'presto' },
+        ],
+    },
+];
diff --git a/tests/rustdoc-js/where-clause.rs b/tests/rustdoc-js/where-clause.rs
new file mode 100644
index 00000000000..808561feee2
--- /dev/null
+++ b/tests/rustdoc-js/where-clause.rs
@@ -0,0 +1,16 @@
+pub struct Nested;
+
+pub trait Trait<T> {
+    fn thank_you(x: T);
+}
+
+pub fn abracadabra<X>(_: X) where X: Trait<Nested> {}
+
+pub fn alacazam<X>() -> X where X: Trait<Nested> {}
+
+pub trait T1 {}
+pub trait T2<'a, T> {
+    fn please(_: &'a T);
+}
+
+pub fn presto<A, B>(_: A, _: B) where A: T1, B: for <'b> T2<'b, Nested> {}