Fixed wrongly const replacing on partial array

ext/opcache/Optimizer/sccp.c

@@ -1249,8 +1249,10 @@ static void sccp_visit_instr(scdf_ctx *scdf, zend_op *opline, zend_ssa_op *ssa_o
 				if (result) {
 					ZVAL_COPY_VALUE(&zv, result);
 					ZVAL_NULL(result);
-				} else {
+				} else if (op1 && !IS_PARTIAL_ARRAY(op1)) {
 					array_init(&zv);
+				} else {
+					empty_partial_array(&zv);
 				}
 
 				if (op1) {

ext/opcache/tests/opt/sccp_023.phpt

@@ -0,0 +1,31 @@
+--TEST--
+SCCP 023: ADD_ARRAY_ELEMENT with partial array
+--INI--
+opcache.enable=1
+opcache.enable_cli=1
+opcache.optimization_level=0
+opcache.opt_debug_level=0
+--SKIPIF--
+<?php require_once('skipif.inc'); ?>
+--FILE--
+<?php
+function a ($field_type, $allowed_values) {
+	$settings = [
+		'list_string' => [
+			'allowed_values' => $allowed_values,
+		],
+	];
+
+	return $settings[$field_type];
+}
+
+var_dump(a("list_string", ["xxx"]));
+?>
+--EXPECTF--
+array(1) {
+  ["allowed_values"]=>
+  array(1) {
+    [0]=>
+    string(3) "xxx"
+  }
+}