Add test for generator with multiple class return types

Author: nikic

Zend/tests/type_declarations/union_types/generator_return_multiple_classes.phpt

@@ -0,0 +1,18 @@
+--TEST--
+Generator return type with multiple classes
+--FILE--
+<?php
+
+interface I {
+    public function test(): Generator|ArrayAccess|array;
+}
+class C implements I {
+    function test(): Generator|ArrayAccess|array {
+        yield;
+    }
+}
+
+?>
+===DONE===
+--EXPECT--
+===DONE===