rustdoc-search: add support for associated types

src/librustdoc/clean/types.rs

@@ -1651,6 +1651,13 @@ impl Type {
         }
     }
 
+    pub(crate) fn generic_args(&self) -> Option<&GenericArgs> {
+        match self {
+            Type::Path { path, .. } => path.generic_args(),
+            _ => None,
+        }
+    }
+
     pub(crate) fn generics(&self) -> Option<Vec<&Type>> {
         match self {
             Type::Path { path, .. } => path.generics(),
@@ -2191,6 +2198,10 @@ impl Path {
         }
     }
 
+    pub(crate) fn generic_args(&self) -> Option<&GenericArgs> {
+        self.segments.last().map(|seg| &seg.args)
+    }
+
     pub(crate) fn generics(&self) -> Option<Vec<&Type>> {
         self.segments.last().and_then(|seg| {
             if let GenericArgs::AngleBracketed { ref args, .. } = seg.args {
@@ -2232,6 +2243,39 @@ impl GenericArgs {
             GenericArgs::Parenthesized { inputs, output } => inputs.is_empty() && output.is_none(),
         }
     }
+    pub(crate) fn bindings<'a>(&'a self) -> Box<dyn Iterator<Item = TypeBinding> + 'a> {
+        match self {
+            &GenericArgs::AngleBracketed { ref bindings, .. } => Box::new(bindings.iter().cloned()),
+            &GenericArgs::Parenthesized { ref output, .. } => Box::new(
+                output
+                    .as_ref()
+                    .map(|ty| TypeBinding {
+                        assoc: PathSegment {
+                            name: sym::Output,
+                            args: GenericArgs::AngleBracketed {
+                                args: Vec::new().into_boxed_slice(),
+                                bindings: ThinVec::new(),
+                            },
+                        },
+                        kind: TypeBindingKind::Equality { term: Term::Type((**ty).clone()) },
+                    })
+                    .into_iter(),
+            ),
+        }
+    }
+}
+
+impl<'a> IntoIterator for &'a GenericArgs {
+    type IntoIter = Box<dyn Iterator<Item = GenericArg> + 'a>;
+    type Item = GenericArg;
+    fn into_iter(self) -> Self::IntoIter {
+        match self {
+            &GenericArgs::AngleBracketed { ref args, .. } => Box::new(args.iter().cloned()),
+            &GenericArgs::Parenthesized { ref inputs, .. } => {
+                Box::new(inputs.iter().cloned().map(GenericArg::Type))
+            }
+        }
+    }
 }
 
 #[derive(Clone, PartialEq, Eq, Debug, Hash)]

src/librustdoc/formats/cache.rs

@@ -369,6 +369,7 @@ impl<'a, 'tcx> DocFolder for CacheBuilder<'a, 'tcx> {
                                 &item,
                                 self.tcx,
                                 clean_impl_generics(self.cache.parent_stack.last()).as_ref(),
+                                parent,
                                 self.cache,
                             ),
                             aliases: item.attrs.get_doc_aliases(),

src/librustdoc/formats/item_type.rs

@@ -49,6 +49,8 @@ pub(crate) enum ItemType {
     ProcAttribute = 23,
     ProcDerive = 24,
     TraitAlias = 25,
+    // This number is reserved for use in JavaScript
+    // Generic = 26,
 }
 
 impl Serialize for ItemType {

src/librustdoc/html/render/mod.rs

@@ -113,6 +113,7 @@ pub(crate) struct IndexItem {
 pub(crate) struct RenderType {
     id: Option<RenderTypeId>,
     generics: Option<Vec<RenderType>>,
+    bindings: Option<Vec<(RenderTypeId, Vec<RenderType>)>>,
 }
 
 impl Serialize for RenderType {
@@ -129,24 +130,47 @@ impl Serialize for RenderType {
             Some(RenderTypeId::Index(idx)) => *idx,
             _ => panic!("must convert render types to indexes before serializing"),
         };
-        if let Some(generics) = &self.generics {
+        if self.generics.is_some() || self.bindings.is_some() {
             let mut seq = serializer.serialize_seq(None)?;
             seq.serialize_element(&id)?;
-            seq.serialize_element(generics)?;
+            seq.serialize_element(self.generics.as_ref().map(Vec::as_slice).unwrap_or_default())?;
+            if self.bindings.is_some() {
+                seq.serialize_element(
+                    self.bindings.as_ref().map(Vec::as_slice).unwrap_or_default(),
+                )?;
+            }
             seq.end()
         } else {
             id.serialize(serializer)
         }
     }
 }
 
-#[derive(Clone, Debug)]
+#[derive(Clone, Copy, Debug)]
 pub(crate) enum RenderTypeId {
     DefId(DefId),
     Primitive(clean::PrimitiveType),
+    AssociatedType(Symbol),
     Index(isize),
 }
 
+impl Serialize for RenderTypeId {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        let id = match &self {
+            // 0 is a sentinel, everything else is one-indexed
+            // concrete type
+            RenderTypeId::Index(idx) if *idx >= 0 => idx + 1,
+            // generic type parameter
+            RenderTypeId::Index(idx) => *idx,
+            _ => panic!("must convert render types to indexes before serializing"),
+        };
+        id.serialize(serializer)
+    }
+}
+
 /// Full type of functions/methods in the search index.
 #[derive(Debug)]
 pub(crate) struct IndexItemFunctionType {
@@ -171,17 +195,22 @@ impl Serialize for IndexItemFunctionType {
         } else {
             let mut seq = serializer.serialize_seq(None)?;
             match &self.inputs[..] {
-                [one] if one.generics.is_none() => seq.serialize_element(one)?,
+                [one] if one.generics.is_none() && one.bindings.is_none() => {
+                    seq.serialize_element(one)?
+                }
                 _ => seq.serialize_element(&self.inputs)?,
             }
             match &self.output[..] {
                 [] if self.where_clause.is_empty() => {}
-                [one] if one.generics.is_none() => seq.serialize_element(one)?,
+                [one] if one.generics.is_none() && one.bindings.is_none() => {
+                    seq.serialize_element(one)?
+                }
                 _ => seq.serialize_element(&self.output)?,
             }
             for constraint in &self.where_clause {
                 if let [one] = &constraint[..]
                     && one.generics.is_none()
+                    && one.bindings.is_none()
                 {
                     seq.serialize_element(one)?;
                 } else {