diff --git a/.github/generated/ast_changes_watch_list.yml b/.github/generated/ast_changes_watch_list.yml
index 9bcbddf6d7f85..ead1e6756bed8 100644
--- a/.github/generated/ast_changes_watch_list.yml
+++ b/.github/generated/ast_changes_watch_list.yml
@@ -13,10 +13,12 @@ src:
   - 'crates/oxc_ast/src/generated/ast_kind.rs'
   - 'crates/oxc_ast/src/generated/derive_clone_in.rs'
   - 'crates/oxc_ast/src/generated/derive_content_eq.rs'
+  - 'crates/oxc_ast/src/generated/derive_dummy.rs'
   - 'crates/oxc_ast/src/generated/derive_estree.rs'
   - 'crates/oxc_ast/src/generated/derive_get_address.rs'
   - 'crates/oxc_ast/src/generated/derive_get_span.rs'
   - 'crates/oxc_ast/src/generated/derive_get_span_mut.rs'
+  - 'crates/oxc_ast/src/generated/derive_take_in.rs'
   - 'crates/oxc_ast/src/generated/get_id.rs'
   - 'crates/oxc_ast/src/serialize.rs'
   - 'crates/oxc_ast_macros/src/generated/mod.rs'
@@ -31,12 +33,14 @@ src:
   - 'crates/oxc_regular_expression/src/generated/derive_estree.rs'
   - 'crates/oxc_regular_expression/src/generated/derive_get_address.rs'
   - 'crates/oxc_span/src/generated/assert_layouts.rs'
+  - 'crates/oxc_span/src/generated/derive_dummy.rs'
   - 'crates/oxc_span/src/generated/derive_estree.rs'
   - 'crates/oxc_span/src/source_type/mod.rs'
   - 'crates/oxc_span/src/span.rs'
   - 'crates/oxc_syntax/src/generated/assert_layouts.rs'
   - 'crates/oxc_syntax/src/generated/derive_clone_in.rs'
   - 'crates/oxc_syntax/src/generated/derive_content_eq.rs'
+  - 'crates/oxc_syntax/src/generated/derive_dummy.rs'
   - 'crates/oxc_syntax/src/generated/derive_estree.rs'
   - 'crates/oxc_syntax/src/lib.rs'
   - 'crates/oxc_syntax/src/module_record.rs'
diff --git a/crates/oxc_allocator/src/lib.rs b/crates/oxc_allocator/src/lib.rs
index 963689874d1f2..ce3621b3bf2fa 100644
--- a/crates/oxc_allocator/src/lib.rs
+++ b/crates/oxc_allocator/src/lib.rs
@@ -24,6 +24,7 @@ mod convert;
 mod from_raw_parts;
 pub mod hash_map;
 pub mod string;
+mod take_in;
 mod vec;
 mod vec2;
 
@@ -34,4 +35,5 @@ pub use clone_in::CloneIn;
 pub use convert::{FromIn, IntoIn};
 pub use hash_map::HashMap;
 pub use string::String;
+pub use take_in::{Dummy, TakeIn};
 pub use vec::Vec;
diff --git a/crates/oxc_allocator/src/take_in.rs b/crates/oxc_allocator/src/take_in.rs
new file mode 100644
index 0000000000000..d26ad25225916
--- /dev/null
+++ b/crates/oxc_allocator/src/take_in.rs
@@ -0,0 +1,138 @@
+use std::{cell::Cell, mem, num};
+
+use crate::{Allocator, Box, Vec};
+
+/// A trait to replace an existing AST node with a dummy.
+pub trait TakeIn<'a>: Dummy<'a> {
+    /// Replace node with a dummy.
+    #[must_use]
+    fn take_in(&mut self, allocator: &'a Allocator) -> Self {
+        let dummy = Dummy::dummy(allocator);
+        mem::replace(self, dummy)
+    }
+}
+
+impl<'a, T> TakeIn<'a> for Vec<'a, T> {}
+
+/// A trait to create a dummy AST node.
+pub trait Dummy<'a>: Sized {
+    /// Create a dummy node.
+    fn dummy(allocator: &'a Allocator) -> Self;
+}
+
+impl<'a, T> Dummy<'a> for Option<T> {
+    /// Create a dummy [`Option`].
+    #[expect(clippy::inline_always)]
+    #[inline(always)]
+    fn dummy(_allocator: &'a Allocator) -> Self {
+        None
+    }
+}
+
+impl<'a, T: Dummy<'a>> Dummy<'a> for Box<'a, T> {
+    /// Create a dummy [`Box`].
+    #[inline]
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Box::new_in(Dummy::dummy(allocator), allocator)
+    }
+}
+
+impl<'a, T> Dummy<'a> for Vec<'a, T> {
+    /// Create a dummy [`Vec`].
+    #[inline]
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Vec::new_in(allocator)
+    }
+}
+
+impl<'a, T: Dummy<'a>> Dummy<'a> for Cell<T> {
+    /// Create a dummy [`Cell`].
+    #[expect(clippy::inline_always)]
+    #[inline(always)]
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Cell::new(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for () {
+    #[inline(always)]
+    fn dummy(_allocator: &'a Allocator) {}
+}
+
+impl<'a> Dummy<'a> for bool {
+    #[expect(clippy::inline_always)]
+    #[inline(always)]
+    fn dummy(_allocator: &'a Allocator) -> Self {
+        false
+    }
+}
+
+impl<'a> Dummy<'a> for &'a str {
+    #[expect(clippy::inline_always)]
+    #[inline(always)]
+    fn dummy(_allocator: &'a Allocator) -> Self {
+        ""
+    }
+}
+
+macro_rules! dummy_impl_int {
+    ($ty:ident) => {
+        impl<'a> Dummy<'a> for $ty {
+            #[inline(always)]
+            fn dummy(_allocator: &'a Allocator) -> Self {
+                0
+            }
+        }
+    };
+}
+
+dummy_impl_int!(u8);
+dummy_impl_int!(u16);
+dummy_impl_int!(u32);
+dummy_impl_int!(u64);
+dummy_impl_int!(u128);
+dummy_impl_int!(usize);
+dummy_impl_int!(i8);
+dummy_impl_int!(i16);
+dummy_impl_int!(i32);
+dummy_impl_int!(i64);
+dummy_impl_int!(i128);
+dummy_impl_int!(isize);
+
+macro_rules! dummy_impl_float {
+    ($ty:ident) => {
+        impl<'a> Dummy<'a> for $ty {
+            #[inline(always)]
+            fn dummy(_allocator: &'a Allocator) -> Self {
+                0.0
+            }
+        }
+    };
+}
+
+dummy_impl_float!(f32);
+dummy_impl_float!(f64);
+
+macro_rules! dummy_impl_non_zero {
+    ($ty:ident) => {
+        impl<'a> Dummy<'a> for num::$ty {
+            #[inline(always)]
+            fn dummy(_allocator: &'a Allocator) -> Self {
+                Self::MIN
+            }
+        }
+    };
+}
+
+dummy_impl_non_zero!(NonZeroU8);
+dummy_impl_non_zero!(NonZeroU16);
+dummy_impl_non_zero!(NonZeroU32);
+dummy_impl_non_zero!(NonZeroU64);
+dummy_impl_non_zero!(NonZeroU128);
+dummy_impl_non_zero!(NonZeroUsize);
+dummy_impl_non_zero!(NonZeroI8);
+dummy_impl_non_zero!(NonZeroI16);
+dummy_impl_non_zero!(NonZeroI32);
+dummy_impl_non_zero!(NonZeroI64);
+dummy_impl_non_zero!(NonZeroI128);
+dummy_impl_non_zero!(NonZeroIsize);
diff --git a/crates/oxc_ast/src/ast/js.rs b/crates/oxc_ast/src/ast/js.rs
index ad1ca827bd4ee..6aa13557e1f32 100644
--- a/crates/oxc_ast/src/ast/js.rs
+++ b/crates/oxc_ast/src/ast/js.rs
@@ -6,7 +6,7 @@
 
 use std::cell::Cell;
 
-use oxc_allocator::{Box, CloneIn, GetAddress, Vec};
+use oxc_allocator::{Box, CloneIn, Dummy, GetAddress, TakeIn, Vec};
 use oxc_ast_macros::ast;
 use oxc_estree::ESTree;
 use oxc_span::{Atom, ContentEq, GetSpan, GetSpanMut, SourceType, Span};
@@ -29,7 +29,7 @@ use super::{macros::inherit_variants, *};
     strict_if = self.source_type.is_strict() || self.has_use_strict_directive(),
 )]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(field_order(span, directives, source_type, hashbang))]
 pub struct Program<'a> {
     pub span: Span,
@@ -55,7 +55,7 @@ inherit_variants! {
 /// [`ast` module docs]: `super`
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum Expression<'a> {
     /// See [`BooleanLiteral`] for AST node details.
     BooleanLiteral(Box<'a, BooleanLiteral>) = 0,
@@ -208,7 +208,7 @@ pub use match_expression;
 /// digits, `$`, or `_`.
 #[ast(visit)]
 #[derive(Debug, Clone)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(
     rename = "Identifier",
     add_fields(decorators = TsEmptyArray, optional = TsFalse, typeAnnotation = TsNull)
@@ -226,7 +226,7 @@ pub struct IdentifierName<'a> {
 /// See: [13.1 Identifiers](https://tc39.es/ecma262/#sec-identifiers)
 #[ast(visit)]
 #[derive(Debug, Clone)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(
     rename = "Identifier",
     add_fields(decorators = TsEmptyArray, optional = TsFalse, typeAnnotation = TsNull)
@@ -252,7 +252,7 @@ pub struct IdentifierReference<'a> {
 /// See: [13.1 Identifiers](https://tc39.es/ecma262/#sec-identifiers)
 #[ast(visit)]
 #[derive(Debug, Clone)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(
     rename = "Identifier",
     add_fields(decorators = TsEmptyArray, optional = TsFalse, typeAnnotation = TsNull)
@@ -278,7 +278,7 @@ pub struct BindingIdentifier<'a> {
 /// See: [13.1 Identifiers](https://tc39.es/ecma262/#sec-identifiers)
 #[ast(visit)]
 #[derive(Debug, Clone)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(rename = "Identifier")]
 pub struct LabelIdentifier<'a> {
     pub span: Span,
@@ -291,7 +291,7 @@ pub struct LabelIdentifier<'a> {
 /// Represents a `this` expression, which is a reference to the current object.
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct ThisExpression {
     pub span: Span,
 }
@@ -301,7 +301,7 @@ pub struct ThisExpression {
 /// Represents an array literal, which can include elements, spread elements, or null values.
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct ArrayExpression<'a> {
     pub span: Span,
     pub elements: Vec<'a, ArrayExpressionElement<'a>>,
@@ -319,7 +319,7 @@ inherit_variants! {
 /// [`ast` module docs]: `super`
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub enum ArrayExpressionElement<'a> {
     /// `...[3, 4]` in `const array = [1, 2, ...[3, 4], null];`
     SpreadElement(Box<'a, SpreadElement<'a>>) = 64,
@@ -339,7 +339,7 @@ pub enum ArrayExpressionElement<'a> {
 /// Serialized as `null` in JSON AST. See `serialize.rs`.
 #[ast(visit)]
 #[derive(Debug, Clone)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(via = ElisionConverter)]
 pub struct Elision {
     pub span: Span,
@@ -353,7 +353,7 @@ pub struct Elision {
 /// If the object literal has a trailing comma, `trailing_comma` contains the span of that comma.
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct ObjectExpression<'a> {
     pub span: Span,
     /// Properties declared in the object
@@ -365,7 +365,7 @@ pub struct ObjectExpression<'a> {
 /// Represents a property in an object literal.
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum ObjectPropertyKind<'a> {
     /// `a: 1` in `const obj = { a: 1 };`
     ObjectProperty(Box<'a, ObjectProperty<'a>>) = 0,
@@ -378,7 +378,7 @@ pub enum ObjectPropertyKind<'a> {
 /// Represents a property in an object literal.
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(rename = "Property", field_order(span, method, shorthand, computed, key, value, kind))]
 pub struct ObjectProperty<'a> {
     pub span: Span,
@@ -398,7 +398,7 @@ inherit_variants! {
 /// [`ast` module docs]: `super`
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum PropertyKey<'a> {
     /// `a` in `const obj = { a: 1 }; obj.a;`
     StaticIdentifier(Box<'a, IdentifierName<'a>>) = 64,
@@ -412,7 +412,7 @@ pub enum PropertyKey<'a> {
 /// Represents the kind of property in an object literal or class.
 #[ast]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-#[generate_derive(CloneIn, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, ContentEq, ESTree)]
 pub enum PropertyKind {
     /// `a: 1` in `const obj = { a: 1 };`
     Init = 0,
@@ -427,7 +427,7 @@ pub enum PropertyKind {
 /// Represents a template literal, which can include quasi elements and expression elements.
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(field_order(span, expressions, quasis))]
 pub struct TemplateLiteral<'a> {
     pub span: Span,
@@ -440,7 +440,7 @@ pub struct TemplateLiteral<'a> {
 /// Represents a tagged template expression, which can include a tag and a quasi.
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TaggedTemplateExpression<'a> {
     pub span: Span,
     pub tag: Expression<'a>,
@@ -454,7 +454,7 @@ pub struct TaggedTemplateExpression<'a> {
 /// Represents a quasi element in a template literal.
 #[ast(visit)]
 #[derive(Debug, Clone)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TemplateElement<'a> {
     pub span: Span,
     pub value: TemplateElementValue<'a>,
@@ -464,7 +464,7 @@ pub struct TemplateElement<'a> {
 /// See [template-strings-cooked-vs-raw](https://exploringjs.com/js/book/ch_template-literals.html#template-strings-cooked-vs-raw)
 #[ast]
 #[derive(Debug, Clone)]
-#[generate_derive(CloneIn, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, ContentEq, ESTree)]
 #[estree(no_type)]
 pub struct TemplateElementValue<'a> {
     /// A raw interpretation where backslashes do not have special meaning.
@@ -484,7 +484,7 @@ pub struct TemplateElementValue<'a> {
 /// <https://tc39.es/ecma262/#prod-MemberExpression>
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum MemberExpression<'a> {
     /// `ar[0]` in `const ar = [1, 2]; ar[0];`
     ComputedMemberExpression(Box<'a, ComputedMemberExpression<'a>>) = 48,
@@ -510,7 +510,7 @@ pub use match_member_expression;
 /// Represents a computed member access expression, which can include an object and an expression.
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(
     rename = "MemberExpression",
     add_fields(computed = True),
@@ -529,7 +529,7 @@ pub struct ComputedMemberExpression<'a> {
 /// Represents a static member access expression, which can include an object and a property.
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(
     rename = "MemberExpression",
     add_fields(computed = False),
@@ -547,7 +547,7 @@ pub struct StaticMemberExpression<'a> {
 /// Represents a private field access expression, which can include an object and a private identifier.
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(
     rename = "MemberExpression",
     add_fields(computed = False),
@@ -579,7 +579,7 @@ pub struct PrivateFieldExpression<'a> {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct CallExpression<'a> {
     pub span: Span,
     pub callee: Expression<'a>,
@@ -607,7 +607,7 @@ pub struct CallExpression<'a> {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct NewExpression<'a> {
     pub span: Span,
     pub callee: Expression<'a>,
@@ -625,7 +625,7 @@ pub struct NewExpression<'a> {
 /// Represents a meta property. The following syntaxes are supported. `import.meta`, `new.target`.
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct MetaProperty<'a> {
     pub span: Span,
     pub meta: IdentifierName<'a>,
@@ -637,7 +637,7 @@ pub struct MetaProperty<'a> {
 /// Represents a spread element, which can include an argument.
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct SpreadElement<'a> {
     pub span: Span,
     /// The expression being spread.
@@ -652,7 +652,7 @@ inherit_variants! {
 /// [`ast` module docs]: `super`
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum Argument<'a> {
     /// `...[1, 2]` in `const arr = [...[1, 2]];`
     SpreadElement(Box<'a, SpreadElement<'a>>) = 64,
@@ -667,7 +667,7 @@ pub enum Argument<'a> {
 /// The following syntaxes are supported: `++a`, `a++`, `--a`, `a--`.
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct UpdateExpression<'a> {
     pub span: Span,
     pub operator: UpdateOperator,
@@ -681,7 +681,7 @@ pub struct UpdateExpression<'a> {
 /// The following syntaxes are supported: `+a`, `-a`, `~a`, `!a`, `delete a`, `void a`, `typeof a`.
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(add_fields(prefix = True), field_order(span, operator, prefix, argument))]
 pub struct UnaryExpression<'a> {
     pub span: Span,
@@ -694,7 +694,7 @@ pub struct UnaryExpression<'a> {
 /// Represents a binary expression, which include a left expression, an operator, and a right expression.
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct BinaryExpression<'a> {
     pub span: Span,
     pub left: Expression<'a>,
@@ -705,7 +705,7 @@ pub struct BinaryExpression<'a> {
 /// `#brand in obj` in `class Foo { #brand; static isFoo(obj) { return #brand in obj; } }`.
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(
     rename = "BinaryExpression",
     add_fields(operator = In),
@@ -723,7 +723,7 @@ pub struct PrivateInExpression<'a> {
 /// The following syntaxes are supported: `||`, `&&` and `??`.
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct LogicalExpression<'a> {
     pub span: Span,
     pub left: Expression<'a>,
@@ -736,7 +736,7 @@ pub struct LogicalExpression<'a> {
 /// Represents a conditional expression, which includes a test, a consequent, and an alternate.
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct ConditionalExpression<'a> {
     pub span: Span,
     pub test: Expression<'a>,
@@ -749,7 +749,7 @@ pub struct ConditionalExpression<'a> {
 /// Represents an assignment expression, which includes an operator, a target, and an expression.
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct AssignmentExpression<'a> {
     pub span: Span,
     pub operator: AssignmentOperator,
@@ -766,7 +766,7 @@ inherit_variants! {
 /// [`ast` module docs]: `super`
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum AssignmentTarget<'a> {
     // `SimpleAssignmentTarget` variants added here by `inherit_variants!` macro
     @inherit SimpleAssignmentTarget
@@ -783,7 +783,7 @@ inherit_variants! {
 /// [`ast` module docs]: `super`
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum SimpleAssignmentTarget<'a> {
     AssignmentTargetIdentifier(Box<'a, IdentifierReference<'a>>) = 0,
     TSAsExpression(Box<'a, TSAsExpression<'a>>) = 1,
@@ -833,7 +833,7 @@ pub use match_simple_assignment_target;
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum AssignmentTargetPattern<'a> {
     ArrayAssignmentTarget(Box<'a, ArrayAssignmentTarget<'a>>) = 8,
     ObjectAssignmentTarget(Box<'a, ObjectAssignmentTarget<'a>>) = 9,
@@ -853,7 +853,7 @@ pub use match_assignment_target_pattern;
 /// Represents an array assignment target, which can include elements and a rest element.
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(rename = "ArrayPattern")]
 pub struct ArrayAssignmentTarget<'a> {
     pub span: Span,
@@ -869,7 +869,7 @@ pub struct ArrayAssignmentTarget<'a> {
 /// Represents an object assignment target, which can include properties and a rest element.
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(rename = "ObjectPattern")]
 pub struct ObjectAssignmentTarget<'a> {
     pub span: Span,
@@ -883,7 +883,7 @@ pub struct ObjectAssignmentTarget<'a> {
 /// Represents a rest element in an array assignment target, which can include a target.
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(rename = "RestElement")]
 pub struct AssignmentTargetRest<'a> {
     pub span: Span,
@@ -899,7 +899,7 @@ inherit_variants! {
 /// [`ast` module docs]: `super`
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum AssignmentTargetMaybeDefault<'a> {
     AssignmentTargetWithDefault(Box<'a, AssignmentTargetWithDefault<'a>>) = 16,
     // `AssignmentTarget` variants added here by `inherit_variants!` macro
@@ -909,7 +909,7 @@ pub enum AssignmentTargetMaybeDefault<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(rename = "AssignmentPattern")]
 pub struct AssignmentTargetWithDefault<'a> {
     pub span: Span,
@@ -921,7 +921,7 @@ pub struct AssignmentTargetWithDefault<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum AssignmentTargetProperty<'a> {
     AssignmentTargetPropertyIdentifier(Box<'a, AssignmentTargetPropertyIdentifier<'a>>) = 0,
     AssignmentTargetPropertyProperty(Box<'a, AssignmentTargetPropertyProperty<'a>>) = 1,
@@ -933,7 +933,7 @@ pub enum AssignmentTargetProperty<'a> {
 /// and an optional init expression.
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(
     rename = "Property",
     add_fields(method = False, shorthand = True, computed = False, kind = Init),
@@ -952,7 +952,7 @@ pub struct AssignmentTargetPropertyIdentifier<'a> {
 /// Represents an assignment target property property, which includes a name and a binding.
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(
     rename = "Property",
     add_fields(method = False, shorthand = False, kind = Init),
@@ -983,7 +983,7 @@ pub struct AssignmentTargetPropertyProperty<'a> {
 /// Represents a sequence expression.
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct SequenceExpression<'a> {
     pub span: Span,
     pub expressions: Vec<'a, Expression<'a>>,
@@ -994,7 +994,7 @@ pub struct SequenceExpression<'a> {
 /// Represents a super expression.
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct Super {
     pub span: Span,
 }
@@ -1004,7 +1004,7 @@ pub struct Super {
 /// Represents an await expression, which can include an argument.
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct AwaitExpression<'a> {
     pub span: Span,
     pub argument: Expression<'a>,
@@ -1015,7 +1015,7 @@ pub struct AwaitExpression<'a> {
 /// Represents a chain expression, which can include an expression.
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct ChainExpression<'a> {
     pub span: Span,
     pub expression: ChainElement<'a>,
@@ -1029,7 +1029,7 @@ inherit_variants! {
 /// [`ast` module docs]: `super`
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum ChainElement<'a> {
     CallExpression(Box<'a, CallExpression<'a>>) = 0,
     /// `foo?.baz!` or `foo?.[bar]!`
@@ -1044,7 +1044,7 @@ pub enum ChainElement<'a> {
 /// Represents a parenthesized expression, which can include an expression.
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct ParenthesizedExpression<'a> {
     pub span: Span,
     pub expression: Expression<'a>,
@@ -1059,7 +1059,7 @@ inherit_variants! {
 /// [`ast` module docs]: `super`
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum Statement<'a> {
     // Statements
     BlockStatement(Box<'a, BlockStatement<'a>>) = 0,
@@ -1092,7 +1092,7 @@ pub enum Statement<'a> {
 /// Represents a directive statement, which can include a string literal.
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(rename = "ExpressionStatement")]
 pub struct Directive<'a> {
     pub span: Span,
@@ -1107,7 +1107,7 @@ pub struct Directive<'a> {
 /// Represents a hashbang directive, which can include a value.
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct Hashbang<'a> {
     pub span: Span,
     pub value: Atom<'a>,
@@ -1119,7 +1119,7 @@ pub struct Hashbang<'a> {
 #[ast(visit)]
 #[scope]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct BlockStatement<'a> {
     pub span: Span,
     pub body: Vec<'a, Statement<'a>>,
@@ -1129,7 +1129,7 @@ pub struct BlockStatement<'a> {
 /// Declarations and the Variable Statement
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum Declaration<'a> {
     VariableDeclaration(Box<'a, VariableDeclaration<'a>>) = 32,
     #[visit(args(flags = ScopeFlags::Function))]
@@ -1164,7 +1164,7 @@ pub use match_declaration;
 /// Represents a variable declaration, which can include a kind, declarations, and modifiers.
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(field_order(span, declarations, kind, declare))]
 pub struct VariableDeclaration<'a> {
     pub span: Span,
@@ -1176,7 +1176,7 @@ pub struct VariableDeclaration<'a> {
 
 #[ast]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-#[generate_derive(CloneIn, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, ContentEq, ESTree)]
 pub enum VariableDeclarationKind {
     Var = 0,
     Let = 1,
@@ -1196,7 +1196,7 @@ pub enum VariableDeclarationKind {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct VariableDeclarator<'a> {
     pub span: Span,
     #[estree(skip)]
@@ -1210,7 +1210,7 @@ pub struct VariableDeclarator<'a> {
 /// Empty Statement
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct EmptyStatement {
     pub span: Span,
 }
@@ -1218,7 +1218,7 @@ pub struct EmptyStatement {
 /// Expression Statement
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(add_fields(directive = ExpressionStatementDirective))] // Only in TS AST
 pub struct ExpressionStatement<'a> {
     pub span: Span,
@@ -1228,7 +1228,7 @@ pub struct ExpressionStatement<'a> {
 /// If Statement
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct IfStatement<'a> {
     pub span: Span,
     pub test: Expression<'a>,
@@ -1239,7 +1239,7 @@ pub struct IfStatement<'a> {
 /// Do-While Statement
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct DoWhileStatement<'a> {
     pub span: Span,
     pub body: Statement<'a>,
@@ -1249,7 +1249,7 @@ pub struct DoWhileStatement<'a> {
 /// While Statement
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct WhileStatement<'a> {
     pub span: Span,
     pub test: Expression<'a>,
@@ -1260,7 +1260,7 @@ pub struct WhileStatement<'a> {
 #[ast(visit)]
 #[scope]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct ForStatement<'a> {
     pub span: Span,
     pub init: Option<ForStatementInit<'a>>,
@@ -1278,7 +1278,7 @@ inherit_variants! {
 /// [`ast` module docs]: `super`
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum ForStatementInit<'a> {
     VariableDeclaration(Box<'a, VariableDeclaration<'a>>) = 64,
     // `Expression` variants added here by `inherit_variants!` macro
@@ -1290,7 +1290,7 @@ pub enum ForStatementInit<'a> {
 #[ast(visit)]
 #[scope]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct ForInStatement<'a> {
     pub span: Span,
     pub left: ForStatementLeft<'a>,
@@ -1307,7 +1307,7 @@ inherit_variants! {
 /// [`ast` module docs]: `super`
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum ForStatementLeft<'a> {
     VariableDeclaration(Box<'a, VariableDeclaration<'a>>) = 16,
     // `AssignmentTarget` variants added here by `inherit_variants!` macro
@@ -1318,7 +1318,7 @@ pub enum ForStatementLeft<'a> {
 #[ast(visit)]
 #[scope]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct ForOfStatement<'a> {
     pub span: Span,
     pub r#await: bool,
@@ -1331,7 +1331,7 @@ pub struct ForOfStatement<'a> {
 /// Continue Statement
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct ContinueStatement<'a> {
     pub span: Span,
     pub label: Option<LabelIdentifier<'a>>,
@@ -1340,7 +1340,7 @@ pub struct ContinueStatement<'a> {
 /// Break Statement
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct BreakStatement<'a> {
     pub span: Span,
     pub label: Option<LabelIdentifier<'a>>,
@@ -1349,7 +1349,7 @@ pub struct BreakStatement<'a> {
 /// Return Statement
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct ReturnStatement<'a> {
     pub span: Span,
     pub argument: Option<Expression<'a>>,
@@ -1358,7 +1358,7 @@ pub struct ReturnStatement<'a> {
 /// With Statement
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct WithStatement<'a> {
     pub span: Span,
     pub object: Expression<'a>,
@@ -1369,7 +1369,7 @@ pub struct WithStatement<'a> {
 #[ast(visit)]
 #[scope]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct SwitchStatement<'a> {
     pub span: Span,
     pub discriminant: Expression<'a>,
@@ -1380,7 +1380,7 @@ pub struct SwitchStatement<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(field_order(span, consequent, test))]
 pub struct SwitchCase<'a> {
     pub span: Span,
@@ -1391,7 +1391,7 @@ pub struct SwitchCase<'a> {
 /// Labelled Statement
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(field_order(span, body, label))]
 pub struct LabeledStatement<'a> {
     pub span: Span,
@@ -1408,7 +1408,7 @@ pub struct LabeledStatement<'a> {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct ThrowStatement<'a> {
     pub span: Span,
     /// The expression being thrown, e.g. `err` in `throw err;`
@@ -1432,7 +1432,7 @@ pub struct ThrowStatement<'a> {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TryStatement<'a> {
     pub span: Span,
     /// Statements in the `try` block
@@ -1458,7 +1458,7 @@ pub struct TryStatement<'a> {
 #[ast(visit)]
 #[scope(flags = ScopeFlags::CatchClause)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct CatchClause<'a> {
     pub span: Span,
     /// The caught error parameter, e.g. `e` in `catch (e) {}`
@@ -1483,7 +1483,7 @@ pub struct CatchClause<'a> {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(no_type, ts_alias = "BindingPattern")]
 pub struct CatchParameter<'a> {
     #[estree(skip)]
@@ -1502,7 +1502,7 @@ pub struct CatchParameter<'a> {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct DebuggerStatement {
     pub span: Span,
 }
@@ -1511,7 +1511,7 @@ pub struct DebuggerStatement {
 /// * <https://tc39.es/ecma262/#prod-BindingPattern>
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(no_type)]
 pub struct BindingPattern<'a> {
     // estree(flatten) the attributes because estree has no `BindingPattern`
@@ -1529,7 +1529,7 @@ pub struct BindingPattern<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum BindingPatternKind<'a> {
     /// `const a = 1`
     BindingIdentifier(Box<'a, BindingIdentifier<'a>>) = 0,
@@ -1546,7 +1546,7 @@ pub enum BindingPatternKind<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(add_fields(decorators = TsEmptyArray))]
 pub struct AssignmentPattern<'a> {
     pub span: Span,
@@ -1556,7 +1556,7 @@ pub struct AssignmentPattern<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct ObjectPattern<'a> {
     pub span: Span,
     pub properties: Vec<'a, BindingProperty<'a>>,
@@ -1566,7 +1566,7 @@ pub struct ObjectPattern<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(
     rename = "Property",
     add_fields(method = False, kind = Init),
@@ -1582,7 +1582,7 @@ pub struct BindingProperty<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(add_fields(decorators = TsEmptyArray, optional = TsFalse, typeAnnotation = TsNull))]
 pub struct ArrayPattern<'a> {
     pub span: Span,
@@ -1602,7 +1602,7 @@ pub struct ArrayPattern<'a> {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(rename = "RestElement")]
 pub struct BindingRestElement<'a> {
     pub span: Span,
@@ -1652,7 +1652,7 @@ pub struct BindingRestElement<'a> {
     strict_if = self.has_use_strict_directive(),
 )]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 // https://github.com/estree/estree/blob/master/es5.md#patterns
 // https://github.com/DefinitelyTyped/DefinitelyTyped/blob/cd61c555bfc93e985b313263a42ed78074570d08/types/estree/index.d.ts#L411
 #[estree(
@@ -1729,7 +1729,7 @@ pub struct Function<'a> {
 
 #[ast]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-#[generate_derive(CloneIn, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, ContentEq, ESTree)]
 #[estree(no_rename_variants)]
 pub enum FunctionType {
     FunctionDeclaration = 0,
@@ -1742,7 +1742,7 @@ pub enum FunctionType {
 /// <https://tc39.es/ecma262/#prod-FormalParameters>
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(
     via = FormalParametersConverter,
     add_ts_def = "
@@ -1765,7 +1765,7 @@ pub struct FormalParameters<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 // Pluralize as `FormalParameterList` to avoid naming clash with `FormalParameters`.
 #[plural(FormalParameterList)]
 #[estree(no_type)]
@@ -1789,7 +1789,7 @@ pub struct FormalParameter<'a> {
 
 #[ast]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-#[generate_derive(CloneIn, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, ContentEq, ESTree)]
 #[estree(no_rename_variants, no_ts_def)]
 pub enum FormalParameterKind {
     /// <https://tc39.es/ecma262/#prod-FormalParameters>
@@ -1805,7 +1805,7 @@ pub enum FormalParameterKind {
 /// <https://tc39.es/ecma262/#prod-FunctionBody>
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(rename = "BlockStatement")]
 pub struct FunctionBody<'a> {
     pub span: Span,
@@ -1822,7 +1822,7 @@ pub struct FunctionBody<'a> {
     strict_if = self.has_use_strict_directive(),
 )]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(
     add_fields(id = Null, generator = False),
     field_order(span, id, expression, generator, r#async, params, body, type_parameters, return_type),
@@ -1851,7 +1851,7 @@ pub struct ArrowFunctionExpression<'a> {
 /// Generator Function Definitions
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct YieldExpression<'a> {
     pub span: Span,
     pub delegate: bool,
@@ -1862,7 +1862,7 @@ pub struct YieldExpression<'a> {
 #[ast(visit)]
 #[scope(flags = ScopeFlags::StrictMode)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[rustfmt::skip]
 #[estree(field_order(
     r#type, span, id, super_class, body,
@@ -1941,7 +1941,7 @@ pub struct Class<'a> {
 
 #[ast]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-#[generate_derive(CloneIn, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, ContentEq, ESTree)]
 #[estree(no_rename_variants)]
 pub enum ClassType {
     /// Class declaration statement
@@ -1959,7 +1959,7 @@ pub enum ClassType {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct ClassBody<'a> {
     pub span: Span,
     pub body: Vec<'a, ClassElement<'a>>,
@@ -1985,7 +1985,7 @@ pub struct ClassBody<'a> {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum ClassElement<'a> {
     StaticBlock(Box<'a, StaticBlock<'a>>) = 0,
     /// Class Methods
@@ -2007,7 +2007,7 @@ pub enum ClassElement<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[rustfmt::skip]
 #[estree(field_order(
     r#type, span, r#static, computed, key, kind, value,
@@ -2042,7 +2042,7 @@ pub struct MethodDefinition<'a> {
 
 #[ast]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-#[generate_derive(CloneIn, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, ContentEq, ESTree)]
 #[estree(no_rename_variants)]
 pub enum MethodDefinitionType {
     MethodDefinition = 0,
@@ -2051,7 +2051,7 @@ pub enum MethodDefinitionType {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[rustfmt::skip]
 #[estree(field_order(
     r#type, span, r#static, computed, key, value,
@@ -2144,7 +2144,7 @@ pub struct PropertyDefinition<'a> {
 
 #[ast]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-#[generate_derive(CloneIn, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, ContentEq, ESTree)]
 #[estree(no_rename_variants)]
 pub enum PropertyDefinitionType {
     PropertyDefinition = 0,
@@ -2153,7 +2153,7 @@ pub enum PropertyDefinitionType {
 
 #[ast]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-#[generate_derive(CloneIn, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, ContentEq, ESTree)]
 pub enum MethodDefinitionKind {
     /// Class constructor
     Constructor = 0,
@@ -2170,7 +2170,7 @@ pub enum MethodDefinitionKind {
 /// See: [MDN - Private class fields](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Classes/Private_class_fields)
 #[ast(visit)]
 #[derive(Debug, Clone)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct PrivateIdentifier<'a> {
     pub span: Span,
     pub name: Atom<'a>,
@@ -2192,7 +2192,7 @@ pub struct PrivateIdentifier<'a> {
 #[ast(visit)]
 #[scope(flags = ScopeFlags::ClassStaticBlock)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct StaticBlock<'a> {
     pub span: Span,
     pub body: Vec<'a, Statement<'a>>,
@@ -2224,7 +2224,7 @@ pub struct StaticBlock<'a> {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum ModuleDeclaration<'a> {
     /// `import hello from './world.js';`
     /// `import * as t from './world.js';`
@@ -2259,7 +2259,7 @@ pub use match_module_declaration;
 
 #[ast]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-#[generate_derive(CloneIn, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, ContentEq, ESTree)]
 #[estree(no_rename_variants)]
 pub enum AccessorPropertyType {
     AccessorProperty = 0,
@@ -2276,7 +2276,7 @@ pub enum AccessorPropertyType {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[rustfmt::skip]
 #[estree(field_order(
     r#type, span, key, value, computed, r#static,
@@ -2326,7 +2326,7 @@ pub struct AccessorProperty<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct ImportExpression<'a> {
     pub span: Span,
     pub source: Expression<'a>,
@@ -2338,7 +2338,7 @@ pub struct ImportExpression<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct ImportDeclaration<'a> {
     pub span: Span,
     /// `None` for `import 'foo'`, `Some([])` for `import {} from 'foo'`
@@ -2362,7 +2362,7 @@ pub struct ImportDeclaration<'a> {
 /// <https://github.com/estree/estree/blob/2b48e56efc223ea477a45b5e034039934c5791fa/stage3/source-phase-imports.md>
 #[ast]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-#[generate_derive(CloneIn, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, ContentEq, ESTree)]
 pub enum ImportPhase {
     Source = 0,
     Defer = 1,
@@ -2370,7 +2370,7 @@ pub enum ImportPhase {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum ImportDeclarationSpecifier<'a> {
     /// import {imported} from "source"
     /// import {imported as local} from "source"
@@ -2385,7 +2385,7 @@ pub enum ImportDeclarationSpecifier<'a> {
 // import {imported as local} from "source"
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct ImportSpecifier<'a> {
     pub span: Span,
     pub imported: ModuleExportName<'a>,
@@ -2414,7 +2414,7 @@ pub struct ImportSpecifier<'a> {
 ///
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct ImportDefaultSpecifier<'a> {
     pub span: Span,
     /// The name of the imported symbol.
@@ -2429,7 +2429,7 @@ pub struct ImportDefaultSpecifier<'a> {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct ImportNamespaceSpecifier<'a> {
     pub span: Span,
     pub local: BindingIdentifier<'a>,
@@ -2437,7 +2437,7 @@ pub struct ImportNamespaceSpecifier<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(no_ts_def)]
 pub struct WithClause<'a> {
     pub span: Span,
@@ -2447,7 +2447,7 @@ pub struct WithClause<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct ImportAttribute<'a> {
     pub span: Span,
     pub key: ImportAttributeKey<'a>,
@@ -2456,7 +2456,7 @@ pub struct ImportAttribute<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub enum ImportAttributeKey<'a> {
     Identifier(IdentifierName<'a>) = 0,
     StringLiteral(StringLiteral<'a>) = 1,
@@ -2475,7 +2475,7 @@ pub enum ImportAttributeKey<'a> {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct ExportNamedDeclaration<'a> {
     pub span: Span,
     pub declaration: Option<Declaration<'a>>,
@@ -2500,7 +2500,7 @@ pub struct ExportNamedDeclaration<'a> {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct ExportDefaultDeclaration<'a> {
     pub span: Span,
     #[estree(skip)]
@@ -2519,7 +2519,7 @@ pub struct ExportDefaultDeclaration<'a> {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct ExportAllDeclaration<'a> {
     pub span: Span,
     /// If this declaration is re-named
@@ -2545,7 +2545,7 @@ pub struct ExportAllDeclaration<'a> {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct ExportSpecifier<'a> {
     pub span: Span,
     pub local: ModuleExportName<'a>,
@@ -2562,7 +2562,7 @@ inherit_variants! {
 /// [`ast` module docs]: `super`
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum ExportDefaultDeclarationKind<'a> {
     #[visit(args(flags = ScopeFlags::Function))]
     FunctionDeclaration(Box<'a, Function<'a>>) = 64,
@@ -2584,7 +2584,7 @@ pub enum ExportDefaultDeclarationKind<'a> {
 /// * <https://github.com/tc39/ecma262/pull/2154>
 #[ast(visit)]
 #[derive(Debug, Clone)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub enum ModuleExportName<'a> {
     IdentifierName(IdentifierName<'a>) = 0,
     /// For `local` in `ExportSpecifier`: `foo` in `export { foo }`
@@ -2596,7 +2596,7 @@ pub enum ModuleExportName<'a> {
 /// See: [runtime.h](https://github.com/v8/v8/blob/5fe0aa3bc79c0a9d3ad546b79211f07105f09585/src/runtime/runtime.h#L43)
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct V8IntrinsicExpression<'a> {
     pub span: Span,
     pub name: IdentifierName<'a>,
diff --git a/crates/oxc_ast/src/ast/jsx.rs b/crates/oxc_ast/src/ast/jsx.rs
index 01b2dc26eb37b..f3f8f278c7a53 100644
--- a/crates/oxc_ast/src/ast/jsx.rs
+++ b/crates/oxc_ast/src/ast/jsx.rs
@@ -4,7 +4,7 @@
 // They are purely markers for codegen used in `tasks/ast_tools` and `crates/oxc_traverse/scripts`. See docs in those crates.
 // Read [`macro@oxc_ast_macros::ast`] for more information.
 
-use oxc_allocator::{Box, CloneIn, GetAddress, Vec};
+use oxc_allocator::{Box, CloneIn, Dummy, GetAddress, TakeIn, Vec};
 use oxc_ast_macros::ast;
 use oxc_estree::ESTree;
 use oxc_span::{Atom, ContentEq, GetSpan, GetSpanMut, Span};
@@ -32,7 +32,7 @@ use super::{inherit_variants, js::*, literal::*, ts::*};
 /// See: [JSX Syntax](https://facebook.github.io/jsx/)
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct JSXElement<'a> {
     /// Node location in source code
     pub span: Span,
@@ -61,7 +61,7 @@ pub struct JSXElement<'a> {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(field_order(span, attributes, name, self_closing, type_arguments))]
 pub struct JSXOpeningElement<'a> {
     /// Node location in source code
@@ -96,7 +96,7 @@ pub struct JSXOpeningElement<'a> {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct JSXClosingElement<'a> {
     /// Node location in source code
     pub span: Span,
@@ -114,7 +114,7 @@ pub struct JSXClosingElement<'a> {
 /// See: [`React.Fragment`](https://react.dev/reference/react/Fragment)
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct JSXFragment<'a> {
     /// Node location in source code
     pub span: Span,
@@ -129,7 +129,7 @@ pub struct JSXFragment<'a> {
 /// JSX Opening Fragment (`<>`)
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(add_fields(attributes = JSXOpeningFragmentAttributes, selfClosing = False))]
 pub struct JSXOpeningFragment {
     /// Node location in source code
@@ -139,7 +139,7 @@ pub struct JSXOpeningFragment {
 /// JSX Closing Fragment (`</>`)
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct JSXClosingFragment {
     /// Node location in source code
     pub span: Span,
@@ -148,7 +148,7 @@ pub struct JSXClosingFragment {
 /// JSX Element Name
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum JSXElementName<'a> {
     /// `<div />`
     Identifier(Box<'a, JSXIdentifier<'a>>) = 0,
@@ -173,7 +173,7 @@ pub enum JSXElementName<'a> {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct JSXNamespacedName<'a> {
     /// Node location in source code
     pub span: Span,
@@ -200,7 +200,7 @@ pub struct JSXNamespacedName<'a> {
 /// [`member expression`]: JSXMemberExpressionObject::MemberExpression
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct JSXMemberExpression<'a> {
     /// Node location in source code
     pub span: Span,
@@ -228,7 +228,7 @@ pub struct JSXMemberExpression<'a> {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum JSXMemberExpressionObject<'a> {
     /// `<Apple.Orange />`
     #[estree(via = JSXElementIdentifierReference)]
@@ -255,7 +255,7 @@ pub enum JSXMemberExpressionObject<'a> {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct JSXExpressionContainer<'a> {
     /// Node location in source code
     pub span: Span,
@@ -272,7 +272,7 @@ inherit_variants! {
 /// [`ast` module docs]: `super`
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub enum JSXExpression<'a> {
     /// An empty expression
     ///
@@ -290,7 +290,7 @@ pub enum JSXExpression<'a> {
 /// An empty JSX expression (`{}`)
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct JSXEmptyExpression {
     /// Node location in source code
     pub span: Span,
@@ -309,7 +309,7 @@ pub struct JSXEmptyExpression {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum JSXAttributeItem<'a> {
     /// A `key="value"` attribute
     Attribute(Box<'a, JSXAttribute<'a>>) = 0,
@@ -330,7 +330,7 @@ pub enum JSXAttributeItem<'a> {
 /// //                 name ^^^ ^^^^ value
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct JSXAttribute<'a> {
     /// Node location in source code
     pub span: Span,
@@ -351,7 +351,7 @@ pub struct JSXAttribute<'a> {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct JSXSpreadAttribute<'a> {
     /// Node location in source code
     pub span: Span,
@@ -376,7 +376,7 @@ pub struct JSXSpreadAttribute<'a> {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum JSXAttributeName<'a> {
     /// An attribute name without a namespace prefix, e.g. `foo` in `foo="bar"`.
     Identifier(Box<'a, JSXIdentifier<'a>>) = 0,
@@ -404,7 +404,7 @@ pub enum JSXAttributeName<'a> {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum JSXAttributeValue<'a> {
     /// `<Component foo="bar" />`
     StringLiteral(Box<'a, StringLiteral<'a>>) = 0,
@@ -423,7 +423,7 @@ pub enum JSXAttributeValue<'a> {
 /// [`IdentifierName`]: super::IdentifierName
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct JSXIdentifier<'a> {
     /// Node location in source code
     pub span: Span,
@@ -439,7 +439,7 @@ pub struct JSXIdentifier<'a> {
 /// Part of a [`JSXElement`].
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum JSXChild<'a> {
     /// `<Foo>Some Text</Foo>`
     Text(Box<'a, JSXText<'a>>) = 0,
@@ -458,7 +458,7 @@ pub enum JSXChild<'a> {
 /// Variant of [`JSXChild`] that represents an object spread (`{...expression}`).
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct JSXSpreadChild<'a> {
     /// Node location in source code
     pub span: Span,
@@ -478,7 +478,7 @@ pub struct JSXSpreadChild<'a> {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct JSXText<'a> {
     /// Node location in source code
     pub span: Span,
diff --git a/crates/oxc_ast/src/ast/literal.rs b/crates/oxc_ast/src/ast/literal.rs
index 3911784fa7683..fc4a695e1a6eb 100644
--- a/crates/oxc_ast/src/ast/literal.rs
+++ b/crates/oxc_ast/src/ast/literal.rs
@@ -7,7 +7,7 @@
 use std::hash::Hash;
 
 use bitflags::bitflags;
-use oxc_allocator::{Box, CloneIn};
+use oxc_allocator::{Box, CloneIn, Dummy, TakeIn};
 use oxc_ast_macros::ast;
 use oxc_estree::ESTree;
 use oxc_regular_expression::ast::Pattern;
@@ -19,7 +19,7 @@ use oxc_syntax::number::{BigintBase, NumberBase};
 /// <https://tc39.es/ecma262/#prod-BooleanLiteral>
 #[ast(visit)]
 #[derive(Debug, Clone)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(rename = "Literal", add_fields(raw = BooleanLiteralRaw))]
 pub struct BooleanLiteral {
     /// Node location in source code
@@ -33,7 +33,7 @@ pub struct BooleanLiteral {
 /// <https://tc39.es/ecma262/#sec-null-literals>
 #[ast(visit)]
 #[derive(Debug, Clone)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(rename = "Literal", add_fields(value = Null, raw = NullLiteralRaw))]
 pub struct NullLiteral {
     /// Node location in source code
@@ -45,7 +45,7 @@ pub struct NullLiteral {
 /// <https://tc39.es/ecma262/#sec-literals-numeric-literals>
 #[ast(visit)]
 #[derive(Debug, Clone)]
-#[generate_derive(CloneIn, ContentEq, GetSpan, GetSpanMut, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, ContentEq, GetSpan, GetSpanMut, ESTree)]
 #[estree(rename = "Literal")]
 pub struct NumericLiteral<'a> {
     /// Node location in source code
@@ -68,7 +68,7 @@ pub struct NumericLiteral<'a> {
 /// <https://tc39.es/ecma262/#sec-literals-string-literals>
 #[ast(visit)]
 #[derive(Debug, Clone)]
-#[generate_derive(CloneIn, ContentEq, GetSpan, GetSpanMut, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, ContentEq, GetSpan, GetSpanMut, ESTree)]
 #[estree(rename = "Literal")]
 pub struct StringLiteral<'a> {
     /// Node location in source code
@@ -93,7 +93,7 @@ pub struct StringLiteral<'a> {
 /// BigInt literal
 #[ast(visit)]
 #[derive(Debug, Clone)]
-#[generate_derive(CloneIn, ContentEq, GetSpan, GetSpanMut, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, ContentEq, GetSpan, GetSpanMut, ESTree)]
 #[estree(
     rename = "Literal",
     add_fields(value = BigIntLiteralValue, bigint = BigIntLiteralBigint),
@@ -116,7 +116,7 @@ pub struct BigIntLiteral<'a> {
 /// <https://tc39.es/ecma262/#sec-literals-regular-expression-literals>
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, ContentEq, GetSpan, GetSpanMut, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, ContentEq, GetSpan, GetSpanMut, ESTree)]
 #[estree(
     rename = "Literal",
     add_fields(value = RegExpLiteralValue),
@@ -140,7 +140,7 @@ pub struct RegExpLiteral<'a> {
 /// <https://tc39.es/ecma262/multipage/text-processing.html#sec-regexp-regular-expression-objects>
 #[ast]
 #[derive(Debug)]
-#[generate_derive(CloneIn, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, ContentEq, ESTree)]
 #[estree(no_type)]
 pub struct RegExp<'a> {
     /// The regex pattern between the slashes
@@ -154,7 +154,7 @@ pub struct RegExp<'a> {
 /// This pattern may or may not be parsed.
 #[ast]
 #[derive(Debug)]
-#[generate_derive(CloneIn, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, ESTree)]
 #[estree(via = RegExpPatternConverter)]
 pub enum RegExpPattern<'a> {
     /// Unparsed pattern. Contains string slice of the pattern.
diff --git a/crates/oxc_ast/src/ast/ts.rs b/crates/oxc_ast/src/ast/ts.rs
index 30671bce13f0e..bed0f3cd4287f 100644
--- a/crates/oxc_ast/src/ast/ts.rs
+++ b/crates/oxc_ast/src/ast/ts.rs
@@ -10,7 +10,7 @@
 
 use std::cell::Cell;
 
-use oxc_allocator::{Box, CloneIn, GetAddress, Vec};
+use oxc_allocator::{Box, CloneIn, Dummy, GetAddress, TakeIn, Vec};
 use oxc_ast_macros::ast;
 use oxc_estree::ESTree;
 use oxc_span::{Atom, ContentEq, GetSpan, GetSpanMut, Span};
@@ -30,7 +30,7 @@ use super::{inherit_variants, js::*, literal::*};
 /// * [TypeScript Handbook - `this` parameters](https://www.typescriptlang.org/docs/handbook/2/functions.html#this-parameters)
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(
     rename = "Identifier",
     add_fields(name = This, decorators = EmptyArray, optional = False),
@@ -67,7 +67,7 @@ pub struct TSThisParameter<'a> {
 #[ast(visit)]
 #[scope]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSEnumDeclaration<'a> {
     pub span: Span,
     pub id: BindingIdentifier<'a>,
@@ -98,7 +98,7 @@ pub struct TSEnumDeclaration<'a> {
 /// * [TypeScript Handbook - Enums](https://www.typescriptlang.org/docs/handbook/enums.html)
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSEnumMember<'a> {
     pub span: Span,
     pub id: TSEnumMemberName<'a>,
@@ -108,7 +108,7 @@ pub struct TSEnumMember<'a> {
 /// TS Enum Member Name
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum TSEnumMemberName<'a> {
     Identifier(Box<'a, IdentifierName<'a>>) = 0,
     String(Box<'a, StringLiteral<'a>>) = 1,
@@ -128,7 +128,7 @@ pub enum TSEnumMemberName<'a> {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSTypeAnnotation<'a> {
     /// starts at the `:` token and ends at the end of the type annotation
     pub span: Span,
@@ -152,7 +152,7 @@ pub struct TSTypeAnnotation<'a> {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSLiteralType<'a> {
     pub span: Span,
     pub literal: TSLiteral<'a>,
@@ -161,7 +161,7 @@ pub struct TSLiteralType<'a> {
 /// A literal in a [`TSLiteralType`].
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum TSLiteral<'a> {
     BooleanLiteral(Box<'a, BooleanLiteral>) = 0,
     NumericLiteral(Box<'a, NumericLiteral<'a>>) = 1,
@@ -184,7 +184,7 @@ pub enum TSLiteral<'a> {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum TSType<'a> {
     // Keyword
     TSAnyKeyword(Box<'a, TSAnyKeyword>) = 0,
@@ -291,7 +291,7 @@ pub use match_ts_type;
     flags = ScopeFlags::TsConditional,
 )]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSConditionalType<'a> {
     pub span: Span,
     /// The type before `extends` in the test expression.
@@ -318,7 +318,7 @@ pub struct TSConditionalType<'a> {
 /// * [TypeScript Handbook - Union Types](https://www.typescriptlang.org/docs/handbook/typescript-in-5-minutes-func.html#unions)
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSUnionType<'a> {
     pub span: Span,
     /// The types in the union.
@@ -340,7 +340,7 @@ pub struct TSUnionType<'a> {
 /// * [TypeScript Handbook - Intersection Types](https://www.typescriptlang.org/docs/handbook/2/objects.html#intersection-types)
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSIntersectionType<'a> {
     pub span: Span,
     pub types: Vec<'a, TSType<'a>>,
@@ -357,7 +357,7 @@ pub struct TSIntersectionType<'a> {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSParenthesizedType<'a> {
     pub span: Span,
     pub type_annotation: TSType<'a>,
@@ -374,7 +374,7 @@ pub struct TSParenthesizedType<'a> {
 /// * [TypeScript Handbook - Keyof Types](https://www.typescriptlang.org/docs/handbook/2/keyof-types.html)
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSTypeOperator<'a> {
     pub span: Span,
     pub operator: TSTypeOperatorOperator,
@@ -385,7 +385,7 @@ pub struct TSTypeOperator<'a> {
 /// Operator in a [`TSTypeOperator`].
 #[ast]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-#[generate_derive(CloneIn, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, ContentEq, ESTree)]
 pub enum TSTypeOperatorOperator {
     Keyof = 0,
     Unique = 1,
@@ -405,7 +405,7 @@ pub enum TSTypeOperatorOperator {
 /// <https://www.typescriptlang.org/docs/handbook/2/objects.html#the-array-type>
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSArrayType<'a> {
     pub span: Span,
     pub element_type: TSType<'a>,
@@ -424,7 +424,7 @@ pub struct TSArrayType<'a> {
 /// <https://www.typescriptlang.org/docs/handbook/2/indexed-access-types.html#handbook-content>
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSIndexedAccessType<'a> {
     pub span: Span,
     pub object_type: TSType<'a>,
@@ -442,7 +442,7 @@ pub struct TSIndexedAccessType<'a> {
 /// <https://www.typescriptlang.org/docs/handbook/2/objects.html#tuple-types>
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSTupleType<'a> {
     pub span: Span,
     pub element_types: Vec<'a, TSTupleElement<'a>>,
@@ -460,7 +460,7 @@ pub struct TSTupleType<'a> {
 /// * [TypeScript Handbook - Tuple Types](https://www.typescriptlang.org/docs/handbook/2/objects.html#tuple-types)
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSNamedTupleMember<'a> {
     pub span: Span,
     pub element_type: TSTupleElement<'a>,
@@ -479,7 +479,7 @@ pub struct TSNamedTupleMember<'a> {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSOptionalType<'a> {
     pub span: Span,
     pub type_annotation: TSType<'a>,
@@ -495,7 +495,7 @@ pub struct TSOptionalType<'a> {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSRestType<'a> {
     pub span: Span,
     pub type_annotation: TSType<'a>,
@@ -511,7 +511,7 @@ inherit_variants! {
 /// [`ast` module docs]: `super`
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum TSTupleElement<'a> {
     // Discriminants start at 64, so that `TSTupleElement::is_ts_type` is a single
     // bitwise AND operation on the discriminant (`discriminant & 63 != 0`).
@@ -533,7 +533,7 @@ pub enum TSTupleElement<'a> {
 /// * [TypeScript Handbook - Any Type](https://www.typescriptlang.org/docs/handbook/2/everyday-types.html#any)
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSAnyKeyword {
     pub span: Span,
 }
@@ -549,7 +549,7 @@ pub struct TSAnyKeyword {
 /// * [TypeScript Handbook - Everyday Types](https://www.typescriptlang.org/docs/handbook/2/everyday-types.html#the-primitives-string-number-and-boolean)
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSStringKeyword {
     pub span: Span,
 }
@@ -565,7 +565,7 @@ pub struct TSStringKeyword {
 /// * [TypeScript Handbook - Everyday Types](https://www.typescriptlang.org/docs/handbook/2/everyday-types.html#the-primitives-string-number-and-boolean)
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSBooleanKeyword {
     pub span: Span,
 }
@@ -581,7 +581,7 @@ pub struct TSBooleanKeyword {
 /// * [TypeScript Handbook - Everyday Types](https://www.typescriptlang.org/docs/handbook/2/everyday-types.html#the-primitives-string-number-and-boolean)
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSNumberKeyword {
     pub span: Span,
 }
@@ -598,7 +598,7 @@ pub struct TSNumberKeyword {
 /// * [TypeScript Handbook - Advanced Topics](https://www.typescriptlang.org/docs/handbook/type-compatibility.html#advanced-topics)
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSNeverKeyword {
     pub span: Span,
 }
@@ -615,7 +615,7 @@ pub struct TSNeverKeyword {
 /// * [microsoft/TypeScript #40580](https://github.com/microsoft/TypeScript/pull/40580)
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSIntrinsicKeyword {
     pub span: Span,
 }
@@ -633,7 +633,7 @@ pub struct TSIntrinsicKeyword {
 /// * [TypeScript Handbook - Advanced Topics](https://www.typescriptlang.org/docs/handbook/type-compatibility.html#advanced-topics)
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSUnknownKeyword {
     pub span: Span,
 }
@@ -650,7 +650,7 @@ pub struct TSUnknownKeyword {
 /// * [TypeScript Handbook - Everyday Types](https://www.typescriptlang.org/docs/handbook/2/everyday-types.html#null-and-undefined)
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSNullKeyword {
     pub span: Span,
 }
@@ -669,42 +669,42 @@ pub struct TSNullKeyword {
 /// * [TypeScript Handbook - Everyday Types](https://www.typescriptlang.org/docs/handbook/2/everyday-types.html#null-and-undefined)
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSUndefinedKeyword {
     pub span: Span,
 }
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSVoidKeyword {
     pub span: Span,
 }
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSSymbolKeyword {
     pub span: Span,
 }
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSThisType {
     pub span: Span,
 }
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSObjectKeyword {
     pub span: Span,
 }
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSBigIntKeyword {
     pub span: Span,
 }
@@ -719,7 +719,7 @@ pub struct TSBigIntKeyword {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSTypeReference<'a> {
     pub span: Span,
     pub type_name: TSTypeName<'a>,
@@ -731,7 +731,7 @@ pub struct TSTypeReference<'a> {
 ///     NamespaceName . IdentifierReference
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum TSTypeName<'a> {
     IdentifierReference(Box<'a, IdentifierReference<'a>>) = 0,
     QualifiedName(Box<'a, TSQualifiedName<'a>>) = 1,
@@ -756,7 +756,7 @@ pub use match_ts_type_name;
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSQualifiedName<'a> {
     pub span: Span,
     pub left: TSTypeName<'a>,
@@ -765,7 +765,7 @@ pub struct TSQualifiedName<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSTypeParameterInstantiation<'a> {
     pub span: Span,
     pub params: Vec<'a, TSType<'a>>,
@@ -790,7 +790,7 @@ pub struct TSTypeParameterInstantiation<'a> {
 /// * [TypeScript Handbook - Variance Annotations](https://www.typescriptlang.org/docs/handbook/2/generics.html#variance-annotations)
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSTypeParameter<'a> {
     pub span: Span,
     /// The name of the parameter, e.g. `T` in `type Foo<T> = ...`.
@@ -809,7 +809,7 @@ pub struct TSTypeParameter<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSTypeParameterDeclaration<'a> {
     pub span: Span,
     pub params: Vec<'a, TSTypeParameter<'a>>,
@@ -826,7 +826,7 @@ pub struct TSTypeParameterDeclaration<'a> {
 #[ast(visit)]
 #[scope]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSTypeAliasDeclaration<'a> {
     pub span: Span,
     /// Type alias's identifier, e.g. `Foo` in `type Foo = number`.
@@ -840,7 +840,7 @@ pub struct TSTypeAliasDeclaration<'a> {
 
 #[ast]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-#[generate_derive(CloneIn, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, ContentEq, ESTree)]
 pub enum TSAccessibility {
     Private = 0,
     Protected = 1,
@@ -859,7 +859,7 @@ pub enum TSAccessibility {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSClassImplements<'a> {
     pub span: Span,
     pub expression: TSTypeName<'a>,
@@ -884,7 +884,7 @@ pub struct TSClassImplements<'a> {
 #[ast(visit)]
 #[scope]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSInterfaceDeclaration<'a> {
     pub span: Span,
     /// The identifier (name) of the interface.
@@ -904,7 +904,7 @@ pub struct TSInterfaceDeclaration<'a> {
 /// Body of a [`TSInterfaceDeclaration`].
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSInterfaceBody<'a> {
     pub span: Span,
     pub body: Vec<'a, TSSignature<'a>>,
@@ -927,7 +927,7 @@ pub struct TSInterfaceBody<'a> {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSPropertySignature<'a> {
     pub span: Span,
     pub computed: bool,
@@ -939,7 +939,7 @@ pub struct TSPropertySignature<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum TSSignature<'a> {
     TSIndexSignature(Box<'a, TSIndexSignature<'a>>) = 0,
     TSPropertySignature(Box<'a, TSPropertySignature<'a>>) = 1,
@@ -961,7 +961,7 @@ pub enum TSSignature<'a> {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(add_fields(accessibility = Null))]
 pub struct TSIndexSignature<'a> {
     pub span: Span,
@@ -973,7 +973,7 @@ pub struct TSIndexSignature<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSCallSignatureDeclaration<'a> {
     pub span: Span,
     pub type_parameters: Option<Box<'a, TSTypeParameterDeclaration<'a>>>,
@@ -985,7 +985,7 @@ pub struct TSCallSignatureDeclaration<'a> {
 
 #[ast]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-#[generate_derive(CloneIn, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, ContentEq, ESTree)]
 pub enum TSMethodSignatureKind {
     Method = 0,
     Get = 1,
@@ -1006,7 +1006,7 @@ pub enum TSMethodSignatureKind {
 #[ast(visit)]
 #[scope]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSMethodSignature<'a> {
     pub span: Span,
     pub key: PropertyKey<'a>,
@@ -1024,7 +1024,7 @@ pub struct TSMethodSignature<'a> {
 #[ast(visit)]
 #[scope]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSConstructSignatureDeclaration<'a> {
     pub span: Span,
     pub type_parameters: Option<Box<'a, TSTypeParameterDeclaration<'a>>>,
@@ -1035,7 +1035,7 @@ pub struct TSConstructSignatureDeclaration<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(rename = "Identifier", add_fields(decorators = EmptyArray, optional = False))]
 pub struct TSIndexSignatureName<'a> {
     pub span: Span,
@@ -1046,7 +1046,7 @@ pub struct TSIndexSignatureName<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSInterfaceHeritage<'a> {
     pub span: Span,
     pub expression: Expression<'a>,
@@ -1075,7 +1075,7 @@ pub struct TSInterfaceHeritage<'a> {
 /// * [TypeScript Handbook - Assertion Functions](https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-7.html#assertion-functions)
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSTypePredicate<'a> {
     pub span: Span,
     /// The identifier the predicate operates on
@@ -1092,7 +1092,7 @@ pub struct TSTypePredicate<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub enum TSTypePredicateName<'a> {
     Identifier(Box<'a, IdentifierName<'a>>) = 0,
     This(TSThisType) = 1,
@@ -1130,7 +1130,7 @@ pub enum TSTypePredicateName<'a> {
     strict_if = self.body.as_ref().is_some_and(TSModuleDeclarationBody::has_use_strict_directive),
 )]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 #[estree(add_fields(global = TSModuleDeclarationGlobal))]
 pub struct TSModuleDeclaration<'a> {
     pub span: Span,
@@ -1160,7 +1160,7 @@ pub struct TSModuleDeclaration<'a> {
 
 #[ast]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-#[generate_derive(CloneIn, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, ContentEq, ESTree)]
 pub enum TSModuleDeclarationKind {
     /// `declare global {}`
     Global = 0,
@@ -1192,7 +1192,7 @@ pub enum TSModuleDeclarationKind {
 /// ```
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub enum TSModuleDeclarationName<'a> {
     Identifier(BindingIdentifier<'a>) = 0,
     StringLiteral(StringLiteral<'a>) = 1,
@@ -1200,7 +1200,7 @@ pub enum TSModuleDeclarationName<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum TSModuleDeclarationBody<'a> {
     TSModuleDeclaration(Box<'a, TSModuleDeclaration<'a>>) = 0,
     TSModuleBlock(Box<'a, TSModuleBlock<'a>>) = 1,
@@ -1209,7 +1209,7 @@ pub enum TSModuleDeclarationBody<'a> {
 // See serializer in serialize.rs
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSModuleBlock<'a> {
     pub span: Span,
     #[estree(rename = "body")]
@@ -1220,7 +1220,7 @@ pub struct TSModuleBlock<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSTypeLiteral<'a> {
     pub span: Span,
     pub members: Vec<'a, TSSignature<'a>>,
@@ -1241,7 +1241,7 @@ pub struct TSTypeLiteral<'a> {
 /// * [TypeScript Handbook - Inferring With Conditional Types](https://www.typescriptlang.org/docs/handbook/2/conditional-types.html#inferring-within-conditional-types)
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSInferType<'a> {
     pub span: Span,
     /// The type bound when the
@@ -1259,7 +1259,7 @@ pub struct TSInferType<'a> {
 /// * [TypeScript Handbook - Typeof Type Operator](https://www.typescriptlang.org/docs/handbook/2/typeof-types.html)
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSTypeQuery<'a> {
     pub span: Span,
     pub expr_name: TSTypeQueryExprName<'a>,
@@ -1274,7 +1274,7 @@ inherit_variants! {
 /// [`ast` module docs]: `super`
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum TSTypeQueryExprName<'a> {
     TSImportType(Box<'a, TSImportType<'a>>) = 2,
     // `TSTypeName` variants added here by `inherit_variants!` macro
@@ -1284,7 +1284,7 @@ pub enum TSTypeQueryExprName<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSImportType<'a> {
     pub span: Span,
     pub argument: TSType<'a>,
@@ -1306,7 +1306,7 @@ pub struct TSImportType<'a> {
 #[ast(visit)]
 #[scope]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSFunctionType<'a> {
     pub span: Span,
     /// Generic type parameters
@@ -1338,7 +1338,7 @@ pub struct TSFunctionType<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSConstructorType<'a> {
     pub span: Span,
     pub r#abstract: bool,
@@ -1371,7 +1371,7 @@ pub struct TSConstructorType<'a> {
 #[ast(visit)]
 #[scope]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSMappedType<'a> {
     pub span: Span,
     /// Key type parameter, e.g. `P` in `[P in keyof T]`.
@@ -1407,7 +1407,7 @@ pub struct TSMappedType<'a> {
 
 #[ast]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-#[generate_derive(CloneIn, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, ContentEq, ESTree)]
 pub enum TSMappedTypeModifierOperator {
     /// e.g. `?` in `{ [P in K]?: T }`
     True = 0,
@@ -1434,7 +1434,7 @@ pub enum TSMappedTypeModifierOperator {
 /// * [TypeScript Handbook - Template Literal Types](https://www.typescriptlang.org/docs/handbook/2/template-literal-types.html#handbook-content)
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSTemplateLiteralType<'a> {
     pub span: Span,
     /// The string parts of the template literal.
@@ -1445,7 +1445,7 @@ pub struct TSTemplateLiteralType<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSAsExpression<'a> {
     pub span: Span,
     pub expression: Expression<'a>,
@@ -1466,7 +1466,7 @@ pub struct TSAsExpression<'a> {
 /// * [TypeScript Handbook - The `satisfies` Operator](https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-9.html#the-satisfies-operator)
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSSatisfiesExpression<'a> {
     pub span: Span,
     /// The value expression being constrained.
@@ -1477,7 +1477,7 @@ pub struct TSSatisfiesExpression<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSTypeAssertion<'a> {
     pub span: Span,
     pub expression: Expression<'a>,
@@ -1486,7 +1486,7 @@ pub struct TSTypeAssertion<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSImportEqualsDeclaration<'a> {
     pub span: Span,
     pub id: BindingIdentifier<'a>,
@@ -1502,7 +1502,7 @@ inherit_variants! {
 /// [`ast` module docs]: `super`
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, GetAddress, ContentEq, ESTree)]
 pub enum TSModuleReference<'a> {
     ExternalModuleReference(Box<'a, TSExternalModuleReference<'a>>) = 2,
     // `TSTypeName` variants added here by `inherit_variants!` macro
@@ -1512,7 +1512,7 @@ pub enum TSModuleReference<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSExternalModuleReference<'a> {
     pub span: Span,
     pub expression: StringLiteral<'a>,
@@ -1520,7 +1520,7 @@ pub struct TSExternalModuleReference<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSNonNullExpression<'a> {
     pub span: Span,
     pub expression: Expression<'a>,
@@ -1552,7 +1552,7 @@ pub struct TSNonNullExpression<'a> {
 /// [`CallExpression`]: crate::ast::js::CallExpression
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct Decorator<'a> {
     pub span: Span,
     pub expression: Expression<'a>,
@@ -1563,7 +1563,7 @@ pub struct Decorator<'a> {
 /// `export = foo`
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSExportAssignment<'a> {
     pub span: Span,
     pub expression: Expression<'a>,
@@ -1574,7 +1574,7 @@ pub struct TSExportAssignment<'a> {
 /// `export as namespace foo`
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSNamespaceExportDeclaration<'a> {
     pub span: Span,
     pub id: IdentifierName<'a>,
@@ -1582,7 +1582,7 @@ pub struct TSNamespaceExportDeclaration<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct TSInstantiationExpression<'a> {
     pub span: Span,
     pub expression: Expression<'a>,
@@ -1592,7 +1592,7 @@ pub struct TSInstantiationExpression<'a> {
 /// See [TypeScript - Type-Only Imports and Exports](https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-8.html)
 #[ast]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-#[generate_derive(CloneIn, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, ContentEq, ESTree)]
 pub enum ImportOrExportKind {
     /// `import { foo } from './foo'`;
     Value = 0,
@@ -1605,7 +1605,7 @@ pub enum ImportOrExportKind {
 /// `type foo = ty?` or `type foo = ?ty`
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct JSDocNullableType<'a> {
     pub span: Span,
     pub type_annotation: TSType<'a>,
@@ -1616,7 +1616,7 @@ pub struct JSDocNullableType<'a> {
 /// `type foo = ty!` or `type foo = !ty`
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct JSDocNonNullableType<'a> {
     pub span: Span,
     pub type_annotation: TSType<'a>,
@@ -1625,7 +1625,7 @@ pub struct JSDocNonNullableType<'a> {
 
 #[ast(visit)]
 #[derive(Debug)]
-#[generate_derive(CloneIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, TakeIn, GetSpan, GetSpanMut, ContentEq, ESTree)]
 pub struct JSDocUnknownType {
     pub span: Span,
 }
diff --git a/crates/oxc_ast/src/ast_impl/literal.rs b/crates/oxc_ast/src/ast_impl/literal.rs
index 2753f35d2900b..69c7535feebf4 100644
--- a/crates/oxc_ast/src/ast_impl/literal.rs
+++ b/crates/oxc_ast/src/ast_impl/literal.rs
@@ -2,7 +2,7 @@
 
 use std::{borrow::Cow, fmt};
 
-use oxc_allocator::CloneIn;
+use oxc_allocator::{Allocator, CloneIn, Dummy};
 use oxc_data_structures::inline_string::InlineString;
 use oxc_regular_expression::ast::Pattern;
 use oxc_span::ContentEq;
@@ -213,11 +213,22 @@ impl ContentEq for RegExpFlags {
 impl<'alloc> CloneIn<'alloc> for RegExpFlags {
     type Cloned = Self;
 
-    fn clone_in(&self, _: &'alloc oxc_allocator::Allocator) -> Self::Cloned {
+    fn clone_in(&self, _: &'alloc Allocator) -> Self::Cloned {
         *self
     }
 }
 
+impl<'a> Dummy<'a> for RegExpFlags {
+    /// Create a dummy [`RegExpFlags`].
+    ///
+    /// Does not allocate any data into arena.
+    #[expect(clippy::inline_always)]
+    #[inline(always)]
+    fn dummy(_: &'a Allocator) -> Self {
+        RegExpFlags::empty()
+    }
+}
+
 impl TryFrom<char> for RegExpFlags {
     type Error = char;
 
diff --git a/crates/oxc_ast/src/generated/derive_dummy.rs b/crates/oxc_ast/src/generated/derive_dummy.rs
new file mode 100644
index 0000000000000..b113c775cb348
--- /dev/null
+++ b/crates/oxc_ast/src/generated/derive_dummy.rs
@@ -0,0 +1,2861 @@
+// Auto-generated code, DO NOT EDIT DIRECTLY!
+// To edit this generated file you have to edit `tasks/ast_tools/src/derives/dummy.rs`
+
+#![allow(unused_variables, clippy::inline_always)]
+
+use oxc_allocator::{Allocator, Dummy};
+
+use crate::ast::js::*;
+use crate::ast::jsx::*;
+use crate::ast::literal::*;
+use crate::ast::ts::*;
+
+impl<'a> Dummy<'a> for Program<'a> {
+    /// Create a dummy [`Program`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            source_type: Dummy::dummy(allocator),
+            source_text: Dummy::dummy(allocator),
+            comments: Dummy::dummy(allocator),
+            hashbang: Dummy::dummy(allocator),
+            directives: Dummy::dummy(allocator),
+            body: Dummy::dummy(allocator),
+            scope_id: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for Expression<'a> {
+    /// Create a dummy [`Expression`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::NullLiteral(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for IdentifierName<'a> {
+    /// Create a dummy [`IdentifierName`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), name: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for IdentifierReference<'a> {
+    /// Create a dummy [`IdentifierReference`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            name: Dummy::dummy(allocator),
+            reference_id: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for BindingIdentifier<'a> {
+    /// Create a dummy [`BindingIdentifier`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            name: Dummy::dummy(allocator),
+            symbol_id: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for LabelIdentifier<'a> {
+    /// Create a dummy [`LabelIdentifier`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), name: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for ThisExpression {
+    /// Create a dummy [`ThisExpression`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for ArrayExpression<'a> {
+    /// Create a dummy [`ArrayExpression`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            elements: Dummy::dummy(allocator),
+            trailing_comma: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for ArrayExpressionElement<'a> {
+    /// Create a dummy [`ArrayExpressionElement`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::Elision(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for Elision {
+    /// Create a dummy [`Elision`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for ObjectExpression<'a> {
+    /// Create a dummy [`ObjectExpression`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            properties: Dummy::dummy(allocator),
+            trailing_comma: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for ObjectPropertyKind<'a> {
+    /// Create a dummy [`ObjectPropertyKind`].
+    ///
+    /// Has cost of making 2 allocations (32 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::SpreadProperty(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for ObjectProperty<'a> {
+    /// Create a dummy [`ObjectProperty`].
+    ///
+    /// Has cost of making 2 allocations (16 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            kind: Dummy::dummy(allocator),
+            key: Dummy::dummy(allocator),
+            value: Dummy::dummy(allocator),
+            method: Dummy::dummy(allocator),
+            shorthand: Dummy::dummy(allocator),
+            computed: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for PropertyKey<'a> {
+    /// Create a dummy [`PropertyKey`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::NullLiteral(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for PropertyKind {
+    /// Create a dummy [`PropertyKind`].
+    ///
+    /// Does not allocate any data into arena.
+    #[inline(always)]
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::Init
+    }
+}
+
+impl<'a> Dummy<'a> for TemplateLiteral<'a> {
+    /// Create a dummy [`TemplateLiteral`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            quasis: Dummy::dummy(allocator),
+            expressions: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TaggedTemplateExpression<'a> {
+    /// Create a dummy [`TaggedTemplateExpression`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            tag: Dummy::dummy(allocator),
+            quasi: Dummy::dummy(allocator),
+            type_arguments: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TemplateElement<'a> {
+    /// Create a dummy [`TemplateElement`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            value: Dummy::dummy(allocator),
+            tail: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TemplateElementValue<'a> {
+    /// Create a dummy [`TemplateElementValue`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { raw: Dummy::dummy(allocator), cooked: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for MemberExpression<'a> {
+    /// Create a dummy [`MemberExpression`].
+    ///
+    /// Has cost of making 2 allocations (64 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::StaticMemberExpression(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for ComputedMemberExpression<'a> {
+    /// Create a dummy [`ComputedMemberExpression`].
+    ///
+    /// Has cost of making 2 allocations (16 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            object: Dummy::dummy(allocator),
+            expression: Dummy::dummy(allocator),
+            optional: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for StaticMemberExpression<'a> {
+    /// Create a dummy [`StaticMemberExpression`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            object: Dummy::dummy(allocator),
+            property: Dummy::dummy(allocator),
+            optional: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for PrivateFieldExpression<'a> {
+    /// Create a dummy [`PrivateFieldExpression`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            object: Dummy::dummy(allocator),
+            field: Dummy::dummy(allocator),
+            optional: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for CallExpression<'a> {
+    /// Create a dummy [`CallExpression`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            callee: Dummy::dummy(allocator),
+            type_arguments: Dummy::dummy(allocator),
+            arguments: Dummy::dummy(allocator),
+            optional: Dummy::dummy(allocator),
+            pure: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for NewExpression<'a> {
+    /// Create a dummy [`NewExpression`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            callee: Dummy::dummy(allocator),
+            arguments: Dummy::dummy(allocator),
+            type_arguments: Dummy::dummy(allocator),
+            pure: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for MetaProperty<'a> {
+    /// Create a dummy [`MetaProperty`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            meta: Dummy::dummy(allocator),
+            property: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for SpreadElement<'a> {
+    /// Create a dummy [`SpreadElement`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), argument: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for Argument<'a> {
+    /// Create a dummy [`Argument`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::NullLiteral(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for UpdateExpression<'a> {
+    /// Create a dummy [`UpdateExpression`].
+    ///
+    /// Has cost of making 1 allocation (32 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            operator: Dummy::dummy(allocator),
+            prefix: Dummy::dummy(allocator),
+            argument: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for UnaryExpression<'a> {
+    /// Create a dummy [`UnaryExpression`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            operator: Dummy::dummy(allocator),
+            argument: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for BinaryExpression<'a> {
+    /// Create a dummy [`BinaryExpression`].
+    ///
+    /// Has cost of making 2 allocations (16 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            left: Dummy::dummy(allocator),
+            operator: Dummy::dummy(allocator),
+            right: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for PrivateInExpression<'a> {
+    /// Create a dummy [`PrivateInExpression`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            left: Dummy::dummy(allocator),
+            right: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for LogicalExpression<'a> {
+    /// Create a dummy [`LogicalExpression`].
+    ///
+    /// Has cost of making 2 allocations (16 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            left: Dummy::dummy(allocator),
+            operator: Dummy::dummy(allocator),
+            right: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for ConditionalExpression<'a> {
+    /// Create a dummy [`ConditionalExpression`].
+    ///
+    /// Has cost of making 3 allocations (24 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            test: Dummy::dummy(allocator),
+            consequent: Dummy::dummy(allocator),
+            alternate: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for AssignmentExpression<'a> {
+    /// Create a dummy [`AssignmentExpression`].
+    ///
+    /// Has cost of making 2 allocations (40 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            operator: Dummy::dummy(allocator),
+            left: Dummy::dummy(allocator),
+            right: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for AssignmentTarget<'a> {
+    /// Create a dummy [`AssignmentTarget`].
+    ///
+    /// Has cost of making 1 allocation (32 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::AssignmentTargetIdentifier(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for SimpleAssignmentTarget<'a> {
+    /// Create a dummy [`SimpleAssignmentTarget`].
+    ///
+    /// Has cost of making 1 allocation (32 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::AssignmentTargetIdentifier(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for AssignmentTargetPattern<'a> {
+    /// Create a dummy [`AssignmentTargetPattern`].
+    ///
+    /// Has cost of making 1 allocation (64 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::ObjectAssignmentTarget(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for ArrayAssignmentTarget<'a> {
+    /// Create a dummy [`ArrayAssignmentTarget`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            elements: Dummy::dummy(allocator),
+            rest: Dummy::dummy(allocator),
+            trailing_comma: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for ObjectAssignmentTarget<'a> {
+    /// Create a dummy [`ObjectAssignmentTarget`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            properties: Dummy::dummy(allocator),
+            rest: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for AssignmentTargetRest<'a> {
+    /// Create a dummy [`AssignmentTargetRest`].
+    ///
+    /// Has cost of making 1 allocation (32 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), target: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for AssignmentTargetMaybeDefault<'a> {
+    /// Create a dummy [`AssignmentTargetMaybeDefault`].
+    ///
+    /// Has cost of making 1 allocation (32 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::AssignmentTargetIdentifier(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for AssignmentTargetWithDefault<'a> {
+    /// Create a dummy [`AssignmentTargetWithDefault`].
+    ///
+    /// Has cost of making 2 allocations (40 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            binding: Dummy::dummy(allocator),
+            init: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for AssignmentTargetProperty<'a> {
+    /// Create a dummy [`AssignmentTargetProperty`].
+    ///
+    /// Has cost of making 1 allocation (56 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::AssignmentTargetPropertyIdentifier(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for AssignmentTargetPropertyIdentifier<'a> {
+    /// Create a dummy [`AssignmentTargetPropertyIdentifier`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            binding: Dummy::dummy(allocator),
+            init: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for AssignmentTargetPropertyProperty<'a> {
+    /// Create a dummy [`AssignmentTargetPropertyProperty`].
+    ///
+    /// Has cost of making 2 allocations (40 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            name: Dummy::dummy(allocator),
+            binding: Dummy::dummy(allocator),
+            computed: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for SequenceExpression<'a> {
+    /// Create a dummy [`SequenceExpression`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), expressions: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for Super {
+    /// Create a dummy [`Super`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for AwaitExpression<'a> {
+    /// Create a dummy [`AwaitExpression`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), argument: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for ChainExpression<'a> {
+    /// Create a dummy [`ChainExpression`].
+    ///
+    /// Has cost of making 2 allocations (32 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), expression: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for ChainElement<'a> {
+    /// Create a dummy [`ChainElement`].
+    ///
+    /// Has cost of making 2 allocations (32 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::TSNonNullExpression(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for ParenthesizedExpression<'a> {
+    /// Create a dummy [`ParenthesizedExpression`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), expression: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for Statement<'a> {
+    /// Create a dummy [`Statement`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::DebuggerStatement(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for Directive<'a> {
+    /// Create a dummy [`Directive`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            expression: Dummy::dummy(allocator),
+            directive: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for Hashbang<'a> {
+    /// Create a dummy [`Hashbang`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), value: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for BlockStatement<'a> {
+    /// Create a dummy [`BlockStatement`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            body: Dummy::dummy(allocator),
+            scope_id: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for Declaration<'a> {
+    /// Create a dummy [`Declaration`].
+    ///
+    /// Has cost of making 1 allocation (56 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::VariableDeclaration(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for VariableDeclaration<'a> {
+    /// Create a dummy [`VariableDeclaration`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            kind: Dummy::dummy(allocator),
+            declarations: Dummy::dummy(allocator),
+            declare: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for VariableDeclarationKind {
+    /// Create a dummy [`VariableDeclarationKind`].
+    ///
+    /// Does not allocate any data into arena.
+    #[inline(always)]
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::Var
+    }
+}
+
+impl<'a> Dummy<'a> for VariableDeclarator<'a> {
+    /// Create a dummy [`VariableDeclarator`].
+    ///
+    /// Has cost of making 1 allocation (32 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            kind: Dummy::dummy(allocator),
+            id: Dummy::dummy(allocator),
+            init: Dummy::dummy(allocator),
+            definite: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for EmptyStatement {
+    /// Create a dummy [`EmptyStatement`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for ExpressionStatement<'a> {
+    /// Create a dummy [`ExpressionStatement`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), expression: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for IfStatement<'a> {
+    /// Create a dummy [`IfStatement`].
+    ///
+    /// Has cost of making 2 allocations (16 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            test: Dummy::dummy(allocator),
+            consequent: Dummy::dummy(allocator),
+            alternate: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for DoWhileStatement<'a> {
+    /// Create a dummy [`DoWhileStatement`].
+    ///
+    /// Has cost of making 2 allocations (16 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            body: Dummy::dummy(allocator),
+            test: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for WhileStatement<'a> {
+    /// Create a dummy [`WhileStatement`].
+    ///
+    /// Has cost of making 2 allocations (16 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            test: Dummy::dummy(allocator),
+            body: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for ForStatement<'a> {
+    /// Create a dummy [`ForStatement`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            init: Dummy::dummy(allocator),
+            test: Dummy::dummy(allocator),
+            update: Dummy::dummy(allocator),
+            body: Dummy::dummy(allocator),
+            scope_id: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for ForStatementInit<'a> {
+    /// Create a dummy [`ForStatementInit`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::NullLiteral(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for ForInStatement<'a> {
+    /// Create a dummy [`ForInStatement`].
+    ///
+    /// Has cost of making 3 allocations (48 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            left: Dummy::dummy(allocator),
+            right: Dummy::dummy(allocator),
+            body: Dummy::dummy(allocator),
+            scope_id: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for ForStatementLeft<'a> {
+    /// Create a dummy [`ForStatementLeft`].
+    ///
+    /// Has cost of making 1 allocation (32 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::AssignmentTargetIdentifier(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for ForOfStatement<'a> {
+    /// Create a dummy [`ForOfStatement`].
+    ///
+    /// Has cost of making 3 allocations (48 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            r#await: Dummy::dummy(allocator),
+            left: Dummy::dummy(allocator),
+            right: Dummy::dummy(allocator),
+            body: Dummy::dummy(allocator),
+            scope_id: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for ContinueStatement<'a> {
+    /// Create a dummy [`ContinueStatement`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), label: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for BreakStatement<'a> {
+    /// Create a dummy [`BreakStatement`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), label: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for ReturnStatement<'a> {
+    /// Create a dummy [`ReturnStatement`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), argument: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for WithStatement<'a> {
+    /// Create a dummy [`WithStatement`].
+    ///
+    /// Has cost of making 2 allocations (16 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            object: Dummy::dummy(allocator),
+            body: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for SwitchStatement<'a> {
+    /// Create a dummy [`SwitchStatement`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            discriminant: Dummy::dummy(allocator),
+            cases: Dummy::dummy(allocator),
+            scope_id: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for SwitchCase<'a> {
+    /// Create a dummy [`SwitchCase`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            test: Dummy::dummy(allocator),
+            consequent: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for LabeledStatement<'a> {
+    /// Create a dummy [`LabeledStatement`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            label: Dummy::dummy(allocator),
+            body: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for ThrowStatement<'a> {
+    /// Create a dummy [`ThrowStatement`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), argument: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TryStatement<'a> {
+    /// Create a dummy [`TryStatement`].
+    ///
+    /// Has cost of making 1 allocation (48 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            block: Dummy::dummy(allocator),
+            handler: Dummy::dummy(allocator),
+            finalizer: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for CatchClause<'a> {
+    /// Create a dummy [`CatchClause`].
+    ///
+    /// Has cost of making 1 allocation (48 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            param: Dummy::dummy(allocator),
+            body: Dummy::dummy(allocator),
+            scope_id: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for CatchParameter<'a> {
+    /// Create a dummy [`CatchParameter`].
+    ///
+    /// Has cost of making 1 allocation (32 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), pattern: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for DebuggerStatement {
+    /// Create a dummy [`DebuggerStatement`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for BindingPattern<'a> {
+    /// Create a dummy [`BindingPattern`].
+    ///
+    /// Has cost of making 1 allocation (32 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            kind: Dummy::dummy(allocator),
+            type_annotation: Dummy::dummy(allocator),
+            optional: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for BindingPatternKind<'a> {
+    /// Create a dummy [`BindingPatternKind`].
+    ///
+    /// Has cost of making 1 allocation (32 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::BindingIdentifier(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for AssignmentPattern<'a> {
+    /// Create a dummy [`AssignmentPattern`].
+    ///
+    /// Has cost of making 2 allocations (40 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            left: Dummy::dummy(allocator),
+            right: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for ObjectPattern<'a> {
+    /// Create a dummy [`ObjectPattern`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            properties: Dummy::dummy(allocator),
+            rest: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for BindingProperty<'a> {
+    /// Create a dummy [`BindingProperty`].
+    ///
+    /// Has cost of making 2 allocations (40 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            key: Dummy::dummy(allocator),
+            value: Dummy::dummy(allocator),
+            shorthand: Dummy::dummy(allocator),
+            computed: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for ArrayPattern<'a> {
+    /// Create a dummy [`ArrayPattern`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            elements: Dummy::dummy(allocator),
+            rest: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for BindingRestElement<'a> {
+    /// Create a dummy [`BindingRestElement`].
+    ///
+    /// Has cost of making 1 allocation (32 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), argument: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for Function<'a> {
+    /// Create a dummy [`Function`].
+    ///
+    /// Has cost of making 1 allocation (56 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            r#type: Dummy::dummy(allocator),
+            id: Dummy::dummy(allocator),
+            generator: Dummy::dummy(allocator),
+            r#async: Dummy::dummy(allocator),
+            declare: Dummy::dummy(allocator),
+            type_parameters: Dummy::dummy(allocator),
+            this_param: Dummy::dummy(allocator),
+            params: Dummy::dummy(allocator),
+            return_type: Dummy::dummy(allocator),
+            body: Dummy::dummy(allocator),
+            scope_id: Dummy::dummy(allocator),
+            pure: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for FunctionType {
+    /// Create a dummy [`FunctionType`].
+    ///
+    /// Does not allocate any data into arena.
+    #[inline(always)]
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::FunctionDeclaration
+    }
+}
+
+impl<'a> Dummy<'a> for FormalParameters<'a> {
+    /// Create a dummy [`FormalParameters`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            kind: Dummy::dummy(allocator),
+            items: Dummy::dummy(allocator),
+            rest: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for FormalParameter<'a> {
+    /// Create a dummy [`FormalParameter`].
+    ///
+    /// Has cost of making 1 allocation (32 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            decorators: Dummy::dummy(allocator),
+            pattern: Dummy::dummy(allocator),
+            accessibility: Dummy::dummy(allocator),
+            readonly: Dummy::dummy(allocator),
+            r#override: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for FormalParameterKind {
+    /// Create a dummy [`FormalParameterKind`].
+    ///
+    /// Does not allocate any data into arena.
+    #[inline(always)]
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::FormalParameter
+    }
+}
+
+impl<'a> Dummy<'a> for FunctionBody<'a> {
+    /// Create a dummy [`FunctionBody`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            directives: Dummy::dummy(allocator),
+            statements: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for ArrowFunctionExpression<'a> {
+    /// Create a dummy [`ArrowFunctionExpression`].
+    ///
+    /// Has cost of making 2 allocations (128 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            expression: Dummy::dummy(allocator),
+            r#async: Dummy::dummy(allocator),
+            type_parameters: Dummy::dummy(allocator),
+            params: Dummy::dummy(allocator),
+            return_type: Dummy::dummy(allocator),
+            body: Dummy::dummy(allocator),
+            scope_id: Dummy::dummy(allocator),
+            pure: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for YieldExpression<'a> {
+    /// Create a dummy [`YieldExpression`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            delegate: Dummy::dummy(allocator),
+            argument: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for Class<'a> {
+    /// Create a dummy [`Class`].
+    ///
+    /// Has cost of making 1 allocation (40 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            r#type: Dummy::dummy(allocator),
+            decorators: Dummy::dummy(allocator),
+            id: Dummy::dummy(allocator),
+            type_parameters: Dummy::dummy(allocator),
+            super_class: Dummy::dummy(allocator),
+            super_type_arguments: Dummy::dummy(allocator),
+            implements: Dummy::dummy(allocator),
+            body: Dummy::dummy(allocator),
+            r#abstract: Dummy::dummy(allocator),
+            declare: Dummy::dummy(allocator),
+            scope_id: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for ClassType {
+    /// Create a dummy [`ClassType`].
+    ///
+    /// Does not allocate any data into arena.
+    #[inline(always)]
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::ClassDeclaration
+    }
+}
+
+impl<'a> Dummy<'a> for ClassBody<'a> {
+    /// Create a dummy [`ClassBody`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), body: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for ClassElement<'a> {
+    /// Create a dummy [`ClassElement`].
+    ///
+    /// Has cost of making 1 allocation (48 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::StaticBlock(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for MethodDefinition<'a> {
+    /// Create a dummy [`MethodDefinition`].
+    ///
+    /// Has cost of making 3 allocations (168 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            r#type: Dummy::dummy(allocator),
+            decorators: Dummy::dummy(allocator),
+            key: Dummy::dummy(allocator),
+            value: Dummy::dummy(allocator),
+            kind: Dummy::dummy(allocator),
+            computed: Dummy::dummy(allocator),
+            r#static: Dummy::dummy(allocator),
+            r#override: Dummy::dummy(allocator),
+            optional: Dummy::dummy(allocator),
+            accessibility: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for MethodDefinitionType {
+    /// Create a dummy [`MethodDefinitionType`].
+    ///
+    /// Does not allocate any data into arena.
+    #[inline(always)]
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::MethodDefinition
+    }
+}
+
+impl<'a> Dummy<'a> for PropertyDefinition<'a> {
+    /// Create a dummy [`PropertyDefinition`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            r#type: Dummy::dummy(allocator),
+            decorators: Dummy::dummy(allocator),
+            key: Dummy::dummy(allocator),
+            value: Dummy::dummy(allocator),
+            computed: Dummy::dummy(allocator),
+            r#static: Dummy::dummy(allocator),
+            declare: Dummy::dummy(allocator),
+            r#override: Dummy::dummy(allocator),
+            optional: Dummy::dummy(allocator),
+            definite: Dummy::dummy(allocator),
+            readonly: Dummy::dummy(allocator),
+            type_annotation: Dummy::dummy(allocator),
+            accessibility: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for PropertyDefinitionType {
+    /// Create a dummy [`PropertyDefinitionType`].
+    ///
+    /// Does not allocate any data into arena.
+    #[inline(always)]
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::PropertyDefinition
+    }
+}
+
+impl<'a> Dummy<'a> for MethodDefinitionKind {
+    /// Create a dummy [`MethodDefinitionKind`].
+    ///
+    /// Does not allocate any data into arena.
+    #[inline(always)]
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::Constructor
+    }
+}
+
+impl<'a> Dummy<'a> for PrivateIdentifier<'a> {
+    /// Create a dummy [`PrivateIdentifier`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), name: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for StaticBlock<'a> {
+    /// Create a dummy [`StaticBlock`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            body: Dummy::dummy(allocator),
+            scope_id: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for ModuleDeclaration<'a> {
+    /// Create a dummy [`ModuleDeclaration`].
+    ///
+    /// Has cost of making 1 allocation (32 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::TSNamespaceExportDeclaration(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for AccessorPropertyType {
+    /// Create a dummy [`AccessorPropertyType`].
+    ///
+    /// Does not allocate any data into arena.
+    #[inline(always)]
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::AccessorProperty
+    }
+}
+
+impl<'a> Dummy<'a> for AccessorProperty<'a> {
+    /// Create a dummy [`AccessorProperty`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            r#type: Dummy::dummy(allocator),
+            decorators: Dummy::dummy(allocator),
+            key: Dummy::dummy(allocator),
+            value: Dummy::dummy(allocator),
+            computed: Dummy::dummy(allocator),
+            r#static: Dummy::dummy(allocator),
+            definite: Dummy::dummy(allocator),
+            type_annotation: Dummy::dummy(allocator),
+            accessibility: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for ImportExpression<'a> {
+    /// Create a dummy [`ImportExpression`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            source: Dummy::dummy(allocator),
+            options: Dummy::dummy(allocator),
+            phase: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for ImportDeclaration<'a> {
+    /// Create a dummy [`ImportDeclaration`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            specifiers: Dummy::dummy(allocator),
+            source: Dummy::dummy(allocator),
+            phase: Dummy::dummy(allocator),
+            with_clause: Dummy::dummy(allocator),
+            import_kind: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for ImportPhase {
+    /// Create a dummy [`ImportPhase`].
+    ///
+    /// Does not allocate any data into arena.
+    #[inline(always)]
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::Source
+    }
+}
+
+impl<'a> Dummy<'a> for ImportDeclarationSpecifier<'a> {
+    /// Create a dummy [`ImportDeclarationSpecifier`].
+    ///
+    /// Has cost of making 1 allocation (40 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::ImportDefaultSpecifier(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for ImportSpecifier<'a> {
+    /// Create a dummy [`ImportSpecifier`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            imported: Dummy::dummy(allocator),
+            local: Dummy::dummy(allocator),
+            import_kind: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for ImportDefaultSpecifier<'a> {
+    /// Create a dummy [`ImportDefaultSpecifier`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), local: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for ImportNamespaceSpecifier<'a> {
+    /// Create a dummy [`ImportNamespaceSpecifier`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), local: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for WithClause<'a> {
+    /// Create a dummy [`WithClause`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            attributes_keyword: Dummy::dummy(allocator),
+            with_entries: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for ImportAttribute<'a> {
+    /// Create a dummy [`ImportAttribute`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            key: Dummy::dummy(allocator),
+            value: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for ImportAttributeKey<'a> {
+    /// Create a dummy [`ImportAttributeKey`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::Identifier(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for ExportNamedDeclaration<'a> {
+    /// Create a dummy [`ExportNamedDeclaration`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            declaration: Dummy::dummy(allocator),
+            specifiers: Dummy::dummy(allocator),
+            source: Dummy::dummy(allocator),
+            export_kind: Dummy::dummy(allocator),
+            with_clause: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for ExportDefaultDeclaration<'a> {
+    /// Create a dummy [`ExportDefaultDeclaration`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            exported: Dummy::dummy(allocator),
+            declaration: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for ExportAllDeclaration<'a> {
+    /// Create a dummy [`ExportAllDeclaration`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            exported: Dummy::dummy(allocator),
+            source: Dummy::dummy(allocator),
+            with_clause: Dummy::dummy(allocator),
+            export_kind: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for ExportSpecifier<'a> {
+    /// Create a dummy [`ExportSpecifier`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            local: Dummy::dummy(allocator),
+            exported: Dummy::dummy(allocator),
+            export_kind: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for ExportDefaultDeclarationKind<'a> {
+    /// Create a dummy [`ExportDefaultDeclarationKind`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::NullLiteral(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for ModuleExportName<'a> {
+    /// Create a dummy [`ModuleExportName`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::IdentifierName(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for V8IntrinsicExpression<'a> {
+    /// Create a dummy [`V8IntrinsicExpression`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            name: Dummy::dummy(allocator),
+            arguments: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for BooleanLiteral {
+    /// Create a dummy [`BooleanLiteral`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), value: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for NullLiteral {
+    /// Create a dummy [`NullLiteral`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for NumericLiteral<'a> {
+    /// Create a dummy [`NumericLiteral`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            value: Dummy::dummy(allocator),
+            raw: Dummy::dummy(allocator),
+            base: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for StringLiteral<'a> {
+    /// Create a dummy [`StringLiteral`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            value: Dummy::dummy(allocator),
+            raw: Dummy::dummy(allocator),
+            lossy: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for BigIntLiteral<'a> {
+    /// Create a dummy [`BigIntLiteral`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            raw: Dummy::dummy(allocator),
+            base: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for RegExpLiteral<'a> {
+    /// Create a dummy [`RegExpLiteral`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            regex: Dummy::dummy(allocator),
+            raw: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for RegExp<'a> {
+    /// Create a dummy [`RegExp`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { pattern: Dummy::dummy(allocator), flags: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for RegExpPattern<'a> {
+    /// Create a dummy [`RegExpPattern`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::Raw(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for JSXElement<'a> {
+    /// Create a dummy [`JSXElement`].
+    ///
+    /// Has cost of making 2 allocations (80 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            opening_element: Dummy::dummy(allocator),
+            closing_element: Dummy::dummy(allocator),
+            children: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for JSXOpeningElement<'a> {
+    /// Create a dummy [`JSXOpeningElement`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            self_closing: Dummy::dummy(allocator),
+            name: Dummy::dummy(allocator),
+            attributes: Dummy::dummy(allocator),
+            type_arguments: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for JSXClosingElement<'a> {
+    /// Create a dummy [`JSXClosingElement`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), name: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for JSXFragment<'a> {
+    /// Create a dummy [`JSXFragment`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            opening_fragment: Dummy::dummy(allocator),
+            closing_fragment: Dummy::dummy(allocator),
+            children: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for JSXOpeningFragment {
+    /// Create a dummy [`JSXOpeningFragment`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for JSXClosingFragment {
+    /// Create a dummy [`JSXClosingFragment`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for JSXElementName<'a> {
+    /// Create a dummy [`JSXElementName`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::ThisExpression(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for JSXNamespacedName<'a> {
+    /// Create a dummy [`JSXNamespacedName`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            namespace: Dummy::dummy(allocator),
+            name: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for JSXMemberExpression<'a> {
+    /// Create a dummy [`JSXMemberExpression`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            object: Dummy::dummy(allocator),
+            property: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for JSXMemberExpressionObject<'a> {
+    /// Create a dummy [`JSXMemberExpressionObject`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::ThisExpression(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for JSXExpressionContainer<'a> {
+    /// Create a dummy [`JSXExpressionContainer`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), expression: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for JSXExpression<'a> {
+    /// Create a dummy [`JSXExpression`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::EmptyExpression(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for JSXEmptyExpression {
+    /// Create a dummy [`JSXEmptyExpression`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for JSXAttributeItem<'a> {
+    /// Create a dummy [`JSXAttributeItem`].
+    ///
+    /// Has cost of making 2 allocations (32 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::SpreadAttribute(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for JSXAttribute<'a> {
+    /// Create a dummy [`JSXAttribute`].
+    ///
+    /// Has cost of making 1 allocation (24 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            name: Dummy::dummy(allocator),
+            value: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for JSXSpreadAttribute<'a> {
+    /// Create a dummy [`JSXSpreadAttribute`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), argument: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for JSXAttributeName<'a> {
+    /// Create a dummy [`JSXAttributeName`].
+    ///
+    /// Has cost of making 1 allocation (24 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::Identifier(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for JSXAttributeValue<'a> {
+    /// Create a dummy [`JSXAttributeValue`].
+    ///
+    /// Has cost of making 1 allocation (24 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::ExpressionContainer(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for JSXIdentifier<'a> {
+    /// Create a dummy [`JSXIdentifier`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), name: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for JSXChild<'a> {
+    /// Create a dummy [`JSXChild`].
+    ///
+    /// Has cost of making 1 allocation (24 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::ExpressionContainer(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for JSXSpreadChild<'a> {
+    /// Create a dummy [`JSXSpreadChild`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), expression: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for JSXText<'a> {
+    /// Create a dummy [`JSXText`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            value: Dummy::dummy(allocator),
+            raw: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSThisParameter<'a> {
+    /// Create a dummy [`TSThisParameter`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            this_span: Dummy::dummy(allocator),
+            type_annotation: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSEnumDeclaration<'a> {
+    /// Create a dummy [`TSEnumDeclaration`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            id: Dummy::dummy(allocator),
+            members: Dummy::dummy(allocator),
+            r#const: Dummy::dummy(allocator),
+            declare: Dummy::dummy(allocator),
+            scope_id: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSEnumMember<'a> {
+    /// Create a dummy [`TSEnumMember`].
+    ///
+    /// Has cost of making 1 allocation (24 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            id: Dummy::dummy(allocator),
+            initializer: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSEnumMemberName<'a> {
+    /// Create a dummy [`TSEnumMemberName`].
+    ///
+    /// Has cost of making 1 allocation (24 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::Identifier(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for TSTypeAnnotation<'a> {
+    /// Create a dummy [`TSTypeAnnotation`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), type_annotation: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TSLiteralType<'a> {
+    /// Create a dummy [`TSLiteralType`].
+    ///
+    /// Has cost of making 1 allocation (16 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), literal: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TSLiteral<'a> {
+    /// Create a dummy [`TSLiteral`].
+    ///
+    /// Has cost of making 1 allocation (16 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::BooleanLiteral(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for TSType<'a> {
+    /// Create a dummy [`TSType`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::TSAnyKeyword(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for TSConditionalType<'a> {
+    /// Create a dummy [`TSConditionalType`].
+    ///
+    /// Has cost of making 4 allocations (32 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            check_type: Dummy::dummy(allocator),
+            extends_type: Dummy::dummy(allocator),
+            true_type: Dummy::dummy(allocator),
+            false_type: Dummy::dummy(allocator),
+            scope_id: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSUnionType<'a> {
+    /// Create a dummy [`TSUnionType`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), types: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TSIntersectionType<'a> {
+    /// Create a dummy [`TSIntersectionType`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), types: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TSParenthesizedType<'a> {
+    /// Create a dummy [`TSParenthesizedType`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), type_annotation: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TSTypeOperator<'a> {
+    /// Create a dummy [`TSTypeOperator`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            operator: Dummy::dummy(allocator),
+            type_annotation: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSTypeOperatorOperator {
+    /// Create a dummy [`TSTypeOperatorOperator`].
+    ///
+    /// Does not allocate any data into arena.
+    #[inline(always)]
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::Keyof
+    }
+}
+
+impl<'a> Dummy<'a> for TSArrayType<'a> {
+    /// Create a dummy [`TSArrayType`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), element_type: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TSIndexedAccessType<'a> {
+    /// Create a dummy [`TSIndexedAccessType`].
+    ///
+    /// Has cost of making 2 allocations (16 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            object_type: Dummy::dummy(allocator),
+            index_type: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSTupleType<'a> {
+    /// Create a dummy [`TSTupleType`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), element_types: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TSNamedTupleMember<'a> {
+    /// Create a dummy [`TSNamedTupleMember`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            element_type: Dummy::dummy(allocator),
+            label: Dummy::dummy(allocator),
+            optional: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSOptionalType<'a> {
+    /// Create a dummy [`TSOptionalType`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), type_annotation: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TSRestType<'a> {
+    /// Create a dummy [`TSRestType`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), type_annotation: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TSTupleElement<'a> {
+    /// Create a dummy [`TSTupleElement`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::TSAnyKeyword(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for TSAnyKeyword {
+    /// Create a dummy [`TSAnyKeyword`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TSStringKeyword {
+    /// Create a dummy [`TSStringKeyword`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TSBooleanKeyword {
+    /// Create a dummy [`TSBooleanKeyword`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TSNumberKeyword {
+    /// Create a dummy [`TSNumberKeyword`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TSNeverKeyword {
+    /// Create a dummy [`TSNeverKeyword`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TSIntrinsicKeyword {
+    /// Create a dummy [`TSIntrinsicKeyword`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TSUnknownKeyword {
+    /// Create a dummy [`TSUnknownKeyword`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TSNullKeyword {
+    /// Create a dummy [`TSNullKeyword`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TSUndefinedKeyword {
+    /// Create a dummy [`TSUndefinedKeyword`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TSVoidKeyword {
+    /// Create a dummy [`TSVoidKeyword`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TSSymbolKeyword {
+    /// Create a dummy [`TSSymbolKeyword`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TSThisType {
+    /// Create a dummy [`TSThisType`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TSObjectKeyword {
+    /// Create a dummy [`TSObjectKeyword`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TSBigIntKeyword {
+    /// Create a dummy [`TSBigIntKeyword`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TSTypeReference<'a> {
+    /// Create a dummy [`TSTypeReference`].
+    ///
+    /// Has cost of making 1 allocation (32 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            type_name: Dummy::dummy(allocator),
+            type_arguments: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSTypeName<'a> {
+    /// Create a dummy [`TSTypeName`].
+    ///
+    /// Has cost of making 1 allocation (32 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::IdentifierReference(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for TSQualifiedName<'a> {
+    /// Create a dummy [`TSQualifiedName`].
+    ///
+    /// Has cost of making 1 allocation (32 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            left: Dummy::dummy(allocator),
+            right: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSTypeParameterInstantiation<'a> {
+    /// Create a dummy [`TSTypeParameterInstantiation`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), params: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TSTypeParameter<'a> {
+    /// Create a dummy [`TSTypeParameter`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            name: Dummy::dummy(allocator),
+            constraint: Dummy::dummy(allocator),
+            default: Dummy::dummy(allocator),
+            r#in: Dummy::dummy(allocator),
+            out: Dummy::dummy(allocator),
+            r#const: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSTypeParameterDeclaration<'a> {
+    /// Create a dummy [`TSTypeParameterDeclaration`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), params: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TSTypeAliasDeclaration<'a> {
+    /// Create a dummy [`TSTypeAliasDeclaration`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            id: Dummy::dummy(allocator),
+            type_parameters: Dummy::dummy(allocator),
+            type_annotation: Dummy::dummy(allocator),
+            declare: Dummy::dummy(allocator),
+            scope_id: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSAccessibility {
+    /// Create a dummy [`TSAccessibility`].
+    ///
+    /// Does not allocate any data into arena.
+    #[inline(always)]
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::Private
+    }
+}
+
+impl<'a> Dummy<'a> for TSClassImplements<'a> {
+    /// Create a dummy [`TSClassImplements`].
+    ///
+    /// Has cost of making 1 allocation (32 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            expression: Dummy::dummy(allocator),
+            type_arguments: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSInterfaceDeclaration<'a> {
+    /// Create a dummy [`TSInterfaceDeclaration`].
+    ///
+    /// Has cost of making 1 allocation (40 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            id: Dummy::dummy(allocator),
+            extends: Dummy::dummy(allocator),
+            type_parameters: Dummy::dummy(allocator),
+            body: Dummy::dummy(allocator),
+            declare: Dummy::dummy(allocator),
+            scope_id: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSInterfaceBody<'a> {
+    /// Create a dummy [`TSInterfaceBody`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), body: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TSPropertySignature<'a> {
+    /// Create a dummy [`TSPropertySignature`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            computed: Dummy::dummy(allocator),
+            optional: Dummy::dummy(allocator),
+            readonly: Dummy::dummy(allocator),
+            key: Dummy::dummy(allocator),
+            type_annotation: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSSignature<'a> {
+    /// Create a dummy [`TSSignature`].
+    ///
+    /// Has cost of making 2 allocations (48 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::TSPropertySignature(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for TSIndexSignature<'a> {
+    /// Create a dummy [`TSIndexSignature`].
+    ///
+    /// Has cost of making 2 allocations (32 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            parameters: Dummy::dummy(allocator),
+            type_annotation: Dummy::dummy(allocator),
+            readonly: Dummy::dummy(allocator),
+            r#static: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSCallSignatureDeclaration<'a> {
+    /// Create a dummy [`TSCallSignatureDeclaration`].
+    ///
+    /// Has cost of making 1 allocation (56 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            type_parameters: Dummy::dummy(allocator),
+            this_param: Dummy::dummy(allocator),
+            params: Dummy::dummy(allocator),
+            return_type: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSMethodSignatureKind {
+    /// Create a dummy [`TSMethodSignatureKind`].
+    ///
+    /// Does not allocate any data into arena.
+    #[inline(always)]
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::Method
+    }
+}
+
+impl<'a> Dummy<'a> for TSMethodSignature<'a> {
+    /// Create a dummy [`TSMethodSignature`].
+    ///
+    /// Has cost of making 2 allocations (64 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            key: Dummy::dummy(allocator),
+            computed: Dummy::dummy(allocator),
+            optional: Dummy::dummy(allocator),
+            kind: Dummy::dummy(allocator),
+            type_parameters: Dummy::dummy(allocator),
+            this_param: Dummy::dummy(allocator),
+            params: Dummy::dummy(allocator),
+            return_type: Dummy::dummy(allocator),
+            scope_id: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSConstructSignatureDeclaration<'a> {
+    /// Create a dummy [`TSConstructSignatureDeclaration`].
+    ///
+    /// Has cost of making 1 allocation (56 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            type_parameters: Dummy::dummy(allocator),
+            params: Dummy::dummy(allocator),
+            return_type: Dummy::dummy(allocator),
+            scope_id: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSIndexSignatureName<'a> {
+    /// Create a dummy [`TSIndexSignatureName`].
+    ///
+    /// Has cost of making 2 allocations (32 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            name: Dummy::dummy(allocator),
+            type_annotation: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSInterfaceHeritage<'a> {
+    /// Create a dummy [`TSInterfaceHeritage`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            expression: Dummy::dummy(allocator),
+            type_arguments: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSTypePredicate<'a> {
+    /// Create a dummy [`TSTypePredicate`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            parameter_name: Dummy::dummy(allocator),
+            asserts: Dummy::dummy(allocator),
+            type_annotation: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSTypePredicateName<'a> {
+    /// Create a dummy [`TSTypePredicateName`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::This(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for TSModuleDeclaration<'a> {
+    /// Create a dummy [`TSModuleDeclaration`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            id: Dummy::dummy(allocator),
+            body: Dummy::dummy(allocator),
+            kind: Dummy::dummy(allocator),
+            declare: Dummy::dummy(allocator),
+            scope_id: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSModuleDeclarationKind {
+    /// Create a dummy [`TSModuleDeclarationKind`].
+    ///
+    /// Does not allocate any data into arena.
+    #[inline(always)]
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::Global
+    }
+}
+
+impl<'a> Dummy<'a> for TSModuleDeclarationName<'a> {
+    /// Create a dummy [`TSModuleDeclarationName`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::Identifier(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for TSModuleDeclarationBody<'a> {
+    /// Create a dummy [`TSModuleDeclarationBody`].
+    ///
+    /// Has cost of making 1 allocation (72 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::TSModuleBlock(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for TSModuleBlock<'a> {
+    /// Create a dummy [`TSModuleBlock`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            directives: Dummy::dummy(allocator),
+            body: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSTypeLiteral<'a> {
+    /// Create a dummy [`TSTypeLiteral`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), members: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TSInferType<'a> {
+    /// Create a dummy [`TSInferType`].
+    ///
+    /// Has cost of making 1 allocation (80 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), type_parameter: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TSTypeQuery<'a> {
+    /// Create a dummy [`TSTypeQuery`].
+    ///
+    /// Has cost of making 1 allocation (32 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            expr_name: Dummy::dummy(allocator),
+            type_arguments: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSTypeQueryExprName<'a> {
+    /// Create a dummy [`TSTypeQueryExprName`].
+    ///
+    /// Has cost of making 1 allocation (32 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::IdentifierReference(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for TSImportType<'a> {
+    /// Create a dummy [`TSImportType`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            argument: Dummy::dummy(allocator),
+            options: Dummy::dummy(allocator),
+            qualifier: Dummy::dummy(allocator),
+            type_arguments: Dummy::dummy(allocator),
+            is_type_of: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSFunctionType<'a> {
+    /// Create a dummy [`TSFunctionType`].
+    ///
+    /// Has cost of making 3 allocations (88 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            type_parameters: Dummy::dummy(allocator),
+            this_param: Dummy::dummy(allocator),
+            params: Dummy::dummy(allocator),
+            return_type: Dummy::dummy(allocator),
+            scope_id: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSConstructorType<'a> {
+    /// Create a dummy [`TSConstructorType`].
+    ///
+    /// Has cost of making 3 allocations (88 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            r#abstract: Dummy::dummy(allocator),
+            type_parameters: Dummy::dummy(allocator),
+            params: Dummy::dummy(allocator),
+            return_type: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSMappedType<'a> {
+    /// Create a dummy [`TSMappedType`].
+    ///
+    /// Has cost of making 1 allocation (80 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            type_parameter: Dummy::dummy(allocator),
+            name_type: Dummy::dummy(allocator),
+            type_annotation: Dummy::dummy(allocator),
+            optional: Dummy::dummy(allocator),
+            readonly: Dummy::dummy(allocator),
+            scope_id: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSMappedTypeModifierOperator {
+    /// Create a dummy [`TSMappedTypeModifierOperator`].
+    ///
+    /// Does not allocate any data into arena.
+    #[inline(always)]
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::True
+    }
+}
+
+impl<'a> Dummy<'a> for TSTemplateLiteralType<'a> {
+    /// Create a dummy [`TSTemplateLiteralType`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            quasis: Dummy::dummy(allocator),
+            types: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSAsExpression<'a> {
+    /// Create a dummy [`TSAsExpression`].
+    ///
+    /// Has cost of making 2 allocations (16 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            expression: Dummy::dummy(allocator),
+            type_annotation: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSSatisfiesExpression<'a> {
+    /// Create a dummy [`TSSatisfiesExpression`].
+    ///
+    /// Has cost of making 2 allocations (16 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            expression: Dummy::dummy(allocator),
+            type_annotation: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSTypeAssertion<'a> {
+    /// Create a dummy [`TSTypeAssertion`].
+    ///
+    /// Has cost of making 2 allocations (16 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            expression: Dummy::dummy(allocator),
+            type_annotation: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSImportEqualsDeclaration<'a> {
+    /// Create a dummy [`TSImportEqualsDeclaration`].
+    ///
+    /// Has cost of making 1 allocation (32 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            id: Dummy::dummy(allocator),
+            module_reference: Dummy::dummy(allocator),
+            import_kind: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for TSModuleReference<'a> {
+    /// Create a dummy [`TSModuleReference`].
+    ///
+    /// Has cost of making 1 allocation (32 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::IdentifierReference(Dummy::dummy(allocator))
+    }
+}
+
+impl<'a> Dummy<'a> for TSExternalModuleReference<'a> {
+    /// Create a dummy [`TSExternalModuleReference`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), expression: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TSNonNullExpression<'a> {
+    /// Create a dummy [`TSNonNullExpression`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), expression: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for Decorator<'a> {
+    /// Create a dummy [`Decorator`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), expression: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TSExportAssignment<'a> {
+    /// Create a dummy [`TSExportAssignment`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), expression: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TSNamespaceExportDeclaration<'a> {
+    /// Create a dummy [`TSNamespaceExportDeclaration`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator), id: Dummy::dummy(allocator) }
+    }
+}
+
+impl<'a> Dummy<'a> for TSInstantiationExpression<'a> {
+    /// Create a dummy [`TSInstantiationExpression`].
+    ///
+    /// Has cost of making 2 allocations (48 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            expression: Dummy::dummy(allocator),
+            type_parameters: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for ImportOrExportKind {
+    /// Create a dummy [`ImportOrExportKind`].
+    ///
+    /// Does not allocate any data into arena.
+    #[inline(always)]
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::Value
+    }
+}
+
+impl<'a> Dummy<'a> for JSDocNullableType<'a> {
+    /// Create a dummy [`JSDocNullableType`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            type_annotation: Dummy::dummy(allocator),
+            postfix: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for JSDocNonNullableType<'a> {
+    /// Create a dummy [`JSDocNonNullableType`].
+    ///
+    /// Has cost of making 1 allocation (8 bytes).
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            span: Dummy::dummy(allocator),
+            type_annotation: Dummy::dummy(allocator),
+            postfix: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for JSDocUnknownType {
+    /// Create a dummy [`JSDocUnknownType`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self { span: Dummy::dummy(allocator) }
+    }
+}
diff --git a/crates/oxc_ast/src/generated/derive_take_in.rs b/crates/oxc_ast/src/generated/derive_take_in.rs
new file mode 100644
index 0000000000000..1080a18ffcdc6
--- /dev/null
+++ b/crates/oxc_ast/src/generated/derive_take_in.rs
@@ -0,0 +1,469 @@
+// Auto-generated code, DO NOT EDIT DIRECTLY!
+// To edit this generated file you have to edit `tasks/ast_tools/src/derives/take_in.rs`
+
+#![allow(clippy::needless_lifetimes)]
+
+use oxc_allocator::TakeIn;
+
+use crate::ast::js::*;
+use crate::ast::jsx::*;
+use crate::ast::literal::*;
+use crate::ast::ts::*;
+
+impl<'a> TakeIn<'a> for Program<'a> {}
+
+impl<'a> TakeIn<'a> for Expression<'a> {}
+
+impl<'a> TakeIn<'a> for IdentifierName<'a> {}
+
+impl<'a> TakeIn<'a> for IdentifierReference<'a> {}
+
+impl<'a> TakeIn<'a> for BindingIdentifier<'a> {}
+
+impl<'a> TakeIn<'a> for LabelIdentifier<'a> {}
+
+impl<'a> TakeIn<'a> for ThisExpression {}
+
+impl<'a> TakeIn<'a> for ArrayExpression<'a> {}
+
+impl<'a> TakeIn<'a> for ArrayExpressionElement<'a> {}
+
+impl<'a> TakeIn<'a> for Elision {}
+
+impl<'a> TakeIn<'a> for ObjectExpression<'a> {}
+
+impl<'a> TakeIn<'a> for ObjectPropertyKind<'a> {}
+
+impl<'a> TakeIn<'a> for ObjectProperty<'a> {}
+
+impl<'a> TakeIn<'a> for PropertyKey<'a> {}
+
+impl<'a> TakeIn<'a> for TemplateLiteral<'a> {}
+
+impl<'a> TakeIn<'a> for TaggedTemplateExpression<'a> {}
+
+impl<'a> TakeIn<'a> for TemplateElement<'a> {}
+
+impl<'a> TakeIn<'a> for TemplateElementValue<'a> {}
+
+impl<'a> TakeIn<'a> for MemberExpression<'a> {}
+
+impl<'a> TakeIn<'a> for ComputedMemberExpression<'a> {}
+
+impl<'a> TakeIn<'a> for StaticMemberExpression<'a> {}
+
+impl<'a> TakeIn<'a> for PrivateFieldExpression<'a> {}
+
+impl<'a> TakeIn<'a> for CallExpression<'a> {}
+
+impl<'a> TakeIn<'a> for NewExpression<'a> {}
+
+impl<'a> TakeIn<'a> for MetaProperty<'a> {}
+
+impl<'a> TakeIn<'a> for SpreadElement<'a> {}
+
+impl<'a> TakeIn<'a> for Argument<'a> {}
+
+impl<'a> TakeIn<'a> for UpdateExpression<'a> {}
+
+impl<'a> TakeIn<'a> for UnaryExpression<'a> {}
+
+impl<'a> TakeIn<'a> for BinaryExpression<'a> {}
+
+impl<'a> TakeIn<'a> for PrivateInExpression<'a> {}
+
+impl<'a> TakeIn<'a> for LogicalExpression<'a> {}
+
+impl<'a> TakeIn<'a> for ConditionalExpression<'a> {}
+
+impl<'a> TakeIn<'a> for AssignmentExpression<'a> {}
+
+impl<'a> TakeIn<'a> for AssignmentTarget<'a> {}
+
+impl<'a> TakeIn<'a> for SimpleAssignmentTarget<'a> {}
+
+impl<'a> TakeIn<'a> for AssignmentTargetPattern<'a> {}
+
+impl<'a> TakeIn<'a> for ArrayAssignmentTarget<'a> {}
+
+impl<'a> TakeIn<'a> for ObjectAssignmentTarget<'a> {}
+
+impl<'a> TakeIn<'a> for AssignmentTargetRest<'a> {}
+
+impl<'a> TakeIn<'a> for AssignmentTargetMaybeDefault<'a> {}
+
+impl<'a> TakeIn<'a> for AssignmentTargetWithDefault<'a> {}
+
+impl<'a> TakeIn<'a> for AssignmentTargetProperty<'a> {}
+
+impl<'a> TakeIn<'a> for AssignmentTargetPropertyIdentifier<'a> {}
+
+impl<'a> TakeIn<'a> for AssignmentTargetPropertyProperty<'a> {}
+
+impl<'a> TakeIn<'a> for SequenceExpression<'a> {}
+
+impl<'a> TakeIn<'a> for Super {}
+
+impl<'a> TakeIn<'a> for AwaitExpression<'a> {}
+
+impl<'a> TakeIn<'a> for ChainExpression<'a> {}
+
+impl<'a> TakeIn<'a> for ChainElement<'a> {}
+
+impl<'a> TakeIn<'a> for ParenthesizedExpression<'a> {}
+
+impl<'a> TakeIn<'a> for Statement<'a> {}
+
+impl<'a> TakeIn<'a> for Directive<'a> {}
+
+impl<'a> TakeIn<'a> for Hashbang<'a> {}
+
+impl<'a> TakeIn<'a> for BlockStatement<'a> {}
+
+impl<'a> TakeIn<'a> for Declaration<'a> {}
+
+impl<'a> TakeIn<'a> for VariableDeclaration<'a> {}
+
+impl<'a> TakeIn<'a> for VariableDeclarator<'a> {}
+
+impl<'a> TakeIn<'a> for EmptyStatement {}
+
+impl<'a> TakeIn<'a> for ExpressionStatement<'a> {}
+
+impl<'a> TakeIn<'a> for IfStatement<'a> {}
+
+impl<'a> TakeIn<'a> for DoWhileStatement<'a> {}
+
+impl<'a> TakeIn<'a> for WhileStatement<'a> {}
+
+impl<'a> TakeIn<'a> for ForStatement<'a> {}
+
+impl<'a> TakeIn<'a> for ForStatementInit<'a> {}
+
+impl<'a> TakeIn<'a> for ForInStatement<'a> {}
+
+impl<'a> TakeIn<'a> for ForStatementLeft<'a> {}
+
+impl<'a> TakeIn<'a> for ForOfStatement<'a> {}
+
+impl<'a> TakeIn<'a> for ContinueStatement<'a> {}
+
+impl<'a> TakeIn<'a> for BreakStatement<'a> {}
+
+impl<'a> TakeIn<'a> for ReturnStatement<'a> {}
+
+impl<'a> TakeIn<'a> for WithStatement<'a> {}
+
+impl<'a> TakeIn<'a> for SwitchStatement<'a> {}
+
+impl<'a> TakeIn<'a> for SwitchCase<'a> {}
+
+impl<'a> TakeIn<'a> for LabeledStatement<'a> {}
+
+impl<'a> TakeIn<'a> for ThrowStatement<'a> {}
+
+impl<'a> TakeIn<'a> for TryStatement<'a> {}
+
+impl<'a> TakeIn<'a> for CatchClause<'a> {}
+
+impl<'a> TakeIn<'a> for CatchParameter<'a> {}
+
+impl<'a> TakeIn<'a> for DebuggerStatement {}
+
+impl<'a> TakeIn<'a> for BindingPattern<'a> {}
+
+impl<'a> TakeIn<'a> for BindingPatternKind<'a> {}
+
+impl<'a> TakeIn<'a> for AssignmentPattern<'a> {}
+
+impl<'a> TakeIn<'a> for ObjectPattern<'a> {}
+
+impl<'a> TakeIn<'a> for BindingProperty<'a> {}
+
+impl<'a> TakeIn<'a> for ArrayPattern<'a> {}
+
+impl<'a> TakeIn<'a> for BindingRestElement<'a> {}
+
+impl<'a> TakeIn<'a> for Function<'a> {}
+
+impl<'a> TakeIn<'a> for FormalParameters<'a> {}
+
+impl<'a> TakeIn<'a> for FormalParameter<'a> {}
+
+impl<'a> TakeIn<'a> for FunctionBody<'a> {}
+
+impl<'a> TakeIn<'a> for ArrowFunctionExpression<'a> {}
+
+impl<'a> TakeIn<'a> for YieldExpression<'a> {}
+
+impl<'a> TakeIn<'a> for Class<'a> {}
+
+impl<'a> TakeIn<'a> for ClassBody<'a> {}
+
+impl<'a> TakeIn<'a> for ClassElement<'a> {}
+
+impl<'a> TakeIn<'a> for MethodDefinition<'a> {}
+
+impl<'a> TakeIn<'a> for PropertyDefinition<'a> {}
+
+impl<'a> TakeIn<'a> for PrivateIdentifier<'a> {}
+
+impl<'a> TakeIn<'a> for StaticBlock<'a> {}
+
+impl<'a> TakeIn<'a> for ModuleDeclaration<'a> {}
+
+impl<'a> TakeIn<'a> for AccessorProperty<'a> {}
+
+impl<'a> TakeIn<'a> for ImportExpression<'a> {}
+
+impl<'a> TakeIn<'a> for ImportDeclaration<'a> {}
+
+impl<'a> TakeIn<'a> for ImportDeclarationSpecifier<'a> {}
+
+impl<'a> TakeIn<'a> for ImportSpecifier<'a> {}
+
+impl<'a> TakeIn<'a> for ImportDefaultSpecifier<'a> {}
+
+impl<'a> TakeIn<'a> for ImportNamespaceSpecifier<'a> {}
+
+impl<'a> TakeIn<'a> for WithClause<'a> {}
+
+impl<'a> TakeIn<'a> for ImportAttribute<'a> {}
+
+impl<'a> TakeIn<'a> for ImportAttributeKey<'a> {}
+
+impl<'a> TakeIn<'a> for ExportNamedDeclaration<'a> {}
+
+impl<'a> TakeIn<'a> for ExportDefaultDeclaration<'a> {}
+
+impl<'a> TakeIn<'a> for ExportAllDeclaration<'a> {}
+
+impl<'a> TakeIn<'a> for ExportSpecifier<'a> {}
+
+impl<'a> TakeIn<'a> for ExportDefaultDeclarationKind<'a> {}
+
+impl<'a> TakeIn<'a> for ModuleExportName<'a> {}
+
+impl<'a> TakeIn<'a> for V8IntrinsicExpression<'a> {}
+
+impl<'a> TakeIn<'a> for BooleanLiteral {}
+
+impl<'a> TakeIn<'a> for NullLiteral {}
+
+impl<'a> TakeIn<'a> for NumericLiteral<'a> {}
+
+impl<'a> TakeIn<'a> for StringLiteral<'a> {}
+
+impl<'a> TakeIn<'a> for BigIntLiteral<'a> {}
+
+impl<'a> TakeIn<'a> for RegExpLiteral<'a> {}
+
+impl<'a> TakeIn<'a> for RegExp<'a> {}
+
+impl<'a> TakeIn<'a> for RegExpPattern<'a> {}
+
+impl<'a> TakeIn<'a> for JSXElement<'a> {}
+
+impl<'a> TakeIn<'a> for JSXOpeningElement<'a> {}
+
+impl<'a> TakeIn<'a> for JSXClosingElement<'a> {}
+
+impl<'a> TakeIn<'a> for JSXFragment<'a> {}
+
+impl<'a> TakeIn<'a> for JSXOpeningFragment {}
+
+impl<'a> TakeIn<'a> for JSXClosingFragment {}
+
+impl<'a> TakeIn<'a> for JSXElementName<'a> {}
+
+impl<'a> TakeIn<'a> for JSXNamespacedName<'a> {}
+
+impl<'a> TakeIn<'a> for JSXMemberExpression<'a> {}
+
+impl<'a> TakeIn<'a> for JSXMemberExpressionObject<'a> {}
+
+impl<'a> TakeIn<'a> for JSXExpressionContainer<'a> {}
+
+impl<'a> TakeIn<'a> for JSXExpression<'a> {}
+
+impl<'a> TakeIn<'a> for JSXEmptyExpression {}
+
+impl<'a> TakeIn<'a> for JSXAttributeItem<'a> {}
+
+impl<'a> TakeIn<'a> for JSXAttribute<'a> {}
+
+impl<'a> TakeIn<'a> for JSXSpreadAttribute<'a> {}
+
+impl<'a> TakeIn<'a> for JSXAttributeName<'a> {}
+
+impl<'a> TakeIn<'a> for JSXAttributeValue<'a> {}
+
+impl<'a> TakeIn<'a> for JSXIdentifier<'a> {}
+
+impl<'a> TakeIn<'a> for JSXChild<'a> {}
+
+impl<'a> TakeIn<'a> for JSXSpreadChild<'a> {}
+
+impl<'a> TakeIn<'a> for JSXText<'a> {}
+
+impl<'a> TakeIn<'a> for TSThisParameter<'a> {}
+
+impl<'a> TakeIn<'a> for TSEnumDeclaration<'a> {}
+
+impl<'a> TakeIn<'a> for TSEnumMember<'a> {}
+
+impl<'a> TakeIn<'a> for TSEnumMemberName<'a> {}
+
+impl<'a> TakeIn<'a> for TSTypeAnnotation<'a> {}
+
+impl<'a> TakeIn<'a> for TSLiteralType<'a> {}
+
+impl<'a> TakeIn<'a> for TSLiteral<'a> {}
+
+impl<'a> TakeIn<'a> for TSType<'a> {}
+
+impl<'a> TakeIn<'a> for TSConditionalType<'a> {}
+
+impl<'a> TakeIn<'a> for TSUnionType<'a> {}
+
+impl<'a> TakeIn<'a> for TSIntersectionType<'a> {}
+
+impl<'a> TakeIn<'a> for TSParenthesizedType<'a> {}
+
+impl<'a> TakeIn<'a> for TSTypeOperator<'a> {}
+
+impl<'a> TakeIn<'a> for TSArrayType<'a> {}
+
+impl<'a> TakeIn<'a> for TSIndexedAccessType<'a> {}
+
+impl<'a> TakeIn<'a> for TSTupleType<'a> {}
+
+impl<'a> TakeIn<'a> for TSNamedTupleMember<'a> {}
+
+impl<'a> TakeIn<'a> for TSOptionalType<'a> {}
+
+impl<'a> TakeIn<'a> for TSRestType<'a> {}
+
+impl<'a> TakeIn<'a> for TSTupleElement<'a> {}
+
+impl<'a> TakeIn<'a> for TSAnyKeyword {}
+
+impl<'a> TakeIn<'a> for TSStringKeyword {}
+
+impl<'a> TakeIn<'a> for TSBooleanKeyword {}
+
+impl<'a> TakeIn<'a> for TSNumberKeyword {}
+
+impl<'a> TakeIn<'a> for TSNeverKeyword {}
+
+impl<'a> TakeIn<'a> for TSIntrinsicKeyword {}
+
+impl<'a> TakeIn<'a> for TSUnknownKeyword {}
+
+impl<'a> TakeIn<'a> for TSNullKeyword {}
+
+impl<'a> TakeIn<'a> for TSUndefinedKeyword {}
+
+impl<'a> TakeIn<'a> for TSVoidKeyword {}
+
+impl<'a> TakeIn<'a> for TSSymbolKeyword {}
+
+impl<'a> TakeIn<'a> for TSThisType {}
+
+impl<'a> TakeIn<'a> for TSObjectKeyword {}
+
+impl<'a> TakeIn<'a> for TSBigIntKeyword {}
+
+impl<'a> TakeIn<'a> for TSTypeReference<'a> {}
+
+impl<'a> TakeIn<'a> for TSTypeName<'a> {}
+
+impl<'a> TakeIn<'a> for TSQualifiedName<'a> {}
+
+impl<'a> TakeIn<'a> for TSTypeParameterInstantiation<'a> {}
+
+impl<'a> TakeIn<'a> for TSTypeParameter<'a> {}
+
+impl<'a> TakeIn<'a> for TSTypeParameterDeclaration<'a> {}
+
+impl<'a> TakeIn<'a> for TSTypeAliasDeclaration<'a> {}
+
+impl<'a> TakeIn<'a> for TSClassImplements<'a> {}
+
+impl<'a> TakeIn<'a> for TSInterfaceDeclaration<'a> {}
+
+impl<'a> TakeIn<'a> for TSInterfaceBody<'a> {}
+
+impl<'a> TakeIn<'a> for TSPropertySignature<'a> {}
+
+impl<'a> TakeIn<'a> for TSSignature<'a> {}
+
+impl<'a> TakeIn<'a> for TSIndexSignature<'a> {}
+
+impl<'a> TakeIn<'a> for TSCallSignatureDeclaration<'a> {}
+
+impl<'a> TakeIn<'a> for TSMethodSignature<'a> {}
+
+impl<'a> TakeIn<'a> for TSConstructSignatureDeclaration<'a> {}
+
+impl<'a> TakeIn<'a> for TSIndexSignatureName<'a> {}
+
+impl<'a> TakeIn<'a> for TSInterfaceHeritage<'a> {}
+
+impl<'a> TakeIn<'a> for TSTypePredicate<'a> {}
+
+impl<'a> TakeIn<'a> for TSTypePredicateName<'a> {}
+
+impl<'a> TakeIn<'a> for TSModuleDeclaration<'a> {}
+
+impl<'a> TakeIn<'a> for TSModuleDeclarationName<'a> {}
+
+impl<'a> TakeIn<'a> for TSModuleDeclarationBody<'a> {}
+
+impl<'a> TakeIn<'a> for TSModuleBlock<'a> {}
+
+impl<'a> TakeIn<'a> for TSTypeLiteral<'a> {}
+
+impl<'a> TakeIn<'a> for TSInferType<'a> {}
+
+impl<'a> TakeIn<'a> for TSTypeQuery<'a> {}
+
+impl<'a> TakeIn<'a> for TSTypeQueryExprName<'a> {}
+
+impl<'a> TakeIn<'a> for TSImportType<'a> {}
+
+impl<'a> TakeIn<'a> for TSFunctionType<'a> {}
+
+impl<'a> TakeIn<'a> for TSConstructorType<'a> {}
+
+impl<'a> TakeIn<'a> for TSMappedType<'a> {}
+
+impl<'a> TakeIn<'a> for TSTemplateLiteralType<'a> {}
+
+impl<'a> TakeIn<'a> for TSAsExpression<'a> {}
+
+impl<'a> TakeIn<'a> for TSSatisfiesExpression<'a> {}
+
+impl<'a> TakeIn<'a> for TSTypeAssertion<'a> {}
+
+impl<'a> TakeIn<'a> for TSImportEqualsDeclaration<'a> {}
+
+impl<'a> TakeIn<'a> for TSModuleReference<'a> {}
+
+impl<'a> TakeIn<'a> for TSExternalModuleReference<'a> {}
+
+impl<'a> TakeIn<'a> for TSNonNullExpression<'a> {}
+
+impl<'a> TakeIn<'a> for Decorator<'a> {}
+
+impl<'a> TakeIn<'a> for TSExportAssignment<'a> {}
+
+impl<'a> TakeIn<'a> for TSNamespaceExportDeclaration<'a> {}
+
+impl<'a> TakeIn<'a> for TSInstantiationExpression<'a> {}
+
+impl<'a> TakeIn<'a> for JSDocNullableType<'a> {}
+
+impl<'a> TakeIn<'a> for JSDocNonNullableType<'a> {}
+
+impl<'a> TakeIn<'a> for JSDocUnknownType {}
diff --git a/crates/oxc_ast/src/lib.rs b/crates/oxc_ast/src/lib.rs
index 22c44f2058dfd..b9880889f5faa 100644
--- a/crates/oxc_ast/src/lib.rs
+++ b/crates/oxc_ast/src/lib.rs
@@ -60,11 +60,13 @@ mod generated {
     pub mod ast_kind;
     pub mod derive_clone_in;
     pub mod derive_content_eq;
+    pub mod derive_dummy;
     #[cfg(feature = "serialize")]
     pub mod derive_estree;
     pub mod derive_get_address;
     pub mod derive_get_span;
     pub mod derive_get_span_mut;
+    pub mod derive_take_in;
     pub mod get_id;
 }
 
diff --git a/crates/oxc_ast_macros/src/generated/mod.rs b/crates/oxc_ast_macros/src/generated/mod.rs
index cdef52ace962b..4397c56c9b70d 100644
--- a/crates/oxc_ast_macros/src/generated/mod.rs
+++ b/crates/oxc_ast_macros/src/generated/mod.rs
@@ -7,6 +7,8 @@ use quote::quote;
 pub fn get_trait_crate_and_generics(trait_name: &str) -> (TokenStream, TokenStream) {
     match trait_name {
         "CloneIn" => (quote!(::oxc_allocator::CloneIn), quote!(< 'static >)),
+        "Dummy" => (quote!(::oxc_allocator::Dummy), quote!(< 'static >)),
+        "TakeIn" => (quote!(::oxc_allocator::TakeIn), quote!(< 'static >)),
         "GetAddress" => (quote!(::oxc_allocator::GetAddress), TokenStream::new()),
         "GetSpan" => (quote!(::oxc_span::GetSpan), TokenStream::new()),
         "GetSpanMut" => (quote!(::oxc_span::GetSpanMut), TokenStream::new()),
diff --git a/crates/oxc_span/src/atom.rs b/crates/oxc_span/src/atom.rs
index 12f953967e325..e9fe82321533a 100644
--- a/crates/oxc_span/src/atom.rs
+++ b/crates/oxc_span/src/atom.rs
@@ -4,7 +4,7 @@ use std::{
     ops::Deref,
 };
 
-use oxc_allocator::{Allocator, CloneIn, FromIn};
+use oxc_allocator::{Allocator, CloneIn, Dummy, FromIn};
 #[cfg(feature = "serialize")]
 use oxc_estree::{ESTree, Serializer as ESTreeSerializer};
 #[cfg(feature = "serialize")]
@@ -71,6 +71,15 @@ impl<'new_alloc> CloneIn<'new_alloc> for Atom<'_> {
     }
 }
 
+impl<'a> Dummy<'a> for Atom<'a> {
+    /// Create a dummy [`Atom`].
+    #[expect(clippy::inline_always)]
+    #[inline(always)]
+    fn dummy(_allocator: &'a Allocator) -> Self {
+        Atom::empty()
+    }
+}
+
 impl<'alloc> FromIn<'alloc, &Atom<'alloc>> for Atom<'alloc> {
     fn from_in(s: &Atom<'alloc>, _: &'alloc Allocator) -> Self {
         *s
diff --git a/crates/oxc_span/src/generated/derive_dummy.rs b/crates/oxc_span/src/generated/derive_dummy.rs
new file mode 100644
index 0000000000000..0dfd3bd2e9c5f
--- /dev/null
+++ b/crates/oxc_span/src/generated/derive_dummy.rs
@@ -0,0 +1,51 @@
+// Auto-generated code, DO NOT EDIT DIRECTLY!
+// To edit this generated file you have to edit `tasks/ast_tools/src/derives/dummy.rs`
+
+#![allow(unused_variables, clippy::inline_always)]
+
+use oxc_allocator::{Allocator, Dummy};
+
+use crate::source_type::*;
+
+impl<'a> Dummy<'a> for SourceType {
+    /// Create a dummy [`SourceType`].
+    ///
+    /// Does not allocate any data into arena.
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self {
+            language: Dummy::dummy(allocator),
+            module_kind: Dummy::dummy(allocator),
+            variant: Dummy::dummy(allocator),
+        }
+    }
+}
+
+impl<'a> Dummy<'a> for Language {
+    /// Create a dummy [`Language`].
+    ///
+    /// Does not allocate any data into arena.
+    #[inline(always)]
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::JavaScript
+    }
+}
+
+impl<'a> Dummy<'a> for ModuleKind {
+    /// Create a dummy [`ModuleKind`].
+    ///
+    /// Does not allocate any data into arena.
+    #[inline(always)]
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::Script
+    }
+}
+
+impl<'a> Dummy<'a> for LanguageVariant {
+    /// Create a dummy [`LanguageVariant`].
+    ///
+    /// Does not allocate any data into arena.
+    #[inline(always)]
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::Standard
+    }
+}
diff --git a/crates/oxc_span/src/lib.rs b/crates/oxc_span/src/lib.rs
index 813497418794b..d8fdbaea95116 100644
--- a/crates/oxc_span/src/lib.rs
+++ b/crates/oxc_span/src/lib.rs
@@ -23,6 +23,7 @@ pub use crate::{
 mod generated {
     #[cfg(debug_assertions)]
     pub mod assert_layouts;
+    mod derive_dummy;
     #[cfg(feature = "serialize")]
     pub mod derive_estree;
 }
diff --git a/crates/oxc_span/src/source_type/mod.rs b/crates/oxc_span/src/source_type/mod.rs
index 75fd6a234da0a..73c25e819d8af 100644
--- a/crates/oxc_span/src/source_type/mod.rs
+++ b/crates/oxc_span/src/source_type/mod.rs
@@ -1,6 +1,6 @@
 use std::{hash::Hash, path::Path};
 
-use oxc_allocator::{Allocator, CloneIn};
+use oxc_allocator::{Allocator, CloneIn, Dummy};
 use oxc_ast_macros::ast;
 use oxc_estree::ESTree;
 
@@ -12,7 +12,7 @@ pub use error::UnknownExtension;
 /// Source Type for JavaScript vs TypeScript / Script vs Module / JSX
 #[ast]
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-#[generate_derive(ESTree)]
+#[generate_derive(Dummy, ESTree)]
 #[estree(no_type, flatten)]
 pub struct SourceType {
     /// JavaScript or TypeScript, default JavaScript
@@ -31,6 +31,7 @@ pub struct SourceType {
 /// JavaScript or TypeScript
 #[ast]
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+#[generate_derive(Dummy)]
 pub enum Language {
     /// Indicates a JavaScript or JSX file
     JavaScript = 0,
@@ -43,7 +44,7 @@ pub enum Language {
 /// Script or Module
 #[ast]
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-#[generate_derive(ESTree)]
+#[generate_derive(Dummy, ESTree)]
 pub enum ModuleKind {
     /// Regular JS script or CommonJS file
     Script = 0,
@@ -63,6 +64,7 @@ pub enum ModuleKind {
 /// JSX for JavaScript and TypeScript
 #[ast]
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+#[generate_derive(Dummy)]
 pub enum LanguageVariant {
     /// Standard JavaScript or TypeScript without any language extensions. Stage
     /// 3 proposals do not count as language extensions.
diff --git a/crates/oxc_span/src/span.rs b/crates/oxc_span/src/span.rs
index 386d0d2e036b2..bebd5ed35bee3 100644
--- a/crates/oxc_span/src/span.rs
+++ b/crates/oxc_span/src/span.rs
@@ -8,7 +8,7 @@ use miette::{LabeledSpan, SourceOffset, SourceSpan};
 #[cfg(feature = "serialize")]
 use serde::{Serialize, Serializer as SerdeSerializer, ser::SerializeMap};
 
-use oxc_allocator::{Allocator, CloneIn};
+use oxc_allocator::{Allocator, CloneIn, Dummy};
 use oxc_ast_macros::ast;
 use oxc_estree::ESTree;
 
@@ -545,6 +545,15 @@ impl<'a> CloneIn<'a> for Span {
     }
 }
 
+impl<'a> Dummy<'a> for Span {
+    /// Create a dummy [`Span`].
+    #[expect(clippy::inline_always)]
+    #[inline(always)]
+    fn dummy(_allocator: &'a Allocator) -> Self {
+        SPAN
+    }
+}
+
 #[cfg(feature = "serialize")]
 impl Serialize for Span {
     fn serialize<S: SerdeSerializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
diff --git a/crates/oxc_syntax/src/generated/derive_dummy.rs b/crates/oxc_syntax/src/generated/derive_dummy.rs
new file mode 100644
index 0000000000000..029098bcf530b
--- /dev/null
+++ b/crates/oxc_syntax/src/generated/derive_dummy.rs
@@ -0,0 +1,79 @@
+// Auto-generated code, DO NOT EDIT DIRECTLY!
+// To edit this generated file you have to edit `tasks/ast_tools/src/derives/dummy.rs`
+
+#![allow(unused_variables, clippy::inline_always)]
+
+use oxc_allocator::{Allocator, Dummy};
+
+use crate::number::*;
+use crate::operator::*;
+
+impl<'a> Dummy<'a> for NumberBase {
+    /// Create a dummy [`NumberBase`].
+    ///
+    /// Does not allocate any data into arena.
+    #[inline(always)]
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::Float
+    }
+}
+
+impl<'a> Dummy<'a> for BigintBase {
+    /// Create a dummy [`BigintBase`].
+    ///
+    /// Does not allocate any data into arena.
+    #[inline(always)]
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::Decimal
+    }
+}
+
+impl<'a> Dummy<'a> for AssignmentOperator {
+    /// Create a dummy [`AssignmentOperator`].
+    ///
+    /// Does not allocate any data into arena.
+    #[inline(always)]
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::Assign
+    }
+}
+
+impl<'a> Dummy<'a> for BinaryOperator {
+    /// Create a dummy [`BinaryOperator`].
+    ///
+    /// Does not allocate any data into arena.
+    #[inline(always)]
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::Equality
+    }
+}
+
+impl<'a> Dummy<'a> for LogicalOperator {
+    /// Create a dummy [`LogicalOperator`].
+    ///
+    /// Does not allocate any data into arena.
+    #[inline(always)]
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::Or
+    }
+}
+
+impl<'a> Dummy<'a> for UnaryOperator {
+    /// Create a dummy [`UnaryOperator`].
+    ///
+    /// Does not allocate any data into arena.
+    #[inline(always)]
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::UnaryPlus
+    }
+}
+
+impl<'a> Dummy<'a> for UpdateOperator {
+    /// Create a dummy [`UpdateOperator`].
+    ///
+    /// Does not allocate any data into arena.
+    #[inline(always)]
+    fn dummy(allocator: &'a Allocator) -> Self {
+        Self::Increment
+    }
+}
diff --git a/crates/oxc_syntax/src/lib.rs b/crates/oxc_syntax/src/lib.rs
index 04a120876878a..ac60130701e6f 100644
--- a/crates/oxc_syntax/src/lib.rs
+++ b/crates/oxc_syntax/src/lib.rs
@@ -26,6 +26,7 @@ mod generated {
     pub mod assert_layouts;
     mod derive_clone_in;
     mod derive_content_eq;
+    mod derive_dummy;
     #[cfg(feature = "serialize")]
     mod derive_estree;
 }
diff --git a/crates/oxc_syntax/src/number.rs b/crates/oxc_syntax/src/number.rs
index 22246c50bb935..d531277bcba40 100644
--- a/crates/oxc_syntax/src/number.rs
+++ b/crates/oxc_syntax/src/number.rs
@@ -1,11 +1,12 @@
 #![expect(missing_docs)] // fixme
-use oxc_allocator::CloneIn;
+
+use oxc_allocator::{CloneIn, Dummy};
 use oxc_ast_macros::ast;
 use oxc_span::ContentEq;
 
 #[ast]
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-#[generate_derive(CloneIn, ContentEq)]
+#[generate_derive(CloneIn, Dummy, ContentEq)]
 pub enum NumberBase {
     Float = 0,
     Decimal = 1,
@@ -22,7 +23,7 @@ impl NumberBase {
 
 #[ast]
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-#[generate_derive(CloneIn, ContentEq)]
+#[generate_derive(CloneIn, Dummy, ContentEq)]
 pub enum BigintBase {
     Decimal = 0,
     Binary = 1,
diff --git a/crates/oxc_syntax/src/operator.rs b/crates/oxc_syntax/src/operator.rs
index 3b65cf0043400..2eede2b4e33dc 100644
--- a/crates/oxc_syntax/src/operator.rs
+++ b/crates/oxc_syntax/src/operator.rs
@@ -2,7 +2,7 @@
 //!
 //! Not all operators are punctuation - some, such as `delete`, are keywords.
 
-use oxc_allocator::CloneIn;
+use oxc_allocator::{CloneIn, Dummy};
 use oxc_ast_macros::ast;
 use oxc_estree::ESTree;
 use oxc_span::ContentEq;
@@ -15,7 +15,7 @@ use crate::precedence::{GetPrecedence, Precedence};
 /// - [13.15 Assignment Operators](https://tc39.es/ecma262/#sec-assignment-operators)
 #[ast]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-#[generate_derive(CloneIn, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, ContentEq, ESTree)]
 pub enum AssignmentOperator {
     /// `=`
     #[estree(rename = "=")]
@@ -159,7 +159,7 @@ impl AssignmentOperator {
 /// - [12.10 Binary Logical Operators](https://tc39.es/ecma262/#sec-binary-logical-operators)
 #[ast]
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-#[generate_derive(CloneIn, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, ContentEq, ESTree)]
 pub enum BinaryOperator {
     /// `==`
     #[estree(rename = "==")]
@@ -416,7 +416,7 @@ impl GetPrecedence for BinaryOperator {
 /// Logical binary operators
 #[ast]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-#[generate_derive(CloneIn, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, ContentEq, ESTree)]
 pub enum LogicalOperator {
     /// `||`
     #[estree(rename = "||")]
@@ -496,7 +496,7 @@ impl GetPrecedence for LogicalOperator {
 /// - [12.5 Unary Operators](https://tc39.es/ecma262/#sec-unary-operators)
 #[ast]
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-#[generate_derive(CloneIn, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, ContentEq, ESTree)]
 pub enum UnaryOperator {
     /// `+`
     #[estree(rename = "+")]
@@ -576,7 +576,7 @@ impl UnaryOperator {
 /// Unary update operators.
 #[ast]
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-#[generate_derive(CloneIn, ContentEq, ESTree)]
+#[generate_derive(CloneIn, Dummy, ContentEq, ESTree)]
 pub enum UpdateOperator {
     /// `++`
     #[estree(rename = "++")]
diff --git a/tasks/ast_tools/src/derives/dummy.rs b/tasks/ast_tools/src/derives/dummy.rs
new file mode 100644
index 0000000000000..85f7fd48f52f2
--- /dev/null
+++ b/tasks/ast_tools/src/derives/dummy.rs
@@ -0,0 +1,263 @@
+//! Derive for `Dummy` trait.
+
+use std::borrow::Cow;
+
+use proc_macro2::TokenStream;
+use quote::quote;
+
+use crate::{
+    codegen::Codegen,
+    schema::{
+        Def, EnumDef, Schema, StructDef, TypeDef, TypeId,
+        extensions::{
+            dummy::{Alloc, MinVariant},
+            layout::GetLayout,
+        },
+    },
+    utils::format_cow,
+};
+
+use super::{Derive, StructOrEnum, define_derive};
+
+/// Derive for `Dummy` trait.
+pub struct DeriveDummy;
+
+define_derive!(DeriveDummy);
+
+impl Derive for DeriveDummy {
+    fn trait_name(&self) -> &'static str {
+        "Dummy"
+    }
+
+    fn trait_has_lifetime(&self) -> bool {
+        true
+    }
+
+    fn crate_name(&self) -> &'static str {
+        "oxc_allocator"
+    }
+
+    fn prelude(&self) -> TokenStream {
+        quote! {
+            #![allow(unused_variables, clippy::inline_always)]
+
+            ///@@line_break
+            use oxc_allocator::{Allocator, Dummy};
+        }
+    }
+
+    /// Initialize `dummy.alloc` on structs and enums
+    fn prepare(&self, schema: &mut Schema, _codegen: &Codegen) {
+        for type_id in schema.types.indices() {
+            let alloc = calculate_alloc(type_id, schema);
+            assert!(alloc != Alloc::NOT_CALCULATED);
+        }
+    }
+
+    fn derive(&self, type_def: StructOrEnum, schema: &Schema) -> TokenStream {
+        match type_def {
+            StructOrEnum::Struct(struct_def) => generate_impl_for_struct(struct_def, schema),
+            StructOrEnum::Enum(enum_def) => generate_impl_for_enum(enum_def, schema),
+        }
+    }
+}
+
+/// Calculate number and size of allocations required to construct a dummy for a type.
+///
+/// Before calculation, set `alloc` to [`Alloc::CALCULATING`].
+/// If `calculate_alloc` is called again for that type, it returns [`Alloc::NOT_CALCULATED`],
+/// which indicates the type has a circular dependency.
+/// This should only happen while calculating the cost of an enum. That variant will not be chosen.
+fn calculate_alloc(type_id: TypeId, schema: &mut Schema) -> Alloc {
+    let type_def = &mut schema.types[type_id];
+    #[expect(clippy::match_same_arms)]
+    match type_def {
+        TypeDef::Struct(struct_def) => {
+            let alloc = &mut struct_def.dummy.alloc;
+            if *alloc == Alloc::NOT_CALCULATED {
+                *alloc = Alloc::CALCULATING;
+                calculate_alloc_for_struct(type_id, schema)
+            } else if *alloc == Alloc::CALCULATING {
+                Alloc::NOT_CALCULATED
+            } else {
+                *alloc
+            }
+        }
+        TypeDef::Enum(enum_def) => {
+            let alloc = &mut enum_def.dummy.alloc;
+            if *alloc == Alloc::NOT_CALCULATED {
+                *alloc = Alloc::CALCULATING;
+                calculate_alloc_for_enum(type_id, schema)
+            } else if *alloc == Alloc::CALCULATING {
+                Alloc::NOT_CALCULATED
+            } else {
+                *alloc
+            }
+        }
+        // Primitives own no further allocation beyond themselves
+        TypeDef::Primitive(_) => Alloc::ZERO,
+        // `Option`s are `None` in dummy nodes
+        TypeDef::Option(_) => Alloc::ZERO,
+        // `Box`es have cost of the inner type plus an allocation of the type itself
+        TypeDef::Box(box_def) => {
+            let inner_type_id = box_def.inner_type_id;
+            let mut alloc = calculate_alloc(inner_type_id, schema);
+            if alloc != Alloc::NOT_CALCULATED {
+                let inner_type = &schema.types[inner_type_id];
+                alloc.bytes_64 += inner_type.layout_64().size;
+                alloc.bytes_32 += inner_type.layout_32().size;
+                alloc.count += 1;
+            }
+            alloc
+        }
+        // `Vec`s are empty in dummy nodes
+        TypeDef::Vec(_) => Alloc::ZERO,
+        // `Cell`s only own allocations if their inner type does
+        TypeDef::Cell(cell_def) => calculate_alloc(cell_def.inner_type_id, schema),
+    }
+}
+
+/// Calculate number and size of allocations required to construct a dummy for a struct.
+///
+/// Equals the total of allocations for all the struct's fields.
+fn calculate_alloc_for_struct(type_id: TypeId, schema: &mut Schema) -> Alloc {
+    let mut alloc = Alloc::ZERO;
+    for field_index in schema.struct_def(type_id).field_indices() {
+        let field_type_id = schema.struct_def(type_id).fields[field_index].type_id;
+        let field_alloc = calculate_alloc(field_type_id, schema);
+        if field_alloc == Alloc::NOT_CALCULATED {
+            alloc = field_alloc;
+            break;
+        }
+        alloc.bytes_64 += field_alloc.bytes_64;
+        alloc.bytes_32 += field_alloc.bytes_32;
+        alloc.count += field_alloc.count;
+    }
+
+    schema.struct_def_mut(type_id).dummy.alloc = alloc;
+
+    alloc
+}
+
+/// Calculate number and size of allocations required to construct a dummy for an enum.
+///
+/// Select the enum variant which has the lowest allocation cost.
+///
+/// Choice is made on these criteria, in order:
+/// * Smallest number of bytes allocated on 64-bit systems.
+/// * Smallest number of bytes allocated on 32-bit systems.
+/// * Smallest number of individual allocations.
+///
+/// Record both the allocation cost, and which variant has the smallest cost.
+fn calculate_alloc_for_enum(type_id: TypeId, schema: &mut Schema) -> Alloc {
+    // All `#[ast]` enums are `#[repr(u8)]` or `#[repr(C, u8)]` so cannot have 0 variants
+    let mut alloc = Alloc::NOT_CALCULATED;
+    let mut min_variant = MinVariant::default();
+
+    // Own variants
+    for variant_index in schema.enum_def(type_id).variant_indices() {
+        let variant_type_id = schema.enum_def(type_id).variants[variant_index].field_type_id;
+        if let Some(variant_type_id) = variant_type_id {
+            let variant_alloc = calculate_alloc(variant_type_id, schema);
+            if variant_alloc < alloc {
+                alloc = variant_alloc;
+                min_variant = MinVariant::Own(variant_index);
+            }
+        } else {
+            alloc = Alloc::ZERO;
+            min_variant = MinVariant::Own(variant_index);
+            break;
+        }
+    }
+
+    // Inherited variants
+    for inherits_index in schema.enum_def(type_id).inherits_indices() {
+        let inherits_type_id = schema.enum_def(type_id).inherits[inherits_index];
+        let inherits_alloc = calculate_alloc_for_enum(inherits_type_id, schema);
+        if inherits_alloc < alloc {
+            alloc = inherits_alloc;
+            min_variant = schema.enum_def(inherits_type_id).dummy.min_variant;
+            if let MinVariant::Own(variant_index) = min_variant {
+                min_variant = MinVariant::Inherited(inherits_type_id, variant_index);
+            }
+        }
+    }
+
+    let dummy = &mut schema.enum_def_mut(type_id).dummy;
+    dummy.alloc = alloc;
+    dummy.min_variant = min_variant;
+
+    alloc
+}
+
+/// Generate `Dummy` impl for struct.
+fn generate_impl_for_struct(struct_def: &StructDef, schema: &Schema) -> TokenStream {
+    let fields = struct_def.fields.iter().map(|field| {
+        let field_ident = field.ident();
+        quote!(#field_ident: Dummy::dummy(allocator))
+    });
+
+    let value = quote! {
+        Self {
+            #(#fields),*
+        }
+    };
+
+    generate_impl(struct_def.name(), &struct_def.ty(schema), &value, struct_def.dummy.alloc, false)
+}
+
+/// Generate `Dummy` impl for enum.
+fn generate_impl_for_enum(enum_def: &EnumDef, schema: &Schema) -> TokenStream {
+    let variant = match enum_def.dummy.min_variant {
+        MinVariant::Own(variant_index) => &enum_def.variants[variant_index],
+        MinVariant::Inherited(inherited_type_id, variant_index) => {
+            &schema.enum_def(inherited_type_id).variants[variant_index]
+        }
+    };
+
+    let variant_ident = variant.ident();
+    let (value, should_inline) = if variant.field_type(schema).is_some() {
+        (quote!( Self::#variant_ident(Dummy::dummy(allocator)) ), false)
+    } else {
+        (quote!( Self::#variant_ident ), true)
+    };
+
+    generate_impl(
+        enum_def.name(),
+        &enum_def.ty(schema),
+        &value,
+        enum_def.dummy.alloc,
+        should_inline,
+    )
+}
+
+/// Generate `Dummy` impl for a type.
+fn generate_impl(
+    name: &str,
+    ty: &TokenStream,
+    value: &TokenStream,
+    alloc: Alloc,
+    should_inline: bool,
+) -> TokenStream {
+    let comment1 = format!(" Create a dummy [`{name}`].");
+    let comment2 = if alloc.bytes_64 == 0 {
+        Cow::Borrowed(" Does not allocate any data into arena.")
+    } else {
+        let s = if alloc.count > 1 { "s" } else { "" };
+        format_cow!(" Has cost of making {} allocation{s} ({} bytes).", alloc.count, alloc.bytes_64)
+    };
+
+    let inline = if should_inline { quote!( #[inline(always)] ) } else { quote!() };
+
+    quote! {
+        impl<'a> Dummy<'a> for #ty {
+            #[doc = #comment1]
+            #[doc = ""]
+            #[doc = #comment2]
+            #inline
+            fn dummy(allocator: &'a Allocator) -> Self {
+                #value
+            }
+        }
+    }
+}
diff --git a/tasks/ast_tools/src/derives/mod.rs b/tasks/ast_tools/src/derives/mod.rs
index dd190941ed6e4..285b6eb2289e3 100644
--- a/tasks/ast_tools/src/derives/mod.rs
+++ b/tasks/ast_tools/src/derives/mod.rs
@@ -16,15 +16,19 @@ use crate::{
 
 mod clone_in;
 mod content_eq;
+mod dummy;
 pub mod estree;
 mod get_address;
 mod get_span;
+mod take_in;
 
 pub use clone_in::DeriveCloneIn;
 pub use content_eq::DeriveContentEq;
+pub use dummy::DeriveDummy;
 pub use estree::DeriveESTree;
 pub use get_address::DeriveGetAddress;
 pub use get_span::{DeriveGetSpan, DeriveGetSpanMut};
+pub use take_in::DeriveTakeIn;
 
 /// Trait to define a derive.
 pub trait Derive: Runner {
diff --git a/tasks/ast_tools/src/derives/take_in.rs b/tasks/ast_tools/src/derives/take_in.rs
new file mode 100644
index 0000000000000..6667f5837005c
--- /dev/null
+++ b/tasks/ast_tools/src/derives/take_in.rs
@@ -0,0 +1,43 @@
+//! Derive for `TakeIn` trait.
+
+use proc_macro2::TokenStream;
+use quote::quote;
+
+use crate::schema::{Def, Schema};
+
+use super::{Derive, StructOrEnum, define_derive};
+
+/// Derive for `TakeIn` trait.
+pub struct DeriveTakeIn;
+
+define_derive!(DeriveTakeIn);
+
+impl Derive for DeriveTakeIn {
+    fn trait_name(&self) -> &'static str {
+        "TakeIn"
+    }
+
+    fn trait_has_lifetime(&self) -> bool {
+        true
+    }
+
+    fn crate_name(&self) -> &'static str {
+        "oxc_allocator"
+    }
+
+    fn prelude(&self) -> TokenStream {
+        quote! {
+            #![allow(clippy::needless_lifetimes)]
+
+            ///@@line_break
+            use oxc_allocator::TakeIn;
+        }
+    }
+
+    fn derive(&self, type_def: StructOrEnum, schema: &Schema) -> TokenStream {
+        let ty = type_def.ty(schema);
+        quote! {
+            impl<'a> TakeIn<'a> for #ty {}
+        }
+    }
+}
diff --git a/tasks/ast_tools/src/main.rs b/tasks/ast_tools/src/main.rs
index e354fee28229c..3dfe814ff1bf6 100644
--- a/tasks/ast_tools/src/main.rs
+++ b/tasks/ast_tools/src/main.rs
@@ -249,6 +249,8 @@ const AST_CHANGES_WATCH_LIST_PATH: &str = ".github/generated/ast_changes_watch_l
 /// Derives (for use with `#[generate_derive]`)
 const DERIVES: &[&(dyn Derive + Sync)] = &[
     &derives::DeriveCloneIn,
+    &derives::DeriveDummy,
+    &derives::DeriveTakeIn,
     &derives::DeriveGetAddress,
     &derives::DeriveGetSpan,
     &derives::DeriveGetSpanMut,
diff --git a/tasks/ast_tools/src/schema/defs/enum.rs b/tasks/ast_tools/src/schema/defs/enum.rs
index c64293e9fffbc..71d2b62fa1b6a 100644
--- a/tasks/ast_tools/src/schema/defs/enum.rs
+++ b/tasks/ast_tools/src/schema/defs/enum.rs
@@ -13,6 +13,7 @@ use super::{
         ast_builder::AstBuilderType,
         clone_in::CloneInType,
         content_eq::ContentEqType,
+        dummy::DummyEnum,
         estree::{ESTreeEnum, ESTreeEnumVariant},
         kind::Kind,
         layout::{GetLayout, Layout},
@@ -43,6 +44,7 @@ pub struct EnumDef {
     pub kind: Kind,
     pub layout: Layout,
     pub clone_in: CloneInType,
+    pub dummy: DummyEnum,
     pub content_eq: ContentEqType,
     pub estree: ESTreeEnum,
 }
@@ -77,6 +79,7 @@ impl EnumDef {
             kind: Kind::default(),
             layout: Layout::default(),
             clone_in: CloneInType::default(),
+            dummy: DummyEnum::default(),
             content_eq: ContentEqType::default(),
             estree: ESTreeEnum::default(),
         }
diff --git a/tasks/ast_tools/src/schema/defs/struct.rs b/tasks/ast_tools/src/schema/defs/struct.rs
index 5f3d5a8f0491b..d5f56f446c403 100644
--- a/tasks/ast_tools/src/schema/defs/struct.rs
+++ b/tasks/ast_tools/src/schema/defs/struct.rs
@@ -12,6 +12,7 @@ use super::{
         ast_builder::{AstBuilderStructField, AstBuilderType},
         clone_in::{CloneInStructField, CloneInType},
         content_eq::{ContentEqStructField, ContentEqType},
+        dummy::DummyStruct,
         estree::{ESTreeStruct, ESTreeStructField},
         kind::Kind,
         layout::{Layout, Offset},
@@ -39,6 +40,7 @@ pub struct StructDef {
     pub layout: Layout,
     pub span: SpanStruct,
     pub clone_in: CloneInType,
+    pub dummy: DummyStruct,
     pub content_eq: ContentEqType,
     pub estree: ESTreeStruct,
 }
@@ -72,6 +74,7 @@ impl StructDef {
             layout: Layout::default(),
             span: SpanStruct::default(),
             clone_in: CloneInType::default(),
+            dummy: DummyStruct::default(),
             content_eq: ContentEqType::default(),
             estree: ESTreeStruct::default(),
         }
diff --git a/tasks/ast_tools/src/schema/extensions/dummy.rs b/tasks/ast_tools/src/schema/extensions/dummy.rs
new file mode 100644
index 0000000000000..4e63f60bdea2b
--- /dev/null
+++ b/tasks/ast_tools/src/schema/extensions/dummy.rs
@@ -0,0 +1,61 @@
+use super::super::TypeId;
+
+/// Details for `Dummy` derive on a struct.
+#[derive(Clone, Copy, Default, Debug)]
+pub struct DummyStruct {
+    /// Details of allocations a dummy enum of this type requires
+    pub alloc: Alloc,
+}
+
+/// Details for `Dummy` derive on an enum.
+#[derive(Clone, Copy, Default, Debug)]
+pub struct DummyEnum {
+    /// Details of allocations a dummy enum of this type requires
+    pub alloc: Alloc,
+    /// Variant which allocates minimum number of bytes
+    pub min_variant: MinVariant,
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
+pub struct Alloc {
+    /// Number of bytes a dummy of this type allocates on 64-bit system
+    pub bytes_64: u32,
+    /// Number of bytes a dummy of this type allocates on 32-bit system
+    pub bytes_32: u32,
+    /// Number of allocations a dummy of this type requires to construct
+    pub count: u32,
+}
+
+impl Alloc {
+    /// [`Alloc`] representing zero cost.
+    pub const ZERO: Self = Self { bytes_64: 0, bytes_32: 0, count: 0 };
+
+    /// Sentinel value for [`Alloc`], indicating that it's not been calculated yet.
+    pub const NOT_CALCULATED: Self = Self { bytes_64: u32::MAX, bytes_32: 0, count: 0 };
+
+    /// Sentinel value for [`Alloc`], indicating that it currently being calculated.
+    /// Used for preventing infinite cycles.
+    pub const CALCULATING: Self = Self { bytes_64: 0, bytes_32: u32::MAX, count: 0 };
+}
+
+impl Default for Alloc {
+    fn default() -> Self {
+        Self::NOT_CALCULATED
+    }
+}
+
+/// Which variant of an enum is the cheapest to generate a dummy for.
+#[derive(Clone, Copy, Debug)]
+pub enum MinVariant {
+    /// Own variant index
+    Own(usize),
+    /// Inherited variant - `TypeId` of the inherited enum and variant index
+    Inherited(TypeId, usize),
+}
+
+impl Default for MinVariant {
+    fn default() -> Self {
+        // Dummy value
+        MinVariant::Own(0)
+    }
+}
diff --git a/tasks/ast_tools/src/schema/mod.rs b/tasks/ast_tools/src/schema/mod.rs
index 1febcfdbc17a8..2b6fc91894701 100644
--- a/tasks/ast_tools/src/schema/mod.rs
+++ b/tasks/ast_tools/src/schema/mod.rs
@@ -18,6 +18,7 @@ pub mod extensions {
     pub mod ast_builder;
     pub mod clone_in;
     pub mod content_eq;
+    pub mod dummy;
     pub mod estree;
     pub mod kind;
     pub mod layout;