fix: handle non call expressions passed to is_rune

Co-authored-by: Copilot <copilot@github.com>

.changeset/salty-jokes-crash.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/mcp': patch
+---
+
+fix: handle non call expressions passed to `is_rune`

packages/mcp-server/src/mcp/autofixers/add-autofixers-issues.test.ts

@@ -775,5 +775,16 @@ describe('add_autofixers_issues', () => {
 				`You are reading the stateful variable "$x" with a "$" prefix. Stateful variables are not stores and should be read without the "$". Please read it as a normal variable "x"`,
 			);
 		});
+
+		// https://github.com/sveltejs/ai-tools/issues/200
+		it('should not crash when reading $-prefixed identifier for variable initialized with member expression', () => {
+			expect(() =>
+				run_autofixers_on_code(`<div>{$x}</div>
+
+					<script>
+					const x = foo.bar;
+					</script>`),
+			).not.toThrow();
+		});
 	});
 });

packages/mcp-server/src/parse/parse.ts

@@ -69,6 +69,8 @@ export function parse(code: string, file_path: string) {
 			return this.all_references.find((r) => r.identifier === id);
 		},
 		is_rune(call: CallExpression, rune?: (typeof runes)[number][]) {
+			// it should always be a call expression but we check just in case because sometimes it's any and TS doesn't complain
+			if (call.type !== 'CallExpression') return false;
 			if (call.callee.type !== 'Identifier' && call.callee.type !== 'MemberExpression')
 				return false;
 			const id = call.callee.type === 'Identifier' ? call.callee : call.callee.object;