Drop the list driver, make attribute values Copy over arena references, and land record-tier offset io on a per-thread record stack

node-graph/libraries/core-types/src/attribute.rs

@@ -3,6 +3,11 @@
 //! collects every declaration so name resolution, defaults, and diagnostics
 //! run at graph compile time. One name belongs to one marker, so a name can
 //! never mean two different types.
+//!
+//! Values are `Copy` and pack directly into record fields. Data with drop
+//! glue rides the arena instead: the marker declares a reference value
+//! (`&str`), the writing kernel parks the payload in the arena, and the
+//! record field carries the eval-lifetime reference.
 
 use crate::list::AnyAttributeValue;
 use glam::{DAffine2, DVec2};
@@ -18,11 +23,15 @@ use std::sync::{LazyLock, Mutex};
 pub trait Attribute: 'static {
 	/// The name as it appears in documents and diagnostics.
 	const NAME: &'static str;
-	/// The value type every read and write of this name shares.
-	type Value: AnyAttributeValue + Clone + Default + std::fmt::Debug;
+	/// The value type every read and write of this name shares. The lifetime
+	/// is the evaluation the value flows in; non-reference values ignore it.
+	type Value<'e>: Copy + Default + std::fmt::Debug;
 	/// The name-specific default, filled where an item lacks the attribute.
-	fn default() -> Self::Value {
-		Self::Value::default()
+	/// Producing a value for any `'e` from no inputs, reference defaults can
+	/// only point at `'static` data, which is what lets the census fill them
+	/// as plain bytes.
+	fn default<'e>() -> Self::Value<'e> {
+		Default::default()
 	}
 }
 
@@ -30,23 +39,25 @@ pub trait Attribute: 'static {
 /// (yielding the declared default where the attribute is absent upstream), an
 /// `Attr<A>` in the return tuple is a write, and the same marker on both
 /// sides is a modify.
-pub struct Attr<A: Attribute>(pub A::Value);
+pub struct Attr<'e, A: Attribute>(pub A::Value<'e>);
 
-impl<A: Attribute> Deref for Attr<A> {
-	type Target = A::Value;
+impl<'e, A: Attribute> Deref for Attr<'e, A> {
+	type Target = A::Value<'e>;
 
-	fn deref(&self) -> &A::Value {
+	fn deref(&self) -> &A::Value<'e> {
 		&self.0
 	}
 }
 
-impl<A: Attribute> Clone for Attr<A> {
+impl<'e, A: Attribute> Clone for Attr<'e, A> {
 	fn clone(&self) -> Self {
-		Attr(self.0.clone())
+		*self
 	}
 }
 
-impl<A: Attribute> std::fmt::Debug for Attr<A> {
+impl<'e, A: Attribute> Copy for Attr<'e, A> {}
+
+impl<'e, A: Attribute> std::fmt::Debug for Attr<'e, A> {
 	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 		f.debug_tuple(A::NAME).field(&self.0).finish()
 	}
@@ -61,20 +72,14 @@ pub struct AttributeInfo {
 	pub default: fn() -> Box<dyn AnyAttributeValue>,
 	pub size: usize,
 	pub align: usize,
-	/// Whether the value is eligible for packed-record fields: no drop glue,
-	/// so its bytes copy freely. Droppable values stay on the erased path
-	/// until the per-type clone/drop glue lands.
-	pub packable: bool,
 	/// Writes the declared default's bytes into a `size`-long slice.
-	/// Meaningful only when `packable`.
 	pub write_default_bytes: fn(&mut [u8]),
 }
 
 fn write_default_bytes<A: Attribute>(out: &mut [u8]) {
-	assert!(!std::mem::needs_drop::<A::Value>(), "default bytes exist only for packable values");
-	assert_eq!(out.len(), size_of::<A::Value>());
-	let value = A::default();
-	unsafe { std::ptr::copy_nonoverlapping((&raw const value).cast::<u8>(), out.as_mut_ptr(), size_of::<A::Value>()) };
+	assert_eq!(out.len(), size_of::<A::Value<'static>>());
+	let value: A::Value<'static> = A::default();
+	unsafe { std::ptr::copy_nonoverlapping((&raw const value).cast::<u8>(), out.as_mut_ptr(), size_of::<A::Value<'static>>()) };
 }
 
 /// All declared attribute names, keyed by name.
@@ -84,15 +89,17 @@ pub static ATTRIBUTE_REGISTRY: LazyLock<Mutex<HashMap<&'static str, AttributeInf
 /// startup (ctor natively, a `__node_registry_attribute_*` export on wasm).
 /// Re-registration at the same value type is idempotent; a second marker
 /// claiming the name at a different value type panics.
-pub fn register<A: Attribute>() {
+pub fn register<A: Attribute>()
+where
+	A::Value<'static>: AnyAttributeValue,
+{
 	let info = AttributeInfo {
 		name: A::NAME,
-		value_type: TypeId::of::<A::Value>(),
-		value_type_name: std::any::type_name::<A::Value>(),
+		value_type: TypeId::of::<A::Value<'static>>(),
+		value_type_name: std::any::type_name::<A::Value<'static>>(),
 		default: || Box::new(A::default()),
-		size: size_of::<A::Value>(),
-		align: align_of::<A::Value>(),
-		packable: !std::mem::needs_drop::<A::Value>(),
+		size: size_of::<A::Value<'static>>(),
+		align: align_of::<A::Value<'static>>(),
 		write_default_bytes: write_default_bytes::<A>,
 	};
 	let conflict = match ATTRIBUTE_REGISTRY.lock().unwrap().entry(A::NAME) {
@@ -124,44 +131,65 @@ pub fn default_value(name: &str) -> Option<Box<dyn AnyAttributeValue>> {
 /// core_types::attribute! {
 ///     /// How visible the content is.
 ///     pub Opacity("opacity"): f64 = 1.;
-///     /// The item's transformation.
-///     pub Transform("transform"): glam::DAffine2;
+///     /// The item's label, parked in the arena by the writer.
+///     pub Label("label"): &str;
 /// }
 /// ```
 ///
 /// The trailing `= expr` is the name-specific default; without it the value
-/// type's `Default` applies.
+/// type's `Default` applies. A `&T` value carries the eval lifetime, so its
+/// default must be `'static` data.
 #[macro_export]
 macro_rules! attribute {
-	($($(#[$meta:meta])* $vis:vis $marker:ident($name:literal): $value:ty $(= $default:expr)?;)+) => {
-		$(
-			$(#[$meta])*
-			$vis struct $marker;
+	() => {};
+	($(#[$meta:meta])* $vis:vis $marker:ident($name:literal): &$value:ty $(= $default:expr)?; $($rest:tt)*) => {
+		$(#[$meta])*
+		$vis struct $marker;
 
-			impl $crate::attribute::Attribute for $marker {
-				const NAME: &'static str = $name;
-				type Value = $value;
-				$(
-					fn default() -> $value {
-						$default
-					}
-				)?
+		impl $crate::attribute::Attribute for $marker {
+			const NAME: &'static str = $name;
+			type Value<'e> = &'e $value;
+			$(
+				fn default<'e>() -> Self::Value<'e> {
+					$default
+				}
+			)?
+		}
+
+		$crate::attribute!(@register $marker);
+		$crate::attribute!($($rest)*);
+	};
+	($(#[$meta:meta])* $vis:vis $marker:ident($name:literal): $value:ty $(= $default:expr)?; $($rest:tt)*) => {
+		$(#[$meta])*
+		$vis struct $marker;
+
+		impl $crate::attribute::Attribute for $marker {
+			const NAME: &'static str = $name;
+			type Value<'e> = $value;
+			$(
+				fn default<'e>() -> Self::Value<'e> {
+					$default
+				}
+			)?
+		}
+
+		$crate::attribute!(@register $marker);
+		$crate::attribute!($($rest)*);
+	};
+	(@register $marker:ident) => {
+		const _: () = {
+			#[cfg(not(target_family = "wasm"))]
+			#[$crate::ctor::ctor]
+			fn register() {
+				$crate::attribute::register::<$marker>();
 			}
 
-			const _: () = {
-				#[cfg(not(target_family = "wasm"))]
-				#[$crate::ctor::ctor]
-				fn register() {
-					$crate::attribute::register::<$marker>();
-				}
-
-				#[cfg(target_family = "wasm")]
-				#[unsafe(export_name = concat!("__node_registry_attribute_", stringify!($marker)))]
-				extern "C" fn register() {
-					$crate::attribute::register::<$marker>();
-				}
-			};
-		)+
+			#[cfg(target_family = "wasm")]
+			#[unsafe(export_name = concat!("__node_registry_attribute_", stringify!($marker)))]
+			extern "C" fn register() {
+				$crate::attribute::register::<$marker>();
+			}
+		};
 	};
 }
 
@@ -180,7 +208,7 @@ attribute! {
 	/// Artboard's top-left corner in document coordinates.
 	pub Location("location"): DVec2;
 	/// A regex named-capture-group's name, or empty for unnamed groups.
-	pub Name("name"): String;
+	pub Name("name"): &str;
 }
 
 #[cfg(test)]
@@ -198,7 +226,7 @@ mod tests {
 	#[test]
 	fn name_specific_default_overrides_the_type_default() {
 		assert_eq!(<Opacity as Attribute>::default(), 1.);
-		assert_eq!(<Name as Attribute>::default(), String::new());
+		assert_eq!(<Name as Attribute>::default(), "");
 	}
 
 	#[test]
@@ -207,6 +235,13 @@ mod tests {
 		assert_eq!(*value.as_any().downcast_ref::<f64>().unwrap(), 1.);
 	}
 
+	#[test]
+	fn reference_values_register_at_the_static_instantiation() {
+		let row = info("name").unwrap();
+		assert_eq!(row.value_type, TypeId::of::<&'static str>());
+		assert_eq!(row.size, size_of::<&str>());
+	}
+
 	#[test]
 	fn reregistration_at_the_same_type_is_idempotent() {
 		register::<Opacity>();
@@ -220,7 +255,7 @@ mod tests {
 		struct Conflict;
 		impl Attribute for Conflict {
 			const NAME: &'static str = "opacity";
-			type Value = bool;
+			type Value<'e> = bool;
 		}
 		register::<Conflict>();
 	}

node-graph/libraries/core-types/src/context.rs

@@ -624,7 +624,6 @@ pub struct EvalScope<'a> {
 	pointer_position: Option<DVec2>,
 	generations: &'a [(SourceId, u64)],
 	arena: &'a Arena,
-	frame: Option<&'a crate::record::Frame>,
 	hash: u64,
 }
 
@@ -636,19 +635,12 @@ impl<'a> EvalScope<'a> {
 			pointer_position,
 			generations,
 			arena,
-			frame: None,
 			hash: 0,
 		};
 		scope.hash = scope.compute_hash(|_| true);
 		scope
 	}
 
-	/// Attaches the record frame. Operational like the arena: not part of the
-	/// scope hash.
-	pub fn with_frame(&self, frame: &'a crate::record::Frame) -> EvalScope<'a> {
-		EvalScope { frame: Some(frame), ..*self }
-	}
-
 	pub fn with_real_time(&self, real_time: Option<f64>) -> EvalScope<'a> {
 		let mut scope = EvalScope { real_time, ..*self };
 		scope.hash = scope.compute_hash(|_| true);
@@ -708,23 +700,6 @@ impl<'a> EvalScope<'a> {
 	pub fn arena(&self) -> &'a Arena {
 		self.arena
 	}
-
-	pub fn frame(&self) -> Option<&'a crate::record::Frame> {
-		self.frame
-	}
-}
-
-/// Read access to the record frame, the operational sibling of
-/// [`ExtractArena`]. `None` on contexts whose scope carries no frame (a
-/// graph without record edges allocates none).
-pub trait ExtractFrame<'e> {
-	fn frame(&self) -> Option<&'e crate::record::Frame>;
-}
-
-impl<'a> ExtractFrame<'a> for ContextImpl<'a> {
-	fn frame(&self) -> Option<&'a crate::record::Frame> {
-		self.scope.frame()
-	}
 }
 
 pub trait ExtractArena {

node-graph/libraries/core-types/src/list.rs

@@ -954,15 +954,6 @@ impl<T> List<T> {
 		}
 	}
 
-	/// Creates a list from element values with no attributes.
-	pub fn from_element_values(element: Vec<T>) -> Self {
-		let len = element.len();
-		Self {
-			element,
-			attributes: Attributes::with_len(len),
-		}
-	}
-
 	/// Creates a list containing a single item from the given [`Item`], preserving its attributes.
 	pub fn new_from_item(item: Item<T>) -> Self {
 		let mut attributes = Attributes::new();
@@ -1009,11 +1000,6 @@ impl<T> List<T> {
 		self.element.iter()
 	}
 
-	/// Consumes the list, returning its element values and dropping its attributes.
-	pub fn into_element_values(self) -> Vec<T> {
-		self.element
-	}
-
 	/// Returns an iterator over mutable references to all element values.
 	pub fn iter_element_values_mut(&mut self) -> std::slice::IterMut<'_, T> {
 		self.element.iter_mut()
@@ -1101,20 +1087,6 @@ impl<T> List<T> {
 		}
 	}
 
-	/// Removes and returns the attribute column for the given key, if present.
-	pub fn take_attribute_dyn(&mut self, key: &str) -> Option<AttributeDyn> {
-		let position = self.attributes.attributes.iter().position(|(k, _)| k == key)?;
-		Some(AttributeDyn(self.attributes.attributes.remove(position).1))
-	}
-
-	/// Replaces (or adds) an attribute, taking ownership of the column, whose length must equal this list's item count.
-	pub fn insert_attribute_dyn(&mut self, key: impl Into<String>, column: AttributeDyn) {
-		assert_eq!(column.len(), self.element.len(), "attribute column length must match the list's item count");
-		let key = key.into();
-		self.attributes.attributes.retain(|(k, _)| k != &key);
-		self.attributes.attributes.push((key, column.0));
-	}
-
 	/// Removes the entire attribute for the given key, if present.
 	pub fn remove_attribute(&mut self, key: &str) {
 		self.attributes.remove_attribute(key);

node-graph/libraries/core-types/src/node.rs

@@ -71,6 +71,14 @@ pub trait Node<Input> {
 		None
 	}
 
+	/// The record layout of this node's output; `None` for element-only
+	/// producers. Consumers read their carrier's layout through this at
+	/// wiring, and the wiring layer derives stack sizing from the same
+	/// layouts, in the dynamic executor and exported source alike.
+	fn layout(&self) -> Option<&crate::record::Layout> {
+		None
+	}
+
 	fn eval_batch<'a>(&self, input: &'a Input, range: Range<u64>, scratch: Option<&'a mut [MaybeUninit<Self::Output>]>) -> BatchStatus<'a, Self::Output>
 	where
 		Input: InjectIndex + Copy,
@@ -133,6 +141,10 @@ where
 		(**self).serialize()
 	}
 
+	fn layout(&self) -> Option<&crate::record::Layout> {
+		(**self).layout()
+	}
+
 	fn eval_batch<'a>(&self, input: &'a Input, range: Range<u64>, scratch: Option<&'a mut [MaybeUninit<Self::Output>]>) -> BatchStatus<'a, Self::Output>
 	where
 		Input: InjectIndex + Copy,
@@ -159,6 +171,10 @@ where
 		(**self).serialize()
 	}
 
+	fn layout(&self) -> Option<&crate::record::Layout> {
+		(**self).layout()
+	}
+
 	fn eval_batch<'a>(&self, input: &'a Input, range: Range<u64>, scratch: Option<&'a mut [MaybeUninit<Self::Output>]>) -> BatchStatus<'a, Self::Output>
 	where
 		Input: InjectIndex + Copy,

node-graph/libraries/core-types/src/record.rs

@@ -1,15 +1,14 @@
 //! The packed-record tier at rank 0. A record is the element at offset 0
 //! plus one field per written attribute; its [`Layout`] is computed at
 //! wiring from the upstream write set and never serialized. Records live as
-//! per-lane views in a per-worker [`Frame`] whose slots are assigned at
-//! wiring, and kernels route them as opaque [`RecordValue`]s that carry
+//! per-lane views on the per-thread record [`stack`], claimed per
+//! evaluation, and kernels route them as opaque [`RecordValue`]s that carry
 //! their provenance. Only generated or wiring code touches offsets, so a
 //! safe kernel cannot misalign a field.
 
 use crate::attribute;
 use crate::gpoll::GPoll;
 use crate::node::Node;
-use std::cell::UnsafeCell;
 
 /// One field of a [`Layout`]: a (name, level) key resolved to an offset.
 /// Levels are numbered innermost-out; only level 0 exists at rank 0.
@@ -97,6 +96,13 @@ impl Layout {
 	}
 }
 
+/// The stand-in fed to a kernel's unbounded `element: T` parameter. The type
+/// system forces the kernel to route it to the element position of its return
+/// tuple, so the passthrough is explicit in the signature while the lowering
+/// carries the element bytes untyped through the copy plan.
+#[derive(Clone, Copy, Debug, Default)]
+pub struct ElToken;
+
 /// A view of one record: a pointer whose layout is proven at wiring.
 #[derive(Clone, Copy, Debug)]
 pub struct Rec(*const u8);
@@ -148,58 +154,89 @@ impl<'e> RecordValue<'e> {
 	}
 }
 
-/// Assigns frame slots at wiring: a bump allocator over slot sizes, aligned
-/// to at most 8 (record layouts never exceed word alignment).
-#[derive(Debug, Default)]
-pub struct FrameLayout {
-	size: usize,
-}
+/// The per-thread record stack: every record evaluation claims its activation
+/// frame at the stack pointer and evaluates its carrier beyond it, so slot
+/// addresses are a property of the evaluating thread and no global assignment
+/// exists. Thread-local by construction, so access is single-threaded without
+/// claims or gates. Records are overwritten per lane and never touch the
+/// arena.
+pub mod stack {
+	use std::cell::Cell;
 
-impl FrameLayout {
-	pub fn slot(&mut self, layout: &Layout) -> usize {
-		assert!(layout.align <= 8, "record layouts align to at most 8");
-		self.size = self.size.next_multiple_of(layout.align.max(1));
-		let offset = self.size;
-		self.size += layout.size;
-		offset
+	struct Stack {
+		base: Cell<*mut u8>,
+		capacity: Cell<usize>,
+		sp: Cell<usize>,
 	}
 
-	pub fn size(&self) -> usize {
-		self.size
-	}
-}
-
-/// The per-worker record frame: every record-producing slot lives at a
-/// wiring-assigned offset. Slots are overwritten per lane and never touch
-/// the arena.
-pub struct Frame {
-	words: Box<[UnsafeCell<u64>]>,
-}
-
-// SAFETY: a frame belongs to one worker; slot writes happen only inside that
-// worker's evaluation, and wiring assigns disjoint offsets per slot.
-unsafe impl Send for Frame {}
-unsafe impl Sync for Frame {}
-
-impl Frame {
-	pub fn new(size: usize) -> Self {
-		Self {
-			words: (0..size.div_ceil(8).max(1)).map(|_| UnsafeCell::new(0)).collect(),
+	impl Stack {
+		fn free(&self) {
+			let base = self.base.get();
+			if !base.is_null() {
+				drop(unsafe { Vec::from_raw_parts(base.cast::<u64>(), 0, self.capacity.get() / 8) });
+			}
 		}
 	}
 
-	/// # Safety
-	/// `offset` must be a slot offset assigned by [`FrameLayout`] for this
-	/// frame, and the caller must be the slot's owning node evaluation.
-	pub unsafe fn slot(&self, offset: usize) -> *mut u8 {
-		debug_assert!(offset <= self.words.len() * 8);
-		unsafe { self.words.as_ptr().cast::<u8>().cast_mut().add(offset) }
+	impl Drop for Stack {
+		fn drop(&mut self) {
+			self.free();
+		}
 	}
-}
 
-impl std::fmt::Debug for Frame {
-	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-		f.debug_struct("Frame").field("bytes", &(self.words.len() * 8)).finish()
+	thread_local! {
+		static STACK: Stack = const {
+			Stack {
+				base: Cell::new(std::ptr::null_mut()),
+				capacity: Cell::new(0),
+				sp: Cell::new(0),
+			}
+		};
+	}
+
+	/// Ensures the calling thread's stack holds `bytes`, the root's wiring-
+	/// derived stack need, and resets the stack pointer. Called only between
+	/// evaluations, like the arena reset: nothing survives it, so frames
+	/// leaked by an interrupted evaluation are reclaimed here.
+	pub fn reserve(bytes: usize) {
+		STACK.with(|stack| {
+			stack.sp.set(0);
+			if stack.capacity.get() >= bytes {
+				return;
+			}
+			let words = bytes.div_ceil(8).max(1);
+			let mut memory = vec![0u64; words];
+			let base = memory.as_mut_ptr().cast::<u8>();
+			std::mem::forget(memory);
+			stack.free();
+			stack.base.set(base);
+			stack.capacity.set(words * 8);
+		});
+	}
+
+	/// Claims `bytes` (rounded to word alignment) at the stack pointer and
+	/// advances past them. The region stays claimed until [`pop`], and stays
+	/// readable until the next `push`. `reserve` derived from the root's
+	/// stack need makes the capacity bound exact, so overflow is a debug
+	/// assertion, not a hot-path branch.
+	pub fn push(bytes: usize) -> *mut u8 {
+		STACK.with(|stack| {
+			let sp = stack.sp.get();
+			let next = sp + bytes.next_multiple_of(8);
+			debug_assert!(next <= stack.capacity.get(), "record stack overflow: reserve() must cover the root's stack need");
+			stack.sp.set(next);
+			unsafe { stack.base.get().add(sp) }
+		})
+	}
+
+	/// Returns the stack pointer to `frame`, a pointer earlier returned by
+	/// [`push`] on this thread, releasing everything above it.
+	pub fn pop(frame: *mut u8) {
+		STACK.with(|stack| {
+			let offset = frame as usize - stack.base.get() as usize;
+			debug_assert!(offset <= stack.sp.get(), "pop target must lie within the claimed stack");
+			stack.sp.set(offset);
+		});
 	}
 }
 
@@ -221,6 +258,13 @@ pub fn copy_plan(from: &Layout, to: &Layout, carry_element: bool) -> Vec<(usize,
 	plan
 }
 
+/// # Safety
+/// `offset` must be a field offset of the layout of the record under
+/// construction at `dst` and `T` the field's type; both are proven at wiring.
+pub unsafe fn write_field<T>(dst: *mut u8, offset: usize, value: T) {
+	unsafe { dst.add(offset).cast::<T>().write(value) }
+}
+
 /// # Safety
 /// `src` must be a record of the plan's source layout and `dst` a buffer of
 /// the plan's target layout; both are proven at wiring.
@@ -235,7 +279,6 @@ pub unsafe fn apply_plan(src: Rec, dst: *mut u8, plan: &[(usize, usize, usize)])
 fn default_fill_bytes(name: &str, size: usize) -> Box<[u8]> {
 	let mut bytes = vec![0u8; size].into_boxed_slice();
 	if let Some(info) = attribute::info(name)
-		&& info.packable
 		&& info.size == size
 	{
 		(info.write_default_bytes)(&mut bytes);
@@ -244,18 +287,18 @@ fn default_fill_bytes(name: &str, size: usize) -> Box<[u8]> {
 }
 
 /// A routing source's wiring-resolved translation: field moves into the
-/// consumer's frame buffer plus census default fill for union fields the
-/// source lacks. Absent when the source's layout already equals the union,
-/// in which case the record pointer forwards untouched.
+/// union layout plus census default fill for union fields the source lacks.
+/// Absent when the source's layout already equals the union, in which case
+/// the record pointer forwards untouched.
 #[derive(Debug)]
 pub struct SourcePlan {
 	moves: Vec<(usize, usize, usize)>,
 	fills: Vec<(usize, Box<[u8]>)>,
-	slot: usize,
+	union_bytes: usize,
 }
 
 impl SourcePlan {
-	pub fn new(source: &Layout, union: &Layout, slot: usize) -> Option<SourcePlan> {
+	pub fn new(source: &Layout, union: &Layout) -> Option<SourcePlan> {
 		if source == union {
 			return None;
 		}
@@ -266,15 +309,18 @@ impl SourcePlan {
 			.filter(|field| source.offset_of(field.name, field.level).is_none())
 			.map(|field| (field.offset, default_fill_bytes(field.name, field.size)))
 			.collect();
-		Some(SourcePlan { moves, fills, slot })
+		Some(SourcePlan {
+			moves,
+			fills,
+			union_bytes: union.size,
+		})
 	}
 
 	/// # Safety
-	/// `src` must be a record of this plan's source layout and `frame` the
-	/// frame whose slot was assigned to this plan at wiring.
-	pub unsafe fn translate(&self, src: Rec, frame: &Frame) -> Rec {
+	/// `src` must be a record of this plan's source layout and `dst` a
+	/// buffer of the plan's union layout.
+	pub unsafe fn translate(&self, src: Rec, dst: *mut u8) -> Rec {
 		unsafe {
-			let dst = frame.slot(self.slot);
 			apply_plan(src, dst, &self.moves);
 			for (offset, bytes) in &self.fills {
 				std::ptr::copy_nonoverlapping(bytes.as_ptr(), dst.add(*offset), bytes.len());
@@ -288,36 +334,37 @@ impl SourcePlan {
 /// Evaluating it yields the source's record translated to the union layout
 /// (or forwarded untouched when the layouts already agree), so the kernel
 /// holds and returns record values without ever seeing the representation.
+/// A translation claims its landing region from the record stack without
+/// popping, so the value survives sibling evaluations; the region is
+/// released with the enclosing frame, which bounds claims at one per source
+/// evaluation the kernel performs.
 pub struct RecordSource<N> {
 	edge: N,
 	plan: Option<SourcePlan>,
 }
 
 impl<N> RecordSource<N> {
-	pub fn wire(edge: N, source: &Layout, union: &Layout, slot: usize) -> Self {
+	pub fn wire(edge: N, source: &Layout, union: &Layout) -> Self {
 		Self {
 			edge,
-			plan: SourcePlan::new(source, union, slot),
+			plan: SourcePlan::new(source, union),
 		}
 	}
 }
 
 impl<'e, C, N> Node<C> for RecordSource<N>
 where
-	C: crate::context::ExtractFrame<'e>,
 	N: Node<C, Output = RecordValue<'e>>,
 {
 	type Output = RecordValue<'e>;
 
 	fn eval(&self, input: &C) -> GPoll<RecordValue<'e>> {
-		let value = self.edge.eval(input);
 		match &self.plan {
-			None => value,
+			None => self.edge.eval(input),
 			Some(plan) => {
-				let Some(frame) = crate::context::ExtractFrame::frame(input) else {
-					return GPoll::error("record frame missing");
-				};
-				value.map(|value| RecordValue::from_rec(unsafe { plan.translate(value.rec(), frame) }))
+				let dst = stack::push(plan.union_bytes);
+				let value = self.edge.eval(input);
+				value.map(|value| RecordValue::from_rec(unsafe { plan.translate(value.rec(), dst) }))
 			}
 		}
 	}
@@ -356,27 +403,15 @@ mod tests {
 		assert!(Layout::union(&[&a, &b]).offset_of("length", 0).is_some());
 	}
 
-	#[test]
-	fn frame_slots_bump_aligned() {
-		let flag = Layout::default().with_writes(0, (1, 1), &[]);
-		let wide = Layout::default().with_writes(0, (8, 8), &[f64_field("opacity")]);
-		let mut frame = FrameLayout::default();
-		assert_eq!(frame.slot(&flag), 0);
-		assert_eq!(frame.slot(&wide), 8);
-		assert_eq!(frame.size(), 24);
-	}
-
 	#[test]
 	fn translation_moves_fields_and_fills_census_defaults() {
 		let source = Layout::default().with_writes(0, (8, 8), &[f64_field("length")]);
 		let union = Layout::union(&[&source, &Layout::default().with_writes(0, (8, 8), &[f64_field("opacity")])]);
-		let mut frame_layout = FrameLayout::default();
-		let slot = frame_layout.slot(&union);
-		let frame = Frame::new(frame_layout.size());
 
-		let plan = SourcePlan::new(&source, &union, slot).unwrap();
+		let plan = SourcePlan::new(&source, &union).unwrap();
 		let record = [5f64, 7f64];
-		let translated = unsafe { plan.translate(Rec::new(record.as_ptr().cast()), &frame) };
+		let mut buffer = vec![0u64; union.size.div_ceil(8)];
+		let translated = unsafe { plan.translate(Rec::new(record.as_ptr().cast()), buffer.as_mut_ptr().cast()) };
 		assert_eq!(unsafe { translated.element::<f64>() }, 5.);
 		assert_eq!(unsafe { translated.read::<f64>(union.offset_of("length", 0).unwrap()) }, 7.);
 		assert_eq!(unsafe { translated.read::<f64>(union.offset_of("opacity", 0).unwrap()) }, 1.);
@@ -385,6 +420,45 @@ mod tests {
 	#[test]
 	fn identity_layouts_forward() {
 		let layout = Layout::default().with_writes(0, (8, 8), &[f64_field("opacity")]);
-		assert!(SourcePlan::new(&layout, &layout.clone(), 0).is_none());
+		assert!(SourcePlan::new(&layout, &layout.clone()).is_none());
+	}
+
+	#[test]
+	fn stack_frames_nest_and_release() {
+		stack::reserve(64);
+		let outer = stack::push(24);
+		let inner = stack::push(8);
+		assert_eq!(inner as usize - outer as usize, 24);
+		stack::pop(outer);
+		assert_eq!(stack::push(8), outer);
+		stack::pop(outer);
+	}
+
+	#[test]
+	fn stack_rounds_frames_to_word_alignment() {
+		stack::reserve(64);
+		let first = stack::push(21);
+		let second = stack::push(8);
+		assert_eq!(second as usize - first as usize, 24);
+		stack::pop(first);
+	}
+
+	#[test]
+	fn each_thread_gets_its_own_stack() {
+		stack::reserve(64);
+		let here = stack::push(8);
+		let here_address = here as usize;
+		std::thread::scope(|scope| {
+			scope
+				.spawn(move || {
+					stack::reserve(64);
+					let there = stack::push(8);
+					assert_ne!(here_address, there as usize, "stacks are per thread");
+					stack::pop(there);
+				})
+				.join()
+				.unwrap();
+		});
+		stack::pop(here);
 	}
 }

node-graph/libraries/core-types/src/registry.rs

@@ -154,6 +154,11 @@ where
 		unsafe { self.ptr.as_ref() }.serialize()
 	}
 
+	fn layout(&self) -> Option<&crate::record::Layout> {
+		// SAFETY: as in eval.
+		unsafe { self.ptr.as_ref() }.layout()
+	}
+
 	fn eval_batch<'a>(&self, input: &'a Input, range: std::ops::Range<u64>, scratch: Option<&'a mut [std::mem::MaybeUninit<Self::Output>]>) -> crate::node::BatchStatus<'a, Self::Output>
 	where
 		Input: crate::context::InjectIndex + Copy,
@@ -167,6 +172,7 @@ pub struct EdgeHandle {
 	node: Box<DynEdge>,
 	share: fn(&DynEdge) -> Box<DynEdge>,
 	serialize: fn(&DynEdge) -> Option<std::sync::Arc<dyn std::any::Any + Send + Sync>>,
+	layout: fn(&DynEdge) -> Option<&crate::record::Layout>,
 	ty: Type,
 }
 
@@ -201,6 +207,7 @@ impl EdgeHandle {
 			node: Box::new(SharedEdge::new(node)),
 			share: |edge| Box::new(edge.downcast_ref::<SharedEdge<N>>().expect("share hook matches the stored edge type").share()),
 			serialize: |edge| Node::<ContextImpl>::serialize(edge.downcast_ref::<SharedEdge<N>>().expect("serialize hook matches the stored edge type")),
+			layout: |edge| Node::<ContextImpl>::layout(edge.downcast_ref::<SharedEdge<N>>().expect("layout hook matches the stored edge type")),
 			ty,
 		}
 	}
@@ -214,6 +221,7 @@ impl EdgeHandle {
 			node: (self.share)(&*self.node),
 			share: self.share,
 			serialize: self.serialize,
+			layout: self.layout,
 			ty: self.ty.clone(),
 		}
 	}
@@ -222,6 +230,10 @@ impl EdgeHandle {
 		(self.serialize)(&*self.node)
 	}
 
+	pub fn layout(&self) -> Option<&crate::record::Layout> {
+		(self.layout)(&*self.node)
+	}
+
 	pub fn downcast<T: 'static>(self) -> Result<SharedEdge<ErasedNode<T>>, ConstructionError> {
 		self.downcast_erased(edge_type::<T>())
 	}

node-graph/node-macro/src/codegen.rs

@@ -39,6 +39,13 @@ pub(crate) fn generate_node_code(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 	// Separate data fields from regular fields
 	let (data_fields, regular_fields): (Vec<_>, Vec<_>) = fields.iter().partition(|f| f.is_data_field);
 
+	let record = record_shape(parsed);
+	let record_skips_carrier = record.as_ref().is_some_and(|shape| shape.skips_carrier());
+	// Record nodes with a `_: ()` primary input have no carrier edge; the unit
+	// field stays visible in the metadata but claims no struct field.
+	let struct_regular_fields: Vec<_> = regular_fields.iter().skip(record_skips_carrier as usize).copied().collect();
+	let struct_regular_field_names: Vec<_> = struct_regular_fields.iter().map(|f| &f.pat_ident.ident).collect();
+
 	// Extract function generics used by data fields
 	let data_field_generics: Vec<_> = fn_generics
 		.iter()
@@ -58,7 +65,7 @@ pub(crate) fn generate_node_code(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 		.collect();
 
 	// Node generics for regular fields (Node0, Node1, ...)
-	let node_generics: Vec<Ident> = regular_fields.iter().enumerate().map(|(i, _)| format_ident!("Node{}", i)).collect();
+	let node_generics: Vec<Ident> = struct_regular_fields.iter().enumerate().map(|(i, _)| format_ident!("Node{}", i)).collect();
 
 	// Extract just the idents from data_field_generics for struct type parameters
 	let data_field_generic_idents: Vec<Ident> = data_field_generics
@@ -108,16 +115,36 @@ pub(crate) fn generate_node_code(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 		quote! { pub(super) #name: #ty }
 	});
 
-	let regular_field_defs = regular_field_names.iter().zip(node_generics.iter()).map(|(name, r#gen)| {
+	let regular_field_defs = struct_regular_field_names.iter().zip(node_generics.iter()).map(|(name, r#gen)| {
 		quote! { pub(super) #name: #r#gen }
 	});
 
+	let record_state_fields: Vec<TokenStream2> = match &record {
+		Some(shape) => {
+			let mut state = vec![quote!(pub(super) __layout: gcore::record::Layout)];
+			if !shape.skips_carrier() {
+				state.push(quote!(pub(super) __plan: ::std::vec::Vec<(usize, usize, usize)>));
+			}
+			state.push(quote!(pub(super) __frame_bytes: usize));
+			state.extend((0..parsed.attribute_reads.len()).map(|index| {
+				let slot = format_ident!("__read_{index}");
+				quote!(pub(super) #slot: Option<usize>)
+			}));
+			state.extend((0..shape.write_markers.len()).map(|index| {
+				let slot = format_ident!("__write_{index}");
+				quote!(pub(super) #slot: usize)
+			}));
+			state
+		}
+		None => Vec::new(),
+	};
+
 	let async_source = parsed.injects_async_source_fields();
 	let slot_value_type = slot_value_type(output_type);
 	let slot_field = async_source
 		.then(|| quote! { pub(super) slot: std::sync::Arc<std::sync::Mutex<std::collections::HashMap<u64, Option<gcore::gpoll::GPoll<#slot_value_type>>>>> })
 		.into_iter();
-	let struct_fields = data_field_defs.chain(regular_field_defs).chain(slot_field);
+	let struct_fields = data_field_defs.chain(regular_field_defs).chain(record_state_fields.iter().cloned()).chain(slot_field);
 
 	// Only regular fields have UI metadata (data fields are internal state)
 	let widget_override: Vec<_> = regular_fields
@@ -215,7 +242,7 @@ pub(crate) fn generate_node_code(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 	let all_implementation_types = all_implementation_types.chain(input.implementations.iter().cloned());
 
 	// Only regular fields are parameters to new()
-	let new_args = node_generics.iter().zip(regular_field_names.iter()).map(|(r#gen, name)| {
+	let new_args = node_generics.iter().zip(struct_regular_field_names.iter()).map(|(r#gen, name)| {
 		quote! { #name: #r#gen }
 	});
 
@@ -223,14 +250,16 @@ pub(crate) fn generate_node_code(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 	let data_inits = data_field_names.iter().map(|name| {
 		quote! { #name: Default::default() }
 	});
-	let regular_inits = regular_field_names.iter().map(|name| {
+	let regular_inits = struct_regular_field_names.iter().map(|name| {
 		quote! { #name }
 	});
 	let slot_init = async_source.then(|| quote! { slot: Default::default() }).into_iter();
 	let all_field_inits = data_inits.chain(regular_inits).chain(slot_init);
 
 	// Data fields may not implement Copy, PartialEq, etc., so only derive Debug and Clone
-	let struct_derives = if data_fields.is_empty() && !async_source {
+	let struct_derives = if record.is_some() {
+		quote!(#[derive(Debug, Clone)])
+	} else if data_fields.is_empty() && !async_source {
 		quote!(#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)])
 	} else {
 		quote!(#[derive(Debug, Clone)])
@@ -253,6 +282,24 @@ pub(crate) fn generate_node_code(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 			register_metadata();
 		}
 	};
+	// Record nodes construct through the generated `wire` fn, which resolves
+	// offsets from the carrier layout; `new` cannot fill that state.
+	let new_impl = match record.is_none() {
+		true => quote! {
+			#[automatically_derived]
+			impl<'n, #(#struct_generic_params,)*> #struct_name<#(#struct_type_params,)*>
+			{
+				#[allow(clippy::too_many_arguments)]
+				pub fn new(#(#new_args,)*) -> Self {
+					Self {
+						#(#all_field_inits,)*
+					}
+				}
+			}
+		},
+		false => quote!(),
+	};
+
 	let import_name = format_ident!("_IMPORT_STUB_{}", mod_name.to_string().to_case(Case::UpperSnake));
 	let node = generate_node_impl(crate_ident, parsed)?;
 	let node_in_mod = node.in_mod;
@@ -330,16 +377,7 @@ pub(crate) fn generate_node_code(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 				#(#struct_fields,)*
 			}
 
-			#[automatically_derived]
-			impl<'n, #(#struct_generic_params,)*> #struct_name<#(#struct_type_params,)*>
-			{
-				#[allow(clippy::too_many_arguments)]
-				pub fn new(#(#new_args,)*) -> Self {
-					Self {
-						#(#all_field_inits,)*
-					}
-				}
-			}
+			#new_impl
 
 			#node_in_mod
 
@@ -612,6 +650,11 @@ pub(crate) fn generate_node_impl(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 			top_level: quote!(),
 		});
 	}
+	let record_token = match record.as_ref().map(|shape| &shape.carrier) {
+		Some(RecordCarrier::Token(token)) => Some(token.clone()),
+		_ => None,
+	};
+	let skips_carrier = record.as_ref().is_some_and(|shape| shape.skips_carrier());
 	let routing = routing_io(parsed);
 	let snapshot_ctx = async_fn && matches!(&parsed.input.ty, Type::Path(path) if path.path.segments.last().is_some_and(|segment| segment.ident == "CtxSnapshot"));
 
@@ -681,8 +724,10 @@ pub(crate) fn generate_node_impl(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 	let mut impl_generics: Vec<TokenStream2> = parsed
 		.fn_generics
 		.iter()
-		.filter(|param| match (param, &routing) {
-			(GenericParam::Type(type_param), Some(routing)) => type_param.ident != routing.generic,
+		.filter(|param| match param {
+			GenericParam::Type(type_param) => {
+				Some(&type_param.ident) != routing.as_ref().map(|routing| &routing.generic) && Some(&type_param.ident) != record_token.as_ref()
+			}
 			_ => true,
 		})
 		.map(&generic_tokens)
@@ -695,7 +740,7 @@ pub(crate) fn generate_node_impl(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 		generics.insert(0, quote!(#lifetime));
 		impl_generics.insert(0, quote!(#lifetime));
 	}
-	if routing.is_some() {
+	if routing.is_some() || record.is_some() {
 		impl_generics.insert(0, quote!('__record));
 	}
 
@@ -704,11 +749,7 @@ pub(crate) fn generate_node_impl(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 	let struct_name = format_ident!("{}Node", parsed.struct_name);
 	let output_type = &parsed.output_type;
 	let trait_output = match (&record, &routing) {
-		(Some(shape), _) => {
-			let element_out = &shape.element_out;
-			syn::parse_quote!(#core_types::list::List<#element_out>)
-		}
-		(None, Some(_)) => syn::parse_quote!(#core_types::record::RecordValue<'__record>),
+		(Some(_), _) | (None, Some(_)) => syn::parse_quote!(#core_types::record::RecordValue<'__record>),
 		(None, None) => slot_value_type(&parsed.output_type),
 	};
 	let raw_lazy = matches!(kernel_kind(&parsed.output_type), KernelKind::Poll(_));
@@ -716,6 +757,7 @@ pub(crate) fn generate_node_impl(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 	let where_predicates: Vec<TokenStream2> = parsed.where_clause.iter().flat_map(|clause| clause.predicates.iter()).map(|predicate| quote!(#predicate)).collect();
 
 	let (data_fields, regular_fields): (Vec<_>, Vec<_>) = parsed.fields.iter().partition(|field| field.is_data_field);
+	let regular_fields: Vec<_> = regular_fields.into_iter().skip(skips_carrier as usize).collect();
 
 	let data_field_generic_idents: Vec<Ident> = parsed
 		.fn_generics
@@ -781,8 +823,8 @@ pub(crate) fn generate_node_impl(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 			let lifetime = lend_lifetime.as_ref().expect("lend fields imply the lend lifetime");
 			quote!(#node_generic: #core_types::node::Node<#ctx_ident, Output = &#lifetime #ty>)
 		}
-		ParsedFieldType::Regular(RegularParsedField { ty, .. }) if record.is_some() && index == 0 => {
-			quote!(#node_generic: #core_types::node::Node<#ctx_ident, Output = #core_types::list::List<#ty>>)
+		ParsedFieldType::Regular(_) if record.is_some() && !skips_carrier && index == 0 => {
+			quote!(#node_generic: #core_types::node::Node<#ctx_ident, Output = #record_value_ty>)
 		}
 		ParsedFieldType::Regular(RegularParsedField { ty, .. }) if routing_source(ty) => {
 			quote!(#node_generic: #core_types::node::Node<#ctx_ident, Output = #record_value_ty>)
@@ -848,12 +890,7 @@ pub(crate) fn generate_node_impl(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 	let eval_values = regular_fields.iter().enumerate().map(|(index, field)| {
 		let name = &field.pat_ident.ident;
 		match &field.ty {
-			ParsedFieldType::Regular(_) if record.is_some() && index == 0 => quote! {
-				let mut __record_list = match __cell.eval_input(#index, &self.#name, __input) {
-					Ok(value) => value,
-					Err(interrupt) => return interrupt.into(),
-				};
-			},
+			ParsedFieldType::Regular(_) if record.is_some() && !skips_carrier && index == 0 => quote!(),
 			ParsedFieldType::Regular(_) => quote! {
 				let #name = match __cell.eval_input(#index, &self.#name, __input) {
 					Ok(value) => value,
@@ -951,10 +988,16 @@ pub(crate) fn generate_node_impl(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 	let body = &parsed.body;
 	let vis = &parsed.vis;
 	let kernel_fields: Vec<&&ParsedField> = regular_fields.iter().filter(|field| !injected_name(&field.pat_ident.ident)).collect();
+	// A bare `Attr<M>` in the return type cannot elide its lifetime, so the
+	// kernel gets a fresh one; reference-valued writes name their real
+	// lifetime explicitly and pass through untouched.
+	let kernel_output = record.as_ref().and_then(|_| inject_attr_lifetimes(&parsed.output_type));
+	let attr_lifetime = kernel_output.is_some().then(|| quote!('__attr,));
+	let kernel_output = kernel_output.map(|ty| quote!(#ty)).unwrap_or_else(|| quote!(#output_type));
 	let kernel = match async_fn {
 		false => quote! {
 			#[allow(clippy::too_many_arguments)]
-			#vis fn #fn_name<#(#generics,)*>(#ctx_pat: &#ctx_ident #(, #data_params)* #(, #kernel_params)*) -> #output_type #fn_where #body
+			#vis fn #fn_name<#attr_lifetime #(#generics,)*>(#ctx_pat: &#ctx_ident #(, #data_params)* #(, #kernel_params)*) -> #kernel_output #fn_where #body
 		},
 		true => {
 			let kernel_generics = parsed.fn_generics.iter().filter(|param| match param {
@@ -1048,61 +1091,43 @@ pub(crate) fn generate_node_impl(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 		}
 	};
 	let record_tail = record.as_ref().map(|shape| {
-		let record_call_args = regular_fields.iter().enumerate().map(|(index, field)| {
+		let carrier_arg = match &shape.carrier {
+			RecordCarrier::None => None,
+			RecordCarrier::Token(_) => Some(quote!(#core_types::record::ElToken)),
+			RecordCarrier::Read(ty) => Some(quote!(unsafe { __src_rec.element::<#ty>() })),
+		}
+		.into_iter();
+		let value_args = regular_fields.iter().skip(if shape.skips_carrier() { 0 } else { 1 }).map(|field| {
 			let name = &field.pat_ident.ident;
-			match (index, &field.ty) {
-				(0, _) => quote!(__element),
-				(_, ParsedFieldType::Regular(RegularParsedField { lend: Some(_), .. })) => quote!(#name),
-				_ => quote!(#name.clone()),
-			}
+			quote!(#name)
 		});
-		let attr_call_args = parsed.attribute_reads.iter().map(|read| {
+		let attr_args = parsed.attribute_reads.iter().map(|read| {
 			let pat = &read.pat_ident.ident;
 			quote!(#pat)
 		});
-		let record_kernel_call = quote!(self::#fn_name(__input #(, &self.#data_names)* #(, #record_call_args)* #(, #attr_call_args)*));
-		let read_columns = parsed.attribute_reads.iter().enumerate().map(|(index, read)| {
-			let marker = &read.marker;
-			let column = format_ident!("__read_{index}");
+		let record_kernel_call = quote!(self::#fn_name(__input #(, &self.#data_names)* #(, #carrier_arg)* #(, #value_args)* #(, #attr_args)*));
+		let carrier_eval = (!shape.skips_carrier()).then(|| {
+			let name = &regular_fields[0].pat_ident.ident;
 			quote! {
-				let #column = __record_list
-					.iter_attribute_values::<<#marker as #core_types::attribute::Attribute>::Value>(<#marker as #core_types::attribute::Attribute>::NAME)
-					.map(|__values| __values.cloned().collect::<::std::vec::Vec<_>>());
+				let __src = match __cell.eval_input(0, &self.#name, __input) {
+					Ok(value) => value,
+					Err(interrupt) => return interrupt.into(),
+				};
+				let __src_rec = #core_types::record::RecordValue::rec(__src);
 			}
 		});
+		let carry = (!shape.skips_carrier()).then(|| quote!(unsafe { #core_types::record::apply_plan(__src_rec, __dst, &self.__plan) };));
 		let read_bindings = parsed.attribute_reads.iter().enumerate().map(|(index, read)| {
 			let pat = &read.pat_ident;
 			let marker = &read.marker;
-			let column = format_ident!("__read_{index}");
+			let slot = format_ident!("__read_{index}");
 			quote! {
-				let #pat = #core_types::attribute::Attr::<#marker>(match &#column {
-					Some(__values) => __values[__index].clone(),
+				let #pat = #core_types::attribute::Attr::<#marker>(match self.#slot {
+					Some(__offset) => unsafe { __src_rec.read(__offset) },
 					None => <#marker as #core_types::attribute::Attribute>::default(),
 				});
 			}
 		});
-		let write_markers = &shape.write_markers;
-		let write_columns: Vec<Ident> = (0..write_markers.len()).map(|index| format_ident!("__write_{index}")).collect();
-		let write_column_decls = write_markers.iter().zip(&write_columns).map(|(marker, column)| {
-			quote! {
-				let mut #column: ::std::vec::Vec<<#marker as #core_types::attribute::Attribute>::Value> = ::std::vec::Vec::with_capacity(__len);
-			}
-		});
-		let write_pats: Vec<Ident> = (0..write_markers.len()).map(|index| format_ident!("__written_{index}")).collect();
-		let destructure = match write_markers.is_empty() {
-			true => quote!(let __element_out = __kernel_value;),
-			false => quote!(let (__element_out #(, #core_types::attribute::Attr(#write_pats))*) = __kernel_value;),
-		};
-		let write_pushes = write_columns.iter().zip(&write_pats).map(|(column, pat)| quote!(#column.push(#pat);));
-		let written_names = write_markers.iter().map(|marker| quote!(<#marker as #core_types::attribute::Attribute>::NAME));
-		let write_inserts = write_markers.iter().zip(&write_columns).map(|(marker, column)| {
-			quote! {
-				__out.insert_attribute_dyn(
-					<#marker as #core_types::attribute::Attribute>::NAME,
-					#core_types::list::AttributeDyn(::std::boxed::Box::new(#core_types::list::Attribute(#column))),
-				);
-			}
-		});
 		let kernel_value = match shape.dialect {
 			RecordDialect::Plain => quote!(#record_kernel_call),
 			RecordDialect::Interrupt => quote! {
@@ -1112,37 +1137,31 @@ pub(crate) fn generate_node_impl(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 				}
 			},
 		};
-		let element_out = &shape.element_out;
+		let attr_binders: Vec<Ident> = (0..shape.write_markers.len()).map(|index| format_ident!("__attr_{index}")).collect();
+		let element_binder = match &shape.element_write {
+			Some(_) => quote!(__element),
+			None => quote!(_),
+		};
+		let destructure = match attr_binders.is_empty() {
+			true => quote!(let #element_binder = __kernel_value;),
+			false => quote!(let (#element_binder #(, #core_types::attribute::Attr(#attr_binders))*) = __kernel_value;),
+		};
+		let element_store = shape.element_write.as_ref().map(|ty| quote!(unsafe { #core_types::record::write_field::<#ty>(__dst, 0, __element) };));
+		let attr_stores = attr_binders.iter().enumerate().map(|(index, binder)| {
+			let slot = format_ident!("__write_{index}");
+			quote!(unsafe { #core_types::record::write_field(__dst, self.#slot, #binder) };)
+		});
 		quote! {
-			let __len = __record_list.len();
-			#(#read_columns)*
-			let __written_names: &[&str] = &[#(#written_names),*];
-			let __carried_keys: ::std::vec::Vec<::std::string::String> = __record_list
-				.attribute_keys()
-				.filter(|__key| !__written_names.contains(__key))
-				.map(::std::string::String::from)
-				.collect();
-			let mut __carried: ::std::vec::Vec<(::std::string::String, #core_types::list::AttributeDyn)> = ::std::vec::Vec::with_capacity(__carried_keys.len());
-			for __key in __carried_keys {
-				if let Some(__column) = __record_list.take_attribute_dyn(&__key) {
-					__carried.push((__key, __column));
-				}
-			}
-			#(#write_column_decls)*
-			let mut __out_elements: ::std::vec::Vec<#element_out> = ::std::vec::Vec::with_capacity(__len);
-			for (__index, __element) in __record_list.into_element_values().into_iter().enumerate() {
-				#(#read_bindings)*
-				let __kernel_value = #kernel_value;
-				#destructure
-				__out_elements.push(__element_out);
-				#(#write_pushes)*
-			}
-			let mut __out = #core_types::list::List::from_element_values(__out_elements);
-			for (__key, __column) in __carried {
-				__out.insert_attribute_dyn(__key, __column);
-			}
-			#(#write_inserts)*
-			__cell.finish(__out)
+			let __dst = #core_types::record::stack::push(self.__frame_bytes);
+			#carrier_eval
+			#carry
+			#(#read_bindings)*
+			let __kernel_value = #kernel_value;
+			#destructure
+			#element_store
+			#(#attr_stores)*
+			#core_types::record::stack::pop(__dst);
+			__cell.finish(#core_types::record::RecordValue::from_rec(unsafe { #core_types::record::Rec::new(__dst.cast_const()) }))
 		}
 	});
 	let eval_tail = match (async_fn, future_kernel) {
@@ -1199,21 +1218,114 @@ pub(crate) fn generate_node_impl(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 	};
 
 	let record_bounds: Vec<TokenStream2> = match &record {
-		Some(_) => regular_fields
-			.iter()
-			.skip(1)
-			.filter_map(|field| match &field.ty {
-				ParsedFieldType::Regular(RegularParsedField { lend: Some(_), .. }) => None,
-				ParsedFieldType::Regular(RegularParsedField { ty, .. }) => Some(quote!(#ty: Clone)),
-				_ => None,
-			})
-			.collect(),
-		None => Vec::new(),
+		Some(shape) if shape.skips_carrier() => {
+			vec![quote!(#ctx_ident: #core_types::context::ExtractArena<ArenaRef = &'__record #core_types::arena::Arena>)]
+		}
+		_ => Vec::new(),
+	};
+
+	let record_layout_impl = match &record {
+		Some(_) => quote! {
+			fn layout(&self) -> Option<&#core_types::record::Layout> {
+				Some(&self.__layout)
+			}
+		},
+		None => quote!(),
 	};
 
 	let entries = entries_tokens(parsed, &struct_name, &data_field_generic_idents, &regular_fields);
 	let cfg = crate::shader_nodes::modify_cfg(&parsed.attributes);
 
+	let record_wiring = record.as_ref().map(|shape| {
+		let layout_fn = format_ident!("{}_layout", fn_name);
+		let write_descs: Vec<TokenStream2> = shape
+			.write_markers
+			.iter()
+			.map(|marker| {
+				quote! {
+					(
+						<#marker as #core_types::attribute::Attribute>::NAME,
+						0u8,
+						::core::mem::size_of::<<#marker as #core_types::attribute::Attribute>::Value<'static>>(),
+						::core::mem::align_of::<<#marker as #core_types::attribute::Attribute>::Value<'static>>(),
+					)
+				}
+			})
+			.collect();
+		let element_dims = match &shape.element_write {
+			Some(ty) => quote!((::core::mem::size_of::<#ty>(), ::core::mem::align_of::<#ty>())),
+			None => quote!((__carrier.element_size, __carrier.element_align)),
+		};
+		let layout_def = match shape.skips_carrier() {
+			true => quote! {
+				#vis fn #layout_fn() -> #core_types::record::Layout {
+					#core_types::record::Layout::default().with_writes(0, #element_dims, &[#(#write_descs),*])
+				}
+			},
+			false => quote! {
+				#vis fn #layout_fn(__carrier: &#core_types::record::Layout) -> #core_types::record::Layout {
+					__carrier.with_writes(__carrier.depth, #element_dims, &[#(#write_descs),*])
+				}
+			},
+		};
+		let edge_args = regular_fields.iter().zip(&node_generics).map(|(field, generic)| {
+			let name = &field.pat_ident.ident;
+			quote!(#name: #generic)
+		});
+		let carrier_layout_param = (!shape.skips_carrier()).then(|| quote!(__carrier_layout: &#core_types::record::Layout,)).into_iter();
+		let layout_binding = match shape.skips_carrier() {
+			true => quote!(let __layout = self::#layout_fn();),
+			false => quote!(let __layout = self::#layout_fn(__carrier_layout);),
+		};
+		let carry_element = shape.carries_element();
+		let plan_binding = (!shape.skips_carrier()).then(|| quote!(let __plan = #core_types::record::copy_plan(__carrier_layout, &__layout, #carry_element);));
+		let read_inits = parsed.attribute_reads.iter().enumerate().map(|(index, read)| {
+			let marker = &read.marker;
+			let slot = format_ident!("__read_{index}");
+			quote!(let #slot = __carrier_layout.offset_of(<#marker as #core_types::attribute::Attribute>::NAME, 0);)
+		});
+		let write_inits = shape.write_markers.iter().enumerate().map(|(index, marker)| {
+			let slot = format_ident!("__write_{index}");
+			quote! {
+				let #slot = __layout
+					.offset_of(<#marker as #core_types::attribute::Attribute>::NAME, 0)
+					.expect("a written attribute is always part of the wired layout");
+			}
+		});
+		let data_inits = data_names.iter().map(|name| quote!(#name: ::core::default::Default::default(),));
+		let edge_inits = regular_fields.iter().map(|field| {
+			let name = &field.pat_ident.ident;
+			quote!(#name,)
+		});
+		let plan_init = (!shape.skips_carrier()).then(|| quote!(__plan,)).into_iter();
+		let read_names = (0..parsed.attribute_reads.len()).map(|index| format_ident!("__read_{index}")).map(|slot| quote!(#slot,));
+		let write_names = (0..shape.write_markers.len()).map(|index| format_ident!("__write_{index}")).map(|slot| quote!(#slot,));
+		quote! {
+			#layout_def
+
+			#[automatically_derived]
+			impl<#(#data_field_generic_idents,)* #(#node_generics,)*> #mod_name::#struct_name<#(#struct_type_params,)*> {
+				#[allow(clippy::too_many_arguments)]
+				#vis fn wire(#(#edge_args,)* #(#carrier_layout_param)*) -> Self {
+					#layout_binding
+					#plan_binding
+					#(#read_inits)*
+					#(#write_inits)*
+					let __frame_bytes = __layout.size.next_multiple_of(8);
+					Self {
+						#(#data_inits)*
+						#(#edge_inits)*
+						__layout,
+						#(#plan_init)*
+						__frame_bytes,
+						#(#read_names)*
+						#(#write_names)*
+					}
+				}
+			}
+		}
+	});
+
 	let top_level = quote! {
 		#cfg
 		#[automatically_derived]
@@ -1239,6 +1351,8 @@ pub(crate) fn generate_node_impl(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 
 			#serialize_impl
 
+			#record_layout_impl
+
 			#batch_impl
 		}
 	};
@@ -1248,6 +1362,8 @@ pub(crate) fn generate_node_impl(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 		top_level: quote! {
 			#kernel
 
+			#record_wiring
+
 			#top_level
 		},
 	})
@@ -1258,20 +1374,90 @@ pub(crate) enum RecordDialect {
 	Interrupt,
 }
 
-/// The record io of a node fn: the output element type and the written
-/// markers. Present exactly when the signature declares attribute reads or
-/// writes in a shape the driver supports (the carrier is the first field);
-/// malformed record io is reported by validation and generates no node impl.
+/// How a record node's primary input lowers.
+pub(crate) enum RecordCarrier {
+	/// `_: ()`: no carrier edge, the kernel writes a fresh record.
+	None,
+	/// An unbounded generic returned in the element position: the element
+	/// bytes carry through the copy plan and the kernel sees `ElToken`.
+	Token(Ident),
+	/// An element type read at offset 0, monomorphized per its
+	/// implementations list where generic.
+	Read(Type),
+}
+
+/// The record io of a node fn: how the carrier lowers, the element write,
+/// and the written markers. Present exactly when the signature declares
+/// attribute reads or writes in a shape the record tier supports; malformed
+/// record io is reported by validation and generates no node impl.
 pub(crate) struct RecordShape {
-	pub(crate) element_out: Type,
+	pub(crate) carrier: RecordCarrier,
+	pub(crate) element_write: Option<Type>,
 	pub(crate) write_markers: Vec<Type>,
 	pub(crate) dialect: RecordDialect,
 }
 
+impl RecordShape {
+	pub(crate) fn skips_carrier(&self) -> bool {
+		matches!(self.carrier, RecordCarrier::None)
+	}
+
+	pub(crate) fn carries_element(&self) -> bool {
+		self.element_write.is_none()
+	}
+}
+
 pub(crate) fn has_record_io(parsed: &ParsedNodeFn) -> bool {
 	!parsed.attribute_reads.is_empty() || record_writes(&slot_value_type(&parsed.output_type)).is_some()
 }
 
+fn inject_attr_lifetimes(output: &Type) -> Option<Type> {
+	struct Injector {
+		changed: bool,
+	}
+
+	impl VisitMut for Injector {
+		fn visit_path_segment_mut(&mut self, segment: &mut syn::PathSegment) {
+			if segment.ident == "Attr"
+				&& let PathArguments::AngleBracketed(args) = &mut segment.arguments
+				&& !args.args.iter().any(|arg| matches!(arg, GenericArgument::Lifetime(_)))
+			{
+				args.args.insert(0, GenericArgument::Lifetime(Lifetime::new("'__attr", proc_macro2::Span::call_site())));
+				self.changed = true;
+			}
+			syn::visit_mut::visit_path_segment_mut(self, segment);
+		}
+	}
+
+	let mut ty = output.clone();
+	let mut injector = Injector { changed: false };
+	injector.visit_type_mut(&mut ty);
+	injector.changed.then_some(ty)
+}
+
+pub(crate) fn contains_open_generic(parsed: &ParsedNodeFn, ty: &Type) -> bool {
+	let ctx_ident = context_param(parsed).map(|ctx| ctx.ident.clone());
+	parsed
+		.fn_generics
+		.iter()
+		.any(|param| matches!(param, GenericParam::Type(type_param) if Some(&type_param.ident) != ctx_ident.as_ref() && type_contains_ident(ty, &type_param.ident)))
+}
+
+pub(crate) fn unbounded_generic(parsed: &ParsedNodeFn, ty: &Type) -> Option<Ident> {
+	let ident = bare_ident(ty)?.clone();
+	let ctx_ident = context_param(parsed).map(|ctx| ctx.ident.clone());
+	parsed
+		.fn_generics
+		.iter()
+		.find(|param| matches!(param, GenericParam::Type(type_param) if type_param.ident == ident && type_param.bounds.is_empty() && Some(&type_param.ident) != ctx_ident.as_ref()))?;
+	if let Some(where_clause) = &parsed.where_clause
+		&& tokens_contain_ident(where_clause.to_token_stream(), &ident)
+	{
+		return None;
+	}
+	Some(ident)
+}
+
 pub(crate) fn record_shape(parsed: &ParsedNodeFn) -> Option<RecordShape> {
 	let (value, dialect) = match kernel_kind(&parsed.output_type) {
 		KernelKind::Plain => (parsed.output_type.clone(), RecordDialect::Plain),
@@ -1282,28 +1468,50 @@ pub(crate) fn record_shape(parsed: &ParsedNodeFn) -> Option<RecordShape> {
 	if parsed.attribute_reads.is_empty() && writes.is_none() {
 		return None;
 	}
-	if parsed.is_async {
+	if parsed.is_async || parsed.fields.iter().any(|field| matches!(field.ty, ParsedFieldType::Node(_))) {
 		return None;
 	}
-	let carrier = parsed.fields.first()?;
-	if carrier.is_data_field {
+	let carrier_field = parsed.fields.first()?;
+	if carrier_field.is_data_field {
 		return None;
 	}
-	let ParsedFieldType::Regular(RegularParsedField { ty, lend: None, .. }) = &carrier.ty else {
+	let ParsedFieldType::Regular(RegularParsedField { ty, lend: None, implementations, .. }) = &carrier_field.ty else {
 		return None;
 	};
-	if matches!(ty, Type::Tuple(tuple) if tuple.elems.is_empty()) {
-		return None;
-	}
-	if parsed.fields.iter().any(|field| matches!(field.ty, ParsedFieldType::Node(_))) {
-		return None;
-	}
-	let (element_out, write_markers) = match writes {
+	let carrier = match ty {
+		Type::Tuple(tuple) if tuple.elems.is_empty() => RecordCarrier::None,
+		ty => match implementations.is_empty().then(|| unbounded_generic(parsed, ty)).flatten() {
+			Some(token) => RecordCarrier::Token(token),
+			None => {
+				if contains_open_generic(parsed, ty) {
+					return None;
+				}
+				RecordCarrier::Read(ty.clone())
+			}
+		},
+	};
+	let (element, write_markers) = match writes {
 		Some(RecordWrites { element, markers }) => (element, markers),
 		None => (value, Vec::new()),
 	};
+	let element_write = match &carrier {
+		RecordCarrier::Token(token) => match bare_ident(&element) {
+			Some(ident) if ident == token => None,
+			_ => return None,
+		},
+		_ => {
+			if contains_open_generic(parsed, &element) {
+				return None;
+			}
+			Some(element)
+		}
+	};
+	if matches!(carrier, RecordCarrier::None) && !parsed.attribute_reads.is_empty() {
+		return None;
+	}
 	Some(RecordShape {
-		element_out,
+		carrier,
+		element_write,
 		write_markers,
 		dialect,
 	})
@@ -1374,7 +1582,7 @@ pub(crate) fn routing_io(parsed: &ParsedNodeFn) -> Option<RoutingIo> {
 	(sources > 0).then(|| RoutingIo { generic: ident })
 }
 
-fn bare_ident(ty: &Type) -> Option<&Ident> {
+pub(crate) fn bare_ident(ty: &Type) -> Option<&Ident> {
 	let Type::Path(path) = ty else { return None };
 	path.path.get_ident()
 }
@@ -1522,6 +1730,9 @@ fn entries_tokens(parsed: &ParsedNodeFn, struct_name: &Ident, data_field_generic
 	if !data_field_generic_idents.is_empty() {
 		return quote!();
 	}
+	if has_record_io(parsed) {
+		return quote!();
+	}
 	let Some(rows) = implementation_rows(parsed, regular_fields) else {
 		return quote!();
 	};
@@ -1554,17 +1765,14 @@ fn entries_tokens(parsed: &ParsedNodeFn, struct_name: &Ident, data_field_generic
 		.map(|field| matches!(&field.ty, ParsedFieldType::Regular(RegularParsedField { lend: Some(_), .. })))
 		.collect();
 
-	let record_carrier = record_shape(parsed).is_some();
 	let entries = rows.iter().map(|row| {
-		let input_types = row.iter().enumerate().zip(&lend_flags).map(|((index, ty), lend)| match (lend, record_carrier && index == 0) {
-			(true, _) => quote!(gcore::registry::lend_edge_type::<#ty>()),
-			(false, true) => quote!(gcore::registry::edge_type::<gcore::list::List<#ty>>()),
-			(false, false) => quote!(gcore::registry::edge_type::<#ty>()),
+		let input_types = row.iter().zip(&lend_flags).map(|(ty, lend)| match lend {
+			true => quote!(gcore::registry::lend_edge_type::<#ty>()),
+			false => quote!(gcore::registry::edge_type::<#ty>()),
 		});
-		let edge_types = row.iter().enumerate().zip(&lend_flags).map(|((index, ty), lend)| match (lend, record_carrier && index == 0) {
-			(true, _) => quote!(gcore::registry::SharedEdge<gcore::registry::ErasedLendNode<#ty>>),
-			(false, true) => quote!(gcore::registry::SharedEdge<gcore::registry::ErasedNode<gcore::list::List<#ty>>>),
-			(false, false) => quote!(gcore::registry::SharedEdge<gcore::registry::ErasedNode<#ty>>),
+		let edge_types = row.iter().zip(&lend_flags).map(|(ty, lend)| match lend {
+			true => quote!(gcore::registry::SharedEdge<gcore::registry::ErasedLendNode<#ty>>),
+			false => quote!(gcore::registry::SharedEdge<gcore::registry::ErasedNode<#ty>>),
 		});
 		let output = quote!(<#struct_name<#(#edge_types),*> as gcore::node::Node<gcore::context::ContextImpl<'static>>>::Output);
 		let (io_output, construct) = match &ref_output_inner {
@@ -1577,10 +1785,9 @@ fn entries_tokens(parsed: &ParsedNodeFn, struct_name: &Ident, data_field_generic
 				quote!(Ok(gcore::registry::EdgeHandle::new(::std::sync::Arc::new(#struct_name::new(#(#names),*)) as ::std::sync::Arc<gcore::registry::ErasedNode<#output>>))),
 			),
 		};
-		let downcasts = names.iter().zip(row.iter().enumerate()).zip(&lend_flags).map(|((name, (index, ty)), lend)| match (lend, record_carrier && index == 0) {
-			(true, _) => quote!(let #name = inputs.next().unwrap().downcast_lend::<#ty>()?;),
-			(false, true) => quote!(let #name = inputs.next().unwrap().downcast::<gcore::list::List<#ty>>()?;),
-			(false, false) => quote!(let #name = inputs.next().unwrap().downcast::<#ty>()?;),
+		let downcasts = names.iter().zip(row.iter()).zip(&lend_flags).map(|((name, ty), lend)| match lend {
+			true => quote!(let #name = inputs.next().unwrap().downcast_lend::<#ty>()?;),
+			false => quote!(let #name = inputs.next().unwrap().downcast::<#ty>()?;),
 		});
 		quote! {
 			gcore::registry::RegistryEntry {

node-graph/node-macro/src/parsing.rs

@@ -716,6 +716,16 @@ fn parse_inputs(inputs: &Punctuated<FnArg, Comma>) -> syn::Result<(Input, Vec<Pa
 					let field = parse_field(pat_ident.clone(), (**ty).clone(), attrs).map_err(|e| Error::new_spanned(pat_ident, format!("Failed to parse argument '{}': {}", pat_ident.ident, e)))?;
 					fields.push(field);
 				}
+			} else if let Pat::Wild(wild) = &**pat {
+				let pat_ident = PatIdent {
+					attrs: wild.attrs.clone(),
+					by_ref: None,
+					mutability: None,
+					ident: format_ident!("_unit{}", index, span = wild.underscore_token.span),
+					subpat: None,
+				};
+				let field = parse_field(pat_ident, (**ty).clone(), attrs).map_err(|e| Error::new_spanned(pat, format!("Failed to parse argument: {e}")))?;
+				fields.push(field);
 			} else {
 				return Err(Error::new_spanned(pat, "Expected a simple identifier for the field name"));
 			}

node-graph/node-macro/src/validation.rs

@@ -49,28 +49,64 @@ fn validate_record_io(parsed: &ParsedNodeFn) {
 		emit_error!(parsed.output_type.span(), "attribute io needs a plain or `Result<_, Interrupt>` kernel, not a `GPoll` one");
 	}
 
-	match parsed.fields.first() {
-		None => emit_error!(
-			parsed.fn_name.span(),
-			"attribute io needs a value carrier as the first parameter after the context"
-		),
-		Some(carrier) => {
-			let valid = !carrier.is_data_field
-				&& matches!(&carrier.ty, ParsedFieldType::Regular(RegularParsedField { ty, lend: None, .. }) if !matches!(ty, Type::Tuple(tuple) if tuple.elems.is_empty()));
-			if !valid {
-				emit_error!(
-					carrier.pat_ident.span(),
-					"attribute io needs a value carrier as the first parameter after the context: an owned element type, not `()`, `#[data]`, `&T`, or `impl Node`"
-				);
-			}
-		}
-	}
 	for field in parsed.fields.iter().skip(1) {
 		if matches!(field.ty, ParsedFieldType::Node(_)) {
 			emit_error!(field.pat_ident.span(), "record nodes take no lazy inputs yet");
 		}
 	}
 
+	let Some(carrier) = parsed.fields.first() else {
+		emit_error!(
+			parsed.fn_name.span(),
+			"attribute io needs a primary input as the first parameter after the context (`_: ()` for none)"
+		);
+		return;
+	};
+	let carrier_ty = match &carrier.ty {
+		ParsedFieldType::Regular(RegularParsedField { ty, lend: None, .. }) if !carrier.is_data_field => Some(ty),
+		_ => None,
+	};
+	let Some(carrier_ty) = carrier_ty else {
+		emit_error!(
+			carrier.pat_ident.span(),
+			"a record node's primary input is an owned element, an unbounded passthrough generic, or `_: ()`; not `#[data]`, `&T`, or `impl Node`"
+		);
+		return;
+	};
+
+	let no_carrier = matches!(carrier_ty, Type::Tuple(tuple) if tuple.elems.is_empty());
+	if no_carrier && !parsed.attribute_reads.is_empty() {
+		emit_error!(carrier.pat_ident.span(), "a node without a primary input has no attributes to read");
+	}
+	let token = match (no_carrier, &carrier.ty) {
+		(false, ParsedFieldType::Regular(RegularParsedField { ty, implementations, .. })) if implementations.is_empty() => crate::codegen::unbounded_generic(parsed, ty),
+		_ => None,
+	};
+	let element = writes.as_ref().map(|writes| &writes.element).unwrap_or(&value);
+	match &token {
+		Some(token) => {
+			if !matches!(crate::codegen::bare_ident(element), Some(ident) if ident == token) {
+				emit_error!(
+					parsed.output_type.span(),
+					"a generic element passes through unchanged: return `{}` in the first tuple position",
+					token
+				);
+			}
+		}
+		None => {
+			if let Some(ident) = crate::codegen::unbounded_generic(parsed, element) {
+				emit_error!(parsed.output_type.span(), "the returned generic element `{}` has no matching input", ident);
+			} else if !no_carrier && crate::codegen::contains_open_generic(parsed, carrier_ty) {
+				emit_error!(
+					carrier.pat_ident.span(),
+					"record element reads are monomorphic for now; use a concrete element type or an unbounded passthrough generic"
+				);
+			} else if crate::codegen::contains_open_generic(parsed, element) {
+				emit_error!(parsed.output_type.span(), "a written element must be a concrete type");
+			}
+		}
+	}
+
 	let mut seen_reads: Vec<String> = Vec::new();
 	for read in &parsed.attribute_reads {
 		let marker = read.marker.to_token_stream().to_string();
@@ -276,7 +312,17 @@ fn validate_primary_input_expose(parsed: &ParsedNodeFn) {
 fn validate_implementations_for_generics(parsed: &ParsedNodeFn) {
 	let has_skip_impl = parsed.attributes.skip_impl;
 	let routing = crate::codegen::routing_io(parsed);
-	let routing_source = |ty: &Type| matches!((&routing, ty), (Some(routing), Type::Path(path)) if path.path.get_ident() == Some(&routing.generic));
+	let record_token = crate::codegen::record_shape(parsed).and_then(|shape| match shape.carrier {
+		crate::codegen::RecordCarrier::Token(token) => Some(token),
+		_ => None,
+	});
+	let opaque_record_generic = |ty: &Type| {
+		let ident = match ty {
+			Type::Path(path) => path.path.get_ident(),
+			_ => None,
+		};
+		ident.is_some() && (ident == routing.as_ref().map(|routing| &routing.generic) || ident == record_token.as_ref())
+	};
 
 	if !has_skip_impl && !parsed.fn_generics.is_empty() {
 		for field in &parsed.fields {
@@ -288,7 +334,7 @@ fn validate_implementations_for_generics(parsed: &ParsedNodeFn) {
 			let pat_ident = &field.pat_ident;
 			match &field.ty {
 				ParsedFieldType::Regular(RegularParsedField { ty, implementations, .. }) => {
-					if routing_source(ty) {
+					if opaque_record_generic(ty) {
 						continue;
 					}
 					if contains_generic_param(ty, &parsed.fn_generics) && implementations.is_empty() {
@@ -308,7 +354,7 @@ fn validate_implementations_for_generics(parsed: &ParsedNodeFn) {
 					implementations,
 					..
 				}) => {
-					if routing_source(output_type) {
+					if opaque_record_generic(output_type) {
 						continue;
 					}
 					if (contains_generic_param(input_type, &parsed.fn_generics) || contains_generic_param(output_type, &parsed.fn_generics)) && implementations.is_empty() {

node-graph/nodes/gcore/src/record.rs

@@ -1,15 +1,19 @@
-//! Pilot record nodes exercising the macro's attribute io over materialized
-//! lists: `Attr<A>` reads, tuple writes, column carry, and the census
-//! defaults. These are the flat-wave law tests; the node forms are the
-//! production authoring surface, the list driver behind them is interim.
+//! Pilot record nodes exercising the macro's record-tier attribute io:
+//! offset reads and writes against record edges, the ElToken byte-carry for
+//! passthrough elements, and the `_: ()` no-carrier form. These are the
+//! flat-wave law tests; the node forms are the production authoring surface,
+//! and the wiring is by hand until the compiler pass constructs layouts.
 
 use core_types::attribute::{Attr, Opacity};
-use core_types::gpoll::{GraphError, Interrupt};
+use core_types::context::ExtractArena;
+use core_types::gpoll::{ErrorKind, GraphError, Interrupt};
 use core_types::{Context, Ctx};
 
 core_types::attribute! {
 	/// Test-only measured length of an element.
 	pub Length("length"): f64;
+	/// Test-only label parked in the arena by its writer.
+	pub Label("label"): &str;
 }
 
 #[node_macro::node(category("Test"))]
@@ -40,6 +44,26 @@ fn scale(_: impl Ctx, element: f64, factor: &f64, opacity: Attr<Opacity>) -> (f6
 	(element * *factor, Attr(*opacity))
 }
 
+#[node_macro::node(category("Test"))]
+fn fade<T>(_: impl Ctx, element: T, factor: f64, opacity: Attr<Opacity>) -> (T, Attr<Opacity>) {
+	(element, Attr(*opacity * factor))
+}
+
+#[node_macro::node(category("Test"))]
+fn source_opacity(_: impl Ctx, _: (), element: f64, opacity: f64) -> (f64, Attr<Opacity>) {
+	(element, Attr(opacity))
+}
+
+#[node_macro::node(category("Test"))]
+fn label<'e>(ctx: impl Ctx + ExtractArena<'e>, element: f64, text: String, label: Attr<Label>) -> Result<(f64, Attr<'e, Label>), Interrupt> {
+	let joined = format!("{}{text}", *label);
+	let (parked, _) = ctx.arena().alloc(joined).ok_or(GraphError {
+		kind: ErrorKind::ArenaExhausted,
+		trace: Vec::new(),
+	})?;
+	Ok((element, Attr(parked.as_str())))
+}
+
 #[node_macro::node(category("Test"))]
 fn pick<T>(ctx: impl Ctx, take_second: bool, first: impl Node<Context<'_>, Output = T>, second: impl Node<Context<'_>, Output = T>) -> Result<T, Interrupt> {
 	if take_second { second.eval(ctx) } else { first.eval(ctx) }
@@ -57,6 +81,7 @@ fn forward_record<T>(_: impl Ctx, element: T) -> T {
 	element
 }
 
+
 #[cfg(test)]
 mod tests {
 	use super::*;
@@ -65,8 +90,8 @@ mod tests {
 	use core_types::attribute::Attribute as AttributeMarker;
 	use core_types::context::{ContextImpl, EvalScope};
 	use core_types::gpoll::GPoll;
-	use core_types::list::List;
 	use core_types::node::Node;
+	use core_types::record::{Layout, Rec, RecordSource, RecordValue, stack};
 
 	struct ValueNode<T>(T);
 
@@ -78,13 +103,30 @@ mod tests {
 		}
 	}
 
-	struct PartialListNode(List<f64>);
+	struct RecordSourceNode<E> {
+		frame_bytes: usize,
+		element: E,
+		fields: Vec<(usize, f64)>,
+		partial: bool,
+	}
 
-	impl<Input> Node<Input> for PartialListNode {
-		type Output = List<f64>;
+	impl<'e, E: Copy> Node<ContextImpl<'e>> for RecordSourceNode<E> {
+		type Output = RecordValue<'e>;
 
-		fn eval(&self, _input: &Input) -> GPoll<List<f64>> {
-			GPoll::Partial(self.0.clone())
+		fn eval(&self, _input: &ContextImpl<'e>) -> GPoll<RecordValue<'e>> {
+			let dst = stack::push(self.frame_bytes);
+			let value = unsafe {
+				dst.cast::<E>().write(self.element);
+				for (offset, value) in &self.fields {
+					dst.add(*offset).cast::<f64>().write(*value);
+				}
+				RecordValue::from_rec(Rec::new(dst))
+			};
+			stack::pop(dst);
+			match self.partial {
+				true => GPoll::Partial(value),
+				false => GPoll::Final(value),
+			}
 		}
 	}
 
@@ -92,12 +134,26 @@ mod tests {
 		EvalScope::new(Some(0.5), None, None, generations, arena)
 	}
 
-	fn elements(list: &List<f64>) -> Vec<f64> {
-		list.iter_element_values().copied().collect()
+	fn f64_layout(names: &[&'static str]) -> Layout {
+		let writes: Vec<(&'static str, u8, usize, usize)> = names.iter().map(|name| (*name, 0, 8, 8)).collect();
+		Layout::default().with_writes(0, (8, 8), &writes)
 	}
 
-	fn column(list: &List<f64>, key: &str) -> Vec<f64> {
-		list.iter_attribute_values::<f64>(key).unwrap().copied().collect()
+	fn frame_bytes(layout: &Layout) -> usize {
+		layout.size.next_multiple_of(8)
+	}
+
+	fn reserve_for(layouts: &[&Layout]) {
+		stack::reserve(layouts.iter().map(|layout| frame_bytes(layout)).sum());
+	}
+
+	fn bare_source(layout: &Layout, element: f64) -> RecordSourceNode<f64> {
+		RecordSourceNode {
+			frame_bytes: frame_bytes(layout),
+			element,
+			fields: vec![],
+			partial: false,
+		}
 	}
 
 	#[test]
@@ -107,15 +163,23 @@ mod tests {
 		let scope = scope_fixture(&generations, &arena);
 		let ctx = ContextImpl::root(&scope);
 
-		let chain = MultiplyOpacityNode::new(
-			MultiplyOpacityNode::new(ValueNode(List::from_element_values(vec![1., 2.])), ValueNode(0.5)),
+		let source_layout = f64_layout(&[]);
+		let modified = multiply_opacity_layout(&source_layout);
+		let stacked = multiply_opacity_layout(&modified);
+		reserve_for(&[&source_layout, &modified, &stacked]);
+
+		let chain = MultiplyOpacityNode::wire(
+			MultiplyOpacityNode::wire(bare_source(&source_layout, 2.), ValueNode(0.5), &source_layout),
 			ValueNode(0.5),
+			&modified,
 		);
-		let GPoll::Final(list) = chain.eval(&ctx) else {
-			panic!("expected a final list");
+		assert_eq!(chain.layout(), Some(&stacked));
+		let GPoll::Final(value) = chain.eval(&ctx) else {
+			panic!("expected a final record");
 		};
-		assert_eq!(elements(&list), vec![1., 2.]);
-		assert_eq!(column(&list, Opacity::NAME), vec![0.25, 0.25]);
+		let rec = value.rec();
+		assert_eq!(unsafe { rec.element::<f64>() }, 2.);
+		assert_eq!(unsafe { rec.read::<f64>(stacked.offset_of(Opacity::NAME, 0).unwrap()) }, 0.25);
 	}
 
 	#[test]
@@ -125,27 +189,38 @@ mod tests {
 		let scope = scope_fixture(&generations, &arena);
 		let ctx = ContextImpl::root(&scope);
 
-		let chain = MeasureNode::new(ValueNode(List::from_element_values(vec![-2., 3.])));
-		let GPoll::Final(list) = chain.eval(&ctx) else {
-			panic!("expected a final list");
+		let source_layout = f64_layout(&[]);
+		let measured = measure_layout(&source_layout);
+		reserve_for(&[&source_layout, &measured]);
+
+		let chain = MeasureNode::wire(bare_source(&source_layout, -2.), &source_layout);
+		let GPoll::Final(value) = chain.eval(&ctx) else {
+			panic!("expected a final record");
 		};
-		assert_eq!(elements(&list), vec![-2., 3.]);
-		assert_eq!(column(&list, Length::NAME), vec![2., 3.]);
+		let rec = value.rec();
+		assert_eq!(unsafe { rec.element::<f64>() }, -2.);
+		assert_eq!(unsafe { rec.read::<f64>(measured.offset_of(Length::NAME, 0).unwrap()) }, 2.);
 	}
 
 	#[test]
-	fn elementwise_write_carries_unrelated_columns() {
+	fn elementwise_write_carries_unrelated_fields() {
 		let arena = Arena::new(1024).unwrap();
 		let generations = [];
 		let scope = scope_fixture(&generations, &arena);
 		let ctx = ContextImpl::root(&scope);
 
-		let chain = MeasureNode::new(MultiplyOpacityNode::new(ValueNode(List::from_element_values(vec![-2., 3.])), ValueNode(0.5)));
-		let GPoll::Final(list) = chain.eval(&ctx) else {
-			panic!("expected a final list");
+		let source_layout = f64_layout(&[]);
+		let modified = multiply_opacity_layout(&source_layout);
+		let measured = measure_layout(&modified);
+		reserve_for(&[&source_layout, &modified, &measured]);
+
+		let chain = MeasureNode::wire(MultiplyOpacityNode::wire(bare_source(&source_layout, -2.), ValueNode(0.5), &source_layout), &modified);
+		let GPoll::Final(value) = chain.eval(&ctx) else {
+			panic!("expected a final record");
 		};
-		assert_eq!(column(&list, Opacity::NAME), vec![0.5, 0.5]);
-		assert_eq!(column(&list, Length::NAME), vec![2., 3.]);
+		let rec = value.rec();
+		assert_eq!(unsafe { rec.read::<f64>(measured.offset_of(Opacity::NAME, 0).unwrap()) }, 0.5);
+		assert_eq!(unsafe { rec.read::<f64>(measured.offset_of(Length::NAME, 0).unwrap()) }, 2.);
 	}
 
 	#[test]
@@ -155,18 +230,83 @@ mod tests {
 		let scope = scope_fixture(&generations, &arena);
 		let ctx = ContextImpl::root(&scope);
 
-		let bare = ShadeNode::new(ValueNode(List::from_element_values(vec![4., 6.])));
-		let GPoll::Final(list) = bare.eval(&ctx) else {
-			panic!("expected a final list");
-		};
-		assert_eq!(elements(&list), vec![4., 6.]);
+		let source_layout = f64_layout(&[]);
+		let modified = multiply_opacity_layout(&source_layout);
+		let shaded = shade_layout(&modified);
+		reserve_for(&[&source_layout, &modified, &shaded]);
 
-		let shaded = ShadeNode::new(MultiplyOpacityNode::new(ValueNode(List::from_element_values(vec![4., 6.])), ValueNode(0.5)));
-		let GPoll::Final(list) = shaded.eval(&ctx) else {
-			panic!("expected a final list");
+		let bare = ShadeNode::wire(bare_source(&source_layout, 4.), &source_layout);
+		let GPoll::Final(value) = bare.eval(&ctx) else {
+			panic!("expected a final record");
 		};
-		assert_eq!(elements(&list), vec![2., 3.]);
-		assert_eq!(column(&list, Opacity::NAME), vec![0.5, 0.5]);
+		assert_eq!(unsafe { value.rec().element::<f64>() }, 4.);
+
+		let chain = ShadeNode::wire(MultiplyOpacityNode::wire(bare_source(&source_layout, 4.), ValueNode(0.5), &source_layout), &modified);
+		let GPoll::Final(value) = chain.eval(&ctx) else {
+			panic!("expected a final record");
+		};
+		let rec = value.rec();
+		assert_eq!(unsafe { rec.element::<f64>() }, 2.);
+		assert_eq!(unsafe { rec.read::<f64>(shaded.offset_of(Opacity::NAME, 0).unwrap()) }, 0.5);
+	}
+
+	#[test]
+	fn token_passthrough_carries_any_element_type() {
+		let arena = Arena::new(1024).unwrap();
+		let generations = [];
+		let scope = scope_fixture(&generations, &arena);
+		let ctx = ContextImpl::root(&scope);
+
+		let f64_source = f64_layout(&[]);
+		let f64_faded = fade_layout(&f64_source);
+		let u32_source = Layout::default().with_writes(0, (4, 4), &[]);
+		let u32_faded = fade_layout(&u32_source);
+		reserve_for(&[&f64_source, &f64_faded, &u32_source, &u32_faded]);
+
+		let wide = FadeNode::wire(bare_source(&f64_source, 8.), ValueNode(0.5), &f64_source);
+		let GPoll::Final(value) = wide.eval(&ctx) else {
+			panic!("expected a final record");
+		};
+		let rec = value.rec();
+		assert_eq!(unsafe { rec.element::<f64>() }, 8.);
+		assert_eq!(unsafe { rec.read::<f64>(f64_faded.offset_of(Opacity::NAME, 0).unwrap()) }, 0.5);
+
+		let narrow = FadeNode::wire(
+			RecordSourceNode {
+				frame_bytes: frame_bytes(&u32_source),
+				element: 7u32,
+				fields: vec![],
+				partial: false,
+			},
+			ValueNode(0.25),
+			&u32_source,
+		);
+		let GPoll::Final(value) = narrow.eval(&ctx) else {
+			panic!("expected a final record");
+		};
+		let rec = value.rec();
+		assert_eq!(unsafe { rec.element::<u32>() }, 7);
+		assert_eq!(unsafe { rec.read::<f64>(u32_faded.offset_of(Opacity::NAME, 0).unwrap()) }, 0.25);
+	}
+
+	#[test]
+	fn no_carrier_form_writes_a_fresh_record() {
+		let arena = Arena::new(1024).unwrap();
+		let generations = [];
+		let scope = scope_fixture(&generations, &arena);
+		let ctx = ContextImpl::root(&scope);
+
+		let layout = source_opacity_layout();
+		reserve_for(&[&layout]);
+
+		let node = SourceOpacityNode::wire(ValueNode(3.), ValueNode(0.25));
+		assert_eq!(Node::<ContextImpl>::layout(&node), Some(&layout));
+		let GPoll::Final(value) = node.eval(&ctx) else {
+			panic!("expected a final record");
+		};
+		let rec = value.rec();
+		assert_eq!(unsafe { rec.element::<f64>() }, 3.);
+		assert_eq!(unsafe { rec.read::<f64>(layout.offset_of(Opacity::NAME, 0).unwrap()) }, 0.25);
 	}
 
 	#[test]
@@ -176,46 +316,48 @@ mod tests {
 		let scope = scope_fixture(&generations, &arena);
 		let ctx = ContextImpl::root(&scope);
 
-		let chain = MultiplyOpacityNode::new(PartialListNode(List::from_element_values(vec![1.])), ValueNode(0.5));
-		let GPoll::Partial(list) = chain.eval(&ctx) else {
-			panic!("expected a partial list");
+		let source_layout = f64_layout(&[]);
+		let modified = multiply_opacity_layout(&source_layout);
+		reserve_for(&[&source_layout, &modified]);
+
+		let chain = MultiplyOpacityNode::wire(
+			RecordSourceNode {
+				frame_bytes: frame_bytes(&source_layout),
+				element: 1.,
+				fields: vec![],
+				partial: true,
+			},
+			ValueNode(0.5),
+			&source_layout,
+		);
+		let GPoll::Partial(value) = chain.eval(&ctx) else {
+			panic!("expected a partial record");
 		};
-		assert_eq!(column(&list, Opacity::NAME), vec![0.5]);
+		assert_eq!(unsafe { value.rec().read::<f64>(modified.offset_of(Opacity::NAME, 0).unwrap()) }, 0.5);
 	}
 
-	use core_types::context::ExtractFrame;
-	use core_types::record::{Frame, FrameLayout, Layout, Rec, RecordSource, RecordValue};
+	#[test]
+	fn interrupt_kernel_errors_stop_the_eval() {
+		let arena = Arena::new(1024).unwrap();
+		let generations = [];
+		let scope = scope_fixture(&generations, &arena);
+		let ctx = ContextImpl::root(&scope);
 
-	struct RecordSourceNode {
-		slot: usize,
-		element: f64,
-		fields: Vec<(usize, f64)>,
-		partial: bool,
-	}
+		let source_layout = f64_layout(&[]);
+		let modified = checked_multiply_opacity_layout(&source_layout);
+		reserve_for(&[&source_layout, &modified]);
 
-	impl<'e> Node<ContextImpl<'e>> for RecordSourceNode {
-		type Output = RecordValue<'e>;
+		let ok = CheckedMultiplyOpacityNode::wire(bare_source(&source_layout, 1.), ValueNode(0.5), &source_layout);
+		let GPoll::Final(value) = ok.eval(&ctx) else {
+			panic!("expected a final record");
+		};
+		assert_eq!(unsafe { value.rec().read::<f64>(modified.offset_of(Opacity::NAME, 0).unwrap()) }, 0.5);
 
-		fn eval(&self, input: &ContextImpl<'e>) -> GPoll<RecordValue<'e>> {
-			let frame = ExtractFrame::frame(input).unwrap();
-			let value = unsafe {
-				let dst = frame.slot(self.slot);
-				dst.cast::<f64>().write(self.element);
-				for (offset, value) in &self.fields {
-					dst.add(*offset).cast::<f64>().write(*value);
-				}
-				RecordValue::from_rec(Rec::new(dst))
-			};
-			match self.partial {
-				true => GPoll::Partial(value),
-				false => GPoll::Final(value),
-			}
-		}
-	}
-
-	fn f64_layout(names: &[&'static str]) -> Layout {
-		let writes: Vec<(&'static str, u8, usize, usize)> = names.iter().map(|name| (*name, 0, 8, 8)).collect();
-		Layout::default().with_writes(0, (8, 8), &writes)
+		let failing = CheckedMultiplyOpacityNode::wire(bare_source(&source_layout, 1.), ValueNode(-1.), &source_layout);
+		let GPoll::Error(error) = failing.eval(&ctx) else {
+			panic!("expected an error");
+		};
+		assert!(error.kind == "negative factor");
 	}
 
 	static FACTOR: f64 = 3.;
@@ -237,61 +379,88 @@ mod tests {
 		let scope = scope_fixture(&generations, &arena);
 		let ctx = ContextImpl::root(&scope);
 
-		let chain = ScaleNode::new(
-			MultiplyOpacityNode::new(ValueNode(List::from_element_values(vec![1., 2.])), ValueNode(0.5)),
+		let source_layout = f64_layout(&[]);
+		let modified = multiply_opacity_layout(&source_layout);
+		let scaled = scale_layout(&modified);
+		reserve_for(&[&source_layout, &modified, &scaled]);
+
+		let chain = ScaleNode::wire(
+			MultiplyOpacityNode::wire(bare_source(&source_layout, 2.), ValueNode(0.5), &source_layout),
 			StaticLendNode(&FACTOR),
+			&modified,
 		);
-		let GPoll::Final(list) = chain.eval(&ctx) else {
-			panic!("expected a final list");
+		let GPoll::Final(value) = chain.eval(&ctx) else {
+			panic!("expected a final record");
 		};
-		assert_eq!(elements(&list), vec![3., 6.]);
-		assert_eq!(column(&list, Opacity::NAME), vec![0.5, 0.5]);
+		let rec = value.rec();
+		assert_eq!(unsafe { rec.element::<f64>() }, 6.);
+		assert_eq!(unsafe { rec.read::<f64>(scaled.offset_of(Opacity::NAME, 0).unwrap()) }, 0.5);
+	}
+
+	#[test]
+	fn parked_reference_attributes_write_and_carry() {
+		let arena = Arena::new(1024).unwrap();
+		let generations = [];
+		let scope = scope_fixture(&generations, &arena);
+		let ctx = ContextImpl::root(&scope);
+
+		let source_layout = f64_layout(&[]);
+		let labeled = label_layout(&source_layout);
+		let relabeled = label_layout(&labeled);
+		reserve_for(&[&source_layout, &labeled, &relabeled]);
+
+		let chain = LabelNode::wire(
+			LabelNode::wire(bare_source(&source_layout, 1.), ValueNode(String::from("a")), &source_layout),
+			ValueNode(String::from("b")),
+			&labeled,
+		);
+		let GPoll::Final(value) = chain.eval(&ctx) else {
+			panic!("expected a final record");
+		};
+		let rec = value.rec();
+		assert_eq!(unsafe { rec.element::<f64>() }, 1.);
+		assert_eq!(unsafe { rec.read::<&str>(relabeled.offset_of(Label::NAME, 0).unwrap()) }, "ab");
+	}
+
+	#[test]
+	fn census_fills_reference_defaults_from_static_data() {
+		let source = f64_layout(&[]);
+		let labeled = Layout::default().with_writes(0, (8, 8), &[(Label::NAME, 0, 16, 8)]);
+
+		let plan = core_types::record::SourcePlan::new(&source, &labeled).unwrap();
+		let record = [5f64];
+		let mut buffer = vec![0u64; labeled.size.div_ceil(8)];
+		let translated = unsafe { plan.translate(Rec::new(record.as_ptr().cast()), buffer.as_mut_ptr().cast()) };
+		assert_eq!(unsafe { translated.element::<f64>() }, 5.);
+		assert_eq!(unsafe { translated.read::<&str>(labeled.offset_of(Label::NAME, 0).unwrap()) }, "");
+	}
+
+	fn f64_record_source(layout: &Layout, element: f64, fields: Vec<(usize, f64)>) -> RecordSourceNode<f64> {
+		RecordSourceNode {
+			frame_bytes: frame_bytes(layout),
+			element,
+			fields,
+			partial: false,
+		}
 	}
 
 	#[test]
 	fn routing_unions_branch_layouts_and_fills_census_defaults() {
 		let arena = Arena::new(1024).unwrap();
 		let generations = [];
+		let scope = scope_fixture(&generations, &arena);
+		let ctx = ContextImpl::root(&scope);
 
 		let layout_a = f64_layout(&["opacity"]);
 		let layout_b = f64_layout(&["length"]);
 		let union = Layout::union(&[&layout_a, &layout_b]);
-
-		let mut frame_layout = FrameLayout::default();
-		let slot_a = frame_layout.slot(&layout_a);
-		let slot_b = frame_layout.slot(&layout_b);
-		let translate_a = frame_layout.slot(&union);
-		let translate_b = frame_layout.slot(&union);
-		let frame = Frame::new(frame_layout.size());
-
-		let scope = scope_fixture(&generations, &arena).with_frame(&frame);
-		let ctx = ContextImpl::root(&scope);
+		reserve_for(&[&layout_a, &layout_b, &union, &union]);
 
 		let taken = |second: bool| {
 			PickNode::new(
 				ValueNode(second),
-				RecordSource::wire(
-					RecordSourceNode {
-						slot: slot_a,
-						element: 1.,
-						fields: vec![(layout_a.offset_of("opacity", 0).unwrap(), 0.5)],
-						partial: false,
-					},
-					&layout_a,
-					&union,
-					translate_a,
-				),
-				RecordSource::wire(
-					RecordSourceNode {
-						slot: slot_b,
-						element: 3.,
-						fields: vec![(layout_b.offset_of("length", 0).unwrap(), 3.)],
-						partial: false,
-					},
-					&layout_b,
-					&union,
-					translate_b,
-				),
+				RecordSource::wire(f64_record_source(&layout_a, 1., vec![(layout_a.offset_of("opacity", 0).unwrap(), 0.5)]), &layout_a, &union),
+				RecordSource::wire(f64_record_source(&layout_b, 3., vec![(layout_b.offset_of("length", 0).unwrap(), 3.)]), &layout_b, &union),
 			)
 		};
 
@@ -316,45 +485,18 @@ mod tests {
 	fn routing_provenance_survives_later_evaluations() {
 		let arena = Arena::new(1024).unwrap();
 		let generations = [];
+		let scope = scope_fixture(&generations, &arena);
+		let ctx = ContextImpl::root(&scope);
 
 		let layout_a = f64_layout(&["opacity"]);
 		let layout_b = f64_layout(&["length"]);
 		let union = Layout::union(&[&layout_a, &layout_b]);
-
-		let mut frame_layout = FrameLayout::default();
-		let slot_a = frame_layout.slot(&layout_a);
-		let slot_b = frame_layout.slot(&layout_b);
-		let translate_a = frame_layout.slot(&union);
-		let translate_b = frame_layout.slot(&union);
-		let frame = Frame::new(frame_layout.size());
-
-		let scope = scope_fixture(&generations, &arena).with_frame(&frame);
-		let ctx = ContextImpl::root(&scope);
+		reserve_for(&[&layout_a, &layout_b, &union, &union]);
 
 		let chain = HoldFirstNode::new(
 			ValueNode(false),
-			RecordSource::wire(
-				RecordSourceNode {
-					slot: slot_a,
-					element: 1.,
-					fields: vec![(layout_a.offset_of("opacity", 0).unwrap(), 0.5)],
-					partial: false,
-				},
-				&layout_a,
-				&union,
-				translate_a,
-			),
-			RecordSource::wire(
-				RecordSourceNode {
-					slot: slot_b,
-					element: 3.,
-					fields: vec![(layout_b.offset_of("length", 0).unwrap(), 3.)],
-					partial: false,
-				},
-				&layout_b,
-				&union,
-				translate_b,
-			),
+			RecordSource::wire(f64_record_source(&layout_a, 1., vec![(layout_a.offset_of("opacity", 0).unwrap(), 0.5)]), &layout_a, &union),
+			RecordSource::wire(f64_record_source(&layout_b, 3., vec![(layout_b.offset_of("length", 0).unwrap(), 3.)]), &layout_b, &union),
 		);
 
 		let GPoll::Final(value) = chain.eval(&ctx) else {
@@ -370,32 +512,25 @@ mod tests {
 	fn identity_layouts_forward_the_record_pointer() {
 		let arena = Arena::new(1024).unwrap();
 		let generations = [];
-
-		let layout = f64_layout(&["opacity"]);
-		let mut frame_layout = FrameLayout::default();
-		let slot = frame_layout.slot(&layout);
-		let frame = Frame::new(frame_layout.size());
-
-		let scope = scope_fixture(&generations, &arena).with_frame(&frame);
+		let scope = scope_fixture(&generations, &arena);
 		let ctx = ContextImpl::root(&scope);
 
+		let layout = f64_layout(&["opacity"]);
+		reserve_for(&[&layout]);
+		let base = stack::push(0);
+		stack::pop(base);
+
 		let chain = ForwardRecordNode::new(RecordSource::wire(
-			RecordSourceNode {
-				slot,
-				element: 4.,
-				fields: vec![(layout.offset_of("opacity", 0).unwrap(), 0.25)],
-				partial: false,
-			},
+			f64_record_source(&layout, 4., vec![(layout.offset_of("opacity", 0).unwrap(), 0.25)]),
 			&layout,
 			&layout.clone(),
-			0,
 		));
 
 		let GPoll::Final(value) = chain.eval(&ctx) else {
 			panic!("expected a final record");
 		};
 		let rec = value.rec();
-		assert_eq!(rec.ptr(), unsafe { frame.slot(slot) }.cast_const());
+		assert_eq!(rec.ptr(), base.cast_const());
 		assert_eq!(unsafe { rec.element::<f64>() }, 4.);
 		assert_eq!(unsafe { rec.read::<f64>(layout.offset_of("opacity", 0).unwrap()) }, 0.25);
 	}
@@ -404,25 +539,21 @@ mod tests {
 	fn partial_routing_sources_downgrade_the_output() {
 		let arena = Arena::new(1024).unwrap();
 		let generations = [];
+		let scope = scope_fixture(&generations, &arena);
+		let ctx = ContextImpl::root(&scope);
 
 		let layout = f64_layout(&["opacity"]);
-		let mut frame_layout = FrameLayout::default();
-		let slot = frame_layout.slot(&layout);
-		let frame = Frame::new(frame_layout.size());
-
-		let scope = scope_fixture(&generations, &arena).with_frame(&frame);
-		let ctx = ContextImpl::root(&scope);
+		reserve_for(&[&layout]);
 
 		let chain = ForwardRecordNode::new(RecordSource::wire(
 			RecordSourceNode {
-				slot,
+				frame_bytes: frame_bytes(&layout),
 				element: 4.,
 				fields: vec![],
 				partial: true,
 			},
 			&layout,
 			&layout.clone(),
-			0,
 		));
 
 		let GPoll::Partial(value) = chain.eval(&ctx) else {
@@ -430,24 +561,4 @@ mod tests {
 		};
 		assert_eq!(unsafe { value.rec().element::<f64>() }, 4.);
 	}
-
-	#[test]
-	fn interrupt_kernel_errors_stop_the_eval() {
-		let arena = Arena::new(1024).unwrap();
-		let generations = [];
-		let scope = scope_fixture(&generations, &arena);
-		let ctx = ContextImpl::root(&scope);
-
-		let ok = CheckedMultiplyOpacityNode::new(ValueNode(List::from_element_values(vec![1.])), ValueNode(0.5));
-		let GPoll::Final(list) = ok.eval(&ctx) else {
-			panic!("expected a final list");
-		};
-		assert_eq!(column(&list, Opacity::NAME), vec![0.5]);
-
-		let failing = CheckedMultiplyOpacityNode::new(ValueNode(List::from_element_values(vec![1.])), ValueNode(-1.));
-		let GPoll::Error(error) = failing.eval(&ctx) else {
-			panic!("expected an error");
-		};
-		assert!(error.kind == "negative factor");
-	}
 }