--- /dev/null
+--TEST--
+CPP defines
+--SKIPIF--
+<?php
+extension_loaded("psi") or die("skip - need ext/psi");
+?>
+--FILE--
+===TEST===
+<?php
+
+var_dump(psi_validate_string(<<<PSI
+#define FOO 1
+#define FOO 1
+#define FOO 2
+#define FOO 2
+PSI
+));
+?>
+===DONE===
+--EXPECT--
+===TEST===
+
+Warning: 'FOO' redefined in <stdin> on line 3
+
+Warning: 'FOO' previously defined in <stdin> on line 2
+bool(true)
+===DONE===