Fixed bug #42817 (clone() on a non-object does not result in a fatal error)

Zend/tests/bug36071.phpt

@@ -6,8 +6,6 @@ error_reporting=4095
 <?php
 $a = clone 0;
 $a[0]->b = 0;
-echo "ok\n";
 ?>
 --EXPECTF--
-Warning: __clone method called on non-object in %sbug36071.php on line 2
-ok
+Fatal error: __clone method called on non-object in %sbug36071.php on line 2

Zend/tests/bug42817.phpt

@@ -0,0 +1,9 @@
+--TEST--
+Bug #42817 (clone() on a non-object does not result in a fatal error)
+--FILE--
+<?php
+$a = clone(null);
+array_push($a->b, $c);
+?>
+--EXPECTF--
+Fatal error: __clone method called on non-object in %sbug42817.php on line 2

Zend/tests/bug42818.phpt

@@ -5,5 +5,5 @@ Bug #42818 ($foo = clone(array()); leaks memory)
 $foo = clone(array());
 ?>
 --EXPECTF--
-Warning: __clone method called on non-object in %sbug42818.php on line 2
+Fatal error: __clone method called on non-object in %sbug42818.php on line 2
 

Zend/zend_vm_def.h

@@ -2579,10 +2579,10 @@ ZEND_VM_HANDLER(110, ZEND_CLONE, CONST|TMP|VAR|UNUSED|CV, ANY)
 	zend_object_clone_obj_t clone_call;
 
 	if (!obj || Z_TYPE_P(obj) != IS_OBJECT) {
-		zend_error(E_WARNING, "__clone method called on non-object");
+		zend_error_noreturn(E_ERROR, "__clone method called on non-object");
 		EX_T(opline->result.u.var).var.ptr = EG(error_zval_ptr);
 		EX_T(opline->result.u.var).var.ptr->refcount++;
-		FREE_OP1();
+		FREE_OP1_IF_VAR();
 		ZEND_VM_NEXT_OPCODE();
 	}