Check redundant type check works

Author: Girgias

Zend/tests/type_declarations/intersection_types/redundant_types/duplicate_parent_type.phpt

@@ -0,0 +1,14 @@
+--TEST--
+Duplicate parent type
+--FILE--
+<?php
+
+class A {}
+class B extends A {
+    public function test(): parent&A&parent {
+    }
+}
+
+?>
+--EXPECTF--
+Fatal error: Duplicate type parent is redundant in %s on line %d

Zend/tests/type_declarations/intersection_types/redundant_types/duplicate_self_type.phpt

@@ -0,0 +1,13 @@
+--TEST--
+Duplicate self type
+--FILE--
+<?php
+
+class A {
+    public function test(): self&A&self {
+    }
+}
+
+?>
+--EXPECTF--
+Fatal error: Duplicate type self is redundant in %s on line %d