WIP

Author: Rich-Harris

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

@@ -90,6 +90,7 @@ export function Identifier(node, context) {
 	if (binding) {
 		if (context.state.expression) {
 			context.state.expression.dependencies.add(binding);
+			context.state.expression.references.add(binding);
 			context.state.expression.has_state ||=
 				binding.kind !== 'static' &&
 				!binding.is_function() &&

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

@@ -13,6 +13,16 @@ export function visit_function(node, context) {
 		scope: context.state.scope
 	};
 
+	if (context.state.expression) {
+		for (const [name] of context.state.scope.references) {
+			const binding = context.state.scope.get(name);
+
+			if (binding) {
+				context.state.expression.references.add(binding);
+			}
+		}
+	}
+
 	context.next({
 		...context.state,
 		function_depth: context.state.function_depth + 1,

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

@@ -6,7 +6,7 @@ import { extract_identifiers } from '../../../../utils/ast.js';
 import * as b from '#compiler/builders';
 import { create_derived } from '../utils.js';
 import { get_value } from './shared/declarations.js';
-import { build_legacy_expression } from './shared/utils.js';
+import { build_legacy_expression, build_legacy_expression_2 } from './shared/utils.js';
 
 /**
  * @param {AST.ConstTag} node
@@ -18,7 +18,7 @@ export function ConstTag(node, context) {
 	if (declaration.id.type === 'Identifier') {
 		const init = context.state.analysis.runes
 			? /** @type {Expression} */ (context.visit(declaration.init))
-			: build_legacy_expression(declaration.init, context);
+			: build_legacy_expression_2(context, declaration.init, node.metadata.expression);
 		context.state.init.push(b.const(declaration.id, create_derived(context.state, b.thunk(init))));
 
 		context.state.transform[declaration.id.name] = { read: get_value };
@@ -46,7 +46,11 @@ export function ConstTag(node, context) {
 		// instead of destructuring it only to return a new object
 		const init = context.state.analysis.runes
 			? /** @type {Expression} */ (context.visit(declaration.init, child_state))
-			: build_legacy_expression(declaration.init, { ...context, state: child_state });
+			: build_legacy_expression_2(
+					{ ...context, state: child_state },
+					declaration.init,
+					node.metadata.expression
+				);
 		const fn = b.arrow(
 			[],
 			b.block([

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

@@ -450,7 +450,7 @@ export function build_legacy_expression_2(context, expression, metadata) {
 
 	const sequence = b.sequence([]);
 
-	for (const binding of metadata.dependencies) {
+	for (const binding of metadata.references) {
 		if (binding.kind === 'normal') {
 			continue;
 		}

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

@@ -62,6 +62,7 @@ export function create_attribute(name, start, end, value) {
 export function create_expression_metadata() {
 	return {
 		dependencies: new Set(),
+		references: new Set(),
 		has_state: false,
 		has_call: false,
 		has_member_expression: false,

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

@@ -279,8 +279,10 @@ export type DeclarationKind =
 	| 'synthetic';
 
 export interface ExpressionMetadata {
-	/** All the bindings that are referenced inside this expression */
+	/** All the bindings that are referenced eagerly (not inside functions) in this expression */
 	dependencies: Set<Binding>;
+	/** All the bindings that are referenced inside this expression, including inside functions */
+	references: Set<Binding>;
 	/** True if the expression references state directly, or _might_ (via member/call expressions) */
 	has_state: boolean;
 	/** True if the expression involves a call expression (often, it will need to be wrapped in a derived) */