diff --git a/tests/bugs/gh167.phpt b/tests/bugs/gh167.phpt
new file mode 100644
index 0000000..97aa302
--- /dev/null
+++ b/tests/bugs/gh167.phpt
@@ -0,0 +1,17 @@
+--TEST--
+uopz_set_return() overload confusion
+--EXTENSIONS--
+uopz
+--INI--
+uopz.disable=0
+--FILE--
+<?php
+class Foo {}
+function foo(): int {
+    return 42;
+}
+uopz_set_return("foo", function() {return 4711;}, true);
+var_dump(foo());
+?>
+--EXPECT--
+int(4711)
diff --git a/uopz.c b/uopz.c
index 9c05307..936f759 100644
--- a/uopz.c
+++ b/uopz.c
@@ -197,6 +197,7 @@ static PHP_FUNCTION(uopz_set_return)
 	uopz_disabled_guard();
 
 	if (uopz_parse_parameters("CSz|b", &clazz, &function, &variable, &execute) != SUCCESS &&
+		!((clazz = NULL)) &&
 		uopz_parse_parameters("Sz|b", &function, &variable, &execute) != SUCCESS) {
 		uopz_refuse_parameters(
 				"unexpected parameter combination, expected (class, function, variable [, execute]) or (function, variable [, execute])");