5 files changed, 871 insertions, 0 deletions
diff --git a/vendor/rowan/src/green/builder.rs b/vendor/rowan/src/green/builder.rs
new file mode 100644
index 000000000..1dbc8bb08
--- /dev/null
+++ b/vendor/rowan/src/green/builder.rs
@@ -0,0 +1,119 @@
+use crate::{
+    cow_mut::CowMut,
+    green::{node_cache::NodeCache, GreenElement, GreenNode, SyntaxKind},
+    NodeOrToken,
+};
+
+/// A checkpoint for maybe wrapping a node. See `GreenNodeBuilder::checkpoint` for details.
+#[derive(Clone, Copy, Debug)]
+pub struct Checkpoint(usize);
+
+/// A builder for a green tree.
+#[derive(Default, Debug)]
+pub struct GreenNodeBuilder<'cache> {
+    cache: CowMut<'cache, NodeCache>,
+    parents: Vec<(SyntaxKind, usize)>,
+    children: Vec<(u64, GreenElement)>,
+}
+
+impl GreenNodeBuilder<'_> {
+    /// Creates new builder.
+    pub fn new() -> GreenNodeBuilder<'static> {
+        GreenNodeBuilder::default()
+    }
+
+    /// Reusing `NodeCache` between different `GreenNodeBuilder`s saves memory.
+    /// It allows to structurally share underlying trees.
+    pub fn with_cache(cache: &mut NodeCache) -> GreenNodeBuilder<'_> {
+        GreenNodeBuilder {
+            cache: CowMut::Borrowed(cache),
+            parents: Vec::new(),
+            children: Vec::new(),
+        }
+    }
+
+    /// Adds new token to the current branch.
+    #[inline]
+    pub fn token(&mut self, kind: SyntaxKind, text: &str) {
+        let (hash, token) = self.cache.token(kind, text);
+        self.children.push((hash, token.into()));
+    }
+
+    /// Start new node and make it current.
+    #[inline]
+    pub fn start_node(&mut self, kind: SyntaxKind) {
+        let len = self.children.len();
+        self.parents.push((kind, len));
+    }
+
+    /// Finish current branch and restore previous
+    /// branch as current.
+    #[inline]
+    pub fn finish_node(&mut self) {
+        let (kind, first_child) = self.parents.pop().unwrap();
+        let (hash, node) = self.cache.node(kind, &mut self.children, first_child);
+        self.children.push((hash, node.into()));
+    }
+
+    /// Prepare for maybe wrapping the next node.
+    /// The way wrapping works is that you first of all get a checkpoint,
+    /// then you place all tokens you want to wrap, and then *maybe* call
+    /// `start_node_at`.
+    /// Example:
+    /// ```rust
+    /// # use rowan::{GreenNodeBuilder, SyntaxKind};
+    /// # const PLUS: SyntaxKind = SyntaxKind(0);
+    /// # const OPERATION: SyntaxKind = SyntaxKind(1);
+    /// # struct Parser;
+    /// # impl Parser {
+    /// #     fn peek(&self) -> Option<SyntaxKind> { None }
+    /// #     fn parse_expr(&mut self) {}
+    /// # }
+    /// # let mut builder = GreenNodeBuilder::new();
+    /// # let mut parser = Parser;
+    /// let checkpoint = builder.checkpoint();
+    /// parser.parse_expr();
+    /// if parser.peek() == Some(PLUS) {
+    ///   // 1 + 2 = Add(1, 2)
+    ///   builder.start_node_at(checkpoint, OPERATION);
+    ///   parser.parse_expr();
+    ///   builder.finish_node();
+    /// }
+    /// ```
+    #[inline]
+    pub fn checkpoint(&self) -> Checkpoint {
+        Checkpoint(self.children.len())
+    }
+
+    /// Wrap the previous branch marked by `checkpoint` in a new branch and
+    /// make it current.
+    #[inline]
+    pub fn start_node_at(&mut self, checkpoint: Checkpoint, kind: SyntaxKind) {
+        let Checkpoint(checkpoint) = checkpoint;
+        assert!(
+            checkpoint <= self.children.len(),
+            "checkpoint no longer valid, was finish_node called early?"
+        );
+
+        if let Some(&(_, first_child)) = self.parents.last() {
+            assert!(
+                checkpoint >= first_child,
+                "checkpoint no longer valid, was an unmatched start_node_at called?"
+            );
+        }
+
+        self.parents.push((kind, checkpoint));
+    }
+
+    /// Complete tree building. Make sure that
+    /// `start_node_at` and `finish_node` calls
+    /// are paired!
+    #[inline]
+    pub fn finish(mut self) -> GreenNode {
+        assert_eq!(self.children.len(), 1);
+        match self.children.pop().unwrap().1 {
+            NodeOrToken::Node(node) => node,
+            NodeOrToken::Token(_) => panic!(),
+        }
+    }
+}
diff --git a/vendor/rowan/src/green/element.rs b/vendor/rowan/src/green/element.rs
new file mode 100644
index 000000000..2d1ce1f61
--- /dev/null
+++ b/vendor/rowan/src/green/element.rs
@@ -0,0 +1,89 @@
+use std::borrow::Cow;
+
+use crate::{
+    green::{GreenNode, GreenToken, SyntaxKind},
+    GreenNodeData, NodeOrToken, TextSize,
+};
+
+use super::GreenTokenData;
+
+pub(super) type GreenElement = NodeOrToken<GreenNode, GreenToken>;
+pub(crate) type GreenElementRef<'a> = NodeOrToken<&'a GreenNodeData, &'a GreenTokenData>;
+
+impl From<GreenNode> for GreenElement {
+    #[inline]
+    fn from(node: GreenNode) -> GreenElement {
+        NodeOrToken::Node(node)
+    }
+}
+
+impl<'a> From<&'a GreenNode> for GreenElementRef<'a> {
+    #[inline]
+    fn from(node: &'a GreenNode) -> GreenElementRef<'a> {
+        NodeOrToken::Node(node)
+    }
+}
+
+impl From<GreenToken> for GreenElement {
+    #[inline]
+    fn from(token: GreenToken) -> GreenElement {
+        NodeOrToken::Token(token)
+    }
+}
+
+impl From<Cow<'_, GreenNodeData>> for GreenElement {
+    #[inline]
+    fn from(cow: Cow<'_, GreenNodeData>) -> Self {
+        NodeOrToken::Node(cow.into_owned())
+    }
+}
+
+impl<'a> From<&'a GreenToken> for GreenElementRef<'a> {
+    #[inline]
+    fn from(token: &'a GreenToken) -> GreenElementRef<'a> {
+        NodeOrToken::Token(token)
+    }
+}
+
+impl GreenElementRef<'_> {
+    pub fn to_owned(self) -> GreenElement {
+        match self {
+            NodeOrToken::Node(it) => NodeOrToken::Node(it.to_owned()),
+            NodeOrToken::Token(it) => NodeOrToken::Token(it.to_owned()),
+        }
+    }
+}
+
+impl GreenElement {
+    /// Returns kind of this element.
+    #[inline]
+    pub fn kind(&self) -> SyntaxKind {
+        self.as_deref().kind()
+    }
+
+    /// Returns the length of the text covered by this element.
+    #[inline]
+    pub fn text_len(&self) -> TextSize {
+        self.as_deref().text_len()
+    }
+}
+
+impl GreenElementRef<'_> {
+    /// Returns kind of this element.
+    #[inline]
+    pub fn kind(&self) -> SyntaxKind {
+        match self {
+            NodeOrToken::Node(it) => it.kind(),
+            NodeOrToken::Token(it) => it.kind(),
+        }
+    }
+
+    /// Returns the length of the text covered by this element.
+    #[inline]
+    pub fn text_len(self) -> TextSize {
+        match self {
+            NodeOrToken::Node(it) => it.text_len(),
+            NodeOrToken::Token(it) => it.text_len(),
+        }
+    }
+}
diff --git a/vendor/rowan/src/green/node.rs b/vendor/rowan/src/green/node.rs
new file mode 100644
index 000000000..e94dc01cf
--- /dev/null
+++ b/vendor/rowan/src/green/node.rs
@@ -0,0 +1,361 @@
+use std::{
+    borrow::{Borrow, Cow},
+    fmt,
+    iter::{self, FusedIterator},
+    mem::{self, ManuallyDrop},
+    ops, ptr, slice,
+};
+
+use countme::Count;
+
+use crate::{
+    arc::{Arc, HeaderSlice, ThinArc},
+    green::{GreenElement, GreenElementRef, SyntaxKind},
+    utility_types::static_assert,
+    GreenToken, NodeOrToken, TextRange, TextSize,
+};
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub(super) struct GreenNodeHead {
+    kind: SyntaxKind,
+    text_len: TextSize,
+    _c: Count<GreenNode>,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub(crate) enum GreenChild {
+    Node { rel_offset: TextSize, node: GreenNode },
+    Token { rel_offset: TextSize, token: GreenToken },
+}
+#[cfg(target_pointer_width = "64")]
+static_assert!(mem::size_of::<GreenChild>() == mem::size_of::<usize>() * 2);
+
+type Repr = HeaderSlice<GreenNodeHead, [GreenChild]>;
+type ReprThin = HeaderSlice<GreenNodeHead, [GreenChild; 0]>;
+#[repr(transparent)]
+pub struct GreenNodeData {
+    data: ReprThin,
+}
+
+impl PartialEq for GreenNodeData {
+    fn eq(&self, other: &Self) -> bool {
+        self.header() == other.header() && self.slice() == other.slice()
+    }
+}
+
+/// Internal node in the immutable tree.
+/// It has other nodes and tokens as children.
+#[derive(Clone, PartialEq, Eq, Hash)]
+#[repr(transparent)]
+pub struct GreenNode {
+    ptr: ThinArc<GreenNodeHead, GreenChild>,
+}
+
+impl ToOwned for GreenNodeData {
+    type Owned = GreenNode;
+
+    #[inline]
+    fn to_owned(&self) -> GreenNode {
+        unsafe {
+            let green = GreenNode::from_raw(ptr::NonNull::from(self));
+            let green = ManuallyDrop::new(green);
+            GreenNode::clone(&green)
+        }
+    }
+}
+
+impl Borrow<GreenNodeData> for GreenNode {
+    #[inline]
+    fn borrow(&self) -> &GreenNodeData {
+        &*self
+    }
+}
+
+impl From<Cow<'_, GreenNodeData>> for GreenNode {
+    #[inline]
+    fn from(cow: Cow<'_, GreenNodeData>) -> Self {
+        cow.into_owned()
+    }
+}
+
+impl fmt::Debug for GreenNodeData {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("GreenNode")
+            .field("kind", &self.kind())
+            .field("text_len", &self.text_len())
+            .field("n_children", &self.children().len())
+            .finish()
+    }
+}
+
+impl fmt::Debug for GreenNode {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let data: &GreenNodeData = &*self;
+        fmt::Debug::fmt(data, f)
+    }
+}
+
+impl fmt::Display for GreenNode {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let data: &GreenNodeData = &*self;
+        fmt::Display::fmt(data, f)
+    }
+}
+
+impl fmt::Display for GreenNodeData {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        for child in self.children() {
+            write!(f, "{}", child)?;
+        }
+        Ok(())
+    }
+}
+
+impl GreenNodeData {
+    #[inline]
+    fn header(&self) -> &GreenNodeHead {
+        &self.data.header
+    }
+
+    #[inline]
+    fn slice(&self) -> &[GreenChild] {
+        self.data.slice()
+    }
+
+    /// Kind of this node.
+    #[inline]
+    pub fn kind(&self) -> SyntaxKind {
+        self.header().kind
+    }
+
+    /// Returns the length of the text covered by this node.
+    #[inline]
+    pub fn text_len(&self) -> TextSize {
+        self.header().text_len
+    }
+
+    /// Children of this node.
+    #[inline]
+    pub fn children(&self) -> Children<'_> {
+        Children { raw: self.slice().iter() }
+    }
+
+    pub(crate) fn child_at_range(
+        &self,
+        rel_range: TextRange,
+    ) -> Option<(usize, TextSize, GreenElementRef<'_>)> {
+        let idx = self
+            .slice()
+            .binary_search_by(|it| {
+                let child_range = it.rel_range();
+                TextRange::ordering(child_range, rel_range)
+            })
+            // XXX: this handles empty ranges
+            .unwrap_or_else(|it| it.saturating_sub(1));
+        let child = &self.slice().get(idx).filter(|it| it.rel_range().contains_range(rel_range))?;
+        Some((idx, child.rel_offset(), child.as_ref()))
+    }
+
+    #[must_use]
+    pub fn replace_child(&self, index: usize, new_child: GreenElement) -> GreenNode {
+        let mut replacement = Some(new_child);
+        let children = self.children().enumerate().map(|(i, child)| {
+            if i == index {
+                replacement.take().unwrap()
+            } else {
+                child.to_owned()
+            }
+        });
+        GreenNode::new(self.kind(), children)
+    }
+    #[must_use]
+    pub fn insert_child(&self, index: usize, new_child: GreenElement) -> GreenNode {
+        // https://github.com/rust-lang/rust/issues/34433
+        self.splice_children(index..index, iter::once(new_child))
+    }
+    #[must_use]
+    pub fn remove_child(&self, index: usize) -> GreenNode {
+        self.splice_children(index..=index, iter::empty())
+    }
+    #[must_use]
+    pub fn splice_children<R, I>(&self, range: R, replace_with: I) -> GreenNode
+    where
+        R: ops::RangeBounds<usize>,
+        I: IntoIterator<Item = GreenElement>,
+    {
+        let mut children: Vec<_> = self.children().map(|it| it.to_owned()).collect();
+        children.splice(range, replace_with);
+        GreenNode::new(self.kind(), children)
+    }
+}
+
+impl ops::Deref for GreenNode {
+    type Target = GreenNodeData;
+
+    #[inline]
+    fn deref(&self) -> &GreenNodeData {
+        unsafe {
+            let repr: &Repr = &self.ptr;
+            let repr: &ReprThin = &*(repr as *const Repr as *const ReprThin);
+            mem::transmute::<&ReprThin, &GreenNodeData>(repr)
+        }
+    }
+}
+
+impl GreenNode {
+    /// Creates new Node.
+    #[inline]
+    pub fn new<I>(kind: SyntaxKind, children: I) -> GreenNode
+    where
+        I: IntoIterator<Item = GreenElement>,
+        I::IntoIter: ExactSizeIterator,
+    {
+        let mut text_len: TextSize = 0.into();
+        let children = children.into_iter().map(|el| {
+            let rel_offset = text_len;
+            text_len += el.text_len();
+            match el {
+                NodeOrToken::Node(node) => GreenChild::Node { rel_offset, node },
+                NodeOrToken::Token(token) => GreenChild::Token { rel_offset, token },
+            }
+        });
+
+        let data = ThinArc::from_header_and_iter(
+            GreenNodeHead { kind, text_len: 0.into(), _c: Count::new() },
+            children,
+        );
+
+        // XXX: fixup `text_len` after construction, because we can't iterate
+        // `children` twice.
+        let data = {
+            let mut data = Arc::from_thin(data);
+            Arc::get_mut(&mut data).unwrap().header.text_len = text_len;
+            Arc::into_thin(data)
+        };
+
+        GreenNode { ptr: data }
+    }
+
+    #[inline]
+    pub(crate) fn into_raw(this: GreenNode) -> ptr::NonNull<GreenNodeData> {
+        let green = ManuallyDrop::new(this);
+        let green: &GreenNodeData = &*green;
+        ptr::NonNull::from(&*green)
+    }
+
+    #[inline]
+    pub(crate) unsafe fn from_raw(ptr: ptr::NonNull<GreenNodeData>) -> GreenNode {
+        let arc = Arc::from_raw(&ptr.as_ref().data as *const ReprThin);
+        let arc = mem::transmute::<Arc<ReprThin>, ThinArc<GreenNodeHead, GreenChild>>(arc);
+        GreenNode { ptr: arc }
+    }
+}
+
+impl GreenChild {
+    #[inline]
+    pub(crate) fn as_ref(&self) -> GreenElementRef {
+        match self {
+            GreenChild::Node { node, .. } => NodeOrToken::Node(node),
+            GreenChild::Token { token, .. } => NodeOrToken::Token(token),
+        }
+    }
+    #[inline]
+    pub(crate) fn rel_offset(&self) -> TextSize {
+        match self {
+            GreenChild::Node { rel_offset, .. } | GreenChild::Token { rel_offset, .. } => {
+                *rel_offset
+            }
+        }
+    }
+    #[inline]
+    fn rel_range(&self) -> TextRange {
+        let len = self.as_ref().text_len();
+        TextRange::at(self.rel_offset(), len)
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct Children<'a> {
+    pub(crate) raw: slice::Iter<'a, GreenChild>,
+}
+
+// NB: forward everything stable that iter::Slice specializes as of Rust 1.39.0
+impl ExactSizeIterator for Children<'_> {
+    #[inline(always)]
+    fn len(&self) -> usize {
+        self.raw.len()
+    }
+}
+
+impl<'a> Iterator for Children<'a> {
+    type Item = GreenElementRef<'a>;
+
+    #[inline]
+    fn next(&mut self) -> Option<GreenElementRef<'a>> {
+        self.raw.next().map(GreenChild::as_ref)
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.raw.size_hint()
+    }
+
+    #[inline]
+    fn count(self) -> usize
+    where
+        Self: Sized,
+    {
+        self.raw.count()
+    }
+
+    #[inline]
+    fn nth(&mut self, n: usize) -> Option<Self::Item> {
+        self.raw.nth(n).map(GreenChild::as_ref)
+    }
+
+    #[inline]
+    fn last(mut self) -> Option<Self::Item>
+    where
+        Self: Sized,
+    {
+        self.next_back()
+    }
+
+    #[inline]
+    fn fold<Acc, Fold>(mut self, init: Acc, mut f: Fold) -> Acc
+    where
+        Fold: FnMut(Acc, Self::Item) -> Acc,
+    {
+        let mut accum = init;
+        while let Some(x) = self.next() {
+            accum = f(accum, x);
+        }
+        accum
+    }
+}
+
+impl<'a> DoubleEndedIterator for Children<'a> {
+    #[inline]
+    fn next_back(&mut self) -> Option<Self::Item> {
+        self.raw.next_back().map(GreenChild::as_ref)
+    }
+
+    #[inline]
+    fn nth_back(&mut self, n: usize) -> Option<Self::Item> {
+        self.raw.nth_back(n).map(GreenChild::as_ref)
+    }
+
+    #[inline]
+    fn rfold<Acc, Fold>(mut self, init: Acc, mut f: Fold) -> Acc
+    where
+        Fold: FnMut(Acc, Self::Item) -> Acc,
+    {
+        let mut accum = init;
+        while let Some(x) = self.next_back() {
+            accum = f(accum, x);
+        }
+        accum
+    }
+}
+
+impl FusedIterator for Children<'_> {}
diff --git a/vendor/rowan/src/green/node_cache.rs b/vendor/rowan/src/green/node_cache.rs
new file mode 100644
index 000000000..c73f3e696
--- /dev/null
+++ b/vendor/rowan/src/green/node_cache.rs
@@ -0,0 +1,157 @@
+use hashbrown::hash_map::RawEntryMut;
+use rustc_hash::FxHasher;
+use std::hash::{BuildHasherDefault, Hash, Hasher};
+
+use crate::{
+    green::GreenElementRef, GreenNode, GreenNodeData, GreenToken, GreenTokenData, NodeOrToken,
+    SyntaxKind,
+};
+
+use super::element::GreenElement;
+
+type HashMap<K, V> = hashbrown::HashMap<K, V, BuildHasherDefault<FxHasher>>;
+
+#[derive(Debug)]
+struct NoHash<T>(T);
+
+/// Interner for GreenTokens and GreenNodes
+// XXX: the impl is a bit tricky. As usual when writing interners, we want to
+// store all values in one HashSet.
+//
+// However, hashing trees is fun: hash of the tree is recursively defined. We
+// maintain an invariant -- if the tree is interned, then all of its children
+// are interned as well.
+//
+// That means that computing the hash naively is wasteful -- we just *know*
+// hashes of children, and we can re-use those.
+//
+// So here we use *raw* API of hashbrown and provide the hashes manually,
+// instead of going via a `Hash` impl. Our manual `Hash` and the
+// `#[derive(Hash)]` are actually different! At some point we had a fun bug,
+// where we accidentally mixed the two hashes, which made the cache much less
+// efficient.
+//
+// To fix that, we additionally wrap the data in `NoHash` wrapper, to make sure
+// we don't accidentally use the wrong hash!
+#[derive(Default, Debug)]
+pub struct NodeCache {
+    nodes: HashMap<NoHash<GreenNode>, ()>,
+    tokens: HashMap<NoHash<GreenToken>, ()>,
+}
+
+fn token_hash(token: &GreenTokenData) -> u64 {
+    let mut h = FxHasher::default();
+    token.kind().hash(&mut h);
+    token.text().hash(&mut h);
+    h.finish()
+}
+
+fn node_hash(node: &GreenNodeData) -> u64 {
+    let mut h = FxHasher::default();
+    node.kind().hash(&mut h);
+    for child in node.children() {
+        match child {
+            NodeOrToken::Node(it) => node_hash(it),
+            NodeOrToken::Token(it) => token_hash(it),
+        }
+        .hash(&mut h)
+    }
+    h.finish()
+}
+
+fn element_id(elem: GreenElementRef<'_>) -> *const () {
+    match elem {
+        NodeOrToken::Node(it) => it as *const GreenNodeData as *const (),
+        NodeOrToken::Token(it) => it as *const GreenTokenData as *const (),
+    }
+}
+
+impl NodeCache {
+    pub(crate) fn node(
+        &mut self,
+        kind: SyntaxKind,
+        children: &mut Vec<(u64, GreenElement)>,
+        first_child: usize,
+    ) -> (u64, GreenNode) {
+        let build_node = move |children: &mut Vec<(u64, GreenElement)>| {
+            GreenNode::new(kind, children.drain(first_child..).map(|(_, it)| it))
+        };
+
+        let children_ref = &children[first_child..];
+        if children_ref.len() > 3 {
+            let node = build_node(children);
+            return (0, node);
+        }
+
+        let hash = {
+            let mut h = FxHasher::default();
+            kind.hash(&mut h);
+            for &(hash, _) in children_ref {
+                if hash == 0 {
+                    let node = build_node(children);
+                    return (0, node);
+                }
+                hash.hash(&mut h);
+            }
+            h.finish()
+        };
+
+        // Green nodes are fully immutable, so it's ok to deduplicate them.
+        // This is the same optimization that Roslyn does
+        // https://github.com/KirillOsenkov/Bliki/wiki/Roslyn-Immutable-Trees
+        //
+        // For example, all `#[inline]` in this file share the same green node!
+        // For `libsyntax/parse/parser.rs`, measurements show that deduping saves
+        // 17% of the memory for green nodes!
+        let entry = self.nodes.raw_entry_mut().from_hash(hash, |node| {
+            node.0.kind() == kind && node.0.children().len() == children_ref.len() && {
+                let lhs = node.0.children();
+                let rhs = children_ref.iter().map(|(_, it)| it.as_deref());
+
+                let lhs = lhs.map(element_id);
+                let rhs = rhs.map(element_id);
+
+                lhs.eq(rhs)
+            }
+        });
+
+        let node = match entry {
+            RawEntryMut::Occupied(entry) => {
+                drop(children.drain(first_child..));
+                entry.key().0.clone()
+            }
+            RawEntryMut::Vacant(entry) => {
+                let node = build_node(children);
+                entry.insert_with_hasher(hash, NoHash(node.clone()), (), |n| node_hash(&n.0));
+                node
+            }
+        };
+
+        (hash, node)
+    }
+
+    pub(crate) fn token(&mut self, kind: SyntaxKind, text: &str) -> (u64, GreenToken) {
+        let hash = {
+            let mut h = FxHasher::default();
+            kind.hash(&mut h);
+            text.hash(&mut h);
+            h.finish()
+        };
+
+        let entry = self
+            .tokens
+            .raw_entry_mut()
+            .from_hash(hash, |token| token.0.kind() == kind && token.0.text() == text);
+
+        let token = match entry {
+            RawEntryMut::Occupied(entry) => entry.key().0.clone(),
+            RawEntryMut::Vacant(entry) => {
+                let token = GreenToken::new(kind, text);
+                entry.insert_with_hasher(hash, NoHash(token.clone()), (), |t| token_hash(&t.0));
+                token
+            }
+        };
+
+        (hash, token)
+    }
+}
diff --git a/vendor/rowan/src/green/token.rs b/vendor/rowan/src/green/token.rs
new file mode 100644
index 000000000..1a4548a43
--- /dev/null
+++ b/vendor/rowan/src/green/token.rs
@@ -0,0 +1,145 @@
+use std::{
+    borrow::Borrow,
+    fmt,
+    mem::{self, ManuallyDrop},
+    ops, ptr,
+};
+
+use countme::Count;
+
+use crate::{
+    arc::{Arc, HeaderSlice, ThinArc},
+    green::SyntaxKind,
+    TextSize,
+};
+
+#[derive(PartialEq, Eq, Hash)]
+struct GreenTokenHead {
+    kind: SyntaxKind,
+    _c: Count<GreenToken>,
+}
+
+type Repr = HeaderSlice<GreenTokenHead, [u8]>;
+type ReprThin = HeaderSlice<GreenTokenHead, [u8; 0]>;
+#[repr(transparent)]
+pub struct GreenTokenData {
+    data: ReprThin,
+}
+
+impl PartialEq for GreenTokenData {
+    fn eq(&self, other: &Self) -> bool {
+        self.kind() == other.kind() && self.text() == other.text()
+    }
+}
+
+/// Leaf node in the immutable tree.
+#[derive(PartialEq, Eq, Hash, Clone)]
+#[repr(transparent)]
+pub struct GreenToken {
+    ptr: ThinArc<GreenTokenHead, u8>,
+}
+
+impl ToOwned for GreenTokenData {
+    type Owned = GreenToken;
+
+    #[inline]
+    fn to_owned(&self) -> GreenToken {
+        unsafe {
+            let green = GreenToken::from_raw(ptr::NonNull::from(self));
+            let green = ManuallyDrop::new(green);
+            GreenToken::clone(&green)
+        }
+    }
+}
+
+impl Borrow<GreenTokenData> for GreenToken {
+    #[inline]
+    fn borrow(&self) -> &GreenTokenData {
+        &*self
+    }
+}
+
+impl fmt::Debug for GreenTokenData {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("GreenToken")
+            .field("kind", &self.kind())
+            .field("text", &self.text())
+            .finish()
+    }
+}
+
+impl fmt::Debug for GreenToken {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let data: &GreenTokenData = &*self;
+        fmt::Debug::fmt(data, f)
+    }
+}
+
+impl fmt::Display for GreenToken {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let data: &GreenTokenData = &*self;
+        fmt::Display::fmt(data, f)
+    }
+}
+
+impl fmt::Display for GreenTokenData {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{}", self.text())
+    }
+}
+
+impl GreenTokenData {
+    /// Kind of this Token.
+    #[inline]
+    pub fn kind(&self) -> SyntaxKind {
+        self.data.header.kind
+    }
+
+    /// Text of this Token.
+    #[inline]
+    pub fn text(&self) -> &str {
+        unsafe { std::str::from_utf8_unchecked(self.data.slice()) }
+    }
+
+    /// Returns the length of the text covered by this token.
+    #[inline]
+    pub fn text_len(&self) -> TextSize {
+        TextSize::of(self.text())
+    }
+}
+
+impl GreenToken {
+    /// Creates new Token.
+    #[inline]
+    pub fn new(kind: SyntaxKind, text: &str) -> GreenToken {
+        let head = GreenTokenHead { kind, _c: Count::new() };
+        let ptr = ThinArc::from_header_and_iter(head, text.bytes());
+        GreenToken { ptr }
+    }
+    #[inline]
+    pub(crate) fn into_raw(this: GreenToken) -> ptr::NonNull<GreenTokenData> {
+        let green = ManuallyDrop::new(this);
+        let green: &GreenTokenData = &*green;
+        ptr::NonNull::from(&*green)
+    }
+
+    #[inline]
+    pub(crate) unsafe fn from_raw(ptr: ptr::NonNull<GreenTokenData>) -> GreenToken {
+        let arc = Arc::from_raw(&ptr.as_ref().data as *const ReprThin);
+        let arc = mem::transmute::<Arc<ReprThin>, ThinArc<GreenTokenHead, u8>>(arc);
+        GreenToken { ptr: arc }
+    }
+}
+
+impl ops::Deref for GreenToken {
+    type Target = GreenTokenData;
+
+    #[inline]
+    fn deref(&self) -> &GreenTokenData {
+        unsafe {
+            let repr: &Repr = &self.ptr;
+            let repr: &ReprThin = &*(repr as *const Repr as *const ReprThin);
+            mem::transmute::<&ReprThin, &GreenTokenData>(repr)
+        }
+    }
+}