Add one more parent test

Exposes an unrelated issue: Line numbers are incorrect.

Author: nikic

Zend/tests/type_declarations/variance/parent_in_class.phpt

@@ -0,0 +1,45 @@
+--TEST--
+Use of parent inside a class that has / has no parent
+--FILE--
+<?php
+
+// Illegal: A::parent is ill-defined
+class A {
+    public function method(parent $x) {}
+}
+class B extends A {
+    public function method(parent $x) {}
+}
+
+// Legal: A2::parent == P2
+class P2 {}
+class A2 extends P2 {
+    public function method(parent $x) {}
+}
+class B2 extends A2 {
+    public function method(P2 $x) {}
+}
+
+// Legal: B3::parent == A3 is subclass of A3::parent == P3 in covariant position
+class P3 {}
+class A3 extends P3 {
+    public function method($x): parent {}
+}
+class B3 extends A3 {
+    public function method($x): parent {}
+}
+
+// Illegal: B4::parent == A4 is subclass of A4::parent == P4 in contravariant position
+class P4 {}
+class A4 extends P4 {
+    public function method(parent $x) {}
+}
+class B4 extends A4 {
+    public function method(parent $x) {}
+}
+
+?>
+--EXPECTF--
+Warning: Declaration of B4::method(A4 $x) should be compatible with A4::method(P4 $x) in %s on line 36
+
+Warning: Declaration of B::method(A $x) should be compatible with A::method(parent $x) in %s on line 36