Add test case for GH-16198

Author: iluuu1994

Zend/tests/gh16198.phpt

@@ -0,0 +1,44 @@
+--TEST--
+GH-16198: Incorrect trait constant conflict when declared via trait
+--FILE--
+<?php
+
+trait T1
+{
+	final public const string C1 = 'T1';
+}
+
+interface I1
+{
+	public const ?string C1 = null;
+	public const ?string C2 = null;
+}
+
+final class O1 implements I1
+{
+	final public const string C2 = 'O1';
+}
+
+final class O2 implements I1
+{
+	use T1;
+}
+
+abstract class A1 implements I1
+{
+}
+
+final class O3 extends A1
+{
+	final public const string C2 = 'O3';
+}
+
+final class O4 extends A1
+{
+	use T1;
+}
+
+?>
+===DONE===
+--EXPECT--
+===DONE===