simplify

packages/svelte/src/compiler/phases/2-analyze/index.js

@@ -77,10 +77,6 @@ import { UseDirective } from './visitors/UseDirective.js';
 import { VariableDeclarator } from './visitors/VariableDeclarator.js';
 import is_reference from 'is-reference';
 import { mark_subtree_dynamic } from './visitors/shared/fragment.js';
-import { is_last_evaluated_expression } from './utils/awaits.js';
-
-/** @type {Array<ExpressionMetadata | null>} */
-const metadata_stack = [];
 
 /**
  * @type {Visitors}
@@ -132,23 +128,9 @@ const visitors = {
 
 		ignore_map.set(node, structuredClone(ignore_stack));
 
-		metadata_stack.push(state.expression);
-
 		const scope = state.scopes.get(node);
 		next(scope !== undefined && scope !== state.scope ? { ...state, scope } : state);
 
-		metadata_stack.pop();
-
-		// if this node set `state.expression`, now that we've visited it we can determine
-		// which `await` expressions need to be wrapped in `$.save(...)`
-		if (state.expression && metadata_stack[metadata_stack.length - 1] === null) {
-			for (const { path, node } of state.expression.awaits) {
-				if (!is_last_evaluated_expression(path, node)) {
-					state.analysis.context_preserving_awaits.add(node);
-				}
-			}
-		}
-
 		if (ignores.length > 0) {
 			pop_ignore();
 		}
@@ -291,7 +273,6 @@ export function analyze_module(source, options) {
 		immutable: true,
 		tracing: false,
 		async_deriveds: new Set(),
-		context_preserving_awaits: new Set(),
 		comments,
 		classes: new Map()
 	};
@@ -538,8 +519,7 @@ export function analyze_component(root, source, options) {
 		undefined_exports: new Map(),
 		snippet_renderers: new Map(),
 		snippets: new Set(),
-		async_deriveds: new Set(),
-		context_preserving_awaits: new Set()
+		async_deriveds: new Set()
 	};
 
 	if (!runes) {

packages/svelte/src/compiler/phases/2-analyze/utils/awaits.js

@@ -1,70 +0,0 @@
-/** @import { Expression, Property, SpreadElement } from 'estree' */
-/** @import { AST } from '#compiler' */
-
-/**
- *
- * @param {AST.SvelteNode[]} path
- * @param {Expression | SpreadElement | Property} node
- */
-export function is_last_evaluated_expression(path, node) {
-	let i = path.length;
-
-	while (i--) {
-		const parent = /** @type {Expression | Property | SpreadElement} */ (path[i]);
-
-		// @ts-expect-error we could probably use a neater/more robust mechanism
-		if (parent.metadata) {
-			return true;
-		}
-
-		switch (parent.type) {
-			case 'ArrayExpression':
-				if (node !== parent.elements.at(-1)) return false;
-				break;
-
-			case 'AssignmentExpression':
-			case 'BinaryExpression':
-			case 'LogicalExpression':
-				if (node === parent.left) return false;
-				break;
-
-			case 'CallExpression':
-			case 'NewExpression':
-				if (node !== parent.arguments.at(-1)) return false;
-				break;
-
-			case 'ConditionalExpression':
-				if (node === parent.test) return false;
-				break;
-
-			case 'MemberExpression':
-				if (parent.computed && node === parent.object) return false;
-				break;
-
-			case 'ObjectExpression':
-				if (node !== parent.properties.at(-1)) return false;
-				break;
-
-			case 'Property':
-				if (node === parent.key) return false;
-				break;
-
-			case 'SequenceExpression':
-				if (node !== parent.expressions.at(-1)) return false;
-				break;
-
-			case 'TaggedTemplateExpression':
-				if (node !== parent.quasi.expressions.at(-1)) return false;
-				break;
-
-			case 'TemplateLiteral':
-				if (node !== parent.expressions.at(-1)) return false;
-				break;
-
-			default:
-				return false;
-		}
-
-		node = parent;
-	}
-}

packages/svelte/src/compiler/phases/2-analyze/visitors/AwaitExpression.js

@@ -7,20 +7,15 @@ import * as e from '../../../errors.js';
  * @param {Context} context
  */
 export function AwaitExpression(node, context) {
-	const tla = context.state.ast_type === 'instance' && context.state.function_depth === 1;
-
-	if (tla) {
-		context.state.analysis.context_preserving_awaits.add(node);
-	}
-
-	let suspend = tla;
+	let suspend = context.state.ast_type === 'instance' && context.state.function_depth === 1;
 
 	if (context.state.expression) {
-		context.state.expression.awaits.push({ node, path: context.path.slice() });
 		context.state.expression.has_await = true;
 		suspend = true;
 	}
 
+	// disallow top-level `await` or `await` in template expressions
+	// unless a) in runes mode and b) opted into `experimental.async`
 	if (suspend) {
 		if (!context.state.options.experimental.async) {
 			e.experimental_async(node);

packages/svelte/src/compiler/phases/3-transform/client/transform-client.js

@@ -702,7 +702,8 @@ export function client_module(analysis, options) {
 		scopes: analysis.module.scopes,
 		state_fields: new Map(),
 		transform: {},
-		in_constructor: false
+		in_constructor: false,
+		is_instance: false
 	};
 
 	const module = /** @type {ESTree.Program} */ (

packages/svelte/src/compiler/phases/3-transform/client/types.d.ts

@@ -21,6 +21,9 @@ export interface ClientTransformState extends TransformState {
 	 */
 	readonly in_constructor: boolean;
 
+	/** `true` if we're transforming the contents of `<script>` */
+	readonly is_instance: boolean;
+
 	readonly transform: Record<
 		string,
 		{
@@ -41,7 +44,6 @@ export interface ComponentClientTransformState extends ClientTransformState {
 	readonly options: ValidatedCompileOptions;
 	readonly hoisted: Array<Statement | ModuleDeclaration>;
 	readonly events: Set<string>;
-	readonly is_instance: boolean;
 	readonly store_to_invalidate?: string;
 
 	/** Stuff that happens before the render effect(s) */

packages/svelte/src/compiler/phases/3-transform/client/visitors/AwaitExpression.js

@@ -1,4 +1,5 @@
-/** @import { AwaitExpression, Expression } from 'estree' */
+/** @import { AST } from '#compiler' */
+/** @import { AwaitExpression, Expression, Property, SpreadElement } from 'estree' */
 /** @import { Context } from '../types' */
 import { dev } from '../../../../state.js';
 import * as b from '../../../../utils/builders.js';
@@ -8,7 +9,9 @@ import * as b from '../../../../utils/builders.js';
  * @param {Context} context
  */
 export function AwaitExpression(node, context) {
-	const save = context.state.analysis.context_preserving_awaits.has(node);
+	const tla = context.state.is_instance && context.state.scope.function_depth === 1;
+
+	const save = tla || !is_last_evaluated_expression(context.path, node);
 
 	if (dev || save) {
 		return b.call(
@@ -24,3 +27,74 @@ export function AwaitExpression(node, context) {
 
 	return context.next();
 }
+
+/**
+ *
+ * @param {AST.SvelteNode[]} path
+ * @param {Expression | SpreadElement | Property} node
+ */
+export function is_last_evaluated_expression(path, node) {
+	let i = path.length;
+
+	while (i--) {
+		const parent = /** @type {Expression | Property | SpreadElement} */ (path[i]);
+
+		console.log(parent.start, parent.type);
+
+		// @ts-expect-error we could probably use a neater/more robust mechanism
+		if (parent.metadata) {
+			return true;
+		}
+
+		switch (parent.type) {
+			case 'ArrayExpression':
+				if (node !== parent.elements.at(-1)) return false;
+				break;
+
+			case 'AssignmentExpression':
+			case 'BinaryExpression':
+			case 'LogicalExpression':
+				if (node === parent.left) return false;
+				break;
+
+			case 'CallExpression':
+			case 'NewExpression':
+				if (node !== parent.arguments.at(-1)) return false;
+				break;
+
+			case 'ConditionalExpression':
+				if (node === parent.test) return false;
+				break;
+
+			case 'MemberExpression':
+				if (parent.computed && node === parent.object) return false;
+				break;
+
+			case 'ObjectExpression':
+				if (node !== parent.properties.at(-1)) return false;
+				break;
+
+			case 'Property':
+				if (node === parent.key) return false;
+				break;
+
+			case 'SequenceExpression':
+				if (node !== parent.expressions.at(-1)) return false;
+				break;
+
+			case 'TaggedTemplateExpression':
+				if (node !== parent.quasi.expressions.at(-1)) return false;
+				break;
+
+			case 'TemplateLiteral':
+				if (node !== parent.expressions.at(-1)) return false;
+				break;
+
+			default:
+				console.log('bailing', parent.start, parent.type);
+				return false;
+		}
+
+		node = parent;
+	}
+}

packages/svelte/src/compiler/phases/nodes.js

@@ -67,8 +67,7 @@ export function create_expression_metadata() {
 		has_call: false,
 		has_member_expression: false,
 		has_assignment: false,
-		has_await: false,
-		awaits: []
+		has_await: false
 	};
 }
 

packages/svelte/src/compiler/phases/types.d.ts

@@ -47,9 +47,6 @@ export interface Analysis {
 
 	/** A set of deriveds that contain `await` expressions */
 	async_deriveds: Set<CallExpression>;
-
-	/** A set of `await` expressions that should preserve context */
-	context_preserving_awaits: Set<AwaitExpression>;
 }
 
 export interface ComponentAnalysis extends Analysis {

packages/svelte/src/compiler/types/index.d.ts

@@ -299,8 +299,6 @@ export interface ExpressionMetadata {
 	has_member_expression: boolean;
 	/** True if the expression includes an assignment or an update */
 	has_assignment: boolean;
-	/** An array of await expressions, so we can figure out which ones need context preservation */
-	awaits: Array<{ node: AwaitExpression; path: AST.SvelteNode[] }>;
 }
 
 export interface StateField {