Add redundant type tests

Author: Girgias

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

@@ -0,0 +1,11 @@
+--TEST--
+Duplicate class alias type
+--FILE--
+<?php
+
+use A as B;
+function foo(): A&B {}
+
+?>
+--EXPECTF--
+Fatal error: Duplicate type A is redundant in %s on line %d

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

@@ -0,0 +1,14 @@
+--TEST--
+Duplicate class alias type at runtime
+--FILE--
+<?php
+
+class A {}
+
+class_alias('A', 'B');
+function foo(): A&B {}
+
+?>
+===DONE===
+--EXPECT--
+===DONE===

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

@@ -0,0 +1,11 @@
+--TEST--
+Duplicate class type
+--FILE--
+<?php
+
+function test(): Foo&A&FOO {
+}
+
+?>
+--EXPECTF--
+Fatal error: Duplicate type FOO is redundant in %s on line %d

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

@@ -0,0 +1,15 @@
+--TEST--
+Intersection with child class
+--FILE--
+<?php
+
+class A {}
+class B extends A {}
+
+function test(): A&B {
+}
+
+?>
+===DONE===
+--EXPECT--
+===DONE===