fix exports error

Author: trueadm

documentation/docs/98-reference/.generated/compile-errors.md

@@ -694,6 +694,12 @@ Cannot use `<slot>` syntax and `{@render ...}` tags in the same component. Migra
 Cannot use explicit children snippet at the same time as implicit children content. Remove either the non-whitespace content or the children snippet block
 ```
 
+### snippet_invalid_export
+
+```
+Cannot export snippet from a `<script module>` if it references logic or expressions inside the component
+```
+
 ### snippet_invalid_rest_parameter
 
 ```

packages/svelte/messages/compile-errors/script.md

@@ -134,6 +134,10 @@
 
 > %name% cannot be used in runes mode
 
+## snippet_invalid_export
+
+> Cannot export snippet from a `<script module>` if it references logic or expressions inside the component
+
 ## snippet_parameter_assignment
 
 > Cannot reassign or bind to snippet parameter

packages/svelte/src/compiler/errors.js

@@ -413,6 +413,15 @@ export function state_invalid_export(node) {
 	e(node, "state_invalid_export", "Cannot export state from a module if it is reassigned. Either export a function returning the state value or only mutate the state value's properties");
 }
 
+/**
+ * Cannot export snippet from a `<script module>` if it references logic or expressions inside the component
+ * @param {null | number | NodeLike} node
+ * @returns {never}
+ */
+export function snippet_invalid_export(node) {
+	e(node, "snippet_invalid_export", "Cannot export snippet from a `<script module>` if it references logic or expressions inside the component");
+}
+
 /**
  * `%rune%(...)` can only be used as a variable declaration initializer or a class field
  * @param {null | number | NodeLike} node

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

@@ -438,7 +438,8 @@ export function analyze_component(root, source, options) {
 				: '',
 			keyframes: []
 		},
-		source
+		source,
+		undefined_exports: new Map()
 	};
 
 	if (!runes) {

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

@@ -27,7 +27,8 @@ export function ExportSpecifier(node, context) {
 			if (binding) binding.reassigned = binding.updated = true;
 		}
 	} else {
-		validate_export(node, context.state.scope, local_name);
+		const undefined_exports = context.state.analysis.undefined_exports;
+		validate_export(node, context.state.scope, local_name, undefined_exports);
 	}
 }
 
@@ -36,10 +37,14 @@ export function ExportSpecifier(node, context) {
  * @param {Node} node
  * @param {Scope} scope
  * @param {string} name
+ * @param {Map<string, Node>} undefined_exports
  */
-function validate_export(node, scope, name) {
+function validate_export(node, scope, name, undefined_exports) {
 	const binding = scope.get(name);
-	if (!binding) return;
+	if (!binding) {
+		undefined_exports.set(name, node);
+		return;
+	}
 
 	if (binding.kind === 'derived') {
 		e.derived_invalid_export(node);

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

@@ -28,6 +28,12 @@ export function SnippetBlock(node, context) {
 		context.path.length === 1 &&
 		context.path[0].type === 'Fragment' &&
 		can_hoist_snippet(node, local_scope, context.state.scopes);
+	const undefined_exports = context.state.analysis.undefined_exports;
+	const name = node.expression.name;
+
+	if (!can_hoist && undefined_exports.has(name)) {
+		e.snippet_invalid_export(/** @type {any} */ (undefined_exports.get(name)));
+	}
 
 	node.metadata = {
 		can_hoist

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

@@ -73,6 +73,7 @@ export interface ComponentAnalysis extends Analysis {
 		keyframes: string[];
 	};
 	source: string;
+	undefined_exports: Map<string, Node>;
 }
 
 declare module 'estree' {

packages/svelte/types/index.d.ts

@@ -1229,6 +1229,9 @@ declare module 'svelte/compiler' {
 			expression: Identifier;
 			parameters: Pattern[];
 			body: Fragment;
+			metadata: {
+				can_hoist: boolean;
+			};
 		}
 
 		export interface Attribute extends BaseNode {