Fix accidental separation on non-mutating method call

Author: iluuu1994

Zend/tests/structs/non_mutating_method.phpt

@@ -0,0 +1,27 @@
+--TEST--
+Non-mutating methods do not cause separation
+--FILE--
+<?php
+
+struct Test {
+    public function test() {
+        var_dump(__METHOD__);
+    }
+}
+
+$a = new Test();
+$b = $a;
+
+$a->test();
+$b->test();
+
+var_dump($a, $b);
+
+?>
+--EXPECT--
+string(10) "Test::test"
+string(10) "Test::test"
+object(Test)#1 (0) {
+}
+object(Test)#1 (0) {
+}

Zend/tests/structs/pre_post_inc_dec.phpt

@@ -8,7 +8,7 @@ struct Box {
         public $value,
     ) {}
 
-    public function preDec() {
+    public mutating function preDec() {
         --$this->value;
     }
 }
@@ -28,7 +28,7 @@ $postInc = $original;
 var_dump($postInc->value++);
 
 $preDecMethod = $original;
-var_dump($preDecMethod->preDec());
+var_dump($preDecMethod->preDec!());
 
 var_dump($preDec);
 var_dump($preInc);

Zend/zend_vm_def.h

@@ -3539,7 +3539,7 @@ ZEND_VM_HOT_OBJ_HANDLER(112, ZEND_INIT_METHOD_CALL, CONST|TMPVAR|UNUSED|THIS|CV,
 	} else {
 		do {
 			if (OP1_TYPE != IS_CONST && EXPECTED(Z_TYPE_P(object) == IS_OBJECT)) {
-				if (OP1_TYPE & (IS_CV|IS_VAR)) {
+				if (OP1_TYPE & (IS_CV|IS_VAR) && UNEXPECTED(opline->extended_value & ZEND_INIT_METHOD_CALL_MUTATING)) {
 					SEPARATE_DATA_OBJ(object);
 				}
 				obj = Z_OBJ_P(object);
@@ -3549,7 +3549,9 @@ ZEND_VM_HOT_OBJ_HANDLER(112, ZEND_INIT_METHOD_CALL, CONST|TMPVAR|UNUSED|THIS|CV,
 
 					object = &ref->val;
 					if (EXPECTED(Z_TYPE_P(object) == IS_OBJECT)) {
-						SEPARATE_DATA_OBJ(object);
+						if (UNEXPECTED(opline->extended_value & ZEND_INIT_METHOD_CALL_MUTATING)) {
+							SEPARATE_DATA_OBJ(object);
+						}
 						obj = Z_OBJ_P(object);
 						if ((OP1_TYPE & IS_VAR) && !needs_addref) {
 							if (UNEXPECTED(GC_DELREF(ref) == 0)) {