diff --git a/testdata/parser/negative/18.pdl b/testdata/parser/negative/18.pdl
new file mode 100644
index 0000000000000000000000000000000000000000..a49586c8dad897d6180d6c8c6fb12ba8728a4166
--- /dev/null
+++ b/testdata/parser/negative/18.pdl
@@ -0,0 +1,8 @@
+#version 100
+
+// illegal subject
+primitive main(in a, out b) {
+	int x = 0;
+	int[] y = {x, x, x};
+	y[0] = (x+y)[0];
+}
\ No newline at end of file