From 5c09035685d0edd4c21453cd4b2f10fe984f913a Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Fri, 19 Sep 2025 19:36:31 -0400
Subject: [PATCH] fix: async hydration (#16797)

* WIP fix async hydration

* add renderer.async method

* update tests

* changeset

* oops

* WIP fix async attributes

* fix

* fix

* all tests passing

* unused

* unused

* remove_nodes -> skip_nodes

* hydration boundaries around slots

* reorder arguments

* add select method

* WIP simplify selects

* WIP

* simplify

* renderer.title

* delete unused compact method

* simplify

* simplify

* simplify

* simplify

* fix TODO

* remove outdated TODO

* remove outdated TODO

* rename call_child_renderer -> create_child_block

* burrito

* add a couple of unit tests
---
 .changeset/six-rabbits-pull.md                |   5 +
 .../client/visitors/shared/component.js       |   2 +-
 .../3-transform/server/transform-server.js    |   8 +-
 .../3-transform/server/visitors/AwaitBlock.js |   4 +-
 .../3-transform/server/visitors/EachBlock.js  |   4 +-
 .../3-transform/server/visitors/IfBlock.js    |   4 +-
 .../server/visitors/RegularElement.js         | 221 +++++++++---------
 .../server/visitors/SlotElement.js            |  13 +-
 .../server/visitors/SvelteBoundary.js         |   8 +-
 .../server/visitors/SvelteElement.js          |  31 ++-
 .../server/visitors/TitleElement.js           |   4 +-
 .../server/visitors/shared/component.js       |  17 +-
 .../server/visitors/shared/element.js         | 136 +++++------
 .../server/visitors/shared/utils.js           |  17 +-
 .../src/internal/client/dom/blocks/async.js   |  27 +++
 .../src/internal/client/dom/blocks/await.js   |   4 +-
 .../internal/client/dom/blocks/boundary.js    |   4 +-
 .../src/internal/client/dom/blocks/each.js    |   6 +-
 .../src/internal/client/dom/blocks/if.js      |   4 +-
 .../src/internal/client/dom/hydration.js      |   7 +-
 packages/svelte/src/internal/server/index.js  | 122 +---------
 .../svelte/src/internal/server/renderer.js    | 206 +++++++++-------
 .../src/internal/server/renderer.test.ts      |  99 +++-----
 .../if-block-mismatch-2/_expected.html        |   2 +-
 .../async-no-pending-attributes/Child.svelte  |   5 +
 .../async-no-pending-attributes/_config.js    |  24 ++
 .../async-no-pending-attributes/main.svelte   |  12 +
 .../_config.js                                |  33 +++
 .../main.svelte                               |  10 +
 .../_expected/server/index.svelte.js          |   2 +-
 .../_expected/server/index.svelte.js          |   2 +-
 .../_expected/server/index.svelte.js          |   2 +-
 .../_expected/server/index.svelte.js          |   2 +-
 .../_expected/server/index.svelte.js          |   8 +-
 34 files changed, 546 insertions(+), 509 deletions(-)
 create mode 100644 .changeset/six-rabbits-pull.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-no-pending-attributes/Child.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-no-pending-attributes/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-no-pending-attributes/main.svelte
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-no-pending-await-in-block/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/async-no-pending-await-in-block/main.svelte

diff --git a/.changeset/six-rabbits-pull.md b/.changeset/six-rabbits-pull.md
new file mode 100644
index 0000000000..55fc8c89b8
--- /dev/null
+++ b/.changeset/six-rabbits-pull.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: async hydration
diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/component.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/component.js
index 7feeebdbbc..5c8ce897f4 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/component.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/component.js
@@ -130,7 +130,7 @@ export function build_component(node, component_name, context) {
 		} else if (attribute.type === 'SpreadAttribute') {
 			const expression = /** @type {Expression} */ (context.visit(attribute));
 
-			if (attribute.metadata.expression.has_state) {
+			if (attribute.metadata.expression.has_state || attribute.metadata.expression.has_await) {
 				props_and_spreads.push(
 					b.thunk(
 						attribute.metadata.expression.has_await || attribute.metadata.expression.has_call
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/transform-server.js b/packages/svelte/src/compiler/phases/3-transform/server/transform-server.js
index 994db533c2..90845fb303 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/transform-server.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/transform-server.js
@@ -40,7 +40,11 @@ import { TitleElement } from './visitors/TitleElement.js';
 import { UpdateExpression } from './visitors/UpdateExpression.js';
 import { VariableDeclaration } from './visitors/VariableDeclaration.js';
 import { SvelteBoundary } from './visitors/SvelteBoundary.js';
-import { call_child_renderer, call_component_renderer } from './visitors/shared/utils.js';
+import {
+	create_child_block,
+	call_component_renderer,
+	create_async_block
+} from './visitors/shared/utils.js';
 
 /** @type {Visitors} */
 const global_visitors = {
@@ -244,7 +248,7 @@ export function server_component(analysis, options) {
 	]);
 
 	if (analysis.instance.has_await) {
-		component_block = b.block([call_child_renderer(component_block, true)]);
+		component_block = b.block([create_child_block(component_block, true)]);
 	}
 
 	// trick esrap into including comments
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/AwaitBlock.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/AwaitBlock.js
index e88f117c5c..132a83ec60 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/AwaitBlock.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/AwaitBlock.js
@@ -2,7 +2,7 @@
 /** @import { AST } from '#compiler' */
 /** @import { ComponentContext } from '../types.js' */
 import * as b from '#compiler/builders';
-import { block_close, call_child_renderer } from './shared/utils.js';
+import { block_close, create_async_block } from './shared/utils.js';
 
 /**
  * @param {AST.AwaitBlock} node
@@ -26,7 +26,7 @@ export function AwaitBlock(node, context) {
 	);
 
 	if (node.metadata.expression.has_await) {
-		statement = call_child_renderer(b.block([statement]), true);
+		statement = create_async_block(b.block([statement]));
 	}
 
 	context.state.template.push(statement, block_close);
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/EachBlock.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/EachBlock.js
index a8821c4ee7..5a7ca8b566 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/EachBlock.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/EachBlock.js
@@ -2,7 +2,7 @@
 /** @import { AST } from '#compiler' */
 /** @import { ComponentContext } from '../types.js' */
 import * as b from '#compiler/builders';
-import { block_close, block_open, block_open_else, call_child_renderer } from './shared/utils.js';
+import { block_close, block_open, block_open_else, create_async_block } from './shared/utils.js';
 
 /**
  * @param {AST.EachBlock} node
@@ -64,7 +64,7 @@ export function EachBlock(node, context) {
 	}
 
 	if (node.metadata.expression.has_await) {
-		state.template.push(call_child_renderer(block, true), block_close);
+		state.template.push(create_async_block(block), block_close);
 	} else {
 		state.template.push(...block.body, block_close);
 	}
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/IfBlock.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/IfBlock.js
index 426e468927..798cb02e49 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/IfBlock.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/IfBlock.js
@@ -2,7 +2,7 @@
 /** @import { AST } from '#compiler' */
 /** @import { ComponentContext } from '../types.js' */
 import * as b from '#compiler/builders';
-import { block_close, block_open, block_open_else, call_child_renderer } from './shared/utils.js';
+import { block_close, block_open, block_open_else, create_async_block } from './shared/utils.js';
 
 /**
  * @param {AST.IfBlock} node
@@ -24,7 +24,7 @@ export function IfBlock(node, context) {
 	let statement = b.if(test, consequent, alternate);
 
 	if (node.metadata.expression.has_await) {
-		statement = call_child_renderer(b.block([statement]), true);
+		statement = create_async_block(b.block([statement]));
 	}
 
 	context.state.template.push(statement, block_close);
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/RegularElement.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/RegularElement.js
index 60ec158b53..14f48d1ce7 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/RegularElement.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/RegularElement.js
@@ -1,4 +1,4 @@
-/** @import { Expression, Statement } from 'estree' */
+/** @import { Expression } from 'estree' */
 /** @import { Location } from 'locate-character' */
 /** @import { AST } from '#compiler' */
 /** @import { ComponentContext, ComponentServerTransformState } from '../types.js' */
@@ -12,7 +12,8 @@ import {
 	process_children,
 	build_template,
 	build_attribute_value,
-	call_child_renderer
+	create_child_block,
+	PromiseOptimiser
 } from './shared/utils.js';
 
 /**
@@ -27,21 +28,38 @@ export function RegularElement(node, context) {
 		...context.state,
 		namespace,
 		preserve_whitespace:
-			context.state.preserve_whitespace || node.name === 'pre' || node.name === 'textarea'
+			context.state.preserve_whitespace || node.name === 'pre' || node.name === 'textarea',
+		init: [],
+		template: []
 	};
 
 	const node_is_void = is_void(node.name);
 
-	context.state.template.push(b.literal(`<${node.name}`));
-	const body = build_element_attributes(node, { ...context, state });
-	context.state.template.push(b.literal(node_is_void ? '/>' : '>')); // add `/>` for XHTML compliance
+	const optimiser = new PromiseOptimiser();
+
+	state.template.push(b.literal(`<${node.name}`));
+	const body = build_element_attributes(node, { ...context, state }, optimiser.transform);
+	state.template.push(b.literal(node_is_void ? '/>' : '>')); // add `/>` for XHTML compliance
 
 	if ((node.name === 'script' || node.name === 'style') && node.fragment.nodes.length === 1) {
-		context.state.template.push(
+		state.template.push(
 			b.literal(/** @type {AST.Text} */ (node.fragment.nodes[0]).data),
 			b.literal(`</${node.name}>`)
 		);
 
+		// TODO this is a real edge case, would be good to DRY this out
+		if (optimiser.expressions.length > 0) {
+			context.state.template.push(
+				create_child_block(
+					b.block([optimiser.apply(), ...state.init, ...build_template(state.template)]),
+					true
+				)
+			);
+		} else {
+			context.state.init.push(...state.init);
+			context.state.template.push(...state.template);
+		}
+
 		return;
 	}
 
@@ -77,114 +95,92 @@ export function RegularElement(node, context) {
 		);
 	}
 
-	let select_with_value = false;
-	let select_with_value_async = false;
-	const template_start = state.template.length;
-
-	if (node.name === 'select') {
-		const value = node.attributes.find(
+	if (
+		node.name === 'select' &&
+		node.attributes.some(
 			(attribute) =>
-				(attribute.type === 'Attribute' || attribute.type === 'BindDirective') &&
-				attribute.name === 'value'
+				((attribute.type === 'Attribute' || attribute.type === 'BindDirective') &&
+					attribute.name === 'value') ||
+				attribute.type === 'SpreadAttribute'
+		)
+	) {
+		const attributes = build_spread_object(
+			node,
+			node.attributes.filter(
+				(attribute) =>
+					attribute.type === 'Attribute' ||
+					attribute.type === 'BindDirective' ||
+					attribute.type === 'SpreadAttribute'
+			),
+			context,
+			optimiser.transform
 		);
 
-		const spread = node.attributes.find((attribute) => attribute.type === 'SpreadAttribute');
-		if (spread) {
-			select_with_value = true;
-			select_with_value_async ||= spread.metadata.expression.has_await;
-
-			state.template.push(
-				b.stmt(
-					b.assignment(
-						'=',
-						b.id('$$renderer.local.select_value'),
-						b.member(
-							build_spread_object(
-								node,
-								node.attributes.filter(
-									(attribute) =>
-										attribute.type === 'Attribute' ||
-										attribute.type === 'BindDirective' ||
-										attribute.type === 'SpreadAttribute'
-								),
-								context
-							),
-							'value',
-							false,
-							true
-						)
-					)
-				)
+		const inner_state = { ...state, template: [], init: [] };
+		process_children(trimmed, { ...context, state: inner_state });
+
+		const fn = b.arrow(
+			[b.id('$$renderer')],
+			b.block([...state.init, ...build_template(inner_state.template)])
+		);
+
+		const statement = b.stmt(b.call('$$renderer.select', attributes, fn));
+
+		if (optimiser.expressions.length > 0) {
+			context.state.template.push(
+				create_child_block(b.block([optimiser.apply(), ...state.init, statement]), true)
 			);
-		} else if (value) {
-			select_with_value = true;
-
-			if (value.type === 'Attribute' && value.value !== true) {
-				select_with_value_async ||= (Array.isArray(value.value) ? value.value : [value.value]).some(
-					(tag) => tag.type === 'ExpressionTag' && tag.metadata.expression.has_await
-				);
-			}
-
-			const left = b.id('$$renderer.local.select_value');
-			if (value.type === 'Attribute') {
-				state.template.push(
-					b.stmt(b.assignment('=', left, build_attribute_value(value.value, context)))
-				);
-			} else if (value.type === 'BindDirective') {
-				state.template.push(
-					b.stmt(
-						b.assignment(
-							'=',
-							left,
-							value.expression.type === 'SequenceExpression'
-								? /** @type {Expression} */ (context.visit(b.call(value.expression.expressions[0])))
-								: /** @type {Expression} */ (context.visit(value.expression))
-						)
-					)
-				);
-			}
+		} else {
+			context.state.template.push(...state.init, statement);
 		}
+
+		return;
 	}
 
-	if (
-		node.name === 'option' &&
-		!node.attributes.some(
-			(attribute) =>
-				attribute.type === 'SpreadAttribute' ||
-				((attribute.type === 'Attribute' || attribute.type === 'BindDirective') &&
-					attribute.name === 'value')
-		)
-	) {
+	if (node.name === 'option') {
+		const attributes = build_spread_object(
+			node,
+			node.attributes.filter(
+				(attribute) =>
+					attribute.type === 'Attribute' ||
+					attribute.type === 'BindDirective' ||
+					attribute.type === 'SpreadAttribute'
+			),
+			context,
+			optimiser.transform
+		);
+
+		let body;
+
 		if (node.metadata.synthetic_value_node) {
-			state.template.push(
-				b.stmt(
-					b.call(
-						'$.simple_valueless_option',
-						b.id('$$renderer'),
-						b.thunk(
-							node.metadata.synthetic_value_node.expression,
-							node.metadata.synthetic_value_node.metadata.expression.has_await
-						)
-					)
-				)
+			body = optimiser.transform(
+				node.metadata.synthetic_value_node.expression,
+				node.metadata.synthetic_value_node.metadata.expression
 			);
 		} else {
 			const inner_state = { ...state, template: [], init: [] };
 			process_children(trimmed, { ...context, state: inner_state });
-			state.template.push(
-				b.stmt(
-					b.call(
-						'$.valueless_option',
-						b.id('$$renderer'),
-						b.arrow(
-							[b.id('$$renderer')],
-							b.block([...inner_state.init, ...build_template(inner_state.template)])
-						)
-					)
-				)
+
+			body = b.arrow(
+				[b.id('$$renderer')],
+				b.block([...state.init, ...build_template(inner_state.template)])
 			);
 		}
-	} else if (body !== null) {
+
+		const statement = b.stmt(b.call('$$renderer.option', attributes, body));
+
+		if (optimiser.expressions.length > 0) {
+			context.state.template.push(
+				create_child_block(b.block([optimiser.apply(), ...state.init, statement]), true)
+			);
+		} else {
+			context.state.template.push(...state.init, statement);
+		}
+
+		return;
+	}
+
+	if (body !== null) {
 		// if this is a `<textarea>` value or a contenteditable binding, we only add
 		// the body if the attribute/binding is falsy
 		const inner_state = { ...state, template: [], init: [] };
@@ -209,17 +205,6 @@ export function RegularElement(node, context) {
 		process_children(trimmed, { ...context, state });
 	}
 
-	if (select_with_value) {
-		// we need to create a child scope so that the `select_value` only applies children of this select element
-		// in an async world, we could technically have two adjacent select elements with async children, in which case
-		// the second element's select_value would override the first element's select_value if the children of the first
-		// element hadn't resolved prior to hitting the second element.
-		const elements = state.template.splice(template_start, Infinity);
-		state.template.push(
-			call_child_renderer(b.block(build_template(elements)), select_with_value_async)
-		);
-	}
-
 	if (!node_is_void) {
 		state.template.push(b.literal(`</${node.name}>`));
 	}
@@ -227,4 +212,16 @@ export function RegularElement(node, context) {
 	if (dev) {
 		state.template.push(b.stmt(b.call('$.pop_element')));
 	}
+
+	if (optimiser.expressions.length > 0) {
+		context.state.template.push(
+			create_child_block(
+				b.block([optimiser.apply(), ...state.init, ...build_template(state.template)]),
+				true
+			)
+		);
+	} else {
+		context.state.init.push(...state.init);
+		context.state.template.push(...state.template);
+	}
 }
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/SlotElement.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/SlotElement.js
index 029a0f0a42..5841aa44d8 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/SlotElement.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/SlotElement.js
@@ -3,10 +3,11 @@
 /** @import { ComponentContext } from '../types.js' */
 import * as b from '#compiler/builders';
 import {
-	empty_comment,
 	build_attribute_value,
 	PromiseOptimiser,
-	call_child_renderer
+	create_async_block,
+	block_open,
+	block_close
 } from './shared/utils.js';
 
 /**
@@ -32,9 +33,9 @@ export function SlotElement(node, context) {
 			const value = build_attribute_value(
 				attribute.value,
 				context,
+				optimiser.transform,
 				false,
-				true,
-				optimiser.transform
+				true
 			);
 
 			if (attribute.name === 'name') {
@@ -66,8 +67,8 @@ export function SlotElement(node, context) {
 
 	const statement =
 		optimiser.expressions.length > 0
-			? call_child_renderer(b.block([optimiser.apply(), b.stmt(slot)]), true)
+			? create_async_block(b.block([optimiser.apply(), b.stmt(slot)]))
 			: b.stmt(slot);
 
-	context.state.template.push(empty_comment, statement, empty_comment);
+	context.state.template.push(block_open, statement, block_close);
 }
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/SvelteBoundary.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/SvelteBoundary.js
index 2e116f57d8..b914c96f4e 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/SvelteBoundary.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/SvelteBoundary.js
@@ -23,7 +23,13 @@ export function SvelteBoundary(node, context) {
 	if (pending_attribute || pending_snippet) {
 		const pending = pending_attribute
 			? b.call(
-					build_attribute_value(pending_attribute.value, context, false, true),
+					build_attribute_value(
+						pending_attribute.value,
+						context,
+						(expression) => expression,
+						false,
+						true
+					),
 					b.id('$$renderer')
 				)
 			: /** @type {BlockStatement} */ (context.visit(pending_snippet.body));
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/SvelteElement.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/SvelteElement.js
index 6ca0997bb6..2e61897924 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/SvelteElement.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/SvelteElement.js
@@ -1,12 +1,12 @@
 /** @import { Location } from 'locate-character' */
-/** @import { BlockStatement, Expression } from 'estree' */
+/** @import { BlockStatement, Expression, Statement } from 'estree' */
 /** @import { AST } from '#compiler' */
 /** @import { ComponentContext } from '../types.js' */
 import { dev, locator } from '../../../../state.js';
 import * as b from '#compiler/builders';
 import { determine_namespace_for_children } from '../../utils.js';
 import { build_element_attributes } from './shared/element.js';
-import { build_template } from './shared/utils.js';
+import { build_template, create_child_block, PromiseOptimiser } from './shared/utils.js';
 
 /**
  * @param {AST.SvelteElement} node
@@ -37,7 +37,9 @@ export function SvelteElement(node, context) {
 		init: []
 	};
 
-	build_element_attributes(node, { ...context, state });
+	const optimiser = new PromiseOptimiser();
+
+	build_element_attributes(node, { ...context, state }, optimiser.transform);
 
 	if (dev) {
 		const location = /** @type {Location} */ (locator(node.start));
@@ -57,18 +59,23 @@ export function SvelteElement(node, context) {
 	const attributes = b.block([...state.init, ...build_template(state.template)]);
 	const children = /** @type {BlockStatement} */ (context.visit(node.fragment, state));
 
-	context.state.template.push(
-		b.stmt(
-			b.call(
-				'$.element',
-				b.id('$$renderer'),
-				tag,
-				attributes.body.length > 0 && b.thunk(attributes),
-				children.body.length > 0 && b.thunk(children)
-			)
+	/** @type {Statement} */
+	let statement = b.stmt(
+		b.call(
+			'$.element',
+			b.id('$$renderer'),
+			tag,
+			attributes.body.length > 0 && b.thunk(attributes),
+			children.body.length > 0 && b.thunk(children)
 		)
 	);
 
+	if (optimiser.expressions.length > 0) {
+		statement = create_child_block(b.block([optimiser.apply(), statement]), true);
+	}
+
+	context.state.template.push(statement);
+
 	if (dev) {
 		context.state.template.push(b.stmt(b.call('$.pop_element')));
 	}
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/TitleElement.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/TitleElement.js
index 191205df28..66f4afc94c 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/TitleElement.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/TitleElement.js
@@ -14,6 +14,8 @@ export function TitleElement(node, context) {
 	template.push(b.literal('</title>'));
 
 	context.state.init.push(
-		b.stmt(b.call('$.build_title', b.id('$$renderer'), b.thunk(b.block(build_template(template)))))
+		b.stmt(
+			b.call('$$renderer.title', b.arrow([b.id('$$renderer')], b.block(build_template(template))))
+		)
 	);
 }
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/component.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/component.js
index 0e81ef5318..d0de750c0e 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/component.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/component.js
@@ -4,8 +4,9 @@
 import {
 	empty_comment,
 	build_attribute_value,
-	call_child_renderer,
-	PromiseOptimiser
+	create_async_block,
+	PromiseOptimiser,
+	build_template
 } from './utils.js';
 import * as b from '#compiler/builders';
 import { is_element_node } from '../../../../nodes.js';
@@ -91,9 +92,9 @@ export function build_inline_component(node, expression, context) {
 			const value = build_attribute_value(
 				attribute.value,
 				context,
+				optimiser.transform,
 				false,
-				true,
-				optimiser.transform
+				true
 			);
 
 			if (attribute.name.startsWith('--')) {
@@ -318,7 +319,7 @@ export function build_inline_component(node, expression, context) {
 	}
 
 	if (optimiser.expressions.length > 0) {
-		statement = call_child_renderer(b.block([optimiser.apply(), statement]), true);
+		statement = create_async_block(b.block([optimiser.apply(), statement]));
 	}
 
 	if (dynamic && custom_css_props.length === 0) {
@@ -327,7 +328,11 @@ export function build_inline_component(node, expression, context) {
 
 	context.state.template.push(statement);
 
-	if (!context.state.skip_hydration_boundaries && custom_css_props.length === 0) {
+	if (
+		!context.state.skip_hydration_boundaries &&
+		custom_css_props.length === 0 &&
+		optimiser.expressions.length === 0
+	) {
 		context.state.template.push(empty_comment);
 	}
 }
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/element.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/element.js
index fbd3a22b1c..da90011259 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/element.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/element.js
@@ -1,5 +1,5 @@
 /** @import { ArrayExpression, Expression, Literal, ObjectExpression } from 'estree' */
-/** @import { AST } from '#compiler' */
+/** @import { AST, ExpressionMetadata } from '#compiler' */
 /** @import { ComponentContext, ComponentServerTransformState } from '../../types.js' */
 import { is_event_attribute, is_text_attribute } from '../../../../../utils/ast.js';
 import { binding_properties } from '../../../../bindings.js';
@@ -30,8 +30,9 @@ const WHITESPACE_INSENSITIVE_ATTRIBUTES = ['class', 'style'];
  * their output to be the child content instead. In this case, an object is returned.
  * @param {AST.RegularElement | AST.SvelteElement} node
  * @param {import('zimmerframe').Context<AST.SvelteNode, ComponentServerTransformState>} context
+ * @param {(expression: Expression, metadata: ExpressionMetadata) => Expression} transform
  */
-export function build_element_attributes(node, context) {
+export function build_element_attributes(node, context, transform) {
 	/** @type {Array<AST.Attribute | AST.SpreadAttribute>} */
 	const attributes = [];
 
@@ -62,7 +63,8 @@ export function build_element_attributes(node, context) {
 						// also see related code in analysis phase
 						attribute.value[0].data = '\n' + attribute.value[0].data;
 					}
-					content = b.call('$.escape', build_attribute_value(attribute.value, context));
+
+					content = b.call('$.escape', build_attribute_value(attribute.value, context, transform));
 				} else if (node.name !== 'select') {
 					// omit value attribute for select elements, it's irrelevant for the initially selected value and has no
 					// effect on the selected value after the user interacts with the select element (the value _property_ does, but not the attribute)
@@ -150,12 +152,12 @@ export function build_element_attributes(node, context) {
 							expression: is_checkbox
 								? b.call(
 										b.member(attribute.expression, 'includes'),
-										build_attribute_value(value_attribute.value, context)
+										build_attribute_value(value_attribute.value, context, transform)
 									)
 								: b.binary(
 										'===',
 										attribute.expression,
-										build_attribute_value(value_attribute.value, context)
+										build_attribute_value(value_attribute.value, context, transform)
 									),
 							metadata: {
 								expression: create_expression_metadata()
@@ -202,30 +204,14 @@ export function build_element_attributes(node, context) {
 	}
 
 	if (has_spread) {
-		build_element_spread_attributes(node, attributes, style_directives, class_directives, context);
-		if (node.name === 'option') {
-			context.state.template.push(
-				b.call(
-					'$.maybe_selected',
-					b.id('$$renderer'),
-					b.member(
-						build_spread_object(
-							node,
-							node.attributes.filter(
-								(attribute) =>
-									attribute.type === 'Attribute' ||
-									attribute.type === 'BindDirective' ||
-									attribute.type === 'SpreadAttribute'
-							),
-							context
-						),
-						'value',
-						false,
-						true
-					)
-				)
-			);
-		}
+		build_element_spread_attributes(
+			node,
+			attributes,
+			style_directives,
+			class_directives,
+			context,
+			transform
+		);
 	} else {
 		const css_hash = node.metadata.scoped ? context.state.analysis.css.hash : null;
 
@@ -240,6 +226,7 @@ export function build_element_attributes(node, context) {
 					build_attribute_value(
 						attribute.value,
 						context,
+						transform,
 						WHITESPACE_INSENSITIVE_ATTRIBUTES.includes(name)
 					)
 				).value;
@@ -260,22 +247,13 @@ export function build_element_attributes(node, context) {
 					);
 				}
 
-				if (node.name === 'option' && name === 'value') {
-					context.state.template.push(
-						b.call(
-							'$.maybe_selected',
-							b.id('$$renderer'),
-							literal_value != null ? b.literal(/** @type {any} */ (literal_value)) : b.void0
-						)
-					);
-				}
-
 				continue;
 			}
 
 			const value = build_attribute_value(
 				attribute.value,
 				context,
+				transform,
 				WHITESPACE_INSENSITIVE_ATTRIBUTES.includes(name)
 			);
 
@@ -286,18 +264,16 @@ export function build_element_attributes(node, context) {
 				}
 				context.state.template.push(b.literal(` ${name}="${escape_html(value.value, true)}"`));
 			} else if (name === 'class') {
-				context.state.template.push(build_attr_class(class_directives, value, context, css_hash));
+				context.state.template.push(
+					build_attr_class(class_directives, value, context, css_hash, transform)
+				);
 			} else if (name === 'style') {
-				context.state.template.push(build_attr_style(style_directives, value, context));
+				context.state.template.push(build_attr_style(style_directives, value, context, transform));
 			} else {
 				context.state.template.push(
 					b.call('$.attr', b.literal(name), value, is_boolean_attribute(name) && b.true)
 				);
 			}
-
-			if (name === 'value' && node.name === 'option') {
-				context.state.template.push(b.call('$.maybe_selected', b.id('$$renderer'), value));
-			}
 		}
 	}
 
@@ -328,17 +304,20 @@ function get_attribute_name(element, attribute) {
  * @param {AST.RegularElement | AST.SvelteElement} element
  * @param {Array<AST.Attribute | AST.SpreadAttribute | AST.BindDirective>} attributes
  * @param {ComponentContext} context
+ * @param {(expression: Expression, metadata: ExpressionMetadata) => Expression} transform
  */
-export function build_spread_object(element, attributes, context) {
-	return b.object(
+export function build_spread_object(element, attributes, context, transform) {
+	const object = b.object(
 		attributes.map((attribute) => {
 			if (attribute.type === 'Attribute') {
 				const name = get_attribute_name(element, attribute);
 				const value = build_attribute_value(
 					attribute.value,
 					context,
+					transform,
 					WHITESPACE_INSENSITIVE_ATTRIBUTES.includes(name)
 				);
+
 				return b.prop('init', b.key(name), value);
 			} else if (attribute.type === 'BindDirective') {
 				const name = get_attribute_name(element, attribute);
@@ -346,12 +325,20 @@ export function build_spread_object(element, attributes, context) {
 					attribute.expression.type === 'SequenceExpression'
 						? b.call(attribute.expression.expressions[0])
 						: /** @type {Expression} */ (context.visit(attribute.expression));
+
 				return b.prop('init', b.key(name), value);
 			}
 
-			return b.spread(/** @type {Expression} */ (context.visit(attribute)));
+			return b.spread(
+				transform(
+					/** @type {Expression} */ (context.visit(attribute)),
+					attribute.metadata.expression
+				)
+			);
 		})
 	);
+
+	return object;
 }
 
 /**
@@ -361,39 +348,48 @@ export function build_spread_object(element, attributes, context) {
  * @param {AST.StyleDirective[]} style_directives
  * @param {AST.ClassDirective[]} class_directives
  * @param {ComponentContext} context
+ * @param {(expression: Expression, metadata: ExpressionMetadata) => Expression} transform
  */
 function build_element_spread_attributes(
 	element,
 	attributes,
 	style_directives,
 	class_directives,
-	context
+	context,
+	transform
 ) {
 	let classes;
 	let styles;
 	let flags = 0;
 
+	let has_await = false;
+
 	if (class_directives.length) {
-		const properties = class_directives.map((directive) =>
-			b.init(
+		const properties = class_directives.map((directive) => {
+			has_await ||= directive.metadata.expression.has_await;
+
+			return b.init(
 				directive.name,
 				directive.expression.type === 'Identifier' && directive.expression.name === directive.name
 					? b.id(directive.name)
 					: /** @type {Expression} */ (context.visit(directive.expression))
-			)
-		);
+			);
+		});
+
 		classes = b.object(properties);
 	}
 
 	if (style_directives.length > 0) {
-		const properties = style_directives.map((directive) =>
-			b.init(
+		const properties = style_directives.map((directive) => {
+			has_await ||= directive.metadata.expression.has_await;
+
+			return b.init(
 				directive.name,
 				directive.value === true
 					? b.id(directive.name)
-					: build_attribute_value(directive.value, context, true)
-			)
-		);
+					: build_attribute_value(directive.value, context, transform, true)
+			);
+		});
 
 		styles = b.object(properties);
 	}
@@ -406,15 +402,18 @@ function build_element_spread_attributes(
 		flags |= ELEMENT_IS_INPUT;
 	}
 
-	const object = build_spread_object(element, attributes, context);
+	const object = build_spread_object(element, attributes, context, transform);
 
 	const css_hash =
 		element.metadata.scoped && context.state.analysis.css.hash
 			? b.literal(context.state.analysis.css.hash)
-			: b.null;
+			: undefined;
 
 	const args = [object, css_hash, classes, styles, flags ? b.literal(flags) : undefined];
-	context.state.template.push(b.call('$.spread_attributes', ...args));
+
+	let call = b.call('$.attributes', ...args);
+
+	context.state.template.push(call);
 }
 
 /**
@@ -423,8 +422,9 @@ function build_element_spread_attributes(
  * @param {Expression} expression
  * @param {ComponentContext} context
  * @param {string | null} hash
+ * @param {(expression: Expression, metadata: ExpressionMetadata) => Expression} transform
  */
-function build_attr_class(class_directives, expression, context, hash) {
+function build_attr_class(class_directives, expression, context, hash, transform) {
 	/** @type {ObjectExpression | undefined} */
 	let directives;
 
@@ -434,7 +434,10 @@ function build_attr_class(class_directives, expression, context, hash) {
 				b.prop(
 					'init',
 					b.literal(directive.name),
-					/** @type {Expression} */ (context.visit(directive.expression, context.state))
+					transform(
+						/** @type {Expression} */ (context.visit(directive.expression, context.state)),
+						directive.metadata.expression
+					)
 				)
 			)
 		);
@@ -457,9 +460,10 @@ function build_attr_class(class_directives, expression, context, hash) {
  *
  * @param {AST.StyleDirective[]} style_directives
  * @param {Expression} expression
- * @param {ComponentContext} context
+ * @param {ComponentContext} context,
+ * @param {(expression: Expression, metadata: ExpressionMetadata) => Expression} transform
  */
-function build_attr_style(style_directives, expression, context) {
+function build_attr_style(style_directives, expression, context, transform) {
 	/** @type {ArrayExpression | ObjectExpression | undefined} */
 	let directives;
 
@@ -471,7 +475,7 @@ function build_attr_style(style_directives, expression, context) {
 			const expression =
 				directive.value === true
 					? b.id(directive.name)
-					: build_attribute_value(directive.value, context, true);
+					: build_attribute_value(directive.value, context, transform, true);
 
 			let name = directive.name;
 			if (name[0] !== '-' || name[1] !== '-') {
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/utils.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/utils.js
index 5e2b34496f..f5132c1cf8 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/utils.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/shared/utils.js
@@ -170,17 +170,17 @@ export function build_template(template) {
  *
  * @param {AST.Attribute['value']} value
  * @param {ComponentContext} context
+ * @param {(expression: Expression, metadata: ExpressionMetadata) => Expression} transform
  * @param {boolean} trim_whitespace
  * @param {boolean} is_component
- * @param {(expression: Expression, metadata: ExpressionMetadata) => Expression} transform
  * @returns {Expression}
  */
 export function build_attribute_value(
 	value,
 	context,
+	transform,
 	trim_whitespace = false,
-	is_component = false,
-	transform = (expression) => expression
+	is_component = false
 ) {
 	if (value === true) {
 		return b.true;
@@ -262,14 +262,23 @@ export function build_getter(node, state) {
 }
 
 /**
+ * Creates a `$$renderer.child(...)` expression statement
  * @param {BlockStatement | Expression} body
  * @param {boolean} async
  * @returns {Statement}
  */
-export function call_child_renderer(body, async) {
+export function create_child_block(body, async) {
 	return b.stmt(b.call('$$renderer.child', b.arrow([b.id('$$renderer')], body, async)));
 }
 
+/**
+ * Creates a `$$renderer.async(...)` expression statement
+ * @param {BlockStatement | Expression} body
+ */
+export function create_async_block(body) {
+	return b.stmt(b.call('$$renderer.async', b.arrow([b.id('$$renderer')], body, true)));
+}
+
 /**
  * @param {BlockStatement | Expression} body
  * @param {Identifier | false} component_fn_id
diff --git a/packages/svelte/src/internal/client/dom/blocks/async.js b/packages/svelte/src/internal/client/dom/blocks/async.js
index 5ec50a5988..6df0739918 100644
--- a/packages/svelte/src/internal/client/dom/blocks/async.js
+++ b/packages/svelte/src/internal/client/dom/blocks/async.js
@@ -1,6 +1,14 @@
 /** @import { TemplateNode, Value } from '#client' */
 import { flatten } from '../../reactivity/async.js';
 import { get } from '../../runtime.js';
+import {
+	hydrate_next,
+	hydrate_node,
+	hydrating,
+	set_hydrate_node,
+	set_hydrating,
+	skip_nodes
+} from '../hydration.js';
 import { get_boundary } from './boundary.js';
 
 /**
@@ -13,7 +21,22 @@ export function async(node, expressions, fn) {
 
 	boundary.update_pending_count(1);
 
+	var was_hydrating = hydrating;
+
+	if (was_hydrating) {
+		hydrate_next();
+
+		var previous_hydrate_node = hydrate_node;
+		var end = skip_nodes(false);
+		set_hydrate_node(end);
+	}
+
 	flatten([], expressions, (values) => {
+		if (was_hydrating) {
+			set_hydrating(true);
+			set_hydrate_node(previous_hydrate_node);
+		}
+
 		try {
 			// get values eagerly to avoid creating blocks if they reject
 			for (const d of values) get(d);
@@ -22,5 +45,9 @@ export function async(node, expressions, fn) {
 		} finally {
 			boundary.update_pending_count(-1);
 		}
+
+		if (was_hydrating) {
+			set_hydrating(false);
+		}
 	});
 }
diff --git a/packages/svelte/src/internal/client/dom/blocks/await.js b/packages/svelte/src/internal/client/dom/blocks/await.js
index 42df41041e..8605812f1e 100644
--- a/packages/svelte/src/internal/client/dom/blocks/await.js
+++ b/packages/svelte/src/internal/client/dom/blocks/await.js
@@ -8,7 +8,7 @@ import {
 	hydrate_next,
 	hydrate_node,
 	hydrating,
-	remove_nodes,
+	skip_nodes,
 	set_hydrate_node,
 	set_hydrating
 } from '../hydration.js';
@@ -140,7 +140,7 @@ export function await_block(node, get_input, pending_fn, then_fn, catch_fn) {
 
 		if (mismatch) {
 			// Hydration mismatch: remove everything inside the anchor and start fresh
-			anchor = remove_nodes();
+			anchor = skip_nodes();
 
 			set_hydrate_node(anchor);
 			set_hydrating(false);
diff --git a/packages/svelte/src/internal/client/dom/blocks/boundary.js b/packages/svelte/src/internal/client/dom/blocks/boundary.js
index 0532f2ca1b..6dde40d889 100644
--- a/packages/svelte/src/internal/client/dom/blocks/boundary.js
+++ b/packages/svelte/src/internal/client/dom/blocks/boundary.js
@@ -21,7 +21,7 @@ import {
 	hydrate_node,
 	hydrating,
 	next,
-	remove_nodes,
+	skip_nodes,
 	set_hydrate_node
 } from '../hydration.js';
 import { get_next_sibling } from '../operations.js';
@@ -335,7 +335,7 @@ export class Boundary {
 		if (hydrating) {
 			set_hydrate_node(/** @type {TemplateNode} */ (this.#hydrate_open));
 			next();
-			set_hydrate_node(remove_nodes());
+			set_hydrate_node(skip_nodes());
 		}
 
 		var did_reset = false;
diff --git a/packages/svelte/src/internal/client/dom/blocks/each.js b/packages/svelte/src/internal/client/dom/blocks/each.js
index 006bf09257..a6369a7211 100644
--- a/packages/svelte/src/internal/client/dom/blocks/each.js
+++ b/packages/svelte/src/internal/client/dom/blocks/each.js
@@ -14,7 +14,7 @@ import {
 	hydrate_node,
 	hydrating,
 	read_hydration_instruction,
-	remove_nodes,
+	skip_nodes,
 	set_hydrate_node,
 	set_hydrating
 } from '../hydration.js';
@@ -209,7 +209,7 @@ export function each(node, flags, get_collection, get_key, render_fn, fallback_f
 
 			if (is_else !== (length === 0)) {
 				// hydration mismatch — remove the server-rendered DOM and start over
-				anchor = remove_nodes();
+				anchor = skip_nodes();
 
 				set_hydrate_node(anchor);
 				set_hydrating(false);
@@ -259,7 +259,7 @@ export function each(node, flags, get_collection, get_key, render_fn, fallback_f
 
 			// remove excess nodes
 			if (length > 0) {
-				set_hydrate_node(remove_nodes());
+				set_hydrate_node(skip_nodes());
 			}
 		}
 
diff --git a/packages/svelte/src/internal/client/dom/blocks/if.js b/packages/svelte/src/internal/client/dom/blocks/if.js
index f418d46538..6349ab8399 100644
--- a/packages/svelte/src/internal/client/dom/blocks/if.js
+++ b/packages/svelte/src/internal/client/dom/blocks/if.js
@@ -6,7 +6,7 @@ import {
 	hydrate_node,
 	hydrating,
 	read_hydration_instruction,
-	remove_nodes,
+	skip_nodes,
 	set_hydrate_node,
 	set_hydrating
 } from '../hydration.js';
@@ -93,7 +93,7 @@ export function if_block(node, fn, elseif = false) {
 			if (!!condition === is_else) {
 				// Hydration mismatch: remove everything inside the anchor and start fresh.
 				// This could happen with `{#if browser}...{/if}`, for example
-				anchor = remove_nodes();
+				anchor = skip_nodes();
 
 				set_hydrate_node(anchor);
 				set_hydrating(false);
diff --git a/packages/svelte/src/internal/client/dom/hydration.js b/packages/svelte/src/internal/client/dom/hydration.js
index 1f80b7922b..5df9536d4d 100644
--- a/packages/svelte/src/internal/client/dom/hydration.js
+++ b/packages/svelte/src/internal/client/dom/hydration.js
@@ -81,9 +81,10 @@ export function next(count = 1) {
 }
 
 /**
- * Removes all nodes starting at `hydrate_node` up until the next hydration end comment
+ * Skips or removes (depending on {@link remove}) all nodes starting at `hydrate_node` up until the next hydration end comment
+ * @param {boolean} remove
  */
-export function remove_nodes() {
+export function skip_nodes(remove = true) {
 	var depth = 0;
 	var node = hydrate_node;
 
@@ -100,7 +101,7 @@ export function remove_nodes() {
 		}
 
 		var next = /** @type {TemplateNode} */ (get_next_sibling(node));
-		node.remove();
+		if (remove) node.remove();
 		node = next;
 	}
 }
diff --git a/packages/svelte/src/internal/server/index.js b/packages/svelte/src/internal/server/index.js
index 1e2d75d6dc..3ff44f8030 100644
--- a/packages/svelte/src/internal/server/index.js
+++ b/packages/svelte/src/internal/server/index.js
@@ -108,13 +108,13 @@ export function css_props(renderer, is_html, props, component, dynamic = false)
 
 /**
  * @param {Record<string, unknown>} attrs
- * @param {string | null} css_hash
+ * @param {string} [css_hash]
  * @param {Record<string, boolean>} [classes]
  * @param {Record<string, string>} [styles]
  * @param {number} [flags]
  * @returns {string}
  */
-export function spread_attributes(attrs, css_hash, classes, styles, flags = 0) {
+export function attributes(attrs, css_hash, classes, styles, flags = 0) {
 	if (styles) {
 		attrs.style = to_style(attrs.style, styles);
 	}
@@ -493,121 +493,3 @@ export function derived(fn) {
 		return updated_value;
 	};
 }
-
-/**
- *
- * @param {Renderer} renderer
- * @param {unknown} value
- */
-export function maybe_selected(renderer, value) {
-	return value === renderer.local.select_value ? ' selected' : '';
-}
-
-/**
- * When an `option` element has no `value` attribute, we need to treat the child
- * content as its `value` to determine whether we should apply the `selected` attribute.
- * This has to be done at runtime, for hopefully obvious reasons. It is also complicated,
- * for sad reasons.
- * @param {Renderer} renderer
- * @param {((renderer: Renderer) => void | Promise<void>)} children
- * @returns {void}
- */
-export function valueless_option(renderer, children) {
-	const i = renderer.length;
-
-	// prior to children, `renderer` has some combination of string/unresolved renderer that ends in `<option ...>`
-	renderer.child(children);
-
-	// post-children, `renderer` has child content, possibly also with some number of hydration comments.
-	// we can compact this last chunk of content to see if it matches the select value...
-	renderer.compact({
-		start: i,
-		fn: (content) => {
-			if (content.body.replace(/<!---->/g, '') === renderer.local.select_value) {
-				// ...and if it does match the select value, we can compact the part of the renderer representing the `<option ...>`
-				// to add the `selected` attribute to the end.
-				renderer.compact({
-					start: i - 1,
-					end: i,
-					fn: (content) => {
-						return { body: content.body.slice(0, -1) + ' selected>', head: content.head };
-					}
-				});
-			}
-			return content;
-		}
-	});
-}
-
-/**
- * In the special case where an `option` element has no `value` attribute but
- * the children of the `option` element are a single expression, we can simplify
- * by running the children and passing the resulting value, which means
- * we don't have to do all of the same parsing nonsense. It also means we can avoid
- * coercing everything to a string.
- * @param {Renderer} renderer
- * @param {(() => unknown)} child
- */
-export function simple_valueless_option(renderer, child) {
-	const result = child();
-
-	/**
-	 * @param {AccumulatedContent} content
-	 * @param {unknown} child_value
-	 * @returns {AccumulatedContent}
-	 */
-	const mark_selected = (content, child_value) => {
-		if (child_value === renderer.local.select_value) {
-			return { body: content.body.slice(0, -1) + ' selected>', head: content.head };
-		}
-		return content;
-	};
-
-	renderer.compact({
-		start: renderer.length - 1,
-		fn: (content) => {
-			if (result instanceof Promise) {
-				return result.then((child_value) => mark_selected(content, child_value));
-			}
-			return mark_selected(content, result);
-		}
-	});
-
-	renderer.child((child_renderer) => {
-		if (result instanceof Promise) {
-			return result.then((child_value) => {
-				child_renderer.push(escape_html(child_value));
-			});
-		}
-		child_renderer.push(escape_html(result));
-	});
-}
-
-/**
- * Since your document can only have one `title`, we have to have some sort of algorithm for determining
- * which one "wins". To do this, we perform a depth-first comparison of where the title was encountered --
- * later ones "win" over earlier ones, regardless of what order the promises resolve in. To accomodate this, we:
- * - Figure out where we are in the content tree (`get_path`)
- * - Render the title in its own child so that it has a defined "slot" in the renderer
- * - Compact that spot so that we get the entire rendered contents of the title
- * - Attempt to set the global title (this is where the "wins" logic based on the path happens)
- *
- * TODO we could optimize this by not even rendering the title if the path wouldn't be accepted
- *
- * @param {Renderer} renderer
- * @param {((renderer: Renderer) => void | Promise<void>)} children
- */
-export function build_title(renderer, children) {
-	const path = renderer.get_path();
-	const i = renderer.length;
-	renderer.child(children);
-	renderer.compact({
-		start: i,
-		fn: ({ head }) => {
-			renderer.global.set_title(head, path);
-			// since we can only ever render the title in this chunk, and title rendering is handled specially,
-			// we can just ditch the results after we've saved them globally
-			return { head: '', body: '' };
-		}
-	});
-}
diff --git a/packages/svelte/src/internal/server/renderer.js b/packages/svelte/src/internal/server/renderer.js
index a77afd68b3..6971f200a0 100644
--- a/packages/svelte/src/internal/server/renderer.js
+++ b/packages/svelte/src/internal/server/renderer.js
@@ -6,6 +6,7 @@ import { pop, push, set_ssr_context, ssr_context } from './context.js';
 import * as e from './errors.js';
 import * as w from './warnings.js';
 import { BLOCK_CLOSE, BLOCK_OPEN } from './hydration.js';
+import { attributes } from './index.js';
 
 /** @typedef {'head' | 'body'} RendererType */
 /** @typedef {{ [key in RendererType]: string }} AccumulatedContent */
@@ -55,12 +56,10 @@ export class Renderer {
 	#parent;
 
 	/**
-	 * Asynchronous work associated with this renderer. `initial` is the promise from the function
-	 * this renderer was passed to (if that function was async), and `followup` is any any additional
-	 * work from `compact` calls that needs to complete prior to collecting this renderer's content.
-	 * @type {{ initial: Promise<void> | undefined, followup: Promise<void>[] }}
+	 * Asynchronous work associated with this renderer
+	 * @type {Promise<void> | undefined}
 	 */
-	promises = { initial: undefined, followup: [] };
+	promise = undefined;
 
 	/**
 	 * State which is associated with the content tree as a whole.
@@ -101,6 +100,15 @@ export class Renderer {
 		head.child(fn);
 	}
 
+	/**
+	 * @param {(renderer: Renderer) => void} fn
+	 */
+	async(fn) {
+		this.#out.push(BLOCK_OPEN);
+		this.child(fn);
+		this.#out.push(BLOCK_CLOSE);
+	}
+
 	/**
 	 * Create a child renderer. The child renderer inherits the state from the parent,
 	 * but has its own content.
@@ -129,7 +137,7 @@ export class Renderer {
 			}
 			// just to avoid unhandled promise rejections -- we'll end up throwing in `collect_async` if something fails
 			result.catch(() => {});
-			child.promises.initial = result;
+			child.promise = result;
 		}
 
 		return child;
@@ -150,29 +158,100 @@ export class Renderer {
 	}
 
 	/**
-	 * @param {string | (() => Promise<string>)} content
+	 * @param {Record<string, any>} attrs
+	 * @param {(renderer: Renderer) => void} fn
 	 */
-	push(content) {
-		if (typeof content === 'function') {
-			this.child(async (renderer) => renderer.push(await content()));
+	select({ value, ...attrs }, fn) {
+		this.push(`<select${attributes(attrs)}>`);
+		this.child((renderer) => {
+			renderer.local.select_value = value;
+			fn(renderer);
+		});
+		this.push('</select>');
+	}
+
+	/**
+	 * @param {Record<string, any>} attrs
+	 * @param {string | number | boolean | ((renderer: Renderer) => void)} body
+	 */
+	option(attrs, body) {
+		this.#out.push(`<option${attributes(attrs)}`);
+
+		/**
+		 * @param {Renderer} renderer
+		 * @param {any} value
+		 * @param {{ head?: string, body: any }} content
+		 */
+		const close = (renderer, value, { head, body }) => {
+			if ('value' in attrs) {
+				value = attrs.value;
+			}
+
+			if (value === this.local.select_value) {
+				renderer.#out.push(' selected');
+			}
+
+			renderer.#out.push(`>${body}</option>`);
+
+			// super edge case, but may as well handle it
+			if (head) {
+				renderer.head((child) => child.push(head));
+			}
+		};
+
+		if (typeof body === 'function') {
+			this.child((renderer) => {
+				const r = new Renderer(this.global, this);
+				body(r);
+
+				if (this.global.mode === 'async') {
+					return r.#collect_content_async().then((content) => {
+						close(renderer, content.body.replaceAll('<!---->', ''), content);
+					});
+				} else {
+					const content = r.#collect_content();
+					close(renderer, content.body.replaceAll('<!---->', ''), content);
+				}
+			});
 		} else {
-			this.#out.push(content);
+			close(this, body, { body });
 		}
 	}
 
 	/**
-	 * Compact everything between `start` and `end` into a single renderer, then call `fn` with the result of that renderer.
-	 * The compacted renderer will be sync if all of the children are sync and {@link fn} is sync, otherwise it will be async.
-	 * @param {{ start: number, end?: number, fn: (content: AccumulatedContent) => AccumulatedContent | Promise<AccumulatedContent> }} args
+	 * @param {(renderer: Renderer) => void} fn
 	 */
-	compact({ start, end = this.#out.length, fn }) {
-		const child = new Renderer(this.global, this);
-		const to_compact = this.#out.splice(start, end - start, child);
+	title(fn) {
+		const path = this.get_path();
+
+		/** @param {string} head */
+		const close = (head) => {
+			this.global.set_title(head, path);
+		};
 
-		if (this.global.mode === 'sync') {
-			Renderer.#compact(fn, child, to_compact, this.type);
+		this.child((renderer) => {
+			const r = new Renderer(renderer.global, renderer);
+			fn(r);
+
+			if (renderer.global.mode === 'async') {
+				return r.#collect_content_async().then((content) => {
+					close(content.head);
+				});
+			} else {
+				const content = r.#collect_content();
+				close(content.head);
+			}
+		});
+	}
+
+	/**
+	 * @param {string | (() => Promise<string>)} content
+	 */
+	push(content) {
+		if (typeof content === 'function') {
+			this.child(async (renderer) => renderer.push(await content()));
 		} else {
-			this.promises.followup.push(Renderer.#compact_async(fn, child, to_compact, this.type));
+			this.#out.push(content);
 		}
 	}
 
@@ -196,7 +275,7 @@ export class Renderer {
 	copy() {
 		const copy = new Renderer(this.global, this.#parent);
 		copy.#out = this.#out.map((item) => (item instanceof Renderer ? item.copy() : item));
-		copy.promises = this.promises;
+		copy.promise = this.promise;
 		return copy;
 	}
 
@@ -218,7 +297,7 @@ export class Renderer {
 			}
 			return item;
 		});
-		this.promises = other.promises;
+		this.promise = other.promise;
 		this.type = other.type;
 	}
 
@@ -355,7 +434,7 @@ export class Renderer {
 		try {
 			const renderer = Renderer.#open_render('sync', component, options);
 
-			const content = Renderer.#collect_content([renderer], renderer.type);
+			const content = renderer.#collect_content();
 			return Renderer.#close_render(content, renderer);
 		} finally {
 			abort();
@@ -376,7 +455,7 @@ export class Renderer {
 		try {
 			const renderer = Renderer.#open_render('async', component, options);
 
-			const content = await Renderer.#collect_content_async([renderer], renderer.type);
+			const content = await renderer.#collect_content_async();
 			return Renderer.#close_render(content, renderer);
 		} finally {
 			abort();
@@ -384,94 +463,41 @@ export class Renderer {
 		}
 	}
 
-	/**
-	 * @param {(content: AccumulatedContent) => AccumulatedContent | Promise<AccumulatedContent>} fn
-	 * @param {Renderer} child
-	 * @param {RendererItem[]} to_compact
-	 * @param {RendererType} type
-	 */
-	static #compact(fn, child, to_compact, type) {
-		const content = Renderer.#collect_content(to_compact, type);
-		const transformed_content = fn(content);
-		if (transformed_content instanceof Promise) {
-			throw new Error(
-				"invariant: Somehow you've encountered asynchronous work while rendering synchronously. If you're seeing this, there's a compiler bug. File an issue!"
-			);
-		} else {
-			Renderer.#push_accumulated_content(child, transformed_content);
-		}
-	}
-
-	/**
-	 * @param {(content: AccumulatedContent) => AccumulatedContent | Promise<AccumulatedContent>} fn
-	 * @param {Renderer} child
-	 * @param {RendererItem[]} to_compact
-	 * @param {RendererType} type
-	 */
-	static async #compact_async(fn, child, to_compact, type) {
-		const content = await Renderer.#collect_content_async(to_compact, type);
-		const transformed_content = await fn(content);
-		Renderer.#push_accumulated_content(child, transformed_content);
-	}
-
 	/**
 	 * Collect all of the code from the `out` array and return it as a string, or a promise resolving to a string.
-	 * @param {RendererItem[]} items
-	 * @param {RendererType} current_type
 	 * @param {AccumulatedContent} content
 	 * @returns {AccumulatedContent}
 	 */
-	static #collect_content(items, current_type, content = { head: '', body: '' }) {
-		for (const item of items) {
+	#collect_content(content = { head: '', body: '' }) {
+		for (const item of this.#out) {
 			if (typeof item === 'string') {
-				content[current_type] += item;
+				content[this.type] += item;
 			} else if (item instanceof Renderer) {
-				Renderer.#collect_content(item.#out, item.type, content);
+				item.#collect_content(content);
 			}
 		}
+
 		return content;
 	}
 
 	/**
 	 * Collect all of the code from the `out` array and return it as a string.
-	 * @param {RendererItem[]} items
-	 * @param {RendererType} current_type
 	 * @param {AccumulatedContent} content
 	 * @returns {Promise<AccumulatedContent>}
 	 */
-	static async #collect_content_async(items, current_type, content = { head: '', body: '' }) {
+	async #collect_content_async(content = { head: '', body: '' }) {
+		await this.promise;
+
 		// no danger to sequentially awaiting stuff in here; all of the work is already kicked off
-		for (const item of items) {
+		for (const item of this.#out) {
 			if (typeof item === 'string') {
-				content[current_type] += item;
-			} else {
-				if (item.promises.initial) {
-					// this represents the async function that's modifying this renderer.
-					// we can't do anything until it's done and we know our `out` array is complete.
-					await item.promises.initial;
-				}
-				for (const followup of item.promises.followup) {
-					// this is sequential because `compact` could synchronously queue up additional followup work
-					await followup;
-				}
-				await Renderer.#collect_content_async(item.#out, item.type, content);
+				content[this.type] += item;
+			} else if (item instanceof Renderer) {
+				await item.#collect_content_async(content);
 			}
 		}
-		return content;
-	}
 
-	/**
-	 * @param {Renderer} tree
-	 * @param {AccumulatedContent} accumulated_content
-	 */
-	static #push_accumulated_content(tree, accumulated_content) {
-		for (const [type, content] of Object.entries(accumulated_content)) {
-			if (!content) continue;
-			const child = new Renderer(tree.global, tree);
-			child.type = /** @type {RendererType} */ (type);
-			child.push(content);
-			tree.#out.push(child);
-		}
+		return content;
 	}
 
 	/**
diff --git a/packages/svelte/src/internal/server/renderer.test.ts b/packages/svelte/src/internal/server/renderer.test.ts
index 7112bacd75..88fbee855a 100644
--- a/packages/svelte/src/internal/server/renderer.test.ts
+++ b/packages/svelte/src/internal/server/renderer.test.ts
@@ -84,26 +84,6 @@ test('creating an async child in a sync context throws', () => {
 	expect(() => Renderer.render(component as unknown as Component).body).toThrow('await_invalid');
 });
 
-test('compact synchronously aggregates a range and can transform into head/body', () => {
-	const component = (renderer: Renderer) => {
-		const start = renderer.length;
-		renderer.push('a');
-		renderer.push('b');
-		renderer.push('c');
-		renderer.compact({
-			start,
-			end: start + 2,
-			fn: (content) => {
-				return { head: '<h>H</h>', body: content.body + 'd' };
-			}
-		});
-	};
-
-	const { head, body } = Renderer.render(component as unknown as Component);
-	expect(head).toBe('<h>H</h>');
-	expect(body).toBe('<!--[-->abdc<!--]-->');
-});
-
 test('local state is shallow-copied to children', () => {
 	const root = new Renderer(new SSRState('sync'));
 	root.local.select_value = 'A';
@@ -132,13 +112,13 @@ test('subsume replaces tree content and state from other', () => {
 	b.global.css.add({ hash: 'h', code: 'c' });
 	b.global.set_title('Title', [1]);
 	b.local.select_value = 'B';
-	b.promises.initial = Promise.resolve();
+	b.promise = Promise.resolve();
 
 	a.subsume(b);
 
 	expect(a.type).toBe('body');
 	expect(a.local.select_value).toBe('B');
-	expect(a.promises).toBe(b.promises);
+	expect(a.promise).toBe(b.promise);
 });
 
 test('subsume refuses to switch modes', () => {
@@ -156,7 +136,7 @@ test('subsume refuses to switch modes', () => {
 	b.global.css.add({ hash: 'h', code: 'c' });
 	b.global.set_title('Title', [1]);
 	b.local.select_value = 'B';
-	b.promises.initial = Promise.resolve();
+	b.promise = Promise.resolve();
 
 	expect(() => a.subsume(b)).toThrow(
 		"invariant: A renderer cannot switch modes. If you're seeing this, there's a compiler bug. File an issue!"
@@ -195,6 +175,38 @@ test('SSRState title ordering favors later lexicographic paths', () => {
 	expect(state.get_title()).toBe('E');
 });
 
+test('selects an option with an explicit value', () => {
+	const component = (renderer: Renderer) => {
+		renderer.select({ value: 2 }, (renderer) => {
+			renderer.option({ value: 1 }, (renderer) => renderer.push('one'));
+			renderer.option({ value: 2 }, (renderer) => renderer.push('two'));
+			renderer.option({ value: 3 }, (renderer) => renderer.push('three'));
+		});
+	};
+
+	const { head, body } = Renderer.render(component as unknown as Component);
+	expect(head).toBe('');
+	expect(body).toBe(
+		'<!--[--><select><option value="1">one</option><option value="2" selected>two</option><option value="3">three</option></select><!--]-->'
+	);
+});
+
+test('selects an option with an implicit value', () => {
+	const component = (renderer: Renderer) => {
+		renderer.select({ value: 'two' }, (renderer) => {
+			renderer.option({}, (renderer) => renderer.push('one'));
+			renderer.option({}, (renderer) => renderer.push('two'));
+			renderer.option({}, (renderer) => renderer.push('three'));
+		});
+	};
+
+	const { head, body } = Renderer.render(component as unknown as Component);
+	expect(head).toBe('');
+	expect(body).toBe(
+		'<!--[--><select><option>one</option><option selected>two</option><option>three</option></select><!--]-->'
+	);
+});
+
 describe('async', () => {
 	beforeAll(() => {
 		enable_async_mode_flag();
@@ -220,28 +232,6 @@ describe('async', () => {
 		expect(() => result.html).toThrow('html_deprecated');
 	});
 
-	test('compact schedules followup when compaction input is async', async () => {
-		const component = (renderer: Renderer) => {
-			renderer.push('a');
-			renderer.child(async ($$renderer) => {
-				await Promise.resolve();
-				$$renderer.push('X');
-			});
-			renderer.push('b');
-			renderer.compact({
-				start: 0,
-				fn: async (content) => ({
-					body: content.body.toLowerCase(),
-					head: await Promise.resolve('')
-				})
-			});
-		};
-
-		const { body, head } = await Renderer.render(component as unknown as Component);
-		expect(head).toBe('');
-		expect(body).toBe('<!--[-->axb<!--]-->');
-	});
-
 	test('push accepts async functions in async context', async () => {
 		const component = (renderer: Renderer) => {
 			renderer.push('a');
@@ -308,25 +298,6 @@ describe('async', () => {
 		expect(body).toBe('<!--[-->start-async-child--end<!--]-->');
 	});
 
-	test('push async functions work with compact operations', async () => {
-		const component = (renderer: Renderer) => {
-			renderer.push('a');
-			renderer.push(async () => {
-				await Promise.resolve();
-				return 'b';
-			});
-			renderer.push('c');
-			renderer.compact({
-				start: 0,
-				fn: (content) => ({ head: '', body: content.body.toUpperCase() })
-			});
-		};
-
-		const { head, body } = await Renderer.render(component as unknown as Component);
-		expect(head).toBe('');
-		expect(body).toBe('<!--[-->ABC<!--]-->');
-	});
-
 	test('push async functions are not supported in sync context', () => {
 		const component = (renderer: Renderer) => {
 			renderer.push('a');
diff --git a/packages/svelte/tests/hydration/samples/if-block-mismatch-2/_expected.html b/packages/svelte/tests/hydration/samples/if-block-mismatch-2/_expected.html
index 08a3809de9..72d1a4f024 100644
--- a/packages/svelte/tests/hydration/samples/if-block-mismatch-2/_expected.html
+++ b/packages/svelte/tests/hydration/samples/if-block-mismatch-2/_expected.html
@@ -1 +1 @@
-<!--[--><!--[--><!--]--> <div><!----><!----></div> hello<!--]-->
+<!--[--><!--[--><!--]--> <div><!--[--><!--]--></div> hello<!--]-->
diff --git a/packages/svelte/tests/runtime-runes/samples/async-no-pending-attributes/Child.svelte b/packages/svelte/tests/runtime-runes/samples/async-no-pending-attributes/Child.svelte
new file mode 100644
index 0000000000..ab87364cb7
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-no-pending-attributes/Child.svelte
@@ -0,0 +1,5 @@
+<script>
+	let { thing } = $props();
+</script>
+
+<p>{thing}</p>
diff --git a/packages/svelte/tests/runtime-runes/samples/async-no-pending-attributes/_config.js b/packages/svelte/tests/runtime-runes/samples/async-no-pending-attributes/_config.js
new file mode 100644
index 0000000000..b8f8f61d96
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-no-pending-attributes/_config.js
@@ -0,0 +1,24 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	skip_mode: ['async-server'],
+
+	async test({ assert, target }) {
+		await tick();
+
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				<p class="cool">cool</p>
+				<p>beans</p>
+
+				<p class="awesome">awesome</p>
+				<p>sauce</p>
+
+				<p class="neato">neato</p>
+				<p>burrito</p>
+			`
+		);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-no-pending-attributes/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-no-pending-attributes/main.svelte
new file mode 100644
index 0000000000..7a8280b314
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-no-pending-attributes/main.svelte
@@ -0,0 +1,12 @@
+<script>
+	import Child from './Child.svelte';
+</script>
+
+<p {...await { class: 'cool'}}>cool</p>
+<Child {...await { thing: 'beans' }} />
+
+<p class={await 'awesome'}>awesome</p>
+<Child thing={await 'sauce'} />
+
+<p {...{}} class={await 'neato'}>neato</p>
+<Child {...{}} thing={await 'burrito'} />
diff --git a/packages/svelte/tests/runtime-runes/samples/async-no-pending-await-in-block/_config.js b/packages/svelte/tests/runtime-runes/samples/async-no-pending-await-in-block/_config.js
new file mode 100644
index 0000000000..35d88f6c8b
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-no-pending-await-in-block/_config.js
@@ -0,0 +1,33 @@
+import { tick } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	mode: ['hydrate'],
+
+	server_props: {
+		browser: false
+	},
+
+	ssrHtml: `
+		<h1>hello from the server</h1>
+		<h2>hello from the server</h2>
+		<h3>hello from the server</h3>
+	`,
+
+	props: {
+		browser: true
+	},
+
+	async test({ assert, target }) {
+		await tick();
+
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+				<h1>hello from the browser</h1>
+				<h2>hello from the browser</h2>
+				<h3>hello from the browser</h3>
+			`
+		);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/async-no-pending-await-in-block/main.svelte b/packages/svelte/tests/runtime-runes/samples/async-no-pending-await-in-block/main.svelte
new file mode 100644
index 0000000000..82e6a57a18
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/async-no-pending-await-in-block/main.svelte
@@ -0,0 +1,10 @@
+<script>
+	let { browser = typeof window !== 'undefined' } = $props();
+</script>
+
+{#if await true}
+	<h1>hello from the {browser ? 'browser' : 'server'}</h1>
+{/if}
+
+<h2>hello from the {browser ? 'browser' : 'server'}</h2>
+<h3>hello from the {browser ? 'browser' : 'server'}</h3>
diff --git a/packages/svelte/tests/snapshot/samples/async-each-fallback-hoisting/_expected/server/index.svelte.js b/packages/svelte/tests/snapshot/samples/async-each-fallback-hoisting/_expected/server/index.svelte.js
index d0c1e37209..c579fda929 100644
--- a/packages/svelte/tests/snapshot/samples/async-each-fallback-hoisting/_expected/server/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/async-each-fallback-hoisting/_expected/server/index.svelte.js
@@ -2,7 +2,7 @@ import 'svelte/internal/flags/async';
 import * as $ from 'svelte/internal/server';
 
 export default function Async_each_fallback_hoisting($$renderer) {
-	$$renderer.child(async ($$renderer) => {
+	$$renderer.async(async ($$renderer) => {
 		const each_array = $.ensure_array_like((await $.save(Promise.resolve([])))());
 
 		if (each_array.length !== 0) {
diff --git a/packages/svelte/tests/snapshot/samples/async-each-hoisting/_expected/server/index.svelte.js b/packages/svelte/tests/snapshot/samples/async-each-hoisting/_expected/server/index.svelte.js
index 4443880165..e87b50e2a4 100644
--- a/packages/svelte/tests/snapshot/samples/async-each-hoisting/_expected/server/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/async-each-hoisting/_expected/server/index.svelte.js
@@ -8,7 +8,7 @@ export default function Async_each_hoisting($$renderer) {
 
 	$$renderer.push(`<!--[-->`);
 
-	$$renderer.child(async ($$renderer) => {
+	$$renderer.async(async ($$renderer) => {
 		const each_array = $.ensure_array_like((await $.save(Promise.resolve([first, second, third])))());
 
 		for (let $$index = 0, $$length = each_array.length; $$index < $$length; $$index++) {
diff --git a/packages/svelte/tests/snapshot/samples/async-if-alternate-hoisting/_expected/server/index.svelte.js b/packages/svelte/tests/snapshot/samples/async-if-alternate-hoisting/_expected/server/index.svelte.js
index 3dbd10204a..df4ad80899 100644
--- a/packages/svelte/tests/snapshot/samples/async-if-alternate-hoisting/_expected/server/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/async-if-alternate-hoisting/_expected/server/index.svelte.js
@@ -2,7 +2,7 @@ import 'svelte/internal/flags/async';
 import * as $ from 'svelte/internal/server';
 
 export default function Async_if_alternate_hoisting($$renderer) {
-	$$renderer.child(async ($$renderer) => {
+	$$renderer.async(async ($$renderer) => {
 		if ((await $.save(Promise.resolve(false)))()) {
 			$$renderer.push('<!--[-->');
 			$$renderer.push(async () => $.escape(await Promise.reject('no no no')));
diff --git a/packages/svelte/tests/snapshot/samples/async-if-hoisting/_expected/server/index.svelte.js b/packages/svelte/tests/snapshot/samples/async-if-hoisting/_expected/server/index.svelte.js
index c0309748a1..1d935f9be8 100644
--- a/packages/svelte/tests/snapshot/samples/async-if-hoisting/_expected/server/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/async-if-hoisting/_expected/server/index.svelte.js
@@ -2,7 +2,7 @@ import 'svelte/internal/flags/async';
 import * as $ from 'svelte/internal/server';
 
 export default function Async_if_hoisting($$renderer) {
-	$$renderer.child(async ($$renderer) => {
+	$$renderer.async(async ($$renderer) => {
 		if ((await $.save(Promise.resolve(true)))()) {
 			$$renderer.push('<!--[-->');
 			$$renderer.push(async () => $.escape(await Promise.resolve('yes yes yes')));
diff --git a/packages/svelte/tests/snapshot/samples/skip-static-subtree/_expected/server/index.svelte.js b/packages/svelte/tests/snapshot/samples/skip-static-subtree/_expected/server/index.svelte.js
index 5bce27d1d8..7a9f6193d7 100644
--- a/packages/svelte/tests/snapshot/samples/skip-static-subtree/_expected/server/index.svelte.js
+++ b/packages/svelte/tests/snapshot/samples/skip-static-subtree/_expected/server/index.svelte.js
@@ -3,5 +3,11 @@ import * as $ from 'svelte/internal/server';
 export default function Skip_static_subtree($$renderer, $$props) {
 	let { title, content } = $$props;
 
-	$$renderer.push(`<header><nav><a href="/">Home</a> <a href="/away">Away</a></nav></header> <main><h1>${$.escape(title)}</h1> <div class="static"><p>we don't need to traverse these nodes</p></div> <p>or</p> <p>these</p> <p>ones</p> ${$.html(content)} <p>these</p> <p>trailing</p> <p>nodes</p> <p>can</p> <p>be</p> <p>completely</p> <p>ignored</p></main> <cant-skip><custom-elements with="attributes"></custom-elements></cant-skip> <div><input autofocus/></div> <div><source muted/></div> <select><option value="a"${$.maybe_selected($$renderer, 'a')}>a</option></select> <img src="..." alt="" loading="lazy"/> <div><img src="..." alt="" loading="lazy"/></div>`);
+	$$renderer.push(`<header><nav><a href="/">Home</a> <a href="/away">Away</a></nav></header> <main><h1>${$.escape(title)}</h1> <div class="static"><p>we don't need to traverse these nodes</p></div> <p>or</p> <p>these</p> <p>ones</p> ${$.html(content)} <p>these</p> <p>trailing</p> <p>nodes</p> <p>can</p> <p>be</p> <p>completely</p> <p>ignored</p></main> <cant-skip><custom-elements with="attributes"></custom-elements></cant-skip> <div><input autofocus/></div> <div><source muted/></div> <select>`);
+
+	$$renderer.option({ value: 'a' }, ($$renderer) => {
+		$$renderer.push(`a`);
+	});
+
+	$$renderer.push(`</select> <img src="..." alt="" loading="lazy"/> <div><img src="..." alt="" loading="lazy"/></div>`);
 }
\ No newline at end of file