diff --git a/testdata/parser/negative/28.pdl b/testdata/parser/negative/28.pdl
new file mode 100644
index 0000000000000000000000000000000000000000..b88d510225d8e269a2d0ca02e22d4f15fdcca56b
--- /dev/null
+++ b/testdata/parser/negative/28.pdl
@@ -0,0 +1,7 @@
+#version 100
+
+int main(int a) {
+    int x = 0;
+    (x + 5)++; // not assignable
+    return x;
+}
\ No newline at end of file