fix: emit `snippet_invalid_export` instead of `undefined_export` for exported snippets

.changeset/thick-snakes-look.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: emit `snippet_invalid_export` instead of `undefined_export` for exported snippets

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

@@ -789,7 +789,14 @@ export function analyze_component(root, source, options) {
 				if (specifier.local.type !== 'Identifier') continue;
 
 				const binding = analysis.module.scope.get(specifier.local.name);
-				if (!binding) e.export_undefined(specifier, specifier.local.name);
+				if (!binding) {
+					const instance_binding = analysis.instance.scope.get(specifier.local.name);
+					if (instance_binding?.kind === 'snippet') {
+						e.snippet_invalid_export(specifier);
+					} else {
+						e.export_undefined(specifier, specifier.local.name);
+					}
+				}
 			}
 		}
 	}