Strip IList nesting from kernel returns at parse time

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

@@ -734,7 +734,7 @@ pub(crate) fn generate_node_impl(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 	let subject_depth = node.inputs.iter().find(|input| input.subject).map_or(0, |input| input.shape.depth);
 	let level_delta = node.output.shape.depth as i8 - subject_depth as i8;
 	let pushed_levels = level_delta.max(0) as u8;
-	let output_row = crate::codegen::ir::strip_ilist(&slot_value_type(&parsed.output_type)).0;
+	let output_row = slot_value_type(&parsed.output_type);
 	let snapshot_ctx = async_fn && matches!(&parsed.input.ty, Type::Path(path) if path.path.segments.last().is_some_and(|segment| segment.ident == "CtxSnapshot"));
 
 	let mut ctx_bounds: Vec<TokenStream2> = match ctx_param {
@@ -1270,7 +1270,7 @@ pub(crate) fn generate_node_impl(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 	// 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_io.then(|| inject_attr_lifetimes(&crate::codegen::ir::strip_ilist(&parsed.output_type).0)).flatten();
+	let kernel_output = record_io.then(|| inject_attr_lifetimes(&parsed.output_type)).flatten();
 	let attr_lifetime = kernel_output.is_some().then(|| quote!('__attr,));
 	let kernel_output = match derive_routing {
 		true => {

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

@@ -82,8 +82,8 @@ fn subject(index: usize, field: &ParsedField, carrier_subject: bool, routing: Op
 }
 
 fn output(parsed: &ParsedNodeFn, generics: &[Ident]) -> Output {
-	// Strip the `IList` rank markers first so the write set is read from the row.
-	let (row, depth) = strip_ilist(&slot_value_type(&parsed.output_type));
+	let row = slot_value_type(&parsed.output_type);
+	let depth = parsed.output_depth;
 	let (element, writes, removes) = match record_writes(&row) {
 		Some(RecordWrites { element, markers, removes }) => (element, markers, removes),
 		None => (row, Vec::new(), Vec::new()),
@@ -167,6 +167,36 @@ pub(crate) fn strip_ilist(ty: &Type) -> (Type, u8) {
 	(element, depth)
 }
 
+/// Strips `IList` rank nesting from the output's value position, preserving the
+/// dialect wrapper (`Result`/`GPoll`), and returns the removed depth.
+pub(crate) fn strip_output_rank(output: &Type) -> (Type, u8) {
+	use crate::codegen::classify::{KernelKind, kernel_kind};
+	match kernel_kind(output) {
+		KernelKind::Plain => strip_ilist(output),
+		KernelKind::Interrupt(inner) | KernelKind::Poll(inner) => {
+			let (row, depth) = strip_ilist(&inner);
+			(replace_first_type_arg(output, row), depth)
+		}
+		KernelKind::Future(_) | KernelKind::FutureInterrupt(_) => (output.clone(), 0),
+	}
+}
+
+fn replace_first_type_arg(ty: &Type, replacement: Type) -> Type {
+	let mut ty = ty.clone();
+	if let Type::Path(path) = &mut ty
+		&& let Some(segment) = path.path.segments.last_mut()
+		&& let PathArguments::AngleBracketed(args) = &mut segment.arguments
+	{
+		for arg in args.args.iter_mut() {
+			if let GenericArgument::Type(inner) = arg {
+				*inner = replacement;
+				break;
+			}
+		}
+	}
+	ty
+}
+
 fn ilist_inner(ty: &Type) -> Option<Type> {
 	let Type::Path(path) = ty else { return None };
 	let segment = path.path.segments.last()?;

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

@@ -33,6 +33,7 @@ pub(crate) struct ParsedNodeFn {
 	pub(crate) where_clause: Option<WhereClause>,
 	pub(crate) input: Input,
 	pub(crate) output_type: Type,
+	pub(crate) output_depth: u8,
 	pub(crate) is_async: bool,
 	pub(crate) fields: Vec<ParsedField>,
 	pub(crate) body: TokenStream2,
@@ -662,7 +663,7 @@ pub(crate) fn parse_node_fn(attr: TokenStream2, item: TokenStream2) -> syn::Resu
 	let is_async = input_fn.sig.asyncness.is_some();
 
 	let (input, fields) = parse_inputs(&input_fn.sig.inputs)?;
-	let output_type = parse_output(&input_fn.sig.output)?;
+	let (output_type, output_depth) = crate::codegen::ir::strip_output_rank(&parse_output(&input_fn.sig.output)?);
 	let where_clause = input_fn.sig.generics.where_clause;
 	let body = input_fn.block.to_token_stream();
 	let description = input_fn
@@ -691,6 +692,7 @@ pub(crate) fn parse_node_fn(attr: TokenStream2, item: TokenStream2) -> syn::Resu
 		fn_generics,
 		input,
 		output_type,
+		output_depth,
 		is_async,
 		fields,
 		where_clause,
@@ -1407,6 +1409,7 @@ mod tests {
 				context_features: vec![],
 			},
 			output_type: parse_quote!(f64),
+			output_depth: 0,
 			is_async: false,
 			fields: vec![ParsedField {
 				pat_ident: pat_ident("b"),
@@ -1485,6 +1488,7 @@ mod tests {
 				context_features: vec![],
 			},
 			output_type: parse_quote!(T),
+			output_depth: 0,
 			is_async: false,
 			fields: vec![
 				ParsedField {
@@ -1578,6 +1582,7 @@ mod tests {
 				context_features: vec![format_ident!("ExtractFootprint")],
 			},
 			output_type: parse_quote!(Vector),
+			output_depth: 0,
 			is_async: false,
 			fields: vec![ParsedField {
 				pat_ident: pat_ident("radius"),
@@ -1652,6 +1657,7 @@ mod tests {
 				context_features: vec![],
 			},
 			output_type: parse_quote!(List<Raster<P>>),
+			output_depth: 0,
 			is_async: false,
 			fields: vec![ParsedField {
 				pat_ident: pat_ident("shadows"),
@@ -1738,6 +1744,7 @@ mod tests {
 				context_features: vec![],
 			},
 			output_type: parse_quote!(f64),
+			output_depth: 0,
 			is_async: false,
 			fields: vec![ParsedField {
 				pat_ident: pat_ident("b"),
@@ -1827,6 +1834,7 @@ mod tests {
 				context_features: vec![],
 			},
 			output_type: parse_quote!(List<Raster<CPU>>),
+			output_depth: 0,
 			is_async: true,
 			fields: vec![ParsedField {
 				pat_ident: pat_ident("path"),
@@ -1901,6 +1909,7 @@ mod tests {
 				context_features: vec![],
 			},
 			output_type: parse_quote!(i32),
+			output_depth: 0,
 			is_async: false,
 			fields: vec![],
 			body: TokenStream2::new(),

node-graph/node-macro/src/shader_nodes/per_pixel_adjust.rs

@@ -317,6 +317,7 @@ impl PerPixelAdjustCodegen<'_> {
 				context_features: self.parsed.input.context_features.clone(),
 			},
 			output_type: raster_gpu,
+			output_depth: 0,
 			is_async: false,
 			fields,
 			body,