perf(visit): Add linear AST traversal (#9452)

**Description:**

Babel decorator pass uses `fastTraverse`, and I think we can have one.

**Related issue:**

 - Closes https://github.com/swc-project/swc/issues/9451

.changeset/olive-pianos-lay.md

@@ -0,0 +1,9 @@
+---
+swc_css_visit: patch
+swc_ecma_visit: patch
+swc_html_visit: patch
+swc_xml_visit: patch
+swc_core: patch
+---
+
+perf(visit): Add linear AST traversal

crates/swc_html_visit/src/generated.rs

@@ -11092,7 +11092,6 @@ pub mod fields {
         #[doc = "Represents [`TokenAndSpan::token`]"]
         Token,
     }
-    #[cfg(any(docsrs, feature = "path"))]
     #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
     pub enum AstParentKind {
         Attribute(AttributeField),
@@ -11131,7 +11130,6 @@ pub mod fields {
             }
         }
     }
-    #[cfg(any(docsrs, feature = "path"))]
     #[derive(Debug, Clone, Copy)]
     pub enum AstParentNodeRef<'ast> {
         Attribute(&'ast Attribute, AttributeField),
@@ -11176,6 +11174,7 @@ pub mod fields {
             }
         }
     }
+    #[cfg(any(docsrs, feature = "path"))]
     impl<'ast> AstParentNodeRef<'ast> {
         #[inline]
         pub fn kind(&self) -> AstParentKind {
@@ -11202,5 +11201,185 @@ pub mod fields {
         }
     }
 }
+impl<'ast> From<&'ast Attribute> for NodeRef<'ast> {
+    fn from(node: &'ast Attribute) -> Self {
+        NodeRef::Attribute(node)
+    }
+}
+impl<'ast> From<&'ast AttributeToken> for NodeRef<'ast> {
+    fn from(node: &'ast AttributeToken) -> Self {
+        NodeRef::AttributeToken(node)
+    }
+}
+impl<'ast> From<&'ast Child> for NodeRef<'ast> {
+    fn from(node: &'ast Child) -> Self {
+        NodeRef::Child(node)
+    }
+}
+impl<'ast> From<&'ast Comment> for NodeRef<'ast> {
+    fn from(node: &'ast Comment) -> Self {
+        NodeRef::Comment(node)
+    }
+}
+impl<'ast> From<&'ast Document> for NodeRef<'ast> {
+    fn from(node: &'ast Document) -> Self {
+        NodeRef::Document(node)
+    }
+}
+impl<'ast> From<&'ast DocumentFragment> for NodeRef<'ast> {
+    fn from(node: &'ast DocumentFragment) -> Self {
+        NodeRef::DocumentFragment(node)
+    }
+}
+impl<'ast> From<&'ast DocumentMode> for NodeRef<'ast> {
+    fn from(node: &'ast DocumentMode) -> Self {
+        NodeRef::DocumentMode(node)
+    }
+}
+impl<'ast> From<&'ast DocumentType> for NodeRef<'ast> {
+    fn from(node: &'ast DocumentType) -> Self {
+        NodeRef::DocumentType(node)
+    }
+}
+impl<'ast> From<&'ast Element> for NodeRef<'ast> {
+    fn from(node: &'ast Element) -> Self {
+        NodeRef::Element(node)
+    }
+}
+impl<'ast> From<&'ast Namespace> for NodeRef<'ast> {
+    fn from(node: &'ast Namespace) -> Self {
+        NodeRef::Namespace(node)
+    }
+}
+impl<'ast> From<&'ast Raw> for NodeRef<'ast> {
+    fn from(node: &'ast Raw) -> Self {
+        NodeRef::Raw(node)
+    }
+}
+impl<'ast> From<&'ast Text> for NodeRef<'ast> {
+    fn from(node: &'ast Text) -> Self {
+        NodeRef::Text(node)
+    }
+}
+impl<'ast> From<&'ast Token> for NodeRef<'ast> {
+    fn from(node: &'ast Token) -> Self {
+        NodeRef::Token(node)
+    }
+}
+impl<'ast> From<&'ast TokenAndSpan> for NodeRef<'ast> {
+    fn from(node: &'ast TokenAndSpan) -> Self {
+        NodeRef::TokenAndSpan(node)
+    }
+}
+#[derive(Debug, Clone, Copy)]
+pub enum NodeRef<'ast> {
+    Attribute(&'ast Attribute),
+    AttributeToken(&'ast AttributeToken),
+    Child(&'ast Child),
+    Comment(&'ast Comment),
+    Document(&'ast Document),
+    DocumentFragment(&'ast DocumentFragment),
+    DocumentMode(&'ast DocumentMode),
+    DocumentType(&'ast DocumentType),
+    Element(&'ast Element),
+    Namespace(&'ast Namespace),
+    Raw(&'ast Raw),
+    Text(&'ast Text),
+    Token(&'ast Token),
+    TokenAndSpan(&'ast TokenAndSpan),
+}
+impl<'ast> NodeRef<'ast> {
+    #[allow(unreachable_patterns)]
+    pub fn raw_children(&'ast self) -> Box<dyn 'ast + Iterator<Item = NodeRef<'ast>>> {
+        match self {
+            NodeRef::Attribute(node) => {
+                let iterator = ::std::iter::empty::<NodeRef<'ast>>().chain(
+                    node.namespace
+                        .iter()
+                        .flat_map(|item| ::std::iter::once(NodeRef::Namespace(&item))),
+                );
+                Box::new(iterator)
+            }
+            NodeRef::AttributeToken(node) => {
+                let iterator = ::std::iter::empty::<NodeRef<'ast>>();
+                Box::new(iterator)
+            }
+            NodeRef::Child(node) => match node {
+                Child::DocumentType(v0) => Box::new(::std::iter::once(NodeRef::DocumentType(v0))),
+                Child::Element(v0) => Box::new(::std::iter::once(NodeRef::Element(v0))),
+                Child::Text(v0) => Box::new(::std::iter::once(NodeRef::Text(v0))),
+                Child::Comment(v0) => Box::new(::std::iter::once(NodeRef::Comment(v0))),
+                _ => Box::new(::std::iter::empty::<NodeRef<'ast>>()),
+            },
+            NodeRef::Comment(node) => {
+                let iterator = ::std::iter::empty::<NodeRef<'ast>>();
+                Box::new(iterator)
+            }
+            NodeRef::Document(node) => {
+                let iterator = ::std::iter::empty::<NodeRef<'ast>>()
+                    .chain(::std::iter::once(NodeRef::DocumentMode(&node.mode)))
+                    .chain(
+                        node.children
+                            .iter()
+                            .flat_map(|item| ::std::iter::once(NodeRef::Child(&item))),
+                    );
+                Box::new(iterator)
+            }
+            NodeRef::DocumentFragment(node) => {
+                let iterator = ::std::iter::empty::<NodeRef<'ast>>().chain(
+                    node.children
+                        .iter()
+                        .flat_map(|item| ::std::iter::once(NodeRef::Child(&item))),
+                );
+                Box::new(iterator)
+            }
+            NodeRef::DocumentMode(node) => match node {
+                _ => Box::new(::std::iter::empty::<NodeRef<'ast>>()),
+            },
+            NodeRef::DocumentType(node) => {
+                let iterator = ::std::iter::empty::<NodeRef<'ast>>();
+                Box::new(iterator)
+            }
+            NodeRef::Element(node) => {
+                let iterator = ::std::iter::empty::<NodeRef<'ast>>()
+                    .chain(::std::iter::once(NodeRef::Namespace(&node.namespace)))
+                    .chain(
+                        node.attributes
+                            .iter()
+                            .flat_map(|item| ::std::iter::once(NodeRef::Attribute(&item))),
+                    )
+                    .chain(
+                        node.children
+                            .iter()
+                            .flat_map(|item| ::std::iter::once(NodeRef::Child(&item))),
+                    )
+                    .chain(
+                        node.content
+                            .iter()
+                            .flat_map(|item| ::std::iter::once(NodeRef::DocumentFragment(&item))),
+                    );
+                Box::new(iterator)
+            }
+            NodeRef::Namespace(node) => match node {
+                _ => Box::new(::std::iter::empty::<NodeRef<'ast>>()),
+            },
+            NodeRef::Raw(node) => match node {
+                _ => Box::new(::std::iter::empty::<NodeRef<'ast>>()),
+            },
+            NodeRef::Text(node) => {
+                let iterator = ::std::iter::empty::<NodeRef<'ast>>();
+                Box::new(iterator)
+            }
+            NodeRef::Token(node) => match node {
+                _ => Box::new(::std::iter::empty::<NodeRef<'ast>>()),
+            },
+            NodeRef::TokenAndSpan(node) => {
+                let iterator = ::std::iter::empty::<NodeRef<'ast>>()
+                    .chain(::std::iter::once(NodeRef::Token(&node.token)));
+                Box::new(iterator)
+            }
+        }
+    }
+}
 #[cfg(any(docsrs, feature = "path"))]
 pub use self::fields::{AstParentKind, AstParentNodeRef};

crates/swc_xml_visit/src/generated.rs

@@ -10660,7 +10660,6 @@ pub mod fields {
         #[doc = "Represents [`TokenAndSpan::token`]"]
         Token,
     }
-    #[cfg(any(docsrs, feature = "path"))]
     #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
     pub enum AstParentKind {
         Attribute(AttributeField),
@@ -10699,7 +10698,6 @@ pub mod fields {
             }
         }
     }
-    #[cfg(any(docsrs, feature = "path"))]
     #[derive(Debug, Clone, Copy)]
     pub enum AstParentNodeRef<'ast> {
         Attribute(&'ast Attribute, AttributeField),
@@ -10744,6 +10742,7 @@ pub mod fields {
             }
         }
     }
+    #[cfg(any(docsrs, feature = "path"))]
     impl<'ast> AstParentNodeRef<'ast> {
         #[inline]
         pub fn kind(&self) -> AstParentKind {
@@ -10770,5 +10769,178 @@ pub mod fields {
         }
     }
 }
+impl<'ast> From<&'ast Attribute> for NodeRef<'ast> {
+    fn from(node: &'ast Attribute) -> Self {
+        NodeRef::Attribute(node)
+    }
+}
+impl<'ast> From<&'ast AttributeToken> for NodeRef<'ast> {
+    fn from(node: &'ast AttributeToken) -> Self {
+        NodeRef::AttributeToken(node)
+    }
+}
+impl<'ast> From<&'ast CdataSection> for NodeRef<'ast> {
+    fn from(node: &'ast CdataSection) -> Self {
+        NodeRef::CdataSection(node)
+    }
+}
+impl<'ast> From<&'ast Child> for NodeRef<'ast> {
+    fn from(node: &'ast Child) -> Self {
+        NodeRef::Child(node)
+    }
+}
+impl<'ast> From<&'ast Comment> for NodeRef<'ast> {
+    fn from(node: &'ast Comment) -> Self {
+        NodeRef::Comment(node)
+    }
+}
+impl<'ast> From<&'ast Document> for NodeRef<'ast> {
+    fn from(node: &'ast Document) -> Self {
+        NodeRef::Document(node)
+    }
+}
+impl<'ast> From<&'ast DocumentMode> for NodeRef<'ast> {
+    fn from(node: &'ast DocumentMode) -> Self {
+        NodeRef::DocumentMode(node)
+    }
+}
+impl<'ast> From<&'ast DocumentType> for NodeRef<'ast> {
+    fn from(node: &'ast DocumentType) -> Self {
+        NodeRef::DocumentType(node)
+    }
+}
+impl<'ast> From<&'ast Element> for NodeRef<'ast> {
+    fn from(node: &'ast Element) -> Self {
+        NodeRef::Element(node)
+    }
+}
+impl<'ast> From<&'ast Namespace> for NodeRef<'ast> {
+    fn from(node: &'ast Namespace) -> Self {
+        NodeRef::Namespace(node)
+    }
+}
+impl<'ast> From<&'ast ProcessingInstruction> for NodeRef<'ast> {
+    fn from(node: &'ast ProcessingInstruction) -> Self {
+        NodeRef::ProcessingInstruction(node)
+    }
+}
+impl<'ast> From<&'ast Text> for NodeRef<'ast> {
+    fn from(node: &'ast Text) -> Self {
+        NodeRef::Text(node)
+    }
+}
+impl<'ast> From<&'ast Token> for NodeRef<'ast> {
+    fn from(node: &'ast Token) -> Self {
+        NodeRef::Token(node)
+    }
+}
+impl<'ast> From<&'ast TokenAndSpan> for NodeRef<'ast> {
+    fn from(node: &'ast TokenAndSpan) -> Self {
+        NodeRef::TokenAndSpan(node)
+    }
+}
+#[derive(Debug, Clone, Copy)]
+pub enum NodeRef<'ast> {
+    Attribute(&'ast Attribute),
+    AttributeToken(&'ast AttributeToken),
+    CdataSection(&'ast CdataSection),
+    Child(&'ast Child),
+    Comment(&'ast Comment),
+    Document(&'ast Document),
+    DocumentMode(&'ast DocumentMode),
+    DocumentType(&'ast DocumentType),
+    Element(&'ast Element),
+    Namespace(&'ast Namespace),
+    ProcessingInstruction(&'ast ProcessingInstruction),
+    Text(&'ast Text),
+    Token(&'ast Token),
+    TokenAndSpan(&'ast TokenAndSpan),
+}
+impl<'ast> NodeRef<'ast> {
+    #[allow(unreachable_patterns)]
+    pub fn raw_children(&'ast self) -> Box<dyn 'ast + Iterator<Item = NodeRef<'ast>>> {
+        match self {
+            NodeRef::Attribute(node) => {
+                let iterator = ::std::iter::empty::<NodeRef<'ast>>().chain(
+                    node.namespace
+                        .iter()
+                        .flat_map(|item| ::std::iter::once(NodeRef::Namespace(&item))),
+                );
+                Box::new(iterator)
+            }
+            NodeRef::AttributeToken(node) => {
+                let iterator = ::std::iter::empty::<NodeRef<'ast>>();
+                Box::new(iterator)
+            }
+            NodeRef::CdataSection(node) => {
+                let iterator = ::std::iter::empty::<NodeRef<'ast>>();
+                Box::new(iterator)
+            }
+            NodeRef::Child(node) => match node {
+                Child::DocumentType(v0) => Box::new(::std::iter::once(NodeRef::DocumentType(v0))),
+                Child::Element(v0) => Box::new(::std::iter::once(NodeRef::Element(v0))),
+                Child::Text(v0) => Box::new(::std::iter::once(NodeRef::Text(v0))),
+                Child::CdataSection(v0) => Box::new(::std::iter::once(NodeRef::CdataSection(v0))),
+                Child::Comment(v0) => Box::new(::std::iter::once(NodeRef::Comment(v0))),
+                Child::ProcessingInstruction(v0) => {
+                    Box::new(::std::iter::once(NodeRef::ProcessingInstruction(v0)))
+                }
+                _ => Box::new(::std::iter::empty::<NodeRef<'ast>>()),
+            },
+            NodeRef::Comment(node) => {
+                let iterator = ::std::iter::empty::<NodeRef<'ast>>();
+                Box::new(iterator)
+            }
+            NodeRef::Document(node) => {
+                let iterator = ::std::iter::empty::<NodeRef<'ast>>().chain(
+                    node.children
+                        .iter()
+                        .flat_map(|item| ::std::iter::once(NodeRef::Child(&item))),
+                );
+                Box::new(iterator)
+            }
+            NodeRef::DocumentMode(node) => match node {
+                _ => Box::new(::std::iter::empty::<NodeRef<'ast>>()),
+            },
+            NodeRef::DocumentType(node) => {
+                let iterator = ::std::iter::empty::<NodeRef<'ast>>();
+                Box::new(iterator)
+            }
+            NodeRef::Element(node) => {
+                let iterator = ::std::iter::empty::<NodeRef<'ast>>()
+                    .chain(
+                        node.attributes
+                            .iter()
+                            .flat_map(|item| ::std::iter::once(NodeRef::Attribute(&item))),
+                    )
+                    .chain(
+                        node.children
+                            .iter()
+                            .flat_map(|item| ::std::iter::once(NodeRef::Child(&item))),
+                    );
+                Box::new(iterator)
+            }
+            NodeRef::Namespace(node) => match node {
+                _ => Box::new(::std::iter::empty::<NodeRef<'ast>>()),
+            },
+            NodeRef::ProcessingInstruction(node) => {
+                let iterator = ::std::iter::empty::<NodeRef<'ast>>();
+                Box::new(iterator)
+            }
+            NodeRef::Text(node) => {
+                let iterator = ::std::iter::empty::<NodeRef<'ast>>();
+                Box::new(iterator)
+            }
+            NodeRef::Token(node) => match node {
+                _ => Box::new(::std::iter::empty::<NodeRef<'ast>>()),
+            },
+            NodeRef::TokenAndSpan(node) => {
+                let iterator = ::std::iter::empty::<NodeRef<'ast>>()
+                    .chain(::std::iter::once(NodeRef::Token(&node.token)));
+                Box::new(iterator)
+            }
+        }
+    }
+}
 #[cfg(any(docsrs, feature = "path"))]
 pub use self::fields::{AstParentKind, AstParentNodeRef};

tools/generate-code/src/generators/visitor.rs

@@ -1261,14 +1261,71 @@ fn extract_generic<'a>(name: &str, ty: &'a Type) -> Option<&'a Type> {
 
     None
 }
+
+fn to_iter(e: TokenStream, ty: &Type, node_names: &[Ident]) -> Option<Expr> {
+    if let Some(ty) = extract_vec(ty) {
+        let inner_expr = to_iter(quote!(item), ty, node_names)?;
+        return Some(parse_quote!(#e.iter().flat_map(|item| #inner_expr)));
+    }
+
+    if let Some(ty) = extract_generic("Option", ty) {
+        let inner_expr = to_iter(quote!(item), ty, node_names)?;
+        return Some(parse_quote!(#e.iter().flat_map(|item| #inner_expr)));
+    }
+
+    if let Some(ty) = extract_generic("Box", ty) {
+        let inner_expr = to_iter(quote!(item), ty, node_names)?;
+        return Some(parse_quote!({
+            let item = &*#e;
+            #inner_expr
+        }));
+    }
+
+    if let Type::Path(p) = ty {
+        let ty = &p.path.segments.last().unwrap().ident;
+
+        if node_names.contains(ty) {
+            return Some(parse_quote!(::std::iter::once(NodeRef::#ty(&#e))));
+        }
+
+        None
+    } else {
+        todo!("to_iter for {:?}", ty);
+    }
+}
+
 fn define_fields(crate_name: &Ident, node_types: &[&Item]) -> Vec<Item> {
     let mut items = Vec::<Item>::new();
     let mut kind_enum_members = Vec::new();
+    let mut parent_enum_members = Vec::new();
     let mut node_ref_enum_members = Vec::new();
 
     let mut kind_set_index_arms = Vec::<Arm>::new();
     let mut node_ref_set_index_arms = Vec::<Arm>::new();
     let mut node_ref_kind_arms = Vec::<Arm>::new();
+    let mut node_ref_iter_next_arms = Vec::<Arm>::new();
+
+    let node_names = node_types
+        .iter()
+        .filter_map(|ty| match ty {
+            Item::Enum(data) => Some(data.ident.clone()),
+            Item::Struct(data) => Some(data.ident.clone()),
+            _ => None,
+        })
+        .collect::<Vec<_>>();
+
+    let is_node_ref_raw = |ty: &Type| match ty {
+        Type::Path(p) => node_names.contains(&p.path.segments.last().unwrap().ident),
+        _ => false,
+    };
+
+    let is_node_ref = |ty: &Type| {
+        if let Some(ty) = extract_generic("Box", ty) {
+            return is_node_ref_raw(ty);
+        }
+
+        is_node_ref_raw(ty)
+    };
 
     {
         let mut defs = Vec::<Item>::new();
@@ -1330,10 +1387,58 @@ fn define_fields(crate_name: &Ident, node_types: &[&Item]) -> Vec<Item> {
                         #type_name(#fields_enum_name)
                     ));
 
-                    node_ref_enum_members.push(quote!(
+                    parent_enum_members.push(quote!(
                         #type_name(&'ast #type_name, #fields_enum_name)
                     ));
 
+                    node_ref_enum_members.push(quote!(
+                        #type_name(&'ast #type_name)
+                    ));
+
+                    items.push(parse_quote!(
+                        impl<'ast> From<&'ast #type_name> for NodeRef<'ast> {
+                            fn from(node: &'ast #type_name) -> Self {
+                                NodeRef::#type_name(node)
+                            }
+                        }
+                    ));
+
+                    {
+                        let mut arms = Vec::<Arm>::new();
+
+                        for variant in &data.variants {
+                            let variant_name = &variant.ident;
+
+                            // TODO: Support all kinds of fields
+                            if variant.fields.len() != 1 {
+                                continue;
+                            }
+
+                            for f in variant.fields.iter().filter(|f| is_node_ref(&f.ty)) {
+                                let mut ty = &f.ty;
+                                if let Some(inner) = extract_generic("Box", ty) {
+                                    ty = inner;
+                                }
+
+                                arms.push(parse_quote!(
+                                    #type_name::#variant_name(v0) => {
+                                        Box::new(::std::iter::once(NodeRef::#ty(v0)))
+                                    },
+                                ));
+                            }
+                        }
+
+                        node_ref_iter_next_arms.push(parse_quote!(
+                            NodeRef::#type_name(node) => {
+                                match node {
+                                    #(#arms)*
+
+                                    _ => Box::new(::std::iter::empty::<NodeRef<'ast>>())
+                                }
+                            }
+                        ));
+                    }
+
                     defs.push(parse_quote!(
                         impl #fields_enum_name {
                             #[inline(always)]
@@ -1361,10 +1466,51 @@ fn define_fields(crate_name: &Ident, node_types: &[&Item]) -> Vec<Item> {
                         #type_name(#fields_enum_name)
                     ));
 
-                    node_ref_enum_members.push(quote!(
+                    parent_enum_members.push(quote!(
                         #type_name(&'ast #type_name, #fields_enum_name)
                     ));
 
+                    node_ref_enum_members.push(quote!(
+                        #type_name(&'ast #type_name)
+                    ));
+
+                    items.push(parse_quote!(
+                        impl<'ast> From<&'ast #type_name> for NodeRef<'ast> {
+                            fn from(node: &'ast #type_name) -> Self {
+                                NodeRef::#type_name(node)
+                            }
+                        }
+                    ));
+
+                    {
+                        let mut iter: Expr = parse_quote!(::std::iter::empty::<NodeRef<'ast>>());
+
+                        match &data.fields {
+                            Fields::Named(fields) => {
+                                for f in fields.named.iter() {
+                                    let ident = &f.ident;
+                                    let iter_expr =
+                                        to_iter(quote!(node.#ident), &f.ty, &node_names);
+                                    if let Some(iter_expr) = iter_expr {
+                                        iter = parse_quote!(#iter.chain(#iter_expr));
+                                    }
+                                }
+                            }
+
+                            Fields::Unnamed(_fields) => {
+                                // TODO: Support unnamed fields
+                            }
+                            Fields::Unit => {}
+                        }
+
+                        node_ref_iter_next_arms.push(parse_quote!(
+                            NodeRef::#type_name(node) => {
+                                let iterator = #iter;
+                                Box::new(iterator)
+                            }
+                        ));
+                    }
+
                     defs.push(parse_quote!(
                         impl #fields_enum_name {
                             pub(crate) fn set_index(&mut self, index: usize) {
@@ -1392,7 +1538,6 @@ fn define_fields(crate_name: &Ident, node_types: &[&Item]) -> Vec<Item> {
 
         {
             defs.push(parse_quote!(
-                #[cfg(any(docsrs, feature = "path"))]
                 #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
                 pub enum AstParentKind {
                     #(#kind_enum_members),*
@@ -1413,9 +1558,14 @@ fn define_fields(crate_name: &Ident, node_types: &[&Item]) -> Vec<Item> {
 
         {
             defs.push(parse_quote!(
-                #[cfg(any(docsrs, feature = "path"))]
                 #[derive(Debug, Clone, Copy)]
                 pub enum AstParentNodeRef<'ast> {
+                    #(#parent_enum_members),*
+                }
+            ));
+            items.push(parse_quote!(
+                #[derive(Debug, Clone, Copy)]
+                pub enum NodeRef<'ast> {
                     #(#node_ref_enum_members),*
                 }
             ));
@@ -1437,6 +1587,7 @@ fn define_fields(crate_name: &Ident, node_types: &[&Item]) -> Vec<Item> {
                 }
             ));
             defs.push(parse_quote!(
+                #[cfg(any(docsrs, feature = "path"))]
                 impl<'ast> AstParentNodeRef<'ast> {
                     #[inline]
                     pub fn kind(&self) -> AstParentKind {
@@ -1446,14 +1597,27 @@ fn define_fields(crate_name: &Ident, node_types: &[&Item]) -> Vec<Item> {
                     }
                 }
             ));
+            items.push(parse_quote!(
+                impl<'ast> NodeRef<'ast> {
+                    #[allow(unreachable_patterns)]
+                    pub fn raw_children(&'ast self) -> Box<dyn 'ast + Iterator<Item = NodeRef<'ast>>> {
+                        match self {
+                            #(#node_ref_iter_next_arms)*
+                        }
+                    }
+                }
+            ));
         }
 
-        items.push(parse_quote!(
-            #[cfg(any(docsrs, feature = "path"))]
-            pub mod fields {
-                #(#defs)*
-            }
-        ));
+        items.insert(
+            0,
+            parse_quote!(
+                #[cfg(any(docsrs, feature = "path"))]
+                pub mod fields {
+                    #(#defs)*
+                }
+            ),
+        );
 
         items.push(parse_quote!(
             #[cfg(any(docsrs, feature = "path"))]